oFmmm X i^ LIBRARY THE UNIVERSITY OF CALIFORNIA SANTA BARBARA PRESENTED BY MRS. ALFRED W. I NGALLS THE BOOK OF WONDERS LLiPr)^(K]l(^ (S HOW MAN BURROWS UNDER THE WATER HUDSON & MANHATTAN R. E This is a picture of a section of one of the world's greatest tunnels, showing how man has learned to construct gre tubes of steel beneath the surface of the water and land, in which to run the swiftly moving trains which carry him rapidly from place to place. THE BOOK OF WONDERS GIVES PLAIN AND SIMPLE ANSWERS TO THE THOUSANDS OF EVERYDAY QUESTIONS THAT ARE ASKED AND WHICH ALL SHOULD BE ABLE TO, BUT CANNOT ANSWER FULLY ILLUSTRATED WITH HUNDREDS OF EDUCATIONAL PICTURES WHICH STIMULATE THE MIND AND GIVE A BIRD'S EYE VIEW OF THE WONDERS OF NATURE and the WONDERS PRODUCED BY MAN Edited and Arranged by RUDOLPH J. BODMER Fully Indexed \9\i PRESBREY SYNDICATE, Inc. 456 Fourtli Avenue Ni:VV \()\iK Copyright, 1914 BY PRESBREY SYNDICATE, Ino Introduction No truly great book needs an explanation of its aim and purpose. A great book just grows, as has this Book of Wonders. It began with the attempt of a father to answer the natural questions of the active mind of a growing boy. It developed into a nightly search for plain, understandable answers to such questions as "What makes it night?" "Where does the VN-ind begin?" "Why is the sky blue?" "Why does it hurt when I cut my finger ?" "Why doesn't it hurt when I cut my hair?" "Why does wood float?" "Why does iron sink?" "Why doesn't an iron ship sink?" on through the maze of thousands of puzzling questions which occur to the child's mind. It has grown until the answers to the mere questions cover practically the entire range of every-day knowledge, and has been arranged in such a form that any child may now find the answer to his own inquiries. As the mind of the child matures, the questions naturally drift toward the things which the genius of man has provided for his comfort and pleasure. We have become so accustomed to the use and benefits of these wonders pro- duced by man that we generally leave out of our books the stories of our great industries, and yet the mind of the child wonders and inquires about them. We have so long worn clothes made of wool or cotton, that we have forgotten the wonder there is in making a bolt of cloth. Every industry has a fascinating story equal to that of the silkworm, which moves is head sixty-five times a minute while spinning his thousand yards of silk. Can you tell What happens when we telephone? How a telegram gets there? What makes an automobile go? How man learned to tell time? How a moving-picture is made? How a camera takes a picture? How rojic is made? How the light gets into the electric bulb? How glass is made? How the music g-^ts into the piano? and liuiKh-cds of others (hat embrace the captivating tales of how man has made use of the wonders of nature .ind turned them to his advantage and comfort? The Book of Wonders docs this with illuminating pictures which stimulate the mind and give a bird's-eye view of each subject step by step. Where shall such a book begin? Shall it begin with the .Story of How 10 INTRODUCTION Man Learned to Light a Fire — he could not cook his footl, see at night, or keep warm without a fire; or should it Ijegin with How ^L-ul Learned to Shoot — he could not protect himself against the beasts of the forest, and, there- fore, could not move about, till the soil or obtain food to cook until he knew how to shoot or destroy. What was the vital thing for man to know before he could really become civilizecT? Some means, of course, by which the things he learned — the knowl- edge he had acquired — could be handed ilown to those who came after him so that they might go on. with the intelligence handed down to them. This required some means of recording his knowledge. i\lan had to learn to write. Without writing there could be no Book of Wonders, and the l)ook, then, begins naturally with the Story of How Man Learned to Write. The Editor. \\Rrn.\(; r.v mkxrax ixdiaxs thought to be .MOKK TIIAX TF.X THOUSAXD YEARS OLD. How Man Learned to Write It is a long time between the day of the cave-dwellers, with their instru- ments of chipped stone, and the ])resent day of the pen. Yet wide a])art as are these points of time, the trend of de- \elopment can with but few obstacles be traced. The story of the pen is a natural sequence of ideas between the first piece of rock scratched upon rock by ])re- historic man, and the bit of metal which now so smoothly records our thoughts. There was a time in the unwritten history of man when necessity prompter! the invention of weapons, and the minds of these primitive men were concentrated upon this point. But the arts of war did not take up their entire time ; some time must have been given to other pursuits. As the mind developed, and as an aid to memory, we find them carving, engraving, incis- ing U])on the rocks their hieroglyphics, which took the form of figures of men, habitations, weapons, and the animals of their period. How Did Writing First Come About? An apparently difficult question to answer, since without writing there can be no record of its origin, and without IMK STVr.US 12 EARLIEST WAYS OF WRITING THE FIRST IMITATION OF WRITING records no facts ; yet the deduction is so clear that the answer is simple. Somewhere far, far back in the dawn of the world, back in the beginning of human history, in the epoch which we have now named the Quaternary Pe- riod, man lived in a dense wilderness surrounded by the wildest and most ferocious beasts. His home was a cave, exposed to the dangers incidental to that time and his surroundings, and he was of necessity compelled to look about for means of defense. With this idea in mind, he found that by striking one stone against another he knocked off chips, which chips could be used as arrow-heads, spears and axes. Follow- ing along these lines he discovered that by rubbing one of these chips against another there was left a mark, which was the first imitation of writing; that the sharper the edge of the chip, the deeper was the scratch, and conse- quently the more distinct the mark. Next it was discovered that certain slones, such as flint, ser])entine and chalcedony, marked more readily than others ; that the elongated chip was handled with more facility ; that by rub- bing one stone against another the f;nest possible points and edges might be obtained. Thus in the Age of Stone was the long, tapering instrument of stone, the first pen, the Stylus, origi- nated. Then came the time, known as the Bronze Age, when men learned to b.ammer metal into shapes, and metal having many advantages over stone, the stylus of stone gave way to one of iron. So we find that in the time of the Egyptians, about fourteen or fifteen WRITING FLUIDS HELPED DEVELOPMENT w^^ THE BRUSH HOW THE CHINESE IMPROVED METHODS centuries B.C., an iron stylus was in use for marking on soapstone, limestone and waxed surfaces. An improvement in this metal stylus was that the blunt end was convex and smooth, the pur- pose of which was to erase and smooth over irregularities. In some cases it was pointed with diamonds, which gave it greater cutting properties. The iron stylus was also used by the Egyptians of that period, as well as in later times, with a mallet, after the manner of the modern chisel (which indeed it resem- bled) for cutting out inscriptions on their monuments. In course of time a marking fluid was discovered, and this made neces- sary a writing instrument which coulaper that has absorbent qualities, but not too absorbent. How Does a Blotter Take Up the Ink of a Blot? It is because the blotter has a very excellent ability to absorb some liquids. The thinner the li(|uid the more easily the blotter will absorb it. Ink is thin — being mostly water — the blotter is of a loose texture and has a rough surface. This gives the blotter the ability to pick up the ink. just as a sponge would do. A sponge has what is called the power of- capillary attraction and so has the blotter. Where Does Chalk Come From? Deposits of chalk are found on some shores of the sea. A piece of chalk such as the teacher uses to illustrate something on the blackboard at school consists of the remains of thousands of. tiny creatures that at one time lived in the sea. All of their bodies except- ing the chalk — called carbonate of lime in scientific language — has disappeared and the chalk that was left was piled up where it fell at the bottom of the ocean, each particle pressing against the other with the water pressing over ir all until it became almost solid. It took thousands of years to make these chalk deposits of the thickness in which they are found. Later on, through changes in the earth's surface, the mountain of chalk was raised until it stood out of the water and thus became accessible to man and school teachers. How Did Men Learn to Talk? Talking and the words used came into being through the desire of men to communicate with each other. Before words became known and used man talked to those about him by the use of signs, gestures and other movements of the body. Even to-day when men meet who cannot talk the same language they will be seen trying to come to an understanding by the use of signs and gestures and generally with fair results. WHY WE COUNT IN TENS 19 The need of more signs and gestures to express a constantly increasing num- ber of objects and thoughts led to the introduction of sounds or combination of sounds made with the vocal cords to accompany certain signs and ges- tures. In this way man eventually de- \ eloped a very considerable faculty for expressing himself. Sign by sign, ges- ture by gesture and sound by sound language was slowly developed. A man would be trying to explain something to another by sign or gesture and to make it more clear would make a sound or combination of sounds to put more expression into his efforts. Finally the other man would understand what was meant and he would tell some one else, using the same signs, gestures and sounds. Later on it would develop that to express thus any certain thought, act or the name of a thing, all of the people in the community would make this same combination of sounds, signs and gestures to express the same thing. Finally the gestures and signs would be dropped and it was found that peo- ple understood perfectly what was meant when only the sound or combi- nation of sounds was produced. That made a word. All the other words were made in the same way, one at a time, until we had enough words to express all the ordinary things and the combi- nation of words became a language. The children learned the language by hearing their parents talk it, and that is how men learned to talk. Kow Did Shaking the Head Come to Mean "No"? The origin of this method of indi- cating "No" is found in the result of the mother's efforts in the animal king- flom of trying to feed her young. A mother animal would be trying to get her young to accept the food she brought them and tried to put it in their mouths. Perhaps, however, the young animal had had sufficient food or (\\(l not fancy the kind of food of- fered. The natural thing t'o do under the circumstances woukl be to close the mouth tight and shake the head from side to side to j^revent the mother from forcing the food into the mouth. Thus we get the closed lips and the shaking the head from side to side to mean "No." In other words, that kind of a way of saying "No" came from an effort to say "I don't want any." How Did a Nod Come to Mean "Yes"? The idea of nodding to mean "Yes" comes from the opposite of the action which, as just described, indicates a "No." When the young animal was anxious to accept the offered food, it made an effort to get at the food quickly. FTence, the pushing forward of the head and the open mouth (always more or less opened when you nod to indi- cate "Yes") and an expression of glad- ness. You will notice if you see any- one nod the head to indicate "Yes" that the lips are open rather than closed, and that there is always a smile or an indication of a smile to accompany it. In other words, the nod to mean "Yes" is only another way of saying "I shall be pleased." Why Do We Count in Tens? When man even in his uncivilized state found it necessary to count, the only implements at hand were his fin- gers and toes, and as he had ten toes and ten fingers, he naturally began counting in tens, and has been doing so ever since. When we to-day count on our fingers we confine ourselves to our fingers leaving our toes stay in our shoes, where they naturally belong. But the first men who counted used both fingers and toes, and so he was able to count twenty before he had to begin over again, while little children to-day, when they count with their fingers, must Ijegin where they started after they reach ten. What Does Man Mean by Counting Himself? The expression "counting himself" was originated by the first man who counted. Such a man would count all of his fingers and toes and the result 20 WHERE THE NAMES OF PEOPLE CAME FROM v.'ould be twenty. Then, so that he would remember the number of times he had counted himself, he made a mark some place each time he reached twenty. The mark he made was a mere scratch in the dirt or on a hoc or some- tliiniij else. To make a scratch you merely, of course, score the surface of whatever you hapiien to be scratchinc^ on, and that is how it happened that the word ''score" in our language to- day means as a term in counting, twenty. There has been a great effort made to change our system of counting in tens to one where you count in twelves. Tiiat would fit in very well with our system of measuring which is based on the foot of twelve inches, and of our calendar for recording the passage of time which has twelve months. There are many arguments in favor of this change, among the principal of which is the fact that it would make our prob- lems of division much easier, for our ten can be evenly divided by but two of our single figures, two and five, whereas twelve can be evenly divided by four of our single figures, viz., two, three, four and six. It is believed that sooner or later the system of count- ing by twelve instead of ten will be adopted by the entire world for count- ing everything. As it is now^ we do part of our counting by one system and part of it by another. Where Did All the Names of People Originate? There is no scientific plan by which jK'ople get their names. There is not much except curious interest to be gleaned from the study of how^ people got their names. In the earliest days of the world, or at least as soon as men had learned to speak by sounds, all known persons, places and groups of human beings must have had names by which they could be spoken of or to, and by which they were recognized. The study of these names and of their survival in civilization enables us in certain in- stances to tell what tribes inhabited certain parts of the earth now peopled by descendants of an entirely different race and of another speecli altogether. We learn such things from the names of mountains and other things, for in- stance, which still cling to them. The story of personal names is very complex, but comes from very simple beginnings. The oldest ])ersonal names were those which indicated a grouj) of peo])le ratiier than individuals who may have been actually related to each other or even bound together for reasons of protection or other conveni- ence. In the races of Asia, y\frica, Aus- tralia and America examination shows tfiat groups of people who considered themselves to be of the same relation- ship, attached to themselves the name of some animal or other object, whether animate or inanimate, from which they claimed to be descended. This animal or object was called the "totem," and thus the earliest and most v.idely spread class and family names are totemistic. Such groups called themselves by names from wolves, tur- tles, bears, suns, moons, birds, and other objects, and these people wore badges with pictures of the animal or object from which they took their names to identify them to other people. When, then, we come to investigate the giving of personal names among the tribes, we see that most uncivilized iLces gave a name to each new-born infant derived from some object or in- cident. So a new-born member of the "Sun" tribe would be named "Dawn," and w^ould be known as "Dawn" of the "Sun" tribe ; or perhaj^s a new-born son of the tribe of "Wolf" would be called "Hungry," and be known as "Hungry W^olf." A member of the "Cloud" tribe would be named "Morn- ing," because he was born in the morn- ing. He would always be known as "Morning Cloud." Later, as society became more estab- lished and paternity became recognized, we find the totem name give way to a gentile name. Among the Greeks and Romans the system was early adopted and proved satisfactory. Thus we have Caius Julius Caesar. Caius indicates HOW DIFFERENT NAMES ORIGINATED 21 that he is Roman ; JuHus is the gentile name given him and the Caesar a sort of hereditary nickname. On the other hand, the early Greeks began the system of introducing a local name instead of the gentile name. Thus Thucydides (obtained from the grandfather), the son of Olorus, of the Deme (township) of Halimusia. This was all right and suited the pur- poses of the Greeks and Romans, who had plenty of time to give full expla- nations in this way. But in Europe, for instance, civilization demanded more speed, and the increase of population demanded more names, so that nick- names and names indicating personal descriptions and peculiarities came into use. Such names as Long, Short, Small, Brown, White, Green and others of the same kind came from this source, and as families grew these sur- names stuck to the family and parents gave their children Christian names to further distinguish them as individuals. Other surnames such as Fowler, Sad- ler, Smith, Farmer, etc., became at- tached to people because of the occupa- tions in which they were engaged, and yet other names were derived from places. The owner of an extensive es- tate would be designated by a Christian name which might be George (after his King) and then to indicate his landownership, von (meaning of) Wood, making the combination of George von Wood, meaning George, the owner of the place called Wood. On the other hand, he might have work- ing for him a laborer who lived at the place and, if his name was Hiram, they woukl, to indicate where he belonged, put the Wood after the Hiram ; but, lest there be confusion as to his class, they would put an At before the Wood and make him Hiram Atwood, inch'cat- ing his Christian name, whore he worked and the fact that he was not a landowner. Many other names were invented in simikir manner. When Adams became so common that there would likely be confusion on account of there being so many of them, a son of one of the Adams family would add to the name the fact that he was a son by writing his name Adamson, and thus start a new family name. Thus, in the same ^v•ay also came Willson, Clarkson, and other names of that kind. For a long time the Jews had only one word for a name, such as Isaac, Jacob, Moses, etc. They became so numerous that it was impossible to dis- tuiguish them, and so a commission was named to give surnames to all the Jews in addition to their other names. As the race was then, as now, held in de- rision by the rulers of many nations into which the tribe had become scat- tered, the people who had charge of the naming of the Jews took advantage of the opportunity to make sport of them, and gave them such names as Rosenstock (Rose bush), Rosenszweig (Rose twig), Rosenbaum (Rose tree), Blumenstock (Flower bush), Blumenthal (Flower valley), etc., etc. Our Christian names are from simi- lar sources, and while many of them are well selected because of their beau- tiful meanings, there are many of them which mean nothing as words as they were only invented for the purpose of giving a new name to a new child. Why Can You Blow Out a Candle? W'hen you light a candle it burns, be- cause the lighted wick heats the wax sufficiently to turn it into gases, which mix with the oxygen in the air and pro- cjuce fire in the form of light. You know it is not easy to light a candle (juickly. You must hold the lighted match to the wick until the wax begins to melt and change to gases. As long as the wax continues hot enough to melt and turn to gas the candle will burn until all burned up; Init if there is a break in the continuous process of changing the wax to gas, the light will go out. Now, when you blow at the lighted candle, you blow the gases which feed the flame away from the lighted wick, and this makes a break in the continuous flow of gas from the wax to taper, and the light goes out. 22 HOW A CAMERA TAKES A PICTURE The Story in a Photograph How Does a Camera Take a Picture? \\'hrn we look upon the surface of a minor we see the image of ourself and our surroundings. The extent of tlie view depends upon the size of the mirror and the distance we are stand- ing from it. If we hold the mirror close to our face we see only the face, or perhaps but a portion of it, and the farther away we are the more the mirror will reflect, only, of course, the various images will be smaller. The mirror reflecting exactly what the eye sees, without doubt had a great influence in inducing the experiments that resulted in the process we call photography. The taking of a photograph with a camera may in a way be compared with the action of your eyes, when you gaze upon your reflection in a mirror, or look at any object or view. Any ob- ject in a light strong enough to render it visible will reflect rays of light from every point. Now. the eye contains a lens very similar in form to that used in a cam- era. This lens collects the rays of light reflected from the object looked at and brings them to a focus in the back of the eye, forming an image or picture of whatever we see, just as the mirror collects the rays of light and reflects them back through the lens of the eye. Certain nerves transmit the impres- sion of the image so focused in the back of the eye to the brain and we experi- ence the sensation of sight. What Is the Eye of the Camera? The lens is the eye of the camera, and the process we call photograi:)hy is the method employed to make per- manent the image the eye or lens of the camera presents to a sensitive surface within the camera. Fig. I shows a simple form of cam- era, it being merely a light tight box with a lens fitted to the front, and a means for holding a sensitive plate at the back, the plate being placed at just the right distance to focus the rays of light admitted through the lens in exactly the same manner as the rays of light pass through the lens of the eye and come to a focus in the back part of the eye. Now, if we could look inside the camera we would note that the image was inverted, or upside down. Fig. 2 will explain this. The rays of light from "A" pass in a straight line through the lens "B" until they are interrupted by "C," upon which they strike, forming an upside down image of the object "A." But, you exclaim, "we do not see things upside down." No, we do not, because some mental process readjusts this during the passing of the impression from the eye to our brain. Let us suppose we have our camera loaded with its sensitive plate or film. HOW A PHOTOGRAPH IS DEVELOPED 23 We select some object or view we wish to photograph, uncover the lens for an instant, and let the light impress the image upon the sensitive surface of the plate or film. Now, how are we going to make this image permanent? If we were to examine the creamy yellow strip of film upon which the [)icture was taken there would seem- ingly be no difference between its pres- ent appearance and before the snap- shot was made. Now let us suppose that this strip of film is a little trundle bed, and in it tucked securely away from the light are many hundreds of little chaps called silver bromides, little roly-poly fellows lying just as close together as possible, and protected by a coverlet of pure white gelatine. Until the sudden flash of light in their faces when the picture was taken, they have been content to lie still and sleep soundly. Now they are seized with a strange unrest, and each little atom is eager to do his part in show- ing your picture to the world. Alone they are powerless, but they have, all unbeknown to them, some powerful chemical friends, who, organized and aided by the photographer, will bring about their transformation. These chemicals, with the help of the pliotog- ra])her, form themselves into a society called the developer. The photographer takes just so many of the tiny feathery crystals of pyro, just so many of the clear little atoms of sulphite of soda, and just so many little crystals of carbonate of soda, and tumbles them all into a beaker of clear cold water. Unaided by each other, any one of these chemicals would be powerless to help their little bromide of silver friends. The first of these chemicals to go to work is the carbo- nate of soda. He tiptoes softly over to the trundle l)Cfl and gently begins turm'ng back the gelatine covers over the little bromide of silver chaps, so that Tyro can find them in the dark. It is Pyro's mission to transform the little silver bromides into silver metal, but he is rather an impulsive chap, so he is accompanied by sulphite of soda, who warns him not to be too rough, and whose sole mission is to strain his eagerness to help his fridids. "Go slow now," says Sulphite, "don't frighten the little silver bromides, or else you'll make them cuddle up in heaps, and the picture won't be as nice as if you wake them up gently and each little bromide stayed just where he belonged." After all the little silver bromides that the light shone on have been trans- formed into metallic silver by the de- veloper, another chemical friend has to step in and carry away all the little bromides that were not awakened by the flash of light. This friend's name is "Hypo," and in a few minutes he has carried away all the little bromides that are still sleeping, so that the trundle bed with the now awakened and transformed silver bromides will, after washing and drying, be called a negative, and ready to print your pictures from. If we take this negative, as it is called, and hold it up to the light, we will see that everything is reversed, not only from right to left, but also that whatever is white or light in color is dark in the negative, and that what would correspond to the darker parts of our picture are the lightest in the negative, and it is from these facts that we give it the name negative. Now, to get our picture as it should be, we must place this negative in contact with a sheet of coated ])aper that is also sensitive to light. So we place the negative and the sheet of sensitive paper in what is called a printing frame, with the negative uppermost, so that the light may shine through the negative, and impress the image ui)on the sheet of sensitive paper. Now, it stands to reason that if the lightest ])arts of our picture are the darkest in the negative that less light cm pass through such j^ortions of the negative in a given time, so that with the proj^er exposure to light the image lijjon the sheet of sensitive paper will be a correct picture of whatever the lens saw. 24 HOW SHOOTING SHELLS ARE PHOTOGRAPHED The swiftest thing that the human race has ever put into motion is the steel projectile of a twelve-inch gun. Xo human eye can follow its flight. Released at a pressure of forty thousand pounds to the square inch — in a heat at which diamonds melt and carbon boils — it hurls through the air at the rate of twenty-five miles a minute, and reaches the mark ahead of its own sound! (Pictures and story by courtesy of McClure's Magazine.) TWENTY-FIVE MILES A MINUTE An Exclusive Story, Illustrated with a Series of Remarkable Photographs Taken WITH the Fastest Camera in the World By Cleveland Moffett One of the most progressive branches of our mihtary service is the Department of Coast Defenses, which, under the far-seeing guidance of Gen- eral E. AL Weaver, holds our shores and harbors in a state of alert prepar- edness against foreign aggression. At Hampton Roads sits the Coast Artil- lery Board, composed of officers and consulting engineers to whom are re- ferred all problems relating to coast artillery, and who have the responsi- bility of testing all new instruments proposed for artillery use. The pur- pose of this article is to describe one among several notable achievements of the Hampton Roads Coast Artillery School, this particular work having been done by Captain F. J. Behr of the Coast Artillery Corps, who, after years of efifort, has recently developed a system that makes it possible to take THE FASTEST CAMERA IN THE WORLD zo r- The big gun, equipped with the fastest camera shutter in the world, about to be fired and the shell photographed. l-or VL-ars a ^'oung otiiccr of the Loast ArliUcry has liecn irying to devise a camera so incredibly swift that it will record every stage of this lightning flight from the gun- barrel to the target. At last he has succeeded. His photographs^ — some of them taken rme hundred thousandth of a second apart — have revealed remarkable and unsuspected facts to the military world. The story of his invention had never before been told. L jiictures of the swiftest moving bodies, the great steel projectiles of our big- gest guns — to seize them with the cam- era's eye as they hurl through the air at enormous velocities or at the very moment of their emergence from the gun muzzles, and to preserve these images, never seen before, for military study and comparison. Captain Behr was ably assisted in this work by Engi- neer J. A. Wilson. Reckoning in Millionths of a Second. Some of the increments and decre- ments of time involved in the series of ])hotographs herewith published (sev- eral of them for the first time) are as small as one ten-lhousandth jiart of a second. And Ca])tain lichr has devised a method of taking photograjjlis of I^rojectiles as they arrive at a steel target and penetrate the tar- get, inch by inch, that involves in- crements or decrements of time as small as the one hundred- thousandth part of a second. To the uninitiated it seems incredible that .«uch infinitesimal divisions of time can 26 THE PROJECTILE EMERGING FROM MORTAR be used in practical calculations ; but every trained physicist knows that in wireless work scientists of to-day speak cr.sually of experiments that take ac- count of tzco-teuths or one-tenth of a )niUionth part of a srro)u!' \%» 4 x: In this photograph— the first of a remarkable series showing five stages of a movnig projectile— the half-ton projectile seems to be standing still, but really it is trayelmg at the rate of 900 miles an hour. The gunners here work in concrete pits 34 feet high. Lnder- neath the mounts are the powder magazines. Each pit has four mortars usually served by an entire Coast Artillery Company. The projectiles are the same as those used in the twelve-inch guns, but less powder is required because mortar projectiles are hurled high in the air, not straight at a vessel, and deliver their destructive blows downward from a great height. THE SMOKE RINGS WHICH APPEAR 27 What happened to the projectile after it leaves the gun, or after the discharge of the gun, and before the projectile has had time to issue from the gun-barrel? What is the action at the muzzle of gases generated ? What shape do these gases assume as they leave the gim? What causes the much-discussed "gas- This second |ili(.loyrapli shows tlic projectile almost entirely out of the nun tar. Us sharp nose may be seen above the "gas-rinj?" forming at its upper end. These "Ras-rings." or "smoke-rings," come without warning, and only occasionally, perhaps once in eight or ten shots. They rise swiftly to the height of fifty or a hundred feet, growing larger and larger, and giving forth a weird, shrieking sound like a second projectile. Some insist that these "smoke-rings" are as hard as steel, owing to the enormous compression of their com- posing gases, and tli'- story is told of a liird lamdit in tin- ji.-illi uf one of tluin and torn to pieces. 28 THE PROJECTILE HIDDEN BY THE SMOKE CONE rings" that sometimes form when a mortar is fired, and oftener do not form? What phenomena attend the arrival of the projectile at a solid steel tnrget? Is the steel actually fused hy the heat of impact? Is it vaporized? Or what ? These are some of the (|ues- t'ons that Captain Behr set himself to folve, or to help in solving, as he worked out his methods of rapid pho- In the third photograph the smoke-cone is almost perfect and gives the famous "powder- puff" effect. It still hides the projectile, although the latter is traveling at a velocity that would take it from New York to Chicago in one hour. At night the "gas-rings" present a startling and fascmating appearance, burning with a reddish orange glow, and whirling with a complicated double motion, strange opalescent balls, like rings of Saturn. A study of these photographs — the first record ever made of the "gas-rings" — has led some experts to the conclusion that the cause of the rings is defective ramming of the projectile. THE PROJECTILE EMERGING FROM SMOKE CONE 29 tography. His aims were strictly mili- tary, but his results make fascinating appeal to the general imagination. P'ancy doing anything in the one hun- dred-thousandth part of a second ! Captain Behr's general idea was to utilize some phenomena connected with tlie discharge to actuate, by electrical The fourth photograph shows the projectile emerging from the smoke-cone about thirty feet above the muzzle of the mortar. The men who fire these mortars from the mor- tar-pits never see the distance target or vessel they are firing at, but point their mortars according to directions transmitted to them (usu^y by telephone) from observers at distant stations. And so great a degree of precisron has been attaipexl that, on certain practice occasions at Hampton Roads, a record of nine hits out of ten shots has been scored on a moving target five miles out in the ocean. This picture shows the smoke-cone as first seen l)y the human rye. 30 THE PROJECTILE HIGH IN THE AIR connections, a work a rapid placed camera mechanism that would shutter in a properly The phenomenon of concussion was tried first — the smash of air against a little swinging door; but this was much too slow. The pro- In the fifth photograph the projectile is seen entirely clear of the smoke-cone and well started on its long flight. Climbing into the sky at this steep angle, it will reach a height of from three to six miles before it begins to descend. There are harbors on our coasts guarded by so many guns and mortars that if these were fired simultaneously they could hurl against a given small area a converging rain of projectiles aggregating more than fifty tons in their combined mass. A minute later they could hurl another fifty tons against the same small area; and so on as long as the ammunition lasted. A CAMERA THAT IS FASTER THAN THE EYE jcctile was hundreds of yards away be- fore the camera had registered its pic- ture. And that chance was gone ! In the next trial, several months bter, Captain Behr arranged to have the electrical connections made or broken by the movement of the gun- carriage itself in recoihng; but the re- sult was unsatisfactory. Nor was he more fortunate at the succeeding target practice, when, having placed the ap- {)?ratus farther forward on the parapet, he had the camera demolished by the force of the concussion and several blades of the rapid shutter broken. He was satisfied, now, that his eflfort to actuate the camera mechanism from the gun-carriage would never give the requisite precision in results, and he saw that he must work with a device fimctioning more reliably. In the months that followed before the next target practice, the Captain did some experimenting, and finally deter- mxined making the projectile itself dis- place a length of piano-wire fixed across the muzzle of the gun, and thus actuate the electrical system and oper- ate the shutter. In this way he elimi- nated troublesome variables of recoil, elasticity of the carriage, etc., leaving to determine only the time element of the electrical system to function. This result was admirable, and, after taking several similar pictures, the captain found that he could now operate with great precision — that is, he could get the same phase of the discharge with almost identical shapes of gas-cone and smoke-cloud, and he could get these every time. In the fall of 1912 Captain Behr succeeded in obtaining a series of ex- tremely rapid photographs showing a twelve-inch mortar battery in action. In taking these pictures the camera was [jlaccd on an elevation about ten feet above the concrete floor and about sixty feet back of the mortars. The electrical f'evice for working the shutter was actuated by the mortar itself in its re- coil. These pictures were taken in about one five-thousandth of a second — which is the more remarkable as the last two were taken in the shaflc after 4.30 A.M. The first three were taken about noon, in the sunshine, as the shadows show. So great was the precision of the electrical device as to render possible the photographic recording of these mortar projectiles, moving at great ve- locities, in almost any desired position after the discharge, say two feet away from the muzzle, or six feet away, or twenty feet away, or right at the muz- zle, as shown in the first mortar pic- ture, where the great projectile has been caught in its flight half way out of the mortar. Pictures Never Seen By the Human Eye. It is interesting to note that of these five mortar pictures, representing five phases of the firing, only the last two are ever seen by the human eye. The far swifter camera, acting in about one five-thousandth of a second, has caught all these phases as reproduced here ; but, to the ordinary observer standing by, the first visible impression after firing is that of the smoke-cone as developed in Number Four. The strange "powder-pufif" efifect shown in Number Three is never seen ; nor the earlier efifects in Numbers One and Two. Nor is any sound heard by an observer or by the gun crew until the third or fourth phase has been reached. This is a matter of simple calculation. Sound travels through the air very slowly as compared with light, and in Numbers One, Two, and Three, al- though the crashing explosion has taken place and the projectile is already started on its long journey, the men (even the lanyard man, who is near- est), have heard nothing, since the sound-waves have not yet had time to reach their ears. Nor has the mortar itself had time to recoil, as it does pres- ently, down into the well in the floor of the pit. The men aboard the towing vessels that drag the floating targets during gun and mortar practice would seem to be in a dangerous position, since the tow-line is not more than two hundred yards long for guns and five hundred yards long for mortars, and a very :v2 PROJECTILES TRAVEL FASTER THAN SOUND Tliis shows one of Captain Behr's earliest eflforts to photograpli the projectile from a twelve-inch gun. The man on the platform has been adjusting the electrical connections that actuate the camera mechanism. The halo effect at the muzzle of the gun is due to compressed air caused by the forward rush of the projectile. The projectile has not yet emerged from the muzzle of the gun. On the right is the place where the "Merrimac" and the "Monitor" had their famous fight. slight error in aim or adjustment might cause a deviation of several hundred yards when the range is eight or ten tliousand yards. As a matter of fact, such errors do not occur, and a gun- pointer who would make a right or left deviation from the target of ten yards, or at the most fifteen yards at a dis- tance of five miles, would be consid- ered unfit for his job. In one or two rare instances a towing vessel has been struck when a projectile has fallen short and then ricochetted to the right, as it invariably does owing to its rota- tion in that direction. The rifling of the gun-barrel causes this rotation. Sometimes these great projectiles ricochet several times, and go bounding over the water as a pebble skips along the surface of a mill-pond, only there may be the distance of a mile or more between these giant leaps. The Projectile Travels Faster Than the Sound It Makes. A strange phenomenon is witnessed by the observer on a towing vessel as he looks, rather uneasily perhaps, to- ward the distant shore battery, that seems to be firing straight at him. First there is a flash and a pufif of smoke; then nothing for a pe- riod of seconds, while the pro- jectile is on its way; then suddenly A GUN THAT PHOTOGRAPHED ITS OWN SHOT 33 In this beautiful picture the hurling projectile was itself the photographer; that is, in passing out of the gun-barrel, it broke a length of piano-wire stretched across the muzzle and thus automatically closed an electrical circuit that actuated the camera mechanism. And so rapid was the shutter that the great shot hurled forth in the discharge photographed here has not yet had time to issue from the smoke-cone, where it is still hidden. c'l great splash as the mass of iron strikes the water. Up to this moment there has been no sound of the dis- charge, no sound of the projectile, since it travels faster than the sound-waves ; but now, after it has buried itself in the ocean, is heard its own unmistak- able voice, a low, buzzing um-m-m-iii approaching from the shore. The pro- jectile itself has arrived before the sound that it makes in transit, and the sound arrives afterward. Last of all i? heard the boom of the discharge. Owing to the great velocity of gun projectiles, it is almost impossible for an observer near the target to see them as they approach ; but a trained eye can discern the slower moving mortar pro- jectiles as they drop out of the sky, shrieking as they come, curving down- ward from a height of four or five miles, half a ton falling from a height of four or five miles. It is difficult to realize what an enor- mous force is released when one of these twelve-inch guns is discharged. The pressure inside of the gun behind tlie projectile is between thirty-five and forty thousand pounds to the square inch. No engine or machine made by man produces anything like this pres- sure. The boiler pressure in steam-en- gines, or in big turbines driven by su- perheated steam, does not exceed two HXPI.ODINCi A SUBMARINH MINI: huiulrcd or three hundred pounds to the square inch. The huge hydrauHc presses that would crumple up a steel girder do not exert a pressure of more than one thousand pounds to the square inch. The only reason a gun-barrel c.'.n resist this pressure (forty thousand l^ounds to the square inch) is that it is l)uilt up in a series of concentric steel hoojjs or tubes shrunk one over the other until there is a resistance ca])acity of from seventv thousand to ninctv This photograph ilkistrates another important form of coast defense— the Mibniarine mine. A target about 5 by 5 feet, with a red flag at its apex, is towed across the mme- tield, the mines being e.xploded electrically from a shore station several miles away. The methods of laying and exploding these mines are carefully kept secrets. In this case a charge of five hundred pounds of the newest explosive was used. Fragments of the shattered target and mine-buoy are seen at the right of the picture. Tons of water are hurled into the air by these explosions, and hundreds of fish are killed or stunned. WHY THE EYES OF SOME PICTURES FOLLOW US 35 thousand pounds to the square inch. Even at rest, the barrels of these great guns are under such enormous compres- sion, from being thus squeezed within these outer steel coverings, that, if the retaining steel jackets were suddenly cut, the tubes would blow themselves into pieces from the violent reaction of release. Not only does this smokeless powder, burning inside these guns, produce enormous pressure, but it generates in- conceivably great heat. Water boils at ioo° Centigrade; iron melts at 1400°; platinum and the most resistant metals a1 2900° ; while the hottest thing on earth is the temperature of the electric arc, in which carbon boils. This tem- perature is between 3000° and 4000° only 450 rounds, that is, the gun would be worn out if fired every three min- utes for a single day. After that a new life may be given it by boring out the inner tube and putting in a new steel lining. A Secret for Which Foreign Govern- ments Would Pay Millions. A few words may be added about the formidable smokeless powder used in these great guns. This powder, in spite of its terrible power, is of innocent ap- pearance, and a small stick of it may be held safely in the hand while it burns with a vivid yellowish flame. There is no danger of its exploding or detonating like gun-cotton, and yet it is made from gun-cotton, treated by a Centigrade, and is believed to be the same as that of these great powder chambers when the gun is fired. Thus ,'i diamond, the hardest substance Inown, would melt in the barrel of a iwelve-incli gun at the moment of dis- ( harge. 'i'he consequence is that at rncli fjischargc of a big gun a thin skin of metal inside the barrel is literally fused, and this leads to rapid erosion of the softcncfl .surfaces under the tear- ing pressure of gases generated. The rifling is worn away; the band over the p'-ojcctile becomes loose-fitting; and soon the huge gun, that has cost such a great sum. is rendered unfit ior ser- vice. The life of a t weive-incli gun is colloiding process that is one of our jealously guarded military secrets. There are foreign governments that would give millions to know exactly how this powder is made and how it is preserved for years without deteriora- tion. The recent destruction of two sliips of the French navy was (hie, it is believed, to deterioration of llieir smokeless powder. Why Do Some Eyes In a Picture Seem to Follow Us? ]f a person's jMcture is taken with the eyes of the person looking directly into the lens or (jpening of tlie eanu'ra, tliiMi the eyes in the picture will always 36 WHY \0V CAN BLOW OUT A CANDLE be directly on and appear to follow whoever is looking at it. This is also true of paintings. If a subject being painted is posed so as to look directly v^ '::^ *# <*r-r- W al the painter, and the artist paints the picture with the eyes so pointed, then the eyes of the picture will follow you. ^^'hen you are looking at a picture of a person and the eyes do not follow you, you will know at once that he was not looking at the camera or artist when the picture was being taken or painted. Where Does a Light Go When It Goes Out? To understand the answer to this question fully you will first have to learn what light is, and particularly that it is not the flame from the gas jet or of the lamp or candle that is actually the light, but that light con- sists of rays or waves in the ether, which is constantly in all space and even in our bodies, coming from the something that is burning. This in the instance above mentioned would be the gas burning as it comes out of the gas jet, the oil in the lamp as it comes up through the wick or the flame of the candle. We are apt to call a lighted gas jet a lamp, or a candle, light, be- cause it is steady. Really, however, there is no such thing as keeping light in a room in an actual sense, for rays of light travel from the substance which produces them faster than any- thing else we know of in the world. The first thing a light wave does when it is once created is to go some place, and it does this at the rate of 186,000 miles per second. If it cannot pene- trate the walls of the room it is either rellected hack in the direction from which it canio or transformed by the objects which it strikes into some other kind of energw ^^'hen you look at the rays coming from a gas jet, you do not sec one ray for more than, say the millionth part of a second, but because these rays of light come so fast one after the other from the burning jet and spread in all directions, they seem to be continuous. So you see that the rays of light are going away as fast as they are coming from the gas jet. They either go on as light or, as said above, are changed into other forms of energy when they strike things they cannot penetrate in the form of light, or rather one thing, which is heat. A large part of it goes into the air in the room in the form of heat, as you well know, now that it is called to your attention. Some of it goes into the furniture and some of :t is changed into another form of heat, which, combining with the chemicals in other things it mixes with, changes their appearance and usefulness. As, for instance, the carpets and hangings in the room, the colors of which be- come faded when exposed to light rays too much. The heat from the light rays is responsible for the fading of colors in our garments as well. When you "put out the light," as we say, or turn ofif the gas, you cut oflf the source of light. Really, then, our ex- pression that "the light goes out" is only true while the gas is lighted, for from the flaming gas jet the light is going out all the time, whereas when the gas is turned off no light is being produced, and when you turn off the gas you do not turn out the light, but only that which makes light. WHY A FIRE GOES OUT Why Does a Fire Go Out? Fire will go out naturally when there is nothing left to burn, or it will go out if it cannot secure enough oxygen out of the air to keep it going. In the first case it dies what we might call a "natural death," and in the latter case the fire practically suffocates. The fire in the open fireplace, if it has plenty of air, will burn up everything burn- able that it can reach. The stones of the fireplace or other parts of a stove will not burn, because they have already been burned, and you cannot burn any- thing a second time, if all of the oxygen in it was burned out of it the first time. Now, then, to burn up a thing, you must first start a fire under it, and then keep a constant draft of air playing on it from beneath, or the fire will die out. The more dif^cult a thing is to l)urn, the more important it is that you have plenty of draft. If the ashes ac- cumulate under the fire the air cannot go through them in sufficient quantity nnd the fire will go out. Other things which prevent the current of air from going up through the fire will cause it to go out. That is why we close the lower door of the furnace, to keep the fire from burning out. When we shut off the draft of air from below, the fire in the furnace burns slowly, i. e., it just hangs on, so to speak. Why Does a Lamp Give a Better Light With the Chimney On? W'licn a lamp is burning without a chimney it generally smokes. That is because the oil which is coming up through the wick is being only ])ar- tially burned. The carbon, which is about one-half of what the oil con- tains, is not being burned at all, and goes off into the air in little black specks with the gases which are thrown ofif. The reason the carbon is not burned when the chimney is off is that there is not sufficient oxygen from the .'lir combining with it, as it is separated from the oil in the partial combustion tliat is going on. To make the carbon \v the oil burn you must mix it with plenty of oxygen at a certain tempera- ture, and this can only be done by forc- ing sufficient oxygen through the flame to bring the heat of the flame to the point where the carbon will combine with it and burn. When you put the cbJmney on the lamp you create a draft which forces more oxygen through the flame, brings the heat up to the proper temperature and enables the carbon to combine with it and burn. When you take the chimney off again the heat goes down, when the draft is shut off and the lamp smokes again. The chimney also protects the flame of the lamp from drafts from the sides and above, and helps to make a brighter light, because a steady light is brighter than a flickering one. The draft created by the chimney also forces the gases produced by the burning oil up and away from the flame. Some of these gases have a tendency to put out a light or a fire. Does Light Weigh Anything? To get at the answer to this question Ave must go back to the definition of light. Light is a wave in the ether and contains no particles of matter. It, therefore, does not weigh anything at all. When men had studied light thor- oughly, however, they came to the con- clusion that it must have the power of pressure, which, from the standpoint of results, would amount to the same thing a? having weight. They reasoned that if you had a perfect balance and let sunlight shine down on one of the sides of the balance, that side should go down under the pressure of light. In their first experiments along this line men failed to show that under such conditions the side of the balance on which the light shone did go down, but by continuous exiieriments it was proved finally that the light did exert a sufficient pressure to cause the scales to go down, and in effect this is the same as having weight; but this has been found to be a common property of rays of various kinds, including heat, 38 WHY A STICK IN WATHR BENDS and we, therefore, do not speak of this quahty as wcii^ht, Init as the power of radiating pressure. Why Does a Stick Seem to Bend When Put in Water? When hght passes from one medium to another, as for example from glass or water to air, or from air or glass to water, the rays of light change their course, thus making them seem to he hent or hroken. The rays of light from the part of the stick in the water take a dilTerent direction from the rays from the part which is out of the water, giving the appearance of breaking or bending at the place where the air and water meet. It is, of course, the light rays which are bent and not the object itself. This bending or changing of the path of light rays is called refraction. If you place a coin in a glass of water so that it may be viewed obliquely, you can apparently see two coins, a small one through the surface of the water and another apparently magnified through the side of the glass. This is due only to the absolute prin- ciple that rays of light change their direction in passing from one thing to another, and on this principle of the rays of light our optical instruments, ii'icluding the microscope, the telescope, the camera and eyeglasses are based. What Makes the Stars Twinkle ? I might tell you, just to show how clever I am, that stars do not twinkle at all. and leave you with that for an answer. But since they really do seem to twinkle, and that is what causes your question, I will tell you. As we have already learned in our talks about the stars and the sky in general, the stars are suns which are constantly th.rowing oft light, just as our sun gives us light, and when this light strikes the air which surrounds the earth it meets many objects — little particles of dust and other things always floating about in it. The light comes to us in the form of rays from tlie stars and some of these rays strike particles of various kinds in the air and are thus interfered with. If you arc looking at a lighted window some distance away ruid there are a lot of boys and girls or men and women running past the window, one after the other, ra])i(lly. it will make the light in the window appear to twinkle. The twinkling is due to the interference which the rays of light encounter while traveling to- ward the eye. Why Does an Onion Make the Tears Come? That is nature's way of protecting the eyes from the smarting which the onion would cause in your eyes if tiie tears did not come quickly and over- come the bad effect so produced. Tears are provided for washing the ball of your eyes. Every time you wink a little tear is released from under the eyelid, and the wink spreads it all over the eyeball. This washes down the front of the eyeball and cleanses it of all dust and other things that fly at the eye from the air. Then the tear runs along a little channel, much like a trough, at the lower part of the eye, and out through a little hole in the eye, and in this case the tear is really onlv an eye-wash. Many things, but more often sadness or injured feelings, start the tears coming so fast from under the eyelid that the little trough at the bottom and the hole in the corner of the eye are too small to hold them or carry them ofif, so they roll over the edge of the lower eyelid and down the face. These are what we call tears. Among other things that will cause tear-glands to cause an over-supply of eye-wash to come down, are onions. What they give off is very trying to the eyes, and so, just as soon as the something which an onion throws off hits the eyeball, the nerves of the eye telegraph the brain to turn on the tears quickly, and they come in a little deluge and counteract the bad effect of the onion. 40 HOW MAN LEARNED TO SHOOT TUi; CAVE MAX OF PREHISTORIC TIMES WHO UNCONSCIOUSLY INVENTED AMMUNITION The First Missile A naked savage found himself in the greatest danger. A wild beast, hungry and fierce was about to at- tack him. Escape was impossible. Re- treat was cut off. He must fight for his life — but how? Should he bite, scratch or kick ? Should he strike with his fist? These were the natural defences of his body, but what were they against the teeth, the claws and the tremendous muscles of his enemy? Should he wrench a dead branch from a tree and use it for a club? That would bring him within striking distance to be torn to pieces before he could deal a second blow. There was but a moment in which to act. Swiftlv he seized a jagged fragment of rock from the ground and hurled it with all his force at the blaz- ing eyes before him; then another, anrl another, until the beast, dazed and bleeding from the unexpected blows, fell back and gave him a chance to escape. He knew that he had saved his life, but there was something else which his dull brain failed to realize. He had invented arms and ammuni- tion ! In other words, he had needed to strike a harder blow than the blow of his fist, at a greater distance than the THE SLING MAN IN ACTION 41 length of his arm, and his brain showed him how to do it. After all, what is a modern rifle but a device which man has made with his brain permitting him to strike an enormously hard blow at a wonderful distance? Firearms are really but a more perfect form of stone-throwing, and this early Cave Man took the first steo that has led down the ages. This strange story of a development The men and women in the Cave Colony suddenly found that one bright- eyed young fellow, with a little straighter forehead than the others, v/as beating them all at hunting. Dur- ing weeks he had been going away mysteriously, for hours each day. Now, whenever he left the cam]:) he was sure to bring home game, while the other men would straggle back for the most part empty-handed. PRACTICE DEVELOPED SOME WONDERFUL MARKSMEN AMONG THE USERS OF THIS PRIMITHTi WEAPON has been taking place slowly through thousands and thousands of years, so that toflay you are able to take a swift shot at distant game instead of merely throwing stones. We do not know the name of the man who invented the sling. Pos- sibly he did not even have a name, but in some way he hit upon a scheme for throwing stones farther, harder, ruid straighter than any of his ancestors. W^as it witchcraft? They decided to investigate. Accor(h"ngly, one morning several of tl:em followed at a careful distance as lie sought the shore of a stream where water- fowl might be found. Parting the leaves, they saw him pick up a pch- blc from the bank and then to their surprise, take off his girdle of skin and place the stone in its center, holding I'olh ends with his right band. 42 THE "LONG BOW" IN SHERWOOD FOREST Stranger still, he whirled the girdle twice around his head, then released one end so that the leather strip flew out and the stone shot straight at a bird in the water. The mystery was solved. They had seen the first slingman in action. The new ])lan worked with great suc- cess, and a little practice made expert marksmen. We know that most of the early races used it for hunting and in war. We find it shown in pictures n\'ide many thousands of years ago in ancient I'^gypt and Assyria. We find it in the Roman Army where the sling- man was called a "funditor." Surely, too, you remember the story of David and Goliath when the young shepherd "prevailed over the Philistine with a sling and with a stone." Yet slings had their drawbacks. A stone slung might kill a bird or even a man. but it was not very effective against big game. What was wanted was a missile to pierce a thick hide. Man had begun to make spears for use in a pinch, but would you like to tackle a husky bear or a well-horned stag with only a s])ear for a weapon ? No more did our undressed ances- tors. The invention of the jrreatly de- sired arm probably came about in a most curious wav. Long ages ago man had learned to make fire by patientlv nil»bing two sticks together, or by twirling a round one between his hands with its point resting upon a flat ])iece of wood. Li this way it could be made to smoke, and finally set fire to a tuft of dried moss, from which he might get a fiame for cooking. This was such hard work that he bethought him to twist a string of sinew about the upright spindle and cause it to twirl by pull- ing alternately at the two string ends, as some savage races still do. From OXE OF ROBIX HOOD b F.\MOUS BAXD KXCOUXTERS A SA\AGE TUSKER AT CLOSE RAXGE DEER=STALKING WITH THE CROSSBOW 43 this it was a simple step to fasten the ends of the two strings to a bent piece of wood, another great advantage since now but one hand was needed to twirl the spindle, and the other could hold it in place. This was the "bow- drill" which also is used to this day. But bent wood is apt to be springy. Suppose that while one were bearing on pretty hard with a well-tightened string, in order to bring fire quickly, the springier piece of wood, bent it into a bow, and strung it with a longer thong. He placed the end of a straight stick against the thong, drew it strongly back, and released it. The shaft whizzed away with force enough to delight him, and lo, there was the first Bow-and-Arrow ! Armed with his bow-and-arrow, man now was lord of creation. No longer was it necessary for him to huddle THIS COMPACT ARM WITH ITS SM..LL BOLT AND GREAT POWER WAS POl'l 1. AR W nil MANY SPORTSMEN point of the spindle should slip from its block. Naturally, it would fly away with some force if the position were just right. There was one man who stopped short when he lost his spindle, for a red-hot i'lca shot suddenly through his brain. <')ncc or twice lie chuckled to him- self softly. Thereupon he arose and began to experiment. Me chose a longer, with his fellows in some cave to avoid being eaten by prowling beasts. In- stead he went where he would and boldly hunted the fiercest of them. In other words, his brain was beginning lo tell, for though his body was still no match for the lion and the bear, he had thought ou'i a way to con(|uer them. Also he was better fed with a greater variety of game. And now, free to come and go wherever he might find it, 44 THE DISCOVERY OF GUNPOWDER he was able to spread into various lands and so to organize the tribes and na- tions which at last gave us civilization and history. A new weapon now came about through warfare. Man has been a sav- age fighting animal through pretty much all his history, but while he tried to kill the other fellow, he objected to being killed himself. Therefore he took to wearing armor. During the Middle Ages he piled on more and more, until at last one of the knights could hardly walk, and it took a strong horse to carry him. When such a one fell, he went over with a crash like a tin-peddler's wagon, and had to be picked up again by some of his men. Such armor would turn most of the arrows. Hence invention got at work again and produced the Cross- bow and its bolt. We have already learned how the tough skin of animals brought about the bow ; now we see that man's artificial iron skin caused the invention of the crossbow. \Miat was the Crossbow ? It was the first real hand-shooting machine. It was another big step toward the day of the rifle. The idea was simple enough. V/ooden bows had already been made as strong as the strongest man could pull, and they wished for still stronger ones — steel ones. How could they pull them? At first they mounted them upon a wooden frame and rested one end on the shoulder for a brace. Then they took to pressing the other end against the ground, and using both hands. Next, it was a bright idea to put a stirrup on this end, in order to hold it with the foot. Still they were not satisfied. "Strong- er, stronger!" they clamored; "give us bows which will kill the enemy farther away than he can shoot at us ! If we cannot set such bows with both arms let us try our backs !" So they fastened "belt-claws" to their stout girdles and tugged the bow strings into place with their back and leg muscles. Who First Discovered the Power of Gunpowder ? Probably the Chinese, although all authorities do not agree. Strange, is it not, that a race still using crossbows in its army should have known of explosives long before the Christian Era, and perhaps as far back as the time of Moses ? Here is a pas- sage from their ancient Centoo Code of Laws: "The magistrate shall not n^ake war with any deceitful machine, or with poisoned weapons, or with can- nons or guns, or any kind of firearms." liut China might as well have been Mars before the age of travel. Our civilization had to work out the prob- lem for itself. It all began through j^laying with fire. It was desired to throw fire on an enemy's buildings, or his ships, and so destroy them. Burning torches were thrown by ma- chines, made of cords and springs, over a city wall, and it became a great study to find the best burning compound with ^vhich to cover these torches. One was needed wdiich would blaze with a great flame and was hard to put out. Hence the early chemists made all possible mixtures of pitch, resin, naphtha, sulphur, saltpeter, etc. ; "Greek fire" w^as one of the most famous. Many of these were made in the monasteries. The monks were pretty much the only people in those days with time for study, and two of these shaven-headed scientists now had a chance to enter history. Roger Bacon was the first. One night he was work- ing his diabolical mixture in the stone- walled laboratory, and watched, by the flickering lights, the progress of a cer- tain interesting combination for which he had used pure instead of imjxirc saltpeter. Suddenly there w^as an explosion, shattering the chemical apparatus and probably alarming the whole building. That explosion proved the new com- bination was not fitted for use as a thrown fire ; it also showed the exist- ence of terrible forces far beyond the power of all bow-springs, even those made of steel. Roger Bacon thus discovered what was practically gunpowder, as far back THE FIRST REAL FIRE ARMS 4.") THE KENTUCKY RIFLE WITH ITS FLINT-LOCK WAS ACCURATE BUT MUST BE MUZZLE-CHARGED as the thirteenth century, and left wri- tings in which he recorded mixing 11.2 parts of the saltpeter, 29.4 of charcoal, and 29 of sulphur. This was the for- mula developed as the result of his in- vestigations. Berthokl Schwartz, a monk of Frei- burg, studied Bacon's works and car- ried on dangerous experiments of his own, so that he is ranked with Bacon for the honor. He was also the first one to rouse the interest of Europe in the great discovery. And then began the first crude, clumsy efforts at gunmaking. Firearms were born. Hand bombards and culverins were among the early types. Some of these were so heavy that a forked sup])ort had to be driven into the ground, and two men were needed, one to hold and aim, the other to prime and fire. Improvements kept coming, however. Guns were lightened and bettered in shape. Somebody thought of putting a flash pan, for the powder, by the side of the touch-hole, and now it was decided to fasten the slow-match in a movable cock upon the barrel, and ignite it with a trigger. These matches were fuses of some slow-burning fiber, like tow, which would keep a spark for a considerable time. Formerly they liad to be carried separately, but the new arrangement was a great con- venience and made the match-lock. The cock, being curved like a snake, was called the "serpentine." About the time sportsmen were through wondering at the convenience of the match-lock, they began to rcali/.e its inc(jnvenience. They found that they burned up a great deal of fuse, and were hard to keep lighted. Both statements were true, so inventors rnckcd their brains again for some- 46 \VH\ WE CALL THLA\ PLSTOLS thing better. They all knew yuu could bring sparks with tlint and steel, and that seemed an idea worth working on. A Nuremberg inventor, in 15 15, hit on the wheel-lock. In this a notched steel wheel was wound up with a key like a clock. Flint or pyrite was held against the jagged edge of the w'heel by the pressure of the serjientine. You pulled the trigger, then "whirr," the wheel revolved, a stream of sparks flew off into the flash-pan, and the gun w^as discharged. This gim worked beautifully, but it was expensive. Wealthy sportsmen could afford them, and so for the first time firearms began to be used for hunting. Some of these sixteenth and seventeenth century nabobs had such guns of beautiful workmanship, so v.Tought and carved and inlaid, that they must have cost a small fortune. You will find them in many large niuseums to this day. But now the robbers had their turn. There are two stories of the inven- tion of the flint-lock. Both deal with robbers, both have good authority, and both may be true, for inventions soine- times are made independently in dif- ferent places. One story runs that the flint-lock which was often styled "Lock a la i\liquelet," from the Spanish word, "Miquelitos" — marauders — told its origin in its name. The other is, that the flint-lock was invented in Holland by gangs of thieves, whose principal business was to steal poultry. In either case the explanation is easy. The match-lock showed its fire at night and wouldn't do for thieves, the wheel-lock was too expensive, so again necessity became the mother of a far-reaching invention. Evervbodv knows what the flint- lock was like, "^'ou simply fastened a Hake of flint in the cock and sna])]ied it against a steel ]ilate. This struck olT sparks which fell into the flash-pan and lircd the charge. It was so practical that it became the form of gun for all uses ; thus gun- niaking began to be a big industry. Invented early in the seventeenth cen- ti'ry, it was used by the hunters and soldiers of the next two hundred years. Old people remember when flint-locks w^ere plentiful everywhere. In fact, tb.ey are still being manufactured and are sold in some parts of Africa and the Orient. One factory in Birming- ham, England, is said to produce a1)out tv>-elve hundred weekly, and Belgium shares in their manufacture. Some of the Arabs use them to this day in the form of strange-looking guns with long, slender muzzles and very light, curved stocks. There were freak inventors in the flint-lock period just as there are to- day. Some of them wrestled with the problem of repeating guns, and put to- gether a number of barrels, even seven iti the case of one carbine. Others tried revolving chambers, like our revolvers, and still others, magazine stocks. Pis- tols came into use in many interesting shapes, but these were too practical to be considered freaks. Pistols, by the way, are named from the town of Pistola. Italy, where they are said to have been invented and first used. We must not forget that rifling was invented about the time that the wheel- lock appeared, and had a great deal to do with the improvement of shoot- ing. Austrians claim its invention for Casper Zollner, of Vienna, who cut straight grooves in the barrel's bore. His jrun is said to have been used for THE MODERN AUTOMATIC RIFLE the first time in 1498, but the ItaHans seem 10 have still better warrant as these significant words appear in old Latin Italian, under date of July 28th, I -1 76, in the inventory of the fortress of Guastalla : "Also one iron gun made with a twist like a snail shell." The rifling made the bullet spin like a top as it flew through the air, thus greatly improving its precision. In the year 1807 the Rev. Alexander John Forsythe, LL.D., got his patent papers for something far better than even the steady old flint. He had in- vented the percussion system. In some form this has been used ever since. \\'hich is to say that when the ham- mer of your gun falls, it doesn't ex- plode the powder, although it seems to. Instead it sets ofif a tiny portion of a very sensitive chemical compound called the "primer," and the explosion of this "primer" makes the powder go off. Of course, the two explosions come so swiftly that your ear hears only a single bang. Primers were tried in different forms called "detonators," but the familiar little copper cap was the most popular. No need to describe them. ^Millions are still made to be used on old-fashioned nipple guns, even in this day of fixed ammunition. But now we come to another great development, the Breech-loader.- Perhaps you have had to handle an old muzzle-loader. It was all right so long as you knew of nothing better, but think of it now that you have your beautiful breech-loader. Do you remember how sometimes you over- loaded, and the kick made your shoulder lame for a week? Or how, when you were excited you shot away your ramrod? The gun fouled too, and was hard to clean, the nipples broke off, the caps split, and the breeches rusted so that vou had to take TirE MUDr.K.N SPOkTbMAN Willi HIS At TD-MA lIC KULli li I'Ktl'AKhD tuK ALL LMtKoh.NL IKS 48 HOW THE FIRST AMERICAN GUN WAS MADE THE FIRST AMERICAN MADE GUXS them to a gunsmith. Yes, in spite of the game it got, it was a lot of trouble, now you come to think of it. How dif- ferent it all is now ! Breech-loaders were hardly new. King Henry MH of England, he of the many wives, had a match-lock arquebus of this type dated 1537. Henry I\' of France even invented one for his army, and others worked a little on the idea from time to time. But it wasn't until fixed ammunition came into use that the breech-loader really came to stay — and that was only the other day. You remember that the Civil War began with muzzle-loaders and ended w'ith breech-loaders. Houiller, the French gunsmith, hit on the great idea of the cartridge. If you were going to use powder, ball and percussion primer to get your game, why not put them all into a neat, handy, gas-tight case? Two men, a smith and his son, l)oth named Eli])halet Remington, in 1816, were working busily one day at their forge in beautiful Ilion Gorge, when, so tradition says, the son asked his father for money to buy a rifle, and met with a refusal. The request was natural for the surrounding hills w^ere full of game. The father must have had his own reasons for refusing, but it started the manufacture of guns in America. Eliphalet, Jr., closed his firm jaws tightly, and began collecting scrap iron on his owm account. This he welded skillfully into a gun-barrel, walked fifteen miles to Utica to have it rifled, HOW AMMUNITION IS MADE 49 TVPKS UF CARTRIDGES A VISIT TO A CARTRIDGE FACTORY and finally had a weaoon of which he might well be proud. In reality, it was such a very good gun that soon the neighbors ordered others like it, and before long the Rem- ington forge found itself hard at work grayish pasty mass is wet fulminate of mercury. Suppose it should dry a trifle too rapidly. It would be the last thing you ever did suppose, for there is force enough in that double handful to blow its 'surroundings into frag- to meet the increasing demand. Sev- eral times each week the stalwart young manufacturer packed a load of gun-barrels upon his back, and tramped all the way to Utica where a gunsmith rifled and finished them. At this time there were no real gun-factories in America, although gunsmiths were lo- cated in most of the larger towns. All gun-barrels were imported from Eng- land or Europe. One of the first shocks you get when you start your visit through a car- tridge factory is the matter-of-fact way in which the operatives, girls in many cases, handle the most terrible com- pounds. \Vc stop, for example, where they arc making primers to go in the head of your loaded shell, in order that it may not miss fire when the bunch of quail whirrs suddenly into tlic air from the sheltering grasses. Tlinl ments. You edge away a little, and no wonder, but the girl who handles it shows no fear as she deftly but care- fully presses it into moulds which sep- arate it into the proper sizes for pri- mers. She knows that in its present moist condition it cannot explode. Or, perhaps, we may be watching one of the many loading machines. I WEIGHING PUL 50 TESTING MATERIALS AND PRODUCTS 'J'here is a certain suggcstiveness in the way the machines are separated by partitions. The man in charge takes a small carrier of powder from a case i'l the outside wall and shuts the door, then carefully empties it into the reser- \uir of his machine, and watches alert- ly while it packs the proper portions into the waiting shells. He looks like a careful man, and needs to be. You do not stand too close. The empty carrier then passes through a little door at the side of the building, and drops into the yawn- ing mouth of an automatic tube. In the twinkling of an eye it appears in front of the operator in one of the distributing stations, where it is re- filled, and returned to its proper load- ing machine, in order to keep the ma- chine going at a perfectly uniform rate ; while at the same time it allows but a minimum amount of powder to remain in the building at any moment. Each machine has but just sufficient powder in its hoi)per to run vmtil a new supply can reach it. Greater precaution than this cannot be imag- ined, illustrating as it does that no efifort has been spared to protect the lives of the operators. It is remarkable that, in an outi)Ut of something like four million per day, every cartridge is perfect. Such things are not accidental. The secret is, inspection. Let us see what that means. It means laboratory tests to start with. Here are brought many samples of the body paper, wad paper, metals, water- proofing mixture, fulminate of mer- cury, sulphur, chlorate of potash, an- timony sulphide, powder, wax, and other ingredients, and even the oper- ating materials such as coal, grease, oil, and soaps. In the laboratory v^-e see expert chemists and metallurgists V ith their test-tubes, scales, Bunsen burners, retorts, tensile machines, microscopes, and other scientific look- ing apparatus, busily hunting for defects. For example, one marker is examin- ing a supply of cupro-nickel, such as is used in jacketing certain bullets. A corner of each strip is first bent over at right angles, then back in the other direction until it is doubled, then straightened. It does not show the slightest sign of breaking or cracking, in spite of the severe treatment, there- fore it is perfect. Let but the least flaw appear, and the shipment is re- jected. Two large iron cylinders descend in the center, coming down through the ceiling from above ; we are invited to look through an open port in one of these. We sec nothing but the whitened opposite wall, against which a light burns. It appears absolutely empty, though within it is raining such a swift shower of invisible metal that if we were to stretch our hands into the apparently vacant space they would be torn from our arms. A large water tank below is churned into foam with the impact of the fall- ing shot, and as we look downward we make out finally the haze of mo- tion. It is so interesting that we take the elevator and rise ten stories to the source of the shower. Here high in the air are the large caldrons where many pigs of lead, with the proper alloy, are melted into a sort of metallic soup. This is fed into small compartments containing sieves or screens, through the meshes of which the shining drops appear and tlien plunge swiftly downward. But this only begins the process. Taken from the water tanks and hoisted up again, the shot pellets, in a second journey down, through com- l)licatcd devices, are sorted, tuml)lcd, jtolishcfl, graded, coated with graphite, and finally stored. Lea The pictures sliown in this sforv were prepared especially to illustrate this story of "II :arneu to Shoot" by the Searchlight Library for the Keniingtoii Arms Company. ow Man FORGING A MONSTER GUN Photri I,:.- II This photograph shows gun ingots after being " stripped " and " cored. Photo.by Bethlehem Steel Co. This photograph shows a gun ingot in the process of being forged under forging press. THINGS TO KNOW ABOUT A BIG GUN 53 11 ii.\ Bethlehem Steel Co. This photograph shows a gun being fired at the Proving Grounds for test. The Parts of a Big* Gun Before going into a description of the manufacture of a big gun it would be well to understand the following definitions : The "breech" of a gun is its rear- end, or that end into which the pro- jectile and powder charge are loaded. The "muzzle" of a gun is its for- ward end. By "calibre" is meant the inside diameter of the gun in inches. A 5-inch gun is one of "minor calibre," and one of 14-inches a gun of "major 'pJibre." The length of a gun is never ex- [jressed in inches or feet, but in the number of times that its calibre is divisible into its length ; thus, when wc say a 12-inch 50-calibre gun, we mean a gun of 12 inches in diajneter, and 12 times 50, or 600 inches long. The "bore" is the hole extending tlirnugh the center of thr gim, from the rear face of the liner to its for- ward end. The "powder chamber" is the rear part of the bore, and extends from the face of the breech plug when closed to the point where the "rifling" begins. The powder chamber is slightly larger in diameter than the rest of the bore. The "rifling" is the name given to the spiral grooves which are cut into the surface of the bore of the gun, and give to the projectile its rotary motion when the gun is fired. With the advent of "iron-clads" and heavily armored fortresses, it became necessary to increase the power of the guns in use, until to- day a 14-inch gun of 45 calibres fires a projectile weighing 1400 pounds, with an initial velocity of 2600 feet per second. An idea of this initial ve- locity may be lx;ttcr obtained by com- p.'irison when vou rrrdi/c thai a Iraiti 54 HOW A BIG GUN WOULD LOOK • E — . * ==1 -, — ■ — ~Tif- -^ - — ■ — '. 1 [ [ 31=:==^ Sketch Showing Construction of a Modern " lUiill u|) " (nin. g^oinsj sixty miles an hour is only traveling at the rate of 88 feet per second. Now. in order to produce such wonderful power in a gun, great 1 pressure must be generated in the bore, and it was soon found that a one-piece gun, whether cast or forged, could not withstand such pressures. To begin with, we may consider this one-piece gun, or any gun, as a tube which must withstand a great pressure from within, so that when a gun is designed care must be taken to see that the material from which it is constructed is strong enough to withstand this pressure. And not only must the gun be sufficiently strong, but it must not be too heavy, so that you see you cannot go on for- ever increasing the thickness of the walls of this tube. Besides, it is gen- erally acknowledged that a simple tube or cylinder cannot be made with walls of sufficient thickness to withstand from within a continued pressure per square inch greater than the tenacity of a square-inch bar of the same ma- terial ; in other words, if the tensile strength of a metal is only twelve tons per square inch, no gim of that metal, however thick its walls, could withstand a pressure of twenty tons per square inch, and the modern big guns are tested at that great a pres- sure. And if we look further into this matter of pressures we find that when a gun is fired the pressure exerts itself ill two ways ; it tends to burst the gun longitudinally or down the middle, and •,i tends to pull the gun apart in the direction of its length. Of course, some method of strengthening this one-piece gun was sought after, with the result that to-day guns are either "built-up" or "unre-ivound." A "built-up" gun is one made of several layers, each layer being sepa- rately constructed and then assembled together. The order of assemblage differs somewhat with the different calibres, but the method of assemblage is essentially the same, that is, the out- side layers are heated and shrunk on the inner ones. This question will be treated at greater length later on. A "wire-wound" gun is one in which the necessary additional strength is obtained by winding wire around an inner tube of steel, each layer being wound with a different tension of the wire ; this type of gun has found great favor with foreign manufacturers. In this country, how- ever, the "built-up" system is used al- most exclusively, and so this descrijv tion will deal with the manufacture of a "built-up" gun. A modern "built-up" gun is com- posed of a liner, a tube, a jacket and hoops. The liner is in one piece and extends the entire length of the bore and car- ries the "rifling" and the powder chamber. The tube is in one piece and en- velops the liner for its entire length. Formerly the tube carried the "rifling" and powder chamber, but due to the wearing out of the "rifling" with con- stant firing, a liner was decided on, so that now when the "rifling" becomes worn, the liner can be removed and a new one substituted. The jacket is usually in two pieces and is shrunk on the tube ; it extends the entire length, and its rear end is th.readed in the inside for the attach- ment of the "breech bushing." Hoops are shrunk on over the jc'.cket and in a big gun are sometimes as many as six or seven in number. The liner, tube, jacket and hoops are made of the finest quality of open hearth steel, and the steel must con- IF YOU WERE TO CUT IT IN TWO 00 A, hoop; B. hoop; C, jacket; D, tube; E, einer; F, hoop. 7 Ill's [)hotograph shows a mould for a '^un in; form to specifications set by the gov- crnnient. The chemical composition having been determined, the necessary ele- ments are weighed out and the whole charged into an open hearth furnace. When the furnace is ready to be t,:pj>efl the molten metal is run into a l.'irge larjle, which in turn is taken l)y .1 crane to the casting pit, where the Kionld is filled. 'I'he ingots for the Photo by lU'thlchem Slccl Co. ;ot under hydraulic press for fluid compression. large calibre guns run from 42-inch to 48-inch in diameter, and after being poured they are immediately run under a hydraulic press, where they are subjected to a pressure of about six tons per square inch to drive out the gases, and then lowered to about 1500 pounds j)ressure ])er s(|uare inch for a certain length of time during tl'.e cooling. This pressure tends lo make llic ingot solid, by expelling the .)(i IAKIMj THIi BORl: 0\ A BlU GUN gases, which would cause blow-holes, and by preventing "piping" and "seg- regation." When a metal cools, the top and sides cool first, and this outer layer shrinks and pulls away from the centre, with the result that a cavity or "pipe" would be formed, but the hy- draulic pressure forces lluid metal into this cavity and so prevents the "pipe." The cooling also causes the various elements to solidify separately, and thev tend to break awav from the and other impurities, rise to the top. The govermnent specifications re- quire that there shall be a 2o7<: dis- card from the upper end and a ^% discard from the lower end. The dis- card having been cut off, the ingot is "cored," that is, its centre is bored out, the diameter of the hole depend- ing on the size of the ingot. The ingot is now ready for the "forge," and on its reccijn in the forge shop it is placed in a furnace to be Photo by Bethlehem Steel C This photograph shows gun ingot in boring mill being cored. mass and collect at the centre ; this is called "segregation," and is also par- tially prevented by fluid compression. .\ solid ingot, however, is obtained, and this is absolutely necessary. After the ingot has cooled suf- ficiently it is "stripped," that is. it i^ removed from the mould, and then it is sent to the shop to have the "dis- card." or extra length, cut off. When the ingot is cast, an extra amount of metal is poured into the mould to per- mit this discard, the theory being that the poorer metal, together with gases heated ; and here great care must be exercised to prevent setting up any additional strains in the ingot. When the ingot was cooling just after cast- ing the metal tended to flow from the centre; the interior is still in a con- dition of strain, and if the cold ingot is now placed in a hot furnace, cracks are apt to form in the centre, causing the forging to later break in service. However, the ingot having been properly heated, it is ready for either the forging hammer or the press. The present-day practice, though, is to HOW THE GUN TUBE IS TEMPERED forge the ingot under a press forge, as the working of the metal causes a certain flow, and as a certain amount of time is necessary for this flow, the continued pressure and slow motion of the press allows the molecules of the metal to adjust themselves more easily, and a better and more homo- geneous forged ingot is produced than if the forging had been done with a hammer. When forging a hollow ingot, a mandrel, merely a cylindrical steel shaft, is placed through the hole in the ingot and the ingot forged on the mandrel, thereby not only is the out- side diameter of the ingot decreased, but the length of the ingot is in- creased. The usual practice is to con- tinue the forging until the original thickness of the walls of the ingot is decreased one-half and until the ingot is within two inches of the required finished diameters. The ingot is now known as a "forging," and the lower end of each ingot as cast will be the breech end of the forging that is made from it. The next process is that of "anneal- ing." This consists in heating the forging to a red heat and then al- lowing it to cool very slowly, and is usually done by hauling the fires in the furnace after the correct temper- ature has been attained and permit- ting both to cool ofl^" together. This process is to relieve the strains set u]) in the metal during forging, and fur- ther, it alters the molecular condition of the steel, making a finer and more homogeneous forging. After annealing, the forging is ready to go to the machine shop to be rough bored and turned. The forging is set in a lathe, the breech end being held by jaws on the face-plate and the muzzle end by a "pot-centre." a large iron ring having several radial I'hiiiij liy hciiiU'lK'in Sii-tl r i lii.^ jihotograph >ho\vs n gun lube ready lu Ik- luwircd iiiIm nil hath for " nil tcin|H-riiig." 58 PUTTING THE PARTS OF A ''BUILT=UP" GUN TOGETHER arms screwed thrt)ugh it. The latiic can now be turned and the forginj^f centered by screwing in or out on the jaws of the face-plate or the radial arms of the "pot-centre." When cen- tered, several surfaces arc turned on the forging for "steady rests" and then all is in readiness for the turning and boring. In both operations of "turning" and "boring," the work revolves while the cutting tools are fed along. Turning is very simple and usually several tools are cutting at the same time, but boring is a more delicate operation, be- cause the workman cannot see what he is doing. .\nd in boring, either a "hog bit" or a "packed bit" is used; a "hog bit" is a half cylinder of cast iron fitted with one cutting tool and used for rough cuts, while a "packed bit" is a full cylinder of wood with metal framing and carrying two tools 180'' apart and used for finishing cuts. Tlie forging, having been rough ma- chined, is now ready to receive its neat treatment in order to give to the steel its required physical characteristics. Every piece of steel used in gun manu- facture must conform to certain speci- fications as regard both its physical and chemical characteristics! The chemical analysis was made at the time the ingot was cast ; now for the treatment of the forging, prior to the physical test as to its tensile strength, clastic limit, elongation and contrac- tion. The "tensile strength" of a metal is tlie unit-stress required to break that metal into parts. If a round bar ten inches in cross-section area will frac- ture under a strain of 120 tons, its ten- sile strength is 120 -^ 10 or 12 tons per square inch. Tensile strength is usually expressed in pounds per s(]uare inch. The "elastic limit" of a metal is the unit-stress required to first nroduce a permanent deformation of the metal. If a bar of metal be subjected to an in- creasing strain, up to a certain point that metal will be perfectly elastic, resuming its normal shape when the strain is removed : at tlie first perma- nent set or deformation, however, tiic elastic limit t)f that metal lias been reached. l*21astic limit is exi)ressed in pounds per square inch. I'.y "elongation" is meant the in- crease in lengtli in a bar when its ten- sile strength is reachetl. If a bar 10 inches long after rupture measures i 1.8 inches, its elongation is 18'/ . By "contraction" is meant the de- crease in cross-section area in a bar when its tensile strength is reached. 1 f a l)ar i scjuare inch in area after rupture is only .75 of a square inch in area, its contraction is 25'^/^ . These definitions being understood, a brief description of the heat treat- ment can be taken up, because it is after this treatment that standard bars are taken from the forgings to under- go the physical tests. The first step consists in "tempering" or hardening the metal. The piece to be tempered is placed in an upright position in a high furnace and uniformly heated to the required temperature. It is then lifted from the furnace through -an opening in the top and carried by a crane to an oil tank of suitable depth and plunged into the oil. This rapid cooling or "tempering in oil" is facili- tated by having the oil tank sur- rounded by a water bath, so arranged that a supply of cold water is con- stantly in circulation to carry the heat from the mass as quickly as possible. This operation produces exceeding toughness, increases the tensile strength and raises the elastic limit of the metal. Now the forging is again annealed, so as to relieve any strains set up by tempering and to soften up the metal to the degree required by the specifica- tions. It also increases materially the elongation and contraction. Great care must be exercised in the heat treat- ment, as the acceptance or rejection of the forging depends upon whether or not the test bars pass the required s;tecifications. The forging is now submitted for test and the test bars taken. In the manufacture of a big gun, four test bars are taken from the breech end and four from the muzzle end of each SEARCHING FOR POSSIBLE DEFECTS 59 forging and these bars sent to the physical laboratory. Quite an elabor- ate testing machine is provided, and if the bars pass the required tests the forging is accepted and is sent to the machine shop for finish-boring and turning. Frequently during finish-boring the work is examined to see that the bit is running true, and great care must be exercised to prevent its running out of alignment. After finish-boring every forging is ''borc-?carched," that is, the bore is '"star-gauged" after being hnish-bored and also the liner of the gun after each assemblage operation. In preparation for the assembling cf the different parts, the tube is the forging to be finished. It is bored and tarned to exact dimensions and care- fully "bore-searched" and "star- gauged." With the data at hand a sketch is made showing the external diameters of the liner under the tube, due allowance being made for the shrinkage when assembling. The liner is next bored to within carefully examined for any cracks, flaws, streaks or discoloration. A special instrument called a "bore- searcher" is used and consists of a long wooden handle which has a mir- ror inclined at 45° at one end, together with a light to illuminate the bore, and so shielded as to obscure the light from the observer. (See sketch.) The bore is also inspected by the foreman after each boring, but the final "bore-searching" is done by an inspector. Now to measure accurately the in- side diameters of long cylinders, such as are used in gun work, a special measuring device called a "star-gauge" is used. Its name is derived from the fact that it has three measuiing points set at 120"^ apart and two measure- ments arc taken, one ® and the the six points making star O Every forging is 7 .35 of an inch of the finished diam- eter, and turned to the dimensions re- quired by the sketch above. This extra metal in the bore is left until the gun is completely assembled and is re- moved in the finish-boring. The liner is then carefully "bore-searched" and "star-gauged" and liner and tube are ready for assembling. The liner is now taken to the shrinking pit and carefully aligned in an upright position with the breech end down. The shrinking ])it is merely a well of square section with room enough to permit workmen to move freely about the gun when it is in ]wsition, and equipped with a movable table at its bottom upon which the gun rests. In the meantime the tube, with breech end down, is being heated in a hot-air furnace. This furnace is a vertical cylinder ])uilt of fire-l)rick and as- bestos and so constructed that air which has been passed in pipes over petroleum burners can enter at tin- jjottom, ])ass around and through the (10 RIFLING A BIG GUN tube and out througli the top to be reheated. This service permits a uni- form heat to be transmitted to the tube and when the desired tempera- ture has been attained the tube is lifted from the furnace by a crane, carried to the shrinking pit and care- fully lowered over the liner, (ireat care must be exercised in this opera- tion to prevent the tube from stick- ing while being lowered into ])lace. Should it happen, the tube should be hoisted off at once, allowed to cool, any roughing of the liner be smoothed off, the tube reheated and a second trial made. When the tube is properly in place a cold s])ray may be turned upon any particular section where it i'^ desired the tube should first grij) the liner. The tube is then left to cool by itself, but cold water is constantly circulating through the liner. When the gun is sufficiently cool for handling purposes, it is hoisted out of the shrinking pit and taken to the shop for careful measurement, the liner be- ing "star-gauged" to note the compres- sion due to the shrinking on of the tube. The same procedure is followed in the case of the jackets and hoops, un- til the entire gun is assembled. The gun is considered coni])k'tely "built- up" when the last hooj) has been shrunk on and is now ready to be finished. Tile gun is now liiiish-bored, as .35 of an inch of metal was left in tlie liner in the first boring. "Packed bits" are used and the greatest care is ex- ercised to keep the bit properly cen- tered and running true. .Vfter this ste]) the gun is linish-turncd and the powder chamber is bored. Following this operation the gun is "bore-searched" for any defects that may have shown up in the finish- boring and chambering, and then care- fully "star-gauged." The gun is then ready to be "rifled." Photo by Bethlehem Steel Co. This photograph shows a gun in the Rifling Machine in the process of being rifled. WHAT MOTION IS 61 The "rifling" of a gun consists in cutting spiral grooves in the surface of the bore from the powder chamber to the muzzle end, and is done from the muzzle end. Rifling is a very diffi- cult operation, and great care must be exercised that the cutting is uniform. The grooves are separated by raised portions called "lands," and after "rifling," these grooves and "lands" are carefully smoothed up to remove the rough edges or burrs caused -by the cutting tools of the "rifling" machine. The necessary holes are now drilled for fitting the breech mechanism and the breech block fitted. This opera- tion usually takes some little time, as quite a bit of hand work is necessary to insure a perfect fit. The "yoke," really another "hoop," is now put on ai the breech end and the gun is com- plete. The centre of gravity of gun and breech mechanism is now determined by balancing on knife edges and the whole then weighed. The breech mechanism is also weighed and the two weights marked on the rear faces of the gun and breech mechanism. The gun is now fitted in its "slide," that part of the mount which carries the trunnions and through which the gun recoils when it is fired, and after it is adjusted, all is in readiness for the "proof-firing" or testing of the gun. What Is Motion? There are practically but two things we see when we use our eyes. One of them is matter, which is a term we apply to the things we see, speaking of them as objects only, and the other is motion which we observe some of the matter to possess. Some of the things we see confuse us, if we bear in mind that everything is either matter or mo- tion. For instance, we see light and know it is not matter and are con- fused until we understand that light is a movement of the ether which sur- rounds us and is in and outside of everything. In the same way we feel heat and may think it is matter thrown off by the fire, when it is only cinfjther kind of motion of this same ether. When we understand these things we see that motion is a very important and real part of the world. When a motion is started it will keep on going forever unless some other force which is able to overcome the motion stops it. When a ball is thrown in the air it would go on for- ever were it not for the law of gravi- tation which pulls it to the earth and the friction of the air on the ball as it goes through the air. When you stop a thrown ball you sometimes realize that motion is a real thing because it stings your hands. We do wonderful things with motion. Many things when you add motion to them acquire quahties which they did not possess before. For instance, an ordinary icicle thrown against a wooden door will break, but if you put it into a gun and give it sufficient motion, it will go right through the door. There is a story of how a man killed another by using an icicle as a bullet. The icicle entered the man's body and killed him. Then, of course, the ice melted and no one could tell how the man received his wound, for no trace of anything like a bullet could be found. A piece of paper has no cut- ting qualities, but if you arrange a cir- cular or square piece of paper with a rod or stick through the center and re- volve it fast enough, you can cut many things while it is whirling. The mo- tion gives it the cutting quahties. You cm take a piece of strong rope and, by tying the ends together, making a circle of it, you can make it roll down the street like a steel hoop if you catch it just the right way and set it spin- ning fast enough before starting it on itF way. A steam engine has no power to pull the train of cars until the wheels are set in motion. So we sec that motion is a very important thing in the world. Motion is the cause of movements of all kinds, the power which takes things from one place to another. Is Perpetual Motion Possible? Perpetual motion will never be pos- sible unless some one discovers a way 62 HOW EXPLOSIONS BREAK WINDOWS to overcome the law of gravitation and also the certainty that materials will eventually wear out. Many men have tried to make a machine that would keej) on moving forever without the application of any power, the con- sumption of fuel within itself, the fall of weights or the unwinding of a spring ; such a machine would be ab- solutely impossible, although many pto])le have been fooled into invest- ing money in machines that appeared to have this power within themselves. How Can an Explosion Break Windows That Are at a Distance? An explosion is a sudden expansion of a substance like gunpowder or sonic elastic tiuid or other substance that has the power to explode under cer- tain conditions with force, and usual- Iv a loud report. Some explosions are comparatively mild and accompanied by a very mild noise, while others are \ery powerful and accompanied by a \ery loud noise. When an explosion occurs, the air and everything sur- rounding the thing that explodes is verv much disturbed. The air sur- rounding the thing that explodes is thrown back in air weaves which are powerful in the exact proportion in which the explosion is powerful. These air waves can be so suddenly thrown back against the objects in the vicinity that not only the windows in the buildings are broken, but often the entire building blown away. The ex- plosion acts in all directions at once with equal force. A great hole may be torn in the earth beneath the ex- plosion. If there is anything over the explosion, that is blown away unless its power of resistance is suf^cient to withstand the power of the explosion. Then, also, the air surrounding on all sides is forced back against everything in its path. \''ery often this air which is sudden- ly forced back by the power of the explosion is thrown against houses at a distance. These houses may be so strongly built as to be able to with- stand the effect of the explosion, but still certain parts of them, such as the windows and the bricks of the chim- ney, may not be able to withstand this sudden pressure of air against thcni and they are forced in. The wind from such an explosion acts on the outside of the windows just the same as though you stood on the outside w ith your hands against the windows and pushed them in. Anything that is thrown against a window with more force than the window glass can re- sist will break the window, and even slight explosions may be so powerful as to throw the air back and away from them with such force as to break- windows at a great distance — (fven a mile or more away. V7hy Do Some Things Bend and Others Break ? When an outside force is apjilied to some objects, some of them will bend and others break. It is due to the fact that in some things the particles have the faculty of sticking together or hanging on to each other, and it is very difftcult to break them away from each other. In such instances, as in the case of a wire, the article will bend when w^e apply the power to it and it will not break, because the particles which make up the wire have the faculty of hanging on to each other. -A piece of glass, however, can be broken right in two by the application of no more force than was used to bend the wire, because the particles which make up the glass haven't the faculty to hang on to each other. If you continue to bend a wire back and forth, however, at the same point, it will finally break apart, because you eventually overcome the ability of the particles in the wire to hang on to each other. It all depends upon the hanging-on ability. Sometimes in undergoing dif- ferent processes an article wdiich will ordinarily only bend will become very brittle or breakable. A steel wire may bend but if you make a steel wire very hard it becomes brittle. On the other hand, glass is very brittle ordinarily, but if you make it very hot, you can bend it into any shape you wish, and WHY A BALL BOUNCES 63 thus the glass-worker makes different shapes to various dishes ; lamp chim- neys, bottles, etc., by heating glass and then bending it. When it becomes cool again, it also becomes brittle or break- able as before. Why Does a Ball Bounce? When you throw a ball against the floor in order to make it bounce the ball gets out of shape as soon as it comes in contact with the floor. As much of it as strikes the floor becomes perfectly flat, and because the ball has a quality known as elasticity, which means the ability to return to its proper shape, it returns to its shape immediately and in doing so forces it- self back into the air and that is the bounce. Of course, the first thing we think of when we consider something that bounces is a ball, and in most cases a rubber ball. We are more familiar with the bouncing qualities of a rub- ber ball. Other balls, like standard baseballs, are not so elastic as a rub- ber ball filled with air, but a solid-rub- ber ball is more elastic and some golf balls are much more elastic than a solid-rubber ball. The principle is the same, when you drive a golf ball, ex- cepting that when you bounce a ball on the floor the floor does the flatten- ing and when you drive a golf ball, the golf club does the flattening. A base- ball flies away from the bat for the same reason. \\'hen you meet a fast- pitched ball squarely on the nose with a good swing, it goes farther and faster than when you hit a slow- pitched ball with an equal swing, be- cause in the case of the fast-pitched ball you flatten the ball out more, and it has so much more to do to recover its proper shape that it bounces away from the bat at much greater speed and goes much further unless caught than a slow-pitched ball under the same circumstances. What Makes a Ball Stop Bouncing? .\ bouncing ball, when y(ju first tl.row it against the wall bounces back a' you about as fast as you throw i1. but if you do not catch it on the re- bound, it goes to the floor again, be- cause the law of gravitation which is the pulling power of the earth, pulls it down again. When it strikes the floor it is again flattened to a certain extent and bounces up again, but does not come back so high. It goes on striking the floor and bouncing back into the air again each time a shorter distance, until the force of gravity has actually overcome its tendency to bounce back. When you bounce a ball on the floor and it bounces up again, the motion of the ball through the air is aft'ected by the friction that the contact with the air produces and this friction of the air overcomes part of the boun- cing ability in the ball also. What Makes a Cold Glass Crack if We Put Hot Water Into It ? Hot water will not always cause a cold glass to crack, but is very apt to, especially a thick glass. The very thin glasses will not crack. The test tubes used by chemists are made of very thin glass, and will not crack when hot liquids are poured into them. When a glass cracks after you have poured a hot liquid into it, it does so because, as soon as the hot liquid is put in, the particles of glass which form the inside of the glass become heated and expand. They begin to do this before the particles which form the outside of the glass become heated, and in their eft'orts to expand the inside particles of glass literally break away from the particles which form the out- side, causing the crack. The same thing happens if you put cold water into a hot glass, excepting in this in- stance the inside particles of the glass contract before the particles which form the outside of the glass have had time to become cool and do likewise. What Causes the Gurgle When I Pour Water from a Bottle? The air trying to get in causes the gurgle. Air has one strong character- istic which stands out above every- thing else. Tt wants lo go some place (i4 \VH\ A COAT HAS SLKEVE BUTTONS else all the time. When it learns of a place where there is no air it wants to go there ahove all things, and goes at it with a rush. Now, when you turn a bottle full of water upside down, the water comes out if the cork is out, of course, and as soon as the water starts out the air strivQS to get in, and every time you hear a gurgle you know the air is get- ting in. Every gurgle is a battle be- tween the water and the air. Some- tunes the air comes and pushes the water back enough to let it slide into the bottle ; sometimes the water pushes the air back, and thus they fight back and forth. The w^ater always gets out and the air always gets in. In doing so they make the gurgle. Where Does the Part of a Stocking Go That Was Where the Hole Comes? Perhaps this is a foolish question, Init many boys and girls have been puzzled for an answer to it. When you put your stockings on they have no holes in the feet, and at night, when you take them oflf, there are often quite large holes in them. The answer is the same as in the case of the lead in the lead-pencil. The lead in the pencil wears away. You can see it wear away be- c.iuse that is what makes the marks. When a hole is coming into your stocking, the stocking on your foot is being rubbed between your foot and something else (probably some part of your shoe) and this constant rubbing will wear through the yarns with which the stocking is knitted. Of course, tlie yarns in the stocking are stretched somewhat when it is on your foot and the rubbing finally cuts through the threads and releases the tension of the threads of yarn, so that not always is as much stocking lost as the size of the hole. But, if you were to look carefully at your foot and inside your shoe, when you first take the stocking off and see the hole, you would find little particles of yarn all about. Why Do Coats Have Buttons On the Sleeves? The practice of putting buttons on coat sleeves, which serve no useful pur- pose at all and do not add to the beauty of the coat, is a relic of very old days. There was a time when i)eople did not use handkerchiefs, and it was com- mon practice for men to wipe their noses on their sleeves. They had coats also in those days, but they did not have buttons on the sleeves. One of tlie old kings finally developed the idea of dressing his soldiers in fancy uni- forms and, as he sat in his ])alace and reviewed his troops, he noticed many of them using the sleeves of their coats as handkerchiefs. He immediately is- sued a decree that all sleeves should have a row of buttons sewed on them, but at a point directly opposite to where they are now on the sleeves. This was done to remind the soldiers that the sleeves of their beautiful uni- forms were not to be used as hand- kerchiefs, and those who attem])ted to draw their sleeves in front of the nose v.ere quickly reminded of the decree by the buttons w^hich scratched them. And so the buttons really had a quite useful purpose at one time, and so also all sleeves had buttons sewed on to them at this place. Later on, however, when the unsightly practice had been cured and people had learned to use handkerchiefs, the buttons remained as a decoration, but their former j^urpose was lost sight of. Then some tailor or leader of fashion had the buttons set en the under side of the sleeves for a change, and it became the fashion to have them there, and the tailors have been sewing them there ever since. Why Has a Long Coat Buttons on the Back? The buttons on the back of a long coat, i. e., one with skirts, had a more sensible reason originally. At one time the skirts of such coats were made very long, and when the wearer moved quickly the tails of the coat flapped about the legs and interfered with prog- ress. So an ingenious gentleman had buttons sewed on to the back and but- tonholes made in the corner of his coat- tails. Then when he was in a hurry he simply buttoned up his skirts and went his way comfortably. WHAT HAPPENS WHEN WE TELEPHONE (•.,") TELEPHONE DISPLAY BOARD Showing in outline the apparatus necessary to complete the simplest kind of a telephone call — to a number in the same exchange The Story in the Telephone Mrs. Smith, at "Subscriber's Station No. I," desires to telephone to Mrs. Jones at "Subscriber's Station No. 2." When she Hfts her receiver, the move- ment causes a tiny white Hght to ap- pear instantly on the switchboard at the Central Office. Directly beneath this light is another and larger lamp, which glows in a way to attract the op- erator's attention immediately. The operator inserts a "plug" in a little hole on the switchboard called a "jack," directly above the tiny light which appeared when Mrs. Smith lifted the receiver. This connects her to Mrs. Smith's line. Then she pushes a listening key on the board, connect- ir.g her telephone set to the line. "Num- ber, please?" she calls. Mrs. Smith gives the number; the oi>erator repeats it to be sure there is no mistake, j)laces another "plug" in a "jack" corresponding to the number of Mrs. Jones' telephone and makes the connection. Each subscriber's telephone has a p.Tticular signal on the switchboard to which it is connected by a pair of wires. Mrs. Smith's wires run from her in- strument to the nearest "cable ter- minal," a gathering point for the wires of various telephones in her neighbor- hood. Here they form part of a group of wires going to the Central Office. These groups, called cables, are made up of from 50 to 600 pairs of wires, ac- cording to the telephone needs of the district the "terminal" serves. When the wires reach the Central Office they pass through the "cable vault" to the "main distrilniting frame," which is the Central Office terminal of the cable. When the wires come to this frame they are in numbered order in the cable. Subscribers living next door to Mrs. Smith may have entirely different call numbers and yet use consecutive wires. Jt is the task of the main frame to re- distribute these wires, so that they will be arranged according to their call numbers and to make it possible to con ncct Mrs. Smith's line with the line (/f anv otlu-r subscriber with the least 66 WHAT HAPPENS WHEN WE TELEPHONE ASKING FOR A MMBKR possible delay. This frame has two parts : the "vertical side" and the "hori- zontal side." Before the wires are re- distributed they are taken to pairs of springs equipped with devices for pro- tecting the lines against outside cur- rents. After leaving the main frame they are taken to the "intermediate dis- tributing frame," the central connect- ing point for various branches of tlic lines going to the switchboard, signal- ing and other apparatus. From the "horizontal side" of this frame, wires go to the switchboard, whore they terminate in little holes known as "mulli])le jacks." They also connect witli the line and position message registers, whore the calls from each line and the calls handled at each operator's ])Osition at the switchboard are re- lordcd. The "multiple jacks" are ad- ditional lorminals ])laco(I at nocossary intervals throughout the switchboard, where they can be used by operators to make connections with any other line on the ])oard. From the "vertical side" of the in- termediate frame Mrs. Smith's wires reach the "line and cut-off relay," an electrically controlled switch which ti'.rns on the light signal that appears on the switchboard when she lifts the re- ceiver from the hook. This "line relay" also extinguishes the light when the operator makes the connection, or when Mrs. Smith returns the receiver to the hook. The swift moving electric current that was set in motion when Mrs. Smith began the call, instantaneously passes tlirough all these devices for safeguard- ing and protecting the subscriber's tele- phone service. The light announcing Mrs. Smith's desire to make a call is called the "line lamp," and is flashing on the switchboard. Directly beneath it is the "pilot lamp," which glows whenever any "line lamp" lights. With the "line lamp" is a "jack" or terminal, where connection can be made with Mrs. Smith's line. This is the "answering jack." WHAT HAPPENS WHEN WE TELEPHONE 67 THE CABLE ^•AULT INTO WHICH THE CABLES PASS AVHEN THEY ENTER THE EXCHANGE AND FROM WHICH THEY ARE LED LTWARD TO THE ^LAIN DISTRIBUTING FRAME When the operator sees the flashing signal of Mrs. Smith's "line lamp," she inserts one end of a pair of "connecting cords," which are on the board before her, in the "answering jack" for Mrs. Smith's line. These "connecting cords" are flexible conductors that put the wires of subscribers in electrical con- nection. Then she pushes forward the "operator's key" directly in front of her and is connected with Mrs. Smith's line. The operator ascertains the number wanted and places the other "connect- ing cord" in the "jack" corresponding to Mrs. Jones' line. If she finds .she Cr.nnot herself connect with Mrs. Jones' "jack," because it is on another part of the board out of her reach, she makes a connection with another operator who can reach Mrs. Jones' line. The second operator then mrdscs the connection with Mrs. Jones' "multiple jack" and places her line in connection with Mrs. Smith's line at the first operator's po- sition. At the same time the first op- erator pushes the operator's key back, thus ringing Mrs. Jones' bell. "Supervisory lamps" on the board before her, connected with the "con- necting cords," tell the operator when Mrs. Jones answers the summons. They flash when the connection is made and one goes out just as soon as Mrs. Jones takes the receiver from the hook to answer. If one of these lamps flashes and dies out alternately it tells the operator that cither Mrs. Smith or Mrs. Jones is trying to attract her attention and she connects herself and ascertains the ])arty's wi.shes. When both subscribers "hang up," both lights flash to indicate the end of the conversation. The o])- erator then disconnects the cords from the subscribers' "jacks" and presses the "message register" button recording the call against Mrs. Smith. 08 ROUTINE OF A TELEPHONE CALL The siil>scril)cr. after looking up in the directory the desired number, taln a succeeding i>age descril)iiig tlie making of a concrete roatl. Tliis picture shows mixing concrete by hand. The sand and cement arc first thoroughly mixed' in the dry state ajid suhsef|iiently the stone and water are addeil. Concrete should be Ihonmghly mixed in order that every prain of sand may be entirely cr.ated with cement, and then these two combined make a rich mortar, which should surround entirely every jjiccc of btonc. 100 HOW CONCRETE BUILDINGS ARE MADE This picture shows how concrete houses or walls are built through the use of what are known as forms. In building a wall we have an inside and outside form, as shown in the picture, between which the concrete is placed. After it hardens the forms are removed. In some operations, such as the construction of a large factory building or great bridge, there is such a vast array of timber construction as to make the scene quite impressive, especially when bridge arches of great span and height are under construction. This is a view of an arch built of concrete during the Jamestown Exposition. It is a striking illustration of how concrete may be used for both ornamental and practical purposes. In no field has concrete proved to be of more value and economy than in the construction of bridges, whether large or small. Some of the largest bridges in the world are built of concrete, and in many cases iron bridges are incased in concrete to keep them from rusting. CONCRETE HOUSES CANNOT BURN 101 This is a curious example of concrete construc- tion. It is a coal pocket, from which locomotives are supplied with fuel. Railroad companies have adtopted it because of its great strength and durability. Just as mammoth structures are created with poured concrete, so we may produce tlie most delicate and ornamental patterns. These are usually cast in plaster molds and often in molds of wood or iron. Where undercut work is re- quired, such as in the sun-dial shown, a wood or metal mold could not he removed without injury to the concrete, and so sculptors have invented the pliable glue mold, which can be easily removed and which will spring back to its original shape if necessary to use it a second time. mJ^ ^^^^i r IP K ■ H ^^^^5 HUBBhDm*'',' 9!i lilLiMMM ^^^ Concrete in dwcllioK ci.umi m ii.,ii nii-.m^ ih,- rljiiiiii.ii ii.n i.f ("nr il;iiu:'i :iii.| .ilsn cd-it of p.TintinK' and repair*. This picture hIiowh a Holii! r(;ncretc hniisc, parts nf wliiih have been cnrnistrd witli brautiful tilcH. ( ..nrrftf h.T« been turrrsvftiHv tiscd in all types of dwellings, from the luimble abode of the workiiiKman to the p.nlnro of the miiltimilllnn.Tirr. An entire house may be made r)f concrete, even to ihc ripfif anfj ptairways, and where a dwellinfi; is constructed of this material throughout, it is proof npnini-t drr and rjci.iy. 102 HOW THE FARMER USES CONCRETE This is an i:Ucrubt::ig txaniplc ul concrete Con- struction. It is a large water tower which will never warp, rust or decay. In this field concrete has been of great service, whether reservoirs are constructed in the form of towers or tanks. As already stated, water does not affect the life or strength of concrete, except to improve it. This is a concrete silo. A silo made of con- crete is merely a huge stone jar in which green food for cattle is preserved. The crop is gath- ered and placed in the silo, thus insuring abun- dance of green and wholesome food throughout dry seasons and during the winter. The contents of the silo is known as silage or ensilage, and is merely corn fodder cut when green. Concrete silos are both storm- and' fire-proof. It is usual to conMder concrete in connection with great engineering enterprises, but nevertheless many millions of barrels are used each year by the farmers of the United States. This picture shows a clean, sanitary and durable concrete stable. In buildings of this character concrete is rapidly sup- planting ■wood, which soon goes to decay, to say nothing of accumulation of filth. HOW CONCRETE ROADS ARE BUILT 103 MECHANICAL CEMKNT MIXER A CONCBUiTE kUAU Our two last pictures relate- to an exceedingly iniporiant and rapidly incrcasinp use of cement. It is the construction of concrete roads. The lirst pitliire shows a concrete road in course of con- struction. The mechaincal mixer referred to ahovc is shown in this jMCture. It is a selfproi)ellmK machine and mixes the concrete very rapidly. AS it comes from the mixer in a wet and '""shy mass it is j.laced' between rigidly staked side forms, where it hardens into impcrishahle rock. 1 he road is brouKht to its shape hy working to and fro a long plank called a template, after which the surface of the road is troweled with wooden floats, giving it a texture which prevents horses and cars from slipping. The last picture shows a narrow concrete road in the state of Maryland. Wherever these roads have been built they mean much to the women anrl children of the community. 1 hev never grind up into mud or dust, and are as pleasant to walk upon as the sidewalks of the city. C hildren, egpecially, delight in them. In Wayne county, Mich., where they have the most celebrate. 1 concrete roads in the world, the childrei. go to and from school on roller skates, and various games are played on the concrete road. 10-i WHAT BECOMES OF THE DUST meaning that iron rods, steel bars or woven wire mesh are imbedded in the concrete. When we speak of a "rein- forced" concrete building, imagine a hnge wire bird cage encrusted within and without with concrete. Place a block, beam or column of concrete upon the ground and it will bear a tremen- dous load, meaning that it has great strength in compression. On the other hand, if we were to place a long beam upon supports at either end. leaving the greater length of it suspended and with- out sup]wrt. it would carry but a small load compared with concrete in com- ]iression. Therefore, in making con- crete beams or girders in a building, strong steel bars are embedded in the concrete to take up what are termed the tensile strains. Why Don't We Make Roads Perfectly Level ? Roads are made with a curving upper surface, i. e., higher in the middle, in order that the rain will drain aw^ay from the road into the gutters or ditches which you find at the sides. You see water has the faculty of run- ning only in one direction, and that is downward. If it cannot go down on one side or the other, it wnll collect in pud- dles and make the road impassable. For this reason we build our roads so they are higher in the middle than at the sides — not much higher ; only about six inches or so — giving them just the gentle slope toward each side that is necessary to allow the water to run off gradually, but sufficiently sloping to keep the water from collecting in pud- dles in the road. Thus after the dust lias been settled by the first rain that falls, most of the surplus rain that falls on the roads finally runs into the ditches at the side of the road. Why Are Some Roads Called Turn- pikes ? Undoubtedly the name turnpike as applied to some roads arose from the f?ct that pikes or gates were set across the roads by the keeper or toll-collector. In addition to collecting tolls, it was a part of the toll-keeper's business to keep the road in repair. His wages and other expenses for doing this were received from the tolls collected from the people who used the road to ride on in car- 1 iages, wagons, etc. In the early days the toll-collector was armed with a pike, a long-handled weapon with a sharp iron head, which he used to prevent people who travelled his road from going by without giving up their toll. Later on a swinging gate was built across the road, which made it un- necessary to use the pike, though the name was retained, for no one could ])ass while the gate barred the way. \\'hen the passerby had paid his tolls, the toll-collector opened the gate and let him pass. If he did not pay the gate remained closed and the driver liad to turn back or decide to pay. Hence comes the name turnpike. In some parts of the country they call these toll roads. What Is Dust? A large part of the dust we see in the roadway when the horses kick it up, or when an automobile passes, is made up of the pulverized dirt of the roadway. It becomes mixed with other things, such as the street de- posits of animals, particles of carbon, etc. Particles of this dust get into our throats, and as there are many germs in it, they are very liable to cause sickness, especially the colds from which we suffer. What Becomes of the Dust? The dust of the roadway is generally blown away by the wind, to come down to earth again wherever the wind hap- pens to carry it — on the lawns, the door- steps or back to the road, perhaps. In any event, the rain which is certain to come sooner or later, washes this dust l)ack into the soil, or into the sewers. Part of it mixes with the soil. The organic matter in dust helps to fertilize the soil, and is therefore useful. Other parts of the dust are oxidized and con- sumed by the air, through the heat of the sun. So you see the dust is contin- ually changing from one thing to an- other. Aie Stones Alive? Real stones are not alive. They do not become stones until they have been burned out-^until tHey have become what is known as dead matter. This is meant entirely in the sense that we commonly think of the mean- ing of the word "alive," which is to be able to breathe and grow. Stones can neither breathe nor grow. They belongf to the inani- mate kingdom of things on the earth. Particles of this dead matter, found in stones, etc., are in many cases taken up by things that are actually alive, and help to form the bodies of living things. The most common thing to be found in rocks and stones is what is called ''silicon," and we find this silicon in the straws of the wheat, oats and corn, and in many other things, but not in a way that can be detected except by chemical analysis. A great many of the things found in stones are found in living things, but rocks and stones are not alive in any sense. What and Why Is Smoke? Smoke is produced only when some- thing which is being burned is burning imperfectly. If we were to put any- thing burnable into the fire and estab- lish just the right amount of draft, and knew how to build our fires prop- erly, there would be no smoke and very little ashes. In the case of the black coal smoke which we think of mostly when we think of smoke at all, the black portion is principally little unburncd particles of coal which pass up the chimney with the gases which are thrown off when the coal is being burned. These gases would be invisible — they really are in- visible — if it were not for the little ])articlc'S of coal which are drawn up the chimney with them. If you look at the chimney from which a wood fire expels the gases you find the smoke very light in color — showing that not so much unl)urned matter is being thrown ofif. A charcoal fire makes no smoke, because the charcoal has had the unburnable things taken out of it beforehand, and the charcoal stove is almost perfect in construction from the standpoint of combustion. Of course, the thickness of the smoke from a coal fire is often increased by the fact that there are unburnable things mixed in with the coal, some of which also pass oft" through the chimney. Why Can't We Burn Stones? We cannot burn anything that has already been burned, and a stone has already been burned. To understand how this is we must first find out what takes place when a thing is burned. When a thing is burning it means merely that that particular thing is tak- ing into its system all of the oxygen of the air that it can combine with. When it has done this it cannot be burned any more. Of course, in doing this the thing originally burned changes its character. The elements in a candle when lighted mix with the oxygen in the air and disappear in the form of of gases. The elements in coal mix v/hen fired with oxygen and change irito ashes, gases and smoke. A stone, however, is the result of a burning that has already taken place. The original element of most of the rocks and stones we see was silicon, and when that combines with oxygen, the result is some form of rock, which you may be able to break up or throw, but which you cannot burn again. What Is Fog? The fog which we generally think of when we speak this word is the fog at or on the sea or other body of water — the one that makes the ships stand by and blow their fog horns. A fog of this kind is nothing more nor less than a clond, come right down to earth and spread out a little more. Teople who have gone U]i into tlu- ;iir in b.il loons and other airships through the clouds, say that the clouds are oiil\' fogs, and that above them it is as clear as it is on a sunshiny day on the water when tlu-re is no fog. 106 WHY IRON SINKS AND WOOD DOES NOT There is another kind of fog which settles down over the huid, especially in the cities. It is a damp mist which combines with the smoke and other impurities in the air and forms a black and dirty cloud about everything. This occurs when the ujiper air ])revents the smoke which rises from a city wath all its people and tires in the furnaces from passing up and away. The up]:»er air acts like a blanket and keeps the misty, smoky air down, until the wind comes along and blows it away. What Becomes of the Smoke? There are a number of things in smoke, and when we know what they are, we will find a natural answer to this cjuestion. First, there are, of course, the little unburned particles of fuel which get carried up the chimney by its drawing power. These naturally fall to the ground of their own weight, once they get beyond the drawing power of the chimney and out of the current of air so formed. Some of the gases are already quite burned out V. hen they pass up the chimney. There is a lot of carbonic acid gas which, of course, mixes with the air and even- tually becomes food for the plants. Then there are some gases which are not entirely burned, and the air burns them still more until they, too, become carbonic acid gas, or water which is also thrown oft by a burning fire. Why Does an Apple Turn Brown When Cut? The reason is that when you cut an apple, the exposure to the air of the inside of the apple causes a chemical change to take place, due to the eftect the oxygen in the air has on what is scientifically known as the enzymes in the apple, or what are commonly called the "ferments." When the peel is un- broken it protects the inside of the apple against this action by the oxygen. The brown color happens to be due to the chemical action. The action is sim- ilar to the action of the air on wet or damp iron or steel, in which case we call it rust. Why Does a Piece of Wood Float in Water? A piece of wootl will float in water because it is lighter than the same amount of water. We do not mean that a ])iece of wood weighing one pound, for instance, would weigh any more than a ])ound of water, of course, but if you took the measurements of each you will iind that it took less bulk to make a ])ound of water than of wood. If you had a piece of wood so shaped that it just filled a glass com- l)letely, and then took another glass and filled it with water, you would iind tiiat the glass containing the water weighed the most. Another name to give to this difference would be to say that the water was more dense than the wood. By the law of gravitation the denser thing will always go to the bot- tom, and as wood is less dense than water, it will stay at the top if put in water. The piece of w'ood has more air in it than the w^ater. If you could expel the air from the piece of wood and then put it in water, it would sink. Why Does Iron Sink In Water? The explanation in regard to the piece of wood floating in water is the beginning of the answer to this ques- tion. A piece of iron is heavier than an equal bulk of w^ater, and will there- fore go to the bottom, as will all things which are more dense than water. A ])iece of iron has no air in it. The par- ticles of a piece of iron are so close together that there is no room for air in it and it will therefore sink in water. A piece of wood from which all of the air had been expelled would also sink. Why Doesn't an Iron Ship Sink? This is a very natural question for you to ask right after you were told why iron sinks in water. The explana- tion is that by making an iron ship in the way we do, we fix it so that it holds a lot of air in between the bottom and sides, making the combination of the two — the iron ship and the air in it — lighter than the water on w^hich it WHY IRON TURNS RED WHEN HEATED 107 sails. Alen thought at one time that a ship would sink if made of iron, and therefore huilt all of their ships of wood. Finally one inventor made a ship of iron and it was one of the won- ders of the world. When we found that iron ships would float if they were built to retain sufficient air to keep them from sinking, we made the hulls of most ships of iron for a time. Now, however, the best ships are made of steel, which is even better. If you bore a hole in the bottom of a ship, the water will run in if the ship is in the water, and the ship will sink, because the water coming in drives out the air ; and when the ship is full of water, the water in it, with the ship itself, are heavier than the water on which it sails, and the ship will go down. Filling a ship with water makes the iron part of the ship just like a bar of iron, so far as its sinking qualities are concerned. pf course, an iron ship must be made long enough and broad enough so that when it is completed there will be sufficient air contained within the hull to make the combination lighter than water. Always, therefore, when a ship is to be built, competent engineers must go over the plans of the vessel and calculate the air capacity, so as to make sure she will float. Nowadays it woukl be difficult to sink a modern vessel by boring one small hole in the bottom, because the bottom and sides are lined with en- closed steel air-chambers, and a ship will keep afloat even if one or a number of holes are made. The reason is, of course, that when you bore a hole into one of these air-chambers the water rushing in will fill that air-chamber v.ith water, but as there is no connec- tion from the inside with the rest of the ship, the water can get no further. Why Does a Poker Get Hot at Both Ends if Left in the Fire? Both ends of the jjoker become heated because the poker is made of iron, anrl iron is a particularly good conductor of heat. To understand this we must look into the (jucstion of what a good conductor of heat is. In this case the particles of iron, which com- bined form the poker, are so close to- gether that when those at the end of the poker which is in the fire get hot, the particles at that end hand the heat on to the particles next to them, and so on until the whole poker is hot. The difiference between a thing which is a good conductor of heat and a thing which is not a good conductor, lies in the ability of the different particles which compose it to hand the heat on to the others. Did you ever notice that the handle of a solid silver spoon will become hot if the spoon is left in hot coft'ee? Sohd silver is a good conductor of heat. A plated spoon is not a good conductor, however, and v/ill not become hot if left in the cup of hot coffee as a solid silver spoon will. Would a Wooden Spoon Get Hot? A wooden spoon would not get hot, because wood is not a good conductor of heat. The atoms which compose the wood have not the power to trans- mit the heat to each other. This is strange, too, when we think that a poker is a good conductor of heat, but will not burn, while wood is not a good conductor, but will burn readily. Per- haps you have already discovered this in connection with a wood fire. One end of a stick of wood may be burning fiercely, and yet you can pick it up by the other end and find it is not even v/arm. This proves to you that wood is not a good conductor of heat, and explains why the handle of a wooden spoon in a bowl of hot soup will not get hot while the handle of a silver spoon will. Why Does Iron Turn Red When Red Hot? The answer is (hat the piece of iron has been liciti'd lo tlic point where it gives off light of its own. The rod vou see is only one stage in (he (Kxrlop- ment of iron lo the ])oint where it makes its own light. If you heat it still more it will make a white light. 108 HOW THE SAND GOT ON THE SEASHORE You know that it produces the hght itself, because if you take a piece of iron into a perfectly dark room and heat it to a white heat it will show bet- ter than where tliere is other light. If you continue the ]:)rocess the iron will melt and change in form. Therefore, the "red hot" name for a piece of iron in that state is a perfect name. It is a \sarning that the iron is coming to a point where if the heating process is continued, it will change its form and in this state, when treated according to known methods, the iron is turned into steel, which has many character- istics that iron does not possess. Now, I can, of course, hear you ask why doesn't an iron kettle get red hot? and I can answer that easily. If you treat thic kettle the same way as you do the jiiece of iron, it will get red hot. The (litTerence is that you are thinking of an iron kettle with water in it. As long as there is any w-ater in the kettle, that keeps it from getting hot. The water inside keeps the kettle from becoming red hot. If you took a hollow rod of iron and filled it with water, it would not become red hot as long as any water remained in the hollow jiortion. How Did the Sand Get on the Seashore? The sand on the seashore is nothing more or less than ground-up sandstone. In dealing with the inanimate things in the world we find that a very important element of all of them has been given the name silicon. When the crust of the earth, which is the part we call the land and rocks, and includes the part under the sea, was a molten mass, this silicon was burned, combining with the oxygen which surrounded every- thing, and produced w^hat is known as silica. Silica is the name given to the thing which is left after you burn silicon. A very large part of this silica was deposited in parts of the earth, and when the crust of the earth cooled ofif it was sand. By pressure and contact with other substances it be- came stuck together, just as you can take wet sand at the seashore to-day and make bricks and houses and tun- nels, excepting that in the case we speak of it was something besides water that pressed and stuck the little ]>:irticles of sand together. They stuck together more permanently. Tlien when the oceans were formed, as shown in another part of this book, nnich of the sandstone was fouiul to be at the bottom and on the shores of the oceans. The action of the water continually washing against the sand- stone gradually broke the sandstone up into the tiny particles of sand again, and this is what makes the sand on the seashore. What Makes a Soap Bubble ? A l)ubl)le is merely a hollow ball of water with air inside. The air in com- ing up through the water in trying to rise out of the water is caught in the water in such a way as to form the bubble, and since the ability of the air inside of the bubble to rise is greater than that of the water which forms the bubble, and which has a ten- dency to pull it down, the bubble rises into the air. The water ball is very thin and keeps running down to the bottom of the ball, where you see it form into drops, and soon this makes the walls of the water bubble so thin that the air bursts through the ball of water, and that is What Makes the Bubble Explode ? Sometimes we blow soap bubbles. W' c mix soap in the water and that makes the walls of the w^ater ball wdiich we produce a little tougher, and it requires a great deal more effort for the air to escape from it, as the soap keeps the water in the walls of the bubble from running down to the bottom for quite some time, and, therefore, soap l)ub- blcs will often travel in the air for some distance. The colors we see on soap bubbles are produced by the rays of sunlight, which strike the bubble and reflect them back to us in colors very similar to those of the rainbow. Why Are Bubbles Round? Bubbles are round because the air whit^i forms the inside of the bubble exerts an equal pressure in all direc- tions. It presses equally against all sides of the bubble at the same time. WHERE DOES SILK COME FROM? 109 The Story in a Yard of Silk God's Creation and Man's Invention. Silk in its finished state is an ideal product. It is at once durable, magnifi- cent to the eye, tender to the touch, and its rustle is soft music to the ear. Hence it is easy to understand why the silkworm, from the earliest times, has been an object of much consideration and concern from a commercial and industrial point of view. In this coun- try alone, we annually expend as much for silk goods as we do for public edu- cation and thirty times as much as we do for foreign missions. Such an in- domitable producer of wealth is the silkworm, and a producer of wealth it has been from an age as remote as when Joseph was down in old Egypt, interpreting the dreams of King Pha- raoh's butler and baker and later that of the King himself. To-day we speak of twenty centuries, and our minds can hardly comprehend such a lapse of time. \\'hat shall we think of the silkworm, that for twice twenty centuries has furnished prac- tically all the raw material for the world's silk supply? Because man's ingenuity is at present actively engaged in the attemjjt to displace it by cheaper substitutes, the thought has come to us that, without going too minutely into mechanical processes, a good opportu- nity is presented to give some interest- ing information in regard to the silk- worm as the creation of the Divine Ifanrj, in contrast to the silkworm as the creation of man. According to Chinese authority, the use of silk dates from 2650 B.C., and it is 'generally conceded that, in point of age, it stands midway among the great textiles, wool and cotton having preceded it, while tlax, hemp and other fibrous plants followed shortly in its train. The first patron of the silkworm w-as Hoang-Ti, Third Emperor of China, and his Empress, Si-Ling-Chi, was the first practical silkworm breeder and silk reeler. It is related of her that she was once walking in the palace gardens when she discovered a strange and re- pulsive looking worm. It was small, of a pale green color, and was feeding greedily on a mulberry leaf. She in- terested the Emperor in this strange creature, and, at the Emperor's sug- gestion, took the fine silken web which the worm finally spun, and was the first to successfully reel the new fila- ment and weave it into cloth. So bene- ficial to the nation was her work con- sidered that her gratified subjects be- stowed upon her the divine title of "Goddess of the Silkworms," and to this day the Chinese celebrate in her honor the "Con-Con Feast," which takes place during the season in which the silkworm eggs are hatched. In accounting for the presence of silkworms in the garden of this early empress, we can rightly conclude that certain parts of China have always abounded in forests of mulberry trees, and that the worms themselves had ex- isted in great nimibers in a wild state and attached their cocoons to the trees for ages before any use was discovered for their web. In fact, such wild silk- worms not onlv abound in ( "Iiin;i to- 110 HOW SILK WAS INTRODUCED INTO EUROPE Illustration by courtesy The Bruluerd & Arnialrong rillk Co. THE INTRODUCTION OF SaK INTO EUROPE Pilgrims brought silkwurm eggs in their staffs, to- getlier with the branches of mul- berry trees, from Cliina to the Court of Justinian at Bj^- zantine, A.D. 555- The pcnaUy for taking silkworm eggs iiut of China was death. The accompany- ing illustration is a reproduction of a mural painting on rep in the Royal Textile Mu- seum at Crefeld, Germany, one of the great silk tex- tile centers of the world. The artist shows the pilgrims presenting the silk- worm eggs and the mulberry branches to Justinian, be- side whom, just in the act of rising, is his famous queen Theodora. day, but have also been found in Southern and Eastern Asia, inhabitini^ the jungles of India, Pegu, Siam and Cochin China, but the cocoons of these worms are, naturally, of a very inferior quality, and are only used for the crud- est kind of work. Silk culture from the time of Hoang-Ti became one of the cher- ished secrets of China. The head- quarters of the industry was in the Province of Chen Tong, where was pro- duced the silk for the royal family. In time the silk and stuffs of China became articles of export to various portions of Asia. Long journeys were made by caravans, occupying two-thirds of a year in going from the cities of China to those of Syria, but the price obtained there exceeded the expense of the journey, and thus left a large margin of profit to the merchants. In this manner, for one thousand years, the Chinese sent their silk to the Persians who, without knowing how or from what it was made, carried it to the Western nations. So carefully did the Orientals guard their secret, that there is reason to be- lieve that Aristotle was the first person in the occidental world to Jearn the true origin of the wrought silk from Persia. In commenting on the silk which was brought from that country on the re- turn of Alexander's victorious army, he described the silkworm as a "horned in- sect," passing through several trans- formations, which produced "bomby- kia," as he called the silk. But the classics must convince one that Aris- totle's discovery did not at once become matter of current knowledge. In fact, for five hundred years after Aristotle's time the common theory of the origin of silk among the Greeks and Romans was that it was either "a fleece which grew upon a tree" (thus confounding it with cotton), or a fibre obtained from the inner bark of a tree ; and some, de- ceived by the glossy and silky fibres of the seed vessels of the plant that cor- responds to our milk or silk weed, be- lieved it to be the product of some plant or flower. So virgil, in speaking of silk, says, "the Seres comb the del- icate fleecings from the leaves." WHEN SILK CULTURE WAS INTRODUCED IN AMERICA 111 In the Sixth Century, A.D., all the raw silk was still being imported from China by way of Persia, when the Ejn- peror Justinian, having engaged in war with Persia, found his supply of raw silk cut off and the manufacturers in great distress. His. foolish legislation did not help the situation, and a crisis was averted only by two Xestorian monks, who came from China with seed of the mulberry tree and a knowledge of the Chinese method of rearing worms. No one, on pain of death, was allowed to export the silkworm eggs from China, but Justinian bribed the monks to return to that country, and in 555 they came back, bringing with them a quantity of silkworm eggs concealed in their pilgrim's staffs. And here let us say that there has only once since been an important importation of eggs from Asia. That was about 1860, when Dr. Pasteur was making a study of a germ disease which was threaten- ing the industry. Consequently, it can truly be said that practically all the silkworms of the Western world are descended from those brought in the eggs by the monks to Constantinople. Justinian gave the control of the silk industry to his own treasurer. W^eavers, brought from Tyre and Berytus, were employed to manufacture the silk, and the whole production was a monopoly of the emperor, he fixing its prices. Under his management, the cost of silk became eight times as great as before, and the Royal Purple was twenty-four times it former price. But this mo- nopoly was not of long duration and, at the death of Justinian in 565, the monopoly ceased, and the spread of the industry commenced in new and di- verse directions. While every detail of the growth of the indu.stry has an unusual interest, as showing how such an insignificant thing as a worm may become a potent factor in Nature's economy, the scope of this article will hardly allow us to more than sketch some of the other more salient points of the history of the silk- wr)rni About the year 910, the silkworms made their appearance in Cordova, Spain, being brought there by the floors. From Spain silk culture soon extended to Greece and Italy. Silk was introduced on this conti- nent through the Spanish Conquest of Mexico, and the first silkworm eggs sold for $60.00 an ounce. A century later royal orders were issued requiring mulberry trees to be planted in the Colony of Virginia, and a fine of twenty pounds of tobacco was imposed for neglect, and fifty pounds of tobacco was given as a bounty for every pound of reeled silk produced. Silk culture spread rapidly in the other Colonies, and to-day the story of the inft"ectual attempts to profitably rear the silkworm in this country is as voluminous as it is interesting. Suf- fice it to say, as a sop to our inherent Yankee pride, that silk culture was in- troduced into Connecticut as early as 1737, the first coat and stockings made from New England silk being worn by Governor Law in 1747, and the first silk dress by his daughter, in 1750. This State, for the eighty-four years following, led all the others 'in thle amount of raw silk produced. In Con- necticut also, was built the first silk mill to be erected on this continent for the special purpose of manufacturing silk goods. This building was constructed in 1810 by Rodney and Horatio Hanks, at Mansfield, and is still standing as an heirloom which has come to us from the infant days of the industry. The silkworm has become domesti- cated, since, during the tong centuries in which it has been cultivated, it has acf|uired many useful peculiarities. Man has striven to increase its silk l)roducing power, and in this he has succeeded, for. by comparing the co- coon of the silkworm of to-day with its wild relations, the cocoon is found to be much larger, even in proportion to the size of the worm that makes it or the moth that issues from it. Tlie moth's loss of the power of flight and the white color of the species are prob- riblv the rc'^ult'^ of domestication. 112 JAPAN THE NATURAL HOME OF THE SILK WORM This picture shows a grove of mulberry •trees from which brauches are being gathered as food for tlie worms. This is often done by the chil- dren. G.\ 1 HKKl.N Mn.HlKKV liUAXCHKS. The moths arc placed upon pieces of card- board, upon which they deposit their eggs. The cards with the eggs are kept in a cool place until the season for hatching arrives. OEPOSITIXG EGG? This picture shows two boys preparing a bed of twigs or branches upon which the worms may spin their cocoons. PREPARING COCOn.NING BEDS.* ♦Illustrations by courtesy The Brainerd & Armstrong Co. HOW THE SILKWORMS ARE CARED FOR 113 HATCHING THE EGGS. As the eggs hatch on the cards, the young worms are re- moved to other cards or trays, where they are fed and cared for. pages ititlcd. and p "Silk, The cocoons are soaked in hot water in the hasins shown in the front to loosen the gum. The silk tlireads then pass tiirougli tin- hands of the operators and are reeled on swifts in the cabinet shown in the rear. A more modern appli- ance for reeling the silk is shown on one of the following pages. ictnres hy courtesy of P.rainerd X: Armstrong Silk Company, the Real versus the imit.ilioii." 114 THE SILKWORM— HOW HE DOES HIS WORK FULL GROWN LARVA — SHOWING POSITION IN MOLTING.* MALE MOTH.* FEMALE MOTH.* BOTTOM VIEW OF CHRYSALIS.* The silk moth exists in four states — egg, larva, chrysalis, and adult. The egg of the moth is nearly round, slight- ly flattened, and closely resembles a turnip s-eed. W'hen first laid it is yel- low, soon turning a gray or slate color if impregnated. It has a small spot on one end called the micropyle, and Avhen the worm hatches, which in our climate is about the first of June, it gnaws a hole through this spot. Black in color, scarcely an eighth of an inch in length, covered with long hair, with a shiny nose, and sixteen small legs, the baby worm is born, 'leaving the shell of the egg white and transparent. Small and tender leaves of the white mulberry or osage orange are fed the young worms which simply pierces them and sucks the sap. Soon the worm becomes large enough to eat the tender portions between the veins of the leaf. In eating they hold the leaves by the six forward feet, and then cut ofif semi-circular slices from the leaf's edge by the sharp upper portion of the mouth. The jaws move sidcwise, and several thousand worms eating make a noise like falling rain. The worms are kept on trays made of matting, that are placed on racks for convenience in handling. The leaves are placed beside the worms, or upon a slatted or perforated tray placed above them, and those that crawl oif are retained, while the weak ones are removed with the old leaves. The worms breathe through spiracles, small holes which look like black spots, one row of nine down each side of the body. They have no eyes, but are quite sen- sitive to a jar, and if you hit the rack they stop eating and throw their heads to one side. They are velvety, sm.ooth, and cold to the touch, and the flesh is firm, almost hard. The pulsation of the blood may be traced on the back of the worm, running towards the head. *The cuts on this page and balance of cuts in the story of silk copyright by the Corticelli Silk Mills. SIXTY=FIVE MOTIONS OF HIS HEAD A MINUTE 115 The worm has four molting seasons, at each of which it sheds its old skin for a new one, since in the very rapid HOW THE SILKWORMS ARE REARED.* growth of the worm the old skin can- not keep pace with the growth of the body. The periods between these dif- ferent molts are called "ages," there being five, the first extending from the time of hatching to the end of the first molt, and the last from the end of the fourth molt to the transformation of the insect into a chrysalis. The time between the four "molts" will be found to vary, depending upon the species of worm. When the worm molts it ceases eat- i"?> g;rows slig'htly lighter in color, fastens itself firmly by the ten prolegs, and especially by the last two, to some object, and holding up its head and the fore part of its body remains in a torpid state for nearly two days. By each successive molt the worm grows lighter, finally becoming a slate or cream' white color, and the hair, which was long at first, gradually dis- appears. The gummy liquid which combines the two strands hardens im- mediately on ex|)ost]re to the air. The worm works incessantly, forcing the silk out by the contraction of its body. The thin, gauze-like network which soon, surrounds it gradually thickens, until, twenty-four hours after beginning to spin, the worm is nearly hidden from view. However, the co- coon is not completed for about three days. The cocoon is tough, strong, and compact, composed of a firm, continu- ous thread, which is, however, not wound in concentric circles, but irregu- larly in short figure eight loops, first in one place and then in another. In do- ing this the worm makes sixty-five el- lepitcal motions of his head a minute or a total of 300,000 in an average co- coon. The motion of the worm's head when starting the cocoon is very rapid, and nine to twelve inches of silk flow SILKWUK.M LATINO.* from the spinneret in a minute, but later the averaige would be about half this amount per minute. 116 SILKWORM- ONE OF THE WORLD'S GREATEST WORKERS SILKWORM PREPARING TO FORM ITS CUCOON. Having attained full growth, the worm is ready to spin its cocoon. It loses its appetite, shrinks nearly an inch in length, grows nearly transparent, often acquiring a pinkish hue, becomes restless, seeks a quiet place or corner, and moves its head from side to side in an eflfort to find objects on which to attach its guy lines within whicli to build its cocoon. The silk is elaborated in a senii-lluid condition in two long, convoluted vessels or glands between the prolegs and head, one upon each side of the alimentary canal. As' these vessels approach the head they grow more slender, and finally unite within the s])inneret, a small double orilicc below the mouth, from which the silk COMPLETED COCOON. COCOON BEGUN — SILKWORM CAN STILL BE SEEN. issues in a glutinous state and appar- ently in a single thread. The color of the worm's prolegs be- fore spinning indicates the color the co- coon will be. This varies in different species, and may be a silvery white, cream, yellow, lemon, or green. When the worm has finished spin- ning, it is one and a quarter inches long. Two days later, by a final molt, its dried-up skin breaks at the nose and is crowded back ofif the body, revealing the chrysalis, an oval cone one inch in length. It is a light yellow in color, and immediately after molting is soft to the touch. The ten prolegs of the worm have disappeared, the four wings of the future moth are folded over the breast, together with the six legs and tw^o feelers, or antennae. It soon turns WHEN THE SILKWORM'S WORK IS DONE 117 :..^^..ii. EMERGING FROM COCOONS. brown, and the skin hardens into a tough shell. Nature provides the co- coon to protect the worm from the elements while it is being transformed into a chrysalis, and thence into the moth. With no jaws, and confined within the narrow space of the cocoon, the moth has some difficulty in escaping. After two or three w^eeks the shell of the chrysalis bursts, and the moth ejects against the end of the cocoon a strongly alkaline liquid which moistens and dissolves the hard, gummy lining. Pushing aside some of the silken threads and breaking others, with crimped and damp wings the moth emerges ; and the exit once effected, the wings soon expand and dry. The escape of the moth, however, breaks so many threads that the co- coons are ruined for reeling, and con- sequently, when ten days old, all those not intended for seed are placed in a steam heater to stifle the chrysalis, and the silk may then be reeled at any future time. The moths are cream white in color. They have no mouths, but do have eyes, which is just the reverse of the case of the worm. From the time it begins to spin until the moth dies, the insect takes no nourishment. The six forward legs of the worm become the legs of the moth. Soon after mating the eggs are laid. The male has broader feelers than the female, is smaller in size, and quite active. The female lays half her eggs, rests a few hours, and then lays the remainder. Her two or three days' life is spent within a space occupying less than six inches in diameter. One moth lays from three to four hundred eggs, depositing them over an even surface. In some species a gum- my liquid sticks the eggs to the object upon which they are laid. In the large cocoon varieties there are full thirty thousand eggs in a single ounce avoir- dupois. It takes from twenty-five hun- dred to three thousand cocoons to make a pound of reeled silk. Do you wonder that, centuries aigo, silk was valued at its weight in gold? Growers of silk in the United States, by working early and late every day during the season, which lasts from six to eight weeks, could scarcely aver- age fifteen cents for a day's labor of ten hours. Silk, once regarded as a luxury, is now considered a necessity. II'IIM UIIKII llli, MOTHS ll.WK IM I K'l ,1 H. 118 HOW THE COCOON IS UNWOUND REELING THE SILK FROM COCOONS BY FOOT POWER, CALLED "RE-REEL SILK. The cocoons are first assorted, those of the same color being placed by themselves, and those of fine and coarse texture likewise. The outside loose silk is then removed, as this cannot be reeled, after which the cocoons are plunged into warm water to soften the "gum" which sticks the threads together. The operator brushes the cocoons with a small broom, to the straws of which their fibers become attached, and then carefully unwinds the loose silk until each cocoon shows but one thread. These three operations are called "soaking," "brushing," and "cleansing." Into one or two compartments in a basin of warm water below the reel are placed four or more cocoons, according to the size of the thread desired. The threads from the cocoons in each compartment are gathered together and, after passing through two separate perforated agates a few inches above the surface of the water, are brought together and twisted around each other several times, then separated and passed upward over the traverse guide-eyes to the reel. The traverse moves to and fro horizontally, dis- tributing the thread in a broad band over the surface of the reel. The rapid crossing of the thread from side to side of the skein in reeling facilitates handling and unwinding without tangling, the natural gum of the silk sticking the threads to each other on the arms of the reel, thus securing the traverse. Silk reeled by hand or foot power is known as "Re-reel" silk, while silk reeled by power machinery is called "Filature." .\ FILATURE — RLELIXG THE SILK FROM COCOONS BV POWER MACHINERY.* WHERE MAN'S WORK ON THE SILK BEGINS 119 DRYING SKEIXS OF SILK. The raw silk is first assorted, ac- cording to the size of the fiber, as fine, medium, and coarse. The skeins are put into canvas bags and then soaked over night in warm soapsuds. This is necessary to soften the natural gum in skeins are dry, they are ready for the first process of manufacturing. The room we now step into is filled with "winding frames," each containing two long rows of "swifts," from which the silk is wound on to bobbins. The bob- WI.NWNG FRAMES — WINDING THE SILK ON BOliUlNS. the silk, which had stuck the threads together on the arms of the reel. Fol- lowing the soaking, the skeins arc straightened out and hung across poles in a steam-heated room, as shown in the accompanying photograph. When the bins are large spools about three inches long, Tilie lx)bbins filled with silk, as wound from the skeins, are next placed on pins of the "doubling frames" ; the thread from several bobbins, accord- ing to the size of the silk desired, is 120 THE SILK IS \\OUND ON SPOOLS DOUBLING FRAMES — THE SILK THREAD IS MADE UNIFORM. passed upward throu,2:H drop wires on to another bobbin. Should one of the threads break, the "drop wire" falls, which action stops the bobbin. By this ingenious device absolute uniformity in the size of silk is secured. The "doub- ling frame'' is shown in one of the pho- tographs herewith. The bobbins taken from the "doub- ling frame" are next placed on a "spin- ner." Driven by an endless belt at the rate of over six thousand turns a minute, the bobbins revolve, the silk from them heing drawn upward on to another bob- bin. This spins the several strands brought together by the "doubling proc- ess" into one thread, the number of turns depending on the kind of silk — Filo silk being spun quite slack, and Machine Twist just the reverse. A transferring machine combines two or three of these strands ; two for sew- ing silk and three for machine twist ; and the bobbin next goes on to the "twisting machine" — a machine that is similar to a "spinner," but the silk is twisted in the opposite direction from the spinning. To stand before these SPINNING SILK.* TWISTING SILK. SILK THREADS READY FOR THE WEAVER 121 WATER STRETCHER — MAKING THE SILK THREAD SMOOTH. machines and watch how rapidly and how accurately they do the work as- signed them is a revelation. No one realizes how nicely the parts are ad- justed. If but one tiny strand breaks that part of the machinery is stopped by an automatic device which works instantaneously. After twistins;', the silk is stretched by an ing'enious ma- chine called a "water-stretcher." This smooths and consolidates the constit- uent fibers, giving an evenness to the silk not to be obtained by any other known process. The bobbins are placed in water and the silk is wound on to the lower of tlie two copper rolls. From the lower roll it passes upward to the upper roll, which turns faster than the lower one, thereby stretching the silk. From the upper roll it passes again on to a bobbin. The dyeing process is a very import- ant one, and upon its success depends the permanency of the various colors. Vast tubs, tanks, and kettles sur- round you on every side, and the hiss- ing steam seems to spring from all quarters. The "gum" of the silk is first boiled out by immersion in strong soapsuds for about four hours. The attendants, standing in heavy "clogs" (big shoes with wooden soles two inches thick), turn the silk on the sticks at intervals until the gum is removed. After the silk is dyed it is put into a "steam finisher," a device looking like a long, narrow box with a cover opening on the side, set upright on top of an iron cylinder. The hanks of silk arc placed upon two pins in the steam chest, the cover fastened, and the live steajii rushes in around the silk. This bright- ens the silk, giving it the lustrous, glossy ap])carancc. The editors arc inclebtcd to the Corticclli Silk Mills, I'Morcncc, Mass., for this story of how silk is made, as well as for permission to iiso their splendid life-like copyriKhled photoKrai)hs of the silkworm. Many teachers will he js'lad to know that they can obtain from the Crjrticelli Silk Mills, at slij,'ht expense, specimen cocoons and other helps for object lesson teaching. 122 ANIMALS THAT CAN LEAP THE GREATEST DISTANCE "What Animal Can Leap the Greatest Distance ? The galago, or flying lemur. This singular animal is a native of the Indian Archipelago. It is from 2 ft. to 3 ft. in length, and is furnished with a sort of membrane on each side of its body connecting its limbs with each other ; this is extended and acts as a parachute \\ hile taking its long leaps, which meas- ure about 300 ft. in an inclined plane. The kangaroo can leap with ease a dis- tance of between 60 ft. and 70 ft. and can spring clean over a horse and take fences from 12 ft. to 14 ft. in height. The animals that can leap the greatest distance in proportion to their size are the flea and the grasshopper, the former being able to leap over an obstacle five hundred times its own height, while the grasshopper can leap for a distance measuring 200 times its own length. The springbok will clear from 30 ft. to 40 ft. at a single bound. The flying squirrel, in leaping from tree to tree often clears 50 ft. in a leap. This an- imal also has a broad fold of skin or membrane connecting its fore and hind legs. A steeplechase horse, called The Chandler, is reported to have covered 39 ft. in a single leap at Warwick some years ago. Some species of antelopes can make a leap 36 ft. in length and 10 ft. in height. A lion and a tiger each clear from 18 ft. to over 20 ft. at a bound while springing on their prey. A salmon often leaps 15 ft. out of the water in ascending the falls of rivers. Why Do We Call Voting Balloting? The term covers all forms of secret voting, as in early times such votes were determined by balls of different colors deposited in the same box, or balls of one color placed in various boxes. The Greeks used shells (ostrakon), whence we derive the term ostracism. In 139 B.C. the Romans voted by tickets. The ballot was first used in America in 1629, when the Salem Church thus chose a pastor. It was employed in the Nether- lands in the same year, but was not established in England until 1872, al- though in Soctland it was used in cases of ostracism in the 17th century. In 1634 the governor of IMassacluisetts was elected by ballot, and the constitu- tions of Pennsylvania, New Jersey and North Carolina adopted in 1776, made this method of voting obligatory. The ballot progressed slowly in the South- ern States, Kentucky retaining the viva voce method until a comparatively re- cent date. In certain states, the con- stitutions stipulate that the legislature shall vote viva voce, i. e., cast their votes orally. Since 1875 ^^^ congress- men have been elected by ballot. In 1888 the Australian ballot system, which requires the names of all the candidates for the various offices to be placed on one large sheet of paper, commonly known as a "blanket" ticket, was adopted in Louisville, Ky., and some sections of Massachusetts. It is now in very general use in this coun- try. The voter, in the privacy of an individual booth, indicates his prefer- ence by making a mark opposite a party emblem or a candidate's name. This system originated in 1851 with Francis S. Button, of South Australia, and Henry George, in a pamphlet, "Eng- li.'^h Elections," published in 1882, was the first to advocate it in the United States. The first bill enacting it into a law here was introduced in the Mich- igan legislature in 1887, but it did not pass until 1889. Why Do We Call a Cab a Hansom? The term is applied usually to a pub- lic vehicle, known in England as a "two- wheeler," or "Hansom" (from the name of the inventor), and drawn by one horse. In a hansom cab, the pas- senger or hirer of the vehicle sits im- mediately in rear of the dashboard, the driver sitting on an elevated perch be- hind, the reins being passed over the top. The term cab is sometimes also applied to a four-seated, closed or open carriage, drawn by one or two horses, the driver sitting in front. The term is also applied to the covered part of a locomotive, in which the engineer and fireman have their stations. The word cab is derived from the cabriolet, a light one-horse carriage, with two seats L«,- WHAT PRODUCES THE COLORS WE SEE? 123 and a calash top. In London, England, the cab or hansom was called the "gon- dola" of the British metropolis by Dis- raeli. "Where Did the Name Calico Come From ? A fabric of cotton cloth, the name be- ing derived from the city of Calicut, in Madras, where it was first manufac- tured, and in 163 1 brought to England by the East India Company. Calico- printing, an ancient Indian and Chi- nese art, has become a great industry in this country and in Britain, as well as in Holland. Who Made the First Postage Stamp? The stick on postage stamps so gen- erally used today was invented by an Englishman James Chalmers in 1834. The English Government passed a bill calling for uniform postage of One Penny in 1840 and furnished envelopes bearing stamps printed on them. The people did not like them, however, and the adhesive stamp invented by Chal- mers was substituted. The first stamps used in America were introduced in 1847. People have, it seems, always preferred to lick their postage stamps. How Many Languages Are There? It is said that there are more than 3,400 languages, including dialects, in the world. Most of them belong, of course, to savage or uncivilized people. There are said to be more than 900 lan- guages used in Asia, almost 600 in Europe, 275 in Africa and more thnn 1,600 languages and dialects which are American. What Is the Deepest Mine In the World? The mine that goes farther down than any other in the world is the rock salt mine near Berlin, Germany which is 4,175 feet. It is not, however, straight down but somewhat slanting. The Calu- met Copper Mine near Lake Superior is at a depth in some places of 3,900 feet. The deepest boring in the world is an artesian well at iVjtsdam, Missouri, which is 5,500 feet deep or more than one mile straight down. What Is Color? What is termed the color-sense is the power or ability to distinguish kinds or varieties of light and their distinctive tints. We owe the faculty of doing this to the structure of the eye and its elaborate connecting nerve machinery. The eye in man is specially sensitive to light, and the sensations w^e feel through it enables us to distinguish the different colors. Over 1,000 mono- chromatic tints are said to be distin- guishable by the retina of the eye, though these numerous tints are, in the main, merely blendings or combinations of the three primary color-sensations, the sense of red, of green and of violet. Each of these colors, it has been dem- onstrated, is produced by light of a varying wave length, while white light is only light in which the primary col- ors are combined in proper proportion. Colored light, on the other hand, as Newton proved, may be produced from white light in one of three ways : First, by refraction in a prism or lens, as ob- served in the rainbow; second, by dif- fraction, as in the blue color of the sky, or in the tints seen in mother-of-pearl ; and third, by absorption, as in the red color of a brick wall, or in the green of grass — the white light which falls upon the wall being wholly absorbed, save by the red, and all that falls upon the grass being absorbed except the green. In art, color means that com- bination or modification of tints which is specially suited to produce a par- ticular or desired effect in painting ; in music, the term denotes a particular interpretation which illustrates the phy- sical analogy between sound and color. Where Did the Term Dixie Originate? The term was applied originally to New York City when slavery existed there. According to a myth or legend, a person named Dixie owned a tract of land on Manhattan Island and had a large number of slaves. As Dixie's slaves increased beyond the re(|uire- ments of the plantation, many were sent 124 HOW BIG THE EARTH IS to distant parts. Nattirally the deported negroes looked upon their early home a? a place of real and ahiding happi- ness, as did those from the "Ole Vir- ginny" of later days. Hence "Dixie" became the synonym for a locality where the negroes were happy and con- tented. In the South, Dixie is taken to mean the Southern States. There the word is supposed to have been derived from Mason and Dixon's line, for- merly dividing the free states from the slave states. It is said to have first come into use there when Texas joinetl the Union, and the negroes sang of it as Dixie. It has been the theme of several popular songs, notably that of Albert Pike, "Southrons, Hear Your Country Call"; that of T. M. Cooley, "Away Down South where Grows the Cotton," and that of Dan Emmett, the refrain usually containing the word ' Dixie" or the words "Dixie's Land." During the Civil War, the tune of "Dixie" w^as to the Southern people what "Yankee Doodle" had always been to the people of the whole Union and what it continued, in war times, to be to the Northern people, the comic na- tional air. The tune is "catchy" to the popular ear and it was played by the bands in the Union army during the war as freely as by those on the other side. During the rejoicing in Wash- iiigton over the surrender of Lee at Appomattox, a band played "Dixie" in front of the White House. President Lincoln began a short speech, immedi- ately afterward, with the remark, "That tune fairly belongs to us now; we've captured it." How Big Is the Earth? The third ])lanet in order of distance from the sun. Mercury and Venus be- ing nearer to it. It is in shape a sphere Slightly flattened at the poles and bulged at the equator, hence it is called an ablate spheroid. The equatorial diam- eter or axis measures 7,926 miles and 1. 041 yds., and the polar diameter is 7,899 miles and 1.023 yds. The earth revolves upon its axis, completing its diurnal or daily revolution in a sidereal day, which is 3 minutes and 55.9 sec- onds shorter than a mean solar day. ll revolves around the sim in one sidereal }ear, which is 365 days, 6 hours, 9 min- utes, and 9 seconds. Its orbit or path around the sun is an ellipse, having the sun in one of the foci. The earth's mean distance from the sun is 93,000,- 000 miles. Its axis is inclined to the plane of its orbit at an angle of 23° 27' 12.68". The circumference at the equator measures 24,899 miles. The total surface is 196,900,278 sq. miles, and the solid contents is 260,000,000,000 cul)ic miles. As we descend into the earth the temperature rises at the rate of 1° Fahr. for every 50 ft. At the depth of 10 or 12 miles the earth is red-hot, and at a depth of 100 miles the temperature is such that at the surface of the earth it would liquefy all solid matter in the earth. What Causes Hail? Hail is the name given to the small masses of ice which fall in showers, and which are called hailstones. When a hailstone is examined it is found usu- ally to consist of a central nucleus of compact snow% surrounded by succes- sive layers of ice and snow. Hail fcdls chiefly in Spring and Summer, and often accompanies a thunderstorm. Hailstones are formed by the gradual rise and fall, through different degrees of temperature (by the action of wind- storms), and they then take on a cov- ering of ice or frozen snow, according as they are carried through a region of rain or snow. With regard to rain, it may be said, in popular language, that under the in- fluence of solar heat, water is con- stantly rising into the air by evapora- tion from the surface of the sea, lakes, rivers, and the moist surface of the ground. Of the vapors thus formed the greater part is returned to the earth as rain. The moisture, originally in- visible, first makes its appearance as cloud, mist or fog ; and under certain atmospheric conditions the condensa- tion proceeds still further until the moisture falls to the earth as rain. Simply and briefly, then, rain is caused by the cooling of the air charged with moisture. WHY WE CALL THEM WISDOM TEETH 125 Why Does a Human Being Have To Learn to Swim? It is strange, isn't it, that almost ev- ery animal, excepting man and possibly the monkey, knows how to swim natur- ally ; others such as birds, horses, dogs, cows, elephants, can swim as soon as they can move about alone. The trouble with man in this connec- tion is that his natural motion is climb- ing. He has been a climber ever since he was developed from the monkey, and when you throw him into the water be- fore he has learned to swim, he natur- ally starts to climb and as a climbing m.otion won't do, for swimming, the man will drown. This climbing motion is as much of an instinct in man and monkeys as the instinct in dogs which causes him to turn round once or twice before he lies down just as his forefathers used to do ages ago when, as wild dogs, they first had to trample the grass before they could lie down comfortably. Why Do I Get Cold in a Warm Room? I suppose you mean the instances when you get cold while in a warm room even when you are perfectly well. This will happen often when all of the moisture in the room outside of what is in your body, is evaporated by the beat in the room. The remedy is, of course, to keep a pan of water some ])lace in the room as the air has become too dry. While heat is necessary to evaporate water, the process of evaporation pro- duces cold. The quicker the evapora- tion the sharper the cold feeling ])ro- duccfl. Now your body is continually c^'aporating the water from your body which comes out in the form of per- spiration through the pores of the skin. This is one of nature's ways of taking the impurities and waste out of the body. You know, of course, don't you, that more than one-half the waste ma- terial which the bf)dy expels from the system comes out through the pf)res of the skin rather than through the canals. When the air in the room becomes too dry, the evaporation on the outside of the body proceeds faster and makes you cold. By keeping water in some vessel in the room you keep the air of the room from becoming too dry. Why Do They Call Them Wisdom Teeth ? The wisdom teeth are the two last molar teeth to grow. They come one on each side of the jaw and arrive somewhere between the ages of twenty and twenty-five years. The name is given them because it is supposed that when a person has developed physically and mentally to the point where he has secured these last two teeth he has also arrived at the age of discretion. It does not necessarily mean that one who has cut his wisdom teeth is wise, but that having lived long enough to grow these, which complete the full set of teeth, the person has passed sufficient actual years that, if he has done what he should to fit himself for life, he should have come by that time at the age of discretion or wisdom. As a matter of fact these teeth grow at about the same age in people whether they are wise or not. What Makes Freckles Come? Freckles are generally caused by the exposure of unprotected parts of the body to the sun, but this will not cause freckles on all people. Only peo])le with certain kinds of sensitive skins freckle. W^hat happens when freckles are produced in this way is this : The sunlight shining on the face, neck or arms of anyone who has a tendency to freckle, has a ])eculiar action on certain cells of the skin which produces a yel- lowish brown coloring pigment, which remains for a time. 'i'hen again the skins of some people arc so peculiarly sensitive the cells de- velop this kind of coloring niatli-r in almost any kind of light and such people are, so to speak, apt to be- freckled for life. 126 HOW MEN LEARNED TO FLY First successful power-driven aeroplane. The Langley monoplane with steam engine, which flew over the Potomac River in 1896. The Flying Boat When Did Man First Try to Fly? Man's desire to conquer the air is older than recorded history. When a kite was flown for the first time the principle of aviation, or dynamic flight, was uncovered. For centuries man has sought the mechanical equivalents for the things that keep a kite flying stead- ily in the air, — the power that lies in the cord that keeps a kite headed into the wind ; an equivalent for the wind's own power ; an equivalent for the tail which controls the kite's lateral and longitudinal balance. Each separate part of the modern flying machine, or aeroplane, was worked out long ago, with the excep- tion of the gas engine light enough and reliable enough to be used for this work. The present generation knows dynamic flight as a commonplace thing, not because we are so much more clever than previous generations in designing flying machines, but because of the de- velopment of the modern gasoline or internal combustion engine. Who Invented Flying? No one invented flying, nor did any one man invent all the separate parts of the flying machine. They are the re- sult of evolution, — of the combined work and thought of hundreds of men, many of whose names are unrecorded. To attempt to find the true beginning of the modern flying machine would be as difficult as attempting to discover who planted the seed of the tree from which one has gathered a rose. But the tree from which all the flying ma- chines, or aeroplanes, of today have sprung undoubtedly is Dr. Samuel Pierrpont Langley, third secretary of the Smithsonian Institution. Some of the Men Who Helped. Taking the most conspicuous names of scientists who worked out various details of the aeroplane during the past century we find that a century ago Sir George Cayley built a machine on lines very similar to those accepted today, and he went so far as to foretell the EARLY TYPES OF FLYING MACHINES 127 One of Dr. Langiey's first models ; a biplane with flexible wing-tips and twin propellers, li. necessity of developing the internal combustion engine before dynamic flight could be a success. Mr. F. H. W'enham, in 1866, also built a flying machine along conventional lines and tried to fly it with a steam engine, which of course, proved too heavy. M. A. Penaud, a Frenchman, in ex- perimenting with models, seems to hive been the first to discover the necessity of vertical and horizontal rudders in maintaining balance. Mr. Horatio Phillips, an Englishman, discovered, and patented, the use of curved instead of flat surfaces for the planes. Otto and Gustav Lilienthal are said to have been the first to attempt to balance aeroplanes by flexing or bending the wings. Various others, including Messrs. Richard Ifarte, Boulton, Mouil- lard, worked out ideas for balancing machines by the use of auxiliary planes which could be set at different angles with regard to the line of flight, thus forcing the machines to different po- sitions by the force of the air rushing against them. Dr. Langley, trained in scientific in- vestigation, conducted an elaborate series of experiments covering many years and costing thousands of dollars to test and prove the value of the claims of the cirlier investigators. Some things which he thought he was the first to discover, — such as the ef- fect of the vertical and horizontal rud- ders, — he later found had already been proven by others. Independently he covered the entire field of experiment and after building hundreds of small models he succeeded, in 1896, in making a machine weighing several pounds equipped with, a very light steam engine which flew safely as long as the fuel lasted. For his early experiments Dr. Langley was afforded financial assist- ance by Mr. William Thaw of Pitts- burg. After the success of his small machines Dr. Lan:^ley was asked to undertake the construction of a large, man-carrying machine, and Congress voted him $.S0.CO0 to carry on the work. A large share of this was spent on the devcloi)mcnt of a very light gaso- line engine. The machine finally was completed. l)ut was twice broken through defective lumching apparatus. Congress and Dr. langley were so ridi- culed by the public press that the ma- chine was temporarilv abandoned. Not, however, tmtil after Dr. Langley had successfully llown a steam driven ma- chine much larger than many of tlie racing acroplines of today. lUit eight years after Dr. Langlev's death, wliii-h is said to have been ression in what is W^ith the exception of M. Bleriot it is doubtful if the others fully realized the .source of their inspiration, — not to call it information. Dr. Bell was interested in Dr. Lang- ley's work for more than ten years be- fore Dr. Langley gave tip. lie ob- served many of the trials, and his re- ports of the first successful flights arc incorporated in the official ptiblications of the Smithsonian Institution. Dr. Bell began some independent experi- ments, btit following Dr. Langley's death he formed the Aerial Experiment Association, to carry on the work left by Dr. I^ingley. Tlie members of this organization were, Mr. Curtiss, at that 130 WHAT TWO BROTHERS ACCOMPLISHED FOR FLYING time the most successful builder of lisrht motors; Lieut. Thomas H. Selfridgc, U. S. A. ; Mr. J. A. D. McCurdy and Air. F. W. Baldwin, two young- Ca- nadian enq-ineers. Mrs. Bell financed the project, furnishing the sum of $35,000 for the experiments. The ^^'ric:ht Brothers, for \\'ilbur \\'ri<:;:ht was joined by his brother (Ir- vine in the experiments, were the first to reap success from the seeds of Dr. Langley's sowing. Mr. Oianute had been experimenting with a biplane form of motorless .glider Avith little success, because of lack of means for balancing the machines in the air, until he was joined by a former employe of Dr. Langley. He appears to have imparted to Mr. Chanute the secret of the sta- bilizing eflfect of the Penaud tail, or combination of vertical and horizontal rudders. Thereafter hundreds of suc- cessful gliding flights were made with the Chanute biplane, though Gianute seems not to have grasped the full sig- nificance of the rudders, — though 'it was well understood by Dr. Langley. To the Chanute machine, as described to him, Mr. Wright added first the idea of flexing or warping the wings, after the fashion set by the Lilienthals. He found, however, as Dr. Langley had found years before, that in attempting to correct lateral balance in this way caused the aeroplane to swerve to such an extent that the fixed vertical rudder, as originally employed, did not correct the upsetting tendency that was de- veloped. Air. Wright then arranged his rudder in such a way that when the wing was warped the rudder turned in a way to offset the swerve. This com- bination was patented all over the world and has resulted in much complicated litigation. To this machine the Wright Brothers added a gasoline motor in December, 1903, and with it made numerous flights during 1904-5. Their claims were not generally credited however until a later date for their experiments had been conducted with considerable secrecy, and during 1906, 1907 and until late in 1908 thev did no more flvingf. In the meantime M. Blcriot had made a copy of one of the earlv Langley tandem monoplane models and made some fairly successful flights with it in Europe. Later, as gasoline motors developed in power for weight, he re- duced the rear surface until the modern monojilane evolved. While P)leriot was working in Eu- rope, Dr. Bell's Aerial Experiment As- sociation in America was evolving still another type of machine, and the mem- bers of the association made the first successful public flights in America. Mr. Curtiss won the Scientific American Trophy for the firs't time on July 4th, 1908, by a straightaway flight of more than a kilometer. The balancing sys- tem emplo}'ed by the A^ E. A. differed from that employed 'by the Wrights and by Bleriot in that small auxiliary planes took the place of warping planes for righting the machine. This they claimed to be a superior method, first, because it eliminated the use of the rud- der as being absolutely essential to the balance of the machine ; second, because it enabled them to make the main planes rigid 'throughout, and conse- quently stronger than the flexible planes. There are several other names that must be mentioned in connection with the early history of successful flight ; these are the Frenchmen. Messrs. Henri Farman, Maurice .Farman, the brothers A'oisin, and Santos Dumont. These produced some of the first notably suc- cessful aeroplanes in Europe but seem to have discovered nothing which has had any marked effect upon the later development of flying machines. M. Farman adopted the auxiliary planes used by the A. E. A^ and modified them to suit his ideas. A'olumes could be, in fact, have been written about the exploits of the first demonstrators of the practical heavier- than-air flying machines, — of the cross- ing of the English Channel by Bleriot, of the flights by Wilbur Wright at Rheims, France; of Mr. Curtiss' win- ning of the first Gordon Bennet Inter- national speed trophy and his flight WONDERFUL RECORDS OF AEROPLANES 131 AEROPLANB "RED WI .AlflllOKDSfQKT^ N.Y down the Hudson from Albany to New York; of Orville Wright's flight at Fort Meyer, and the death of Lieut. Selfridge who was flying with him. The barest record of these interesting ac- compHshments would fill volumes. Of the aeroplane proper it is enou'ijh to say here that since 1908 its develop- ment has been too rapid for accurate recording. In strength, in speed, in reliability, in size and carrying capacity, it has developed at a remarkable rate. At this writing the speed record is about 130 miles per hour; the duration record is more than 24 hours, non-stop; the distance record is- some 1,300 miles in one day; the altitude record some 26,000 feet. New records succeed the old ones with such rapidity that prob- ably before this can be printed all these present records will have been greatly eclipsed. Meantime the aeroplane has de- veloped greatly in other directions. In flying over .land with the early types of machines many fatal accidents oc- curred, particularly to the fliers who gave exhibitions everywhere during 1909, 1910 and 1911. A majority of these accidents were indirectly due to The lji|)lanc in wliuli Ti. H. Turtiss flt-vv from Alliaiiy tn \' rapidly both in this country and in I'.urojtc. 'I'he cxi)ericnces of furnish the financial support for Mr. Curtiss' attempt to build a machine to fly across the Atlantic Ocean, from America to Europe. If the venture is suc- cessful it is expected the crossing will be made in a fraction of the time taken by the fastest Transatlantic liners. The discovery of new metals and new maiui- facturing methods will certainly result in the development of light motors that may ibe relied upon to run for days without stopping, and automatically stable aero])lancs seem to be not far away. This will result in overland flight as safe and sure as we now enjoy over water. 134 INSIDE OF A MODERN FLYING BOAT Inlcrior arrangenu-nt of modern tl\ing boat, showing fuel tank and instrument hoard. Six-passenger flying boat hull. This machine will fly i,ooo miles without stopping for fuel. FUN IN A FLYING BOAT 13.5 l'l\iiig at speed of a mile a minute. Monuplanc Hying boat, Imilt for R. V. Morris. 1 i'lsl ^^^^^ / g 1 ^4^ IBf / f t- . ,.._,_: <'^' In a flying Iki.h mh [ilci m. li 136 GREATEST PRESENT VALUE OF AEROF>LANE At present the rjreatest value of tlic aeroplane seems to be for military reconnaissance and all the great powers are striving their utmost to secure su- premacy in the air. l'>ance, Germany, Russia and England have to date spent millions in develo])ing aeroplane fleets. Only the government of the Ignited States has failed as yet to appreciate tlie military significance of the ilying machine. If the relative aeronautical strength of the world's nations were represented alphabetically the U. S. would naturally scarce have to change its initial, U being slightly in advance of Z -which wouki stand for Zululand. But even with its auodest equipment the navy fliers of the United States proved the great worth of the aeroplane and the flying boat, when during the recent trouble in Mexico the air scouts gathered in a few minutes information that could only have been secured by days of cavalry scouting before the advent of the flying machine. Indeed, the. name of Lieut. P. N. L. Bellinger, the most able of the naval fliers at ^'era Cruz, has figured more prominently in the despatches from the front than that of anv other officer connected with the expedition. Flying seems certain in the very near future to take its place as the fastest, safest and most comfortable mode of conveyance. The flying boat will ren- der quickly accessible the vast country lying along the great rivers of Soutli America, Africa, and Australia; it will bridge the great lakes and the oceans ; bring near together the islands of tlu' Pacific and Indian oceans. It will make imperative, because of the speed with which distances will be traversed, of a language common to all ])eoplcs; and treble man's life without extending his years by uiaking' it ])ossih1c to see and do three times as much in the same length of time. Ten years ago on that day, December 17, 1913, Wiibur and Orville Wright made four flights on the coast of North Carolina near Roanoke Island, a spot historic in America's history as the site of the first English settlement in the Western Hemisphere. Tlie first flight started fromi level ground against a 27-mile wind. After a run of 40 feet on a monorail track, the machine lifted and covered a dis- tance of 120 feet over the ground in 12 seconds. It had a speed through the air of a little over 45 feet per sec- Flying liver military post in Curtiss l»iplane. TEN YEARS OF FLYING ond, and the flight, if made in cahn air, would have covered a distance of over 540 feet. Altogether four flights were made on the 17th. The first and third by Or- ville Wright, the second and fourth by Wilbur Wright. The last flight was the longest, covering a distance of 852 feet over the ground in 59 seconds. After the fourth flight, a gust of wind struck the machine standing on the grounci and rolled it over, injuring it to an ex- tent that imade further flights with it impossible for that year. The gliding experiments of Lilienthal in 1896 led the AWight Brothers to become interested in flight. The next four years were spent in reading and theorizing. In tlife Fall of 1900 practical experiments were begun with a man- carrying glider. These experiments were carried on from the sand hills near Kitty Hawk, North Carolina. The first glider was without a tail, the lateral equilibrium and the right and left steer- ing were obtained by w^arping of the main surfaces. A flexible forward ele- vator was used. This machine was flown as a kite with and without opera- tor, and several glides were made with it. A second machine w;as designed of larger size, and many glides were made with it in 1901. This machine was sim- ilar to the one of 1900 but had slightly deeper curved surfaces. Experiments with this machine demonstrated the in- accuracy of all the recognized tables of air pressures, upon which its design had been based. In 1902 a third glider -was con- structed, based, upon tables of air pres- sures made by the Wright 1 brothers themselves. The lateral control was maintained by warping surfaces, and a vertical rear rudder oi)erated in con- junction with the surfaces. Nearly a thousand glifling flights were made with this machine. In 1903, the Wright Brothers de- signed a machine to 1>e rlriven with a motor. They also designed and built their own motor This had four liori- zotit;i1 cvlindfT';, 4 in. bv 4 in., and (]v- 138 INTERESTING GOVERNMENTS IN FLYING MACHINES vcloped 12 h. ]>. Two propellers, turn- ing in opposite directions, were driven by chains from the engine. After many delays the machine was finally ready and was flown on the 17th of December, l'X)3, as related above. In the Spring of VX)4, power flights were continued near Dayton with a ma- chine similar to the one flown in VX)3^ but slightly heavier. The first comj)lcte circle was accom- l)lisiied on the 20th of September, 1904, in a flight covering a distance of aibout one mile. Altogether 105 flights were attem]ited during the year, the longest of which were two of five minutes each, covering a distance of about three miles. All of the flights were started from a monorail. After September a derrick and a fall- ing weight were used to assist in launch- ing the machine. It was not till 1908 that the Wright Rrothers found purchasers for their in- vention. In that year they made a con- tract to furnish one machine to the Sig- nal Corps of the United States Army and to sell the rights to their invention in France to a French company. In l)oth cases they agreed to carry a pass- enger in addition to the operator, fuel sufficient for a flight of 100 miles, and to make a speed of 40 miles an hour. After making some preliminary prac- tice flights at their old experiment grounds near Kitty Hawk in May, 1908, Wilbur Wright went to France to give demonstrations before the French Syn- dicate and Orville Wright to Washing- ton to deliver the machine to the United States Signal Corps. The machines used by Wilbur Wright had been stand- ing in bond in the warehouse at Havre since August of the year before. Ow- ing to damage done to the machine in shipment, it was not ready for the of- ficial demonstrations until late in the year. Meanwhile Orville Wright in Sep- tember, 1908, started demonstrations of the machine contracted for by the Ignited States Government. On the 9th he made two flights, one of 57 minutes, and the other one hour and 2 minutes. WHERE THE WIND BEGINS 139 world's records. On the 10th and 11th, these records were increased and on the 12th a flight of 1 hour and 15 min- utes was made. On the 17th, the tests were terminated by an accident in which Lieutenant Sel fridge met his death and Mr. \\'right was severely injured, so that he Avas not able to complete the tests until the following year. Four days after the accident, on the 21st of September, Wilbur Wright made a flight of 1 hour and 31 minutes at Le Mans, France, which record he improved several times during the fol- lowing months, and on the 31st of De- cember, won the Michelin Trophy by a flight, in which he remained in the air 2 hours and 24 minutes. Where Is the Wind When It Is Not Blowing ? The answer is, of course, that there isn't any wind then. To understand this perfectly we must study a little and find out what wind is. In plain w^ords it is nothing more than moving air. If you make a hole in the bottom of a pail of water the water will run out slowly. If you knock the wdiole bottom out of the pail filled with water, the water will rush out before you know it. That is about what happens to make the wind. The air is constantly full of air currents, like the currents you can see in a river. Down the middle of the river you may notice a softly- flowing current going straight. Along the shores there will be little side cur- rents going in all directions, and you may find some little whirlpools. That is exactly what we should see in the air if we could see air currents. Where Does the Wind Begin? The movement of these currents of air leaves many i)ockets of space where there is no air, and when one of these is uncovered the air rushes in and cre- ates a wind in doing so. These air currents are continually pressing against each other to get some place else. They change their direction ac- cording to the pressure that is being applied to them. Sometimes the pres- sure will be very light in one part of the air, many miles away perhaps, and then the air in another part, which is under great pressure, will rush with great force into the part wdiere the pressure is light, and thus form a big wind. When the pressure stops the wind stops. We have probably felt the wind which comes out of the valve of the automobile tire when the cap is taken ofif to pump up the tire. It is a real wind that comes out. The reason is that the air in the tube of the tire is under great pressure, and when the op- portunity is given to get where the pressure is light it starts for that place with a rush and comes out of the valve a real wind. What Causes the Wind's Whistle ? The whistle of the wind is caused very much like the whistle you make witii your mouth or the noise made by the steam escaping through the spout of the kettle. You do not hear the wind whistle when you are out in it. You can hear it when you are in the house and the wind is blowing hard. When the wind blows against the house it tries to get in through all the crevices, under the cracks of the doors, down the chimneys, wherever it finds an opening. And whenever it starts through an opening that is too small for it. it makes a noise like the steam com- ing out of the si)out of the kettle, provided the opening is of a certain shape. Not all the noises made by the wind, however, are made in this way. The wind in blowing against things makes them vibrate like the strings of a piano or violin, and when things vibrate, as we have already seen, they produce sound waves, which, when they strike our ears, produce sounds of various kinds. The wind even on ordinary days makes the telegraph and telephone wires hum, as you can prove to yourself by placing your car against a telegraph 140 WHY THE AIR NEVER GETS USED UP or telei)hone pole, ami whenever the wind makes anything vibrate, a great many queer sounds are produced, whicli often frighten us more than they should. Why Does the Air Never Get Used Up? Simply because it is constantly being replenished. The three gases, oxygen, nitrogen and carbonic acid gas, which are found in the air about us, are con- stantly being used up. All living animal creatures are at all times taking oxygen out of the air to live on. Certain mi- crobes are using up quantities of the nitrogen all the time, and the plants live on the carbonic acid gas. But while these different kinds of life between them use up the air, they give back something also. The plants give off oxygen. The bodies of the animals and plants when they die decompose, and as they are full of nitrogen, that is given back to the air in that way, and then all living creatures are always throwing off carbonic acid gas through their lungs, and thus everything that is taken out of the air is put back again. The plants live on carbonic acid gas, and give us back oxygen. The living creatures live on oxygen and give off carbonic acid gas, and when they die their bodies put back in the air the nitrogen which the microbes take out, and so, consumption and pro- duction are about equal all the time. Why Can't We See Air? We cannot see air because it has no color and is perfectly transparent. If at times it appears that there is color in the air it is not the air you see, but some little particles of various sub- stances in it. Sometimes you think- when you look off toward a range of mountains or hills, for instance, that the air is blue. You know the grass and trees on the mountains are green, so it cannot be they that have turned blue, and so you think the air is blue. But it is only the sunlight reflected to your eyes from the little particles of dirt and other substances which fill the air at all times which makes the blue that you see, and not the air. Pure air is a mixture of gases with- out any color and is perfectly transpar- ent. Air is nearly entirely composed of a gas called nitrogen — the remainder being oxygen with a little water and carbonic acid gas, which latter is thrown off in breathing. This is, how- ever, but a very small percentage. Air has been and still can be reduced to a licjuid state, and with the use of it in this form many seemingly wonder- ful things can be done, which are inter- esting to look at, but have not as yet become commercially practical. Why Does Thunder Always Come After the Lightning? This occurs simply because lightning or light travels so much more quickly than sound. Light travels at the rate of 186,000 miles per second, and sound travels only at the rate of 1090 feet ])er second when the temperature is at 32 degrees. Now, the thunder and light- m"ng come at the same time and ])lace in the air, but the light travels so much faster that you see the lightning often quite some seconds before you hear the thunder. In fact, you can tell quite accurately how far away from you the flash of lightning and clap of thunder are by taking a watch and noting the number of seconds which elapse be- tween the flash of the lightning and the time when you hear the roll of the thunder. If as much as five seconds elapse you can figure that it was about a mile away from you, since sound travels only about iioo feet per second and there are 5280 feet in a mile. When the thunder and lightning come close together you may know that it is near b} , and when they come at the same time you may be sure it is very close. \\'hen, therefore, you see the lightning and then have to wait several seconds for the noise of the thunder, you may rest easy about the lightning hurting you, because you know then it is too far away to harm you, and when it is so close that the lightning and thunder come simullaneouslv, there is no use WHY IT IS WARM IN SUMMER Ul being afraid, because if you were to be struck you would have been struck at the same instant or before you would have had time to notice that the light- ning and thunder come together. How Big Is the Sun? It is very difificult to gain a clear idea of how very large the sun really is. We know from the scientists who have m.easured it with their accurate meas- uring instruments that it is 865,000 miles through it, and that at its largest part it is 2,722,000 miles around. Now, you can see why I said it is very dif- ficult to get a clear conception of the sun's size. A mile is quite a long dis- tance to walk on a hot day. Now, the earth is 8000 miles through. If there were a tunnel right through the earth, like the subway, and ^ou started to walk it, it would take you 83 1-3 days if you walked day and night without stopping to rest or eat, if you kept going at the rate of four miles every hour. This would be a long, hot walk, for, of course, the inside of the earth is hot, as we have already learned. It would take an automobile, going at the rate of 40 miles an hour night and day, about nine days to make the trip through such a subway from one side of the earth to tiie other. That makes it look like a pretty big old earthy doesn't it? But let us see what would happen if we started to do the same thing on the sun. The sun is 865,000 miles through. If you were to walk through a similar tunnel on the sun at four miles per hour it would take you 20 years, not counting the stops, and an automobile going 40 miles an hour day and night would take two years and a half to make the trip one way. The sun is ninety million miles frf)in the earth and an automobile travelling at the rate of forty miles j)er hour day and night on a straight road, without stoj)i)ing, wcnild be 257 years in get- ting there. When we stop to think of how big the bulk of the sun is it is altogether beyond us. We have a general idea that our earth is a pretty large affair as worlds go, and yet we cannot conceive how much the bulk of the earth amounts to. Still, the sun is so large that it could contain a million worlds like our own. How Hot Is the Sun? We think the sun is pretty hot in summer when the thermometer goes up to 90 degrees in the shade or out. We begin to get sunburned long before it reaches that high. But right on the stm's surface it is between 10,000 and 15,000 degrees hot. That is, of course, a degree of heat w^hich we cannot con- ceive. How much hotter still it is on the inside of the sun w^e don't as yet know. It must be awfully hot there. Why Is It Warm in Summer? It is warm in summer because at that season of the year the heat rays of the sun strike our part of the earth through less air. The blanket of air which surrounds the earth is very much in comparison as to thickness like the peeling of an orange and surrounds the earth in just the same way. If you stick a pin straight into an imi)eeled orange you only have to stick it in a little way before you reach the juicy part of the orange, but if you stick the pin in at an angle the pin will travel a much longer ways through pure peeling be- fore it strikes the juicy part. Now, then, in summer the rays of the sun come down to us straight through the peeling of air, and less of the heat is lost by contact with the air, and that makes it warmer in summer. The ex- planation also accounts for your next question. Why Is It Cold in Winter? In winter the heat rays of the sun slriUe at f)ur ])art of the earth at the angle at which you stick the pin into the orange when you wish to make it travel through the most peeling. In 142 WHY WE HAVE FINGER NAILS winter the rays strike the earth at sueli an angle that a ' r iBb ,^,^, ,,::«,. FACTORY BEET BINS FILLED TO CAPACITY. As they arrive by rail from receiving stations, or by team, or traction engines from the farm, beets are stored in bins or sheds, the capacity of which ranges from 6000 to 35,000 tons per factory, depending upon location and general climatic conditions. The bins are V shaped, about 3 feet wide at the bottom, 20 to 30 feet at the top, and they are 20 to 30 teet high. As beets are needed, beginning at one end of the bin the loose three-foot planks at the bottom are removed one at a time, and with hooks attached to long poles the beets are rolled into the fiume or cement channel below, in which they are floated into the factory. This is not only to save labor, but to loosen up the dirt which attaches to the beets, thus partially washing them. The water which is used in the flumes is warm water from the factorv. TYPICAL AM ERIC AX BEET SUG.\R FACTORY. These factories cost from half a million to three million dollars. They consume from 500 to 3,000 tons of beets per day, and during the "campaign," which usually lasts about three months, will produce from 12 to 75 million pounds of granulated sugar. There are 73 of these factories, located in 16 States, from Ohio to California. Buring the operating season they give employment to from 400 to 1000 men each. WASHING THE SUGAR BEETS 149 CHEMICAL LABORATORY. In termed beet-sugar factory each set of apparatus for performing a given process is "station." In the chemical laboratory the juices and products from each station are tested hourly to check up the correctness of the work and to determine the losses of sugar in each process in the factory. After beiriK floaterl in from the sheds the Itccts are elcv.iteil from the tlimu' t.i a wasltcT, where they are given an afWitional washing before being sliced. From the washer they are elevaft'd and dropped into an automatic scale of a capacity of 700 to 1500 pounds. From the scale they pass to the Blicers, where with triangular knives they are cut into long, slender slices, which look something like "shoestring" potatoes. '1 hesc slices drop through the upright chute seen at tlic right siped sense of smell than others, 'i'iie lower animals have a much keener sense of smell than people. A great many of them can follow a trail for miles merely by the smell of the foot-prints, and it is said that a deer will note the pres- ence of man or any other animal that may subject him to danger even when miles away, the odor being carried to him through the air. How Do We Taste Things? The sense of taste is closely asso- ciated with the sense of smell. In fact we do a good deal of what we think is tasting by using our sense of smell. A cold in the nose will some- times destroy almost altogether the taste of food, so that there is a very close connection between the sense of taste and the sense of smell. The sense of taste comes to us through the tongue, which is the prin- cipal organ of taste. The remainder of our sense of taste lies in the surface of the palate and in the throat. As in the case of the other senses, the sensation of taste is given us through nerves, the ends of which are all through those parts of the tongue, the palate and the throat, which con- tribute to this sense. More nerves of taste are located in the back part of the tongue than on the front, and it is said that when you have to swal- low a bad dose of medicine it won't taste so much if you put it on the front part of your tongue and then swallow, because there are so few tasting nerves there. The extreme tip of the tongue, however, is very thickly covered witb the ends of the taste nerves. In like manner one could have the front end of the tongue cut ofT and still retain most of the sense of taste. Now, in order to ])roduce tbe sen- sation of taste, the substance to be tasted nuist come in contact with something whicli mixes with it and causes the sensation of taste. This is wbat liappcns wlicn we tasti" any- tbing. Tbi' juices or li(|uids wliich are caused to How wlien anything is put into tbe moutli act on the sub- 156 HOW WE SEE THINGS stances which enter and give the taste nerves a chance to taste them. Really the nerves of taste are so jjlaccd in the mouth as to be regular guards or in- spectors of what shall go into the stomach. You can see how well they are arranged. In the tip of the tongue quite a few of them ; in the hack ])art of the tongue a great many nerves, for from there the food goes into the throat, which delivers it to the stomach ; then those in the palate and in the throat. They are arranged so that the laste nerves have ample opportunity to test what comes in and to give warning to the brain of vvhat is being sent to the stomach. Sometimes the things that come into the mouth are so distasteful to the nerves of taste tiiat they refuse to hand it over to the stomach, but instead cause the dis- tasteful substance to be thrown out again immediately. It is said that a good rule to follow in eating Avould be to swallow only such things as are pleasing to the sense of taste. On this principle many children would decide to eat nothing but candy, but do you know, if you tried that, the continuous tasting of sweets by our sense of taste nerves would cause them to repel further in- sertion of candy after a while. You know that too much of a good thing is bad for you, and that is what makes you feel badly when you have eaten too much of one thing. What Happens When We See ? Of course, it is the eyes with wdiich we see things. When we think of the things with which we see, we think only of eyes, which give us our sense of vision, but there are certain forms of animal life which have no eyes but which have what are called eye spots or eye points, which are sensitive to light and which are merely spots. These eye spots may be located in any part of the body, and are often found in great numbers on the same body. These rude eyes are, however, not real eyes. They are, as has already been said, sen- sitive to light, but are found only in some of the very low forms of anima'l life which live in the water. A real eye is an organ in which the ])arts are so arranged that oi)tical images may be formed. As animal life becomes developed to a higher scale, the parts which contain the making of real eyes become more distinct although, of course, the eyes themselves are not so highly developed as in man. One of the hrst kinds of li f e which has eyes with a definite struc- tural character are the worms, snails, etc., though their sense of vision is more or less dim. When we come to the family of mol- lusks, however, low down in the scale of life though they are, we find them to possess eyes which enable them to see almost as well as animals wdiich have a backbone, although this kind of eyes is constructed in a very different manner than the eyes of vertebrate animals referred to. As we ascend "the scale of animal life in the study of eyes, we come next to the crustaceous, which is an important division of animal life that embraces the crabs and lobsters, shrimps, crawfish, and insects such as sand-hoppers, beach-fleas, wood-lice, fish-lice, barnacles. The eyes of such animals are quite developed, but the number that each will have varies. Some have only a single eye and others two, four, six or eight, but only cer- tain kinds of this class of life have more than two eyes. The spiders generally have the most. In vertebrates, which is the class of animal life to which we belong, the number of eyes is almost always two and no more. The eyes are formed in special sockets in the skull, which are called eye sockets or orbits. This ar- rangement of placing them in a socket is of great advantage because the eye is thus protected from chance of in- jury except from one direction — the front. These animals have also eye- lids, eyebrows and eyelashes, which serve as a further protection to the eyes. The principal parts of the eye are arranged in a globe-like ball called the eyeball. This eyeball is movable WHAT ENABLES US TO HEAR 157 in the socket under control of various muscles. The eyeball is almost sur- rounded by a membrane which is opaque in most parts, but very transparent at the front. This transparent portion of the surrounding membrane is called the cornea, and is quite hard. This is the outside coat of the eye. The second coat of membrane consists of parts of various names and contains the iris. The third coat is the retina, which is the end of the optic nerve entering the eye full from behind and expanded into a membrane which spreads out over the second coat. The retina or optic nerve receives optical impressions focused upon it by the crystalline lens. These impressions are carried along the optic nerve to the brain, and the brain then receives the sensation of seeing the image. The eye- ball is hollow, and its three surrounding coats form what is practically the same as the interior of a camera. The crys- talline lens of the eye acts the same as the lens in the camera. This crys- talline lens is suspended within the eye- ball right in front of the transparent oj^ening in the front of the eyeball, and when the rays of light strike this lens it focuses them on the retina, which is the same as the film in your camera. Why Can We Hear? We can hear because nature has pro- vided us with a very wonderful organ called the ear and which catches the sound waves that come through the air into the ear and make a part of the ear vibrate. In man and mammals the ear is gen- erally found on the outside of the body, but the jjrincij^al part of the ear is lo- caterl within the skull. W^hat we call ears are only the funnel-shaped exten- sions on the outside of the head which are not so very important so far as licaring is concerned, because they only help the real car to hear more easily. The outside of the car gathers in the sound waves and, because it is much larger than tlie little hole which takes the sounds in to the real ear, v.e can detect more sounds by having this funnel-shaped arrangement on the outside. The inside of the ear contains an ear- drum or tympanum which is separated from the outside part of the ear by a membrane. Behind this eardrum is the real hearing part of the ear in a laby- rinth containing the nerves of hearing. Now, when a sound wave strikes the membrane which hangs over the open- ing before the eardrum, the mem- brane vibrates and transmits the sound wave through the eardrum into the inner ear which contains the ends of the nerves by which we hear. These nerves, on receiving the sensation, transmit it to the brain which thus re- cords the impression of sounds. As we descend the scale of animal life from the mammals downward, the ear becomes a more and more simple organ. In the vertebrates which are not mammals, there is no external ear at all, and we find great simplifications of the ear the lower down in the scale we go. What Is a Totem Pole For? Before people had individual names, the savage people who lived in clans or tribes referred to themselves in the name of some natural object, usually an animal which they assumed as the name or emblem of the clan or tribe. These names never applied to one in- dividual more than another, but only to the clan or tribe, so that everyone in a tribe which had taken the "wolf" for its emblem was known as "Wolf." Later on they began to distinguish in- dividuals by giving them additional names characteristic of the individual, such as "Lonely W^olf," "Growling W^olf," or other names. The name of this animal was then the emblem of one tribe. They, therefore, placed this em- blem upon their bodies, their clothes, utensils, etc. Through this, these em- blems also l)ecame at times idols of worship and so they erected poles upon which their emblems wore engraved, 'ihe word totem is a Nortii Anu'rican Indian word meaning "faiuily token." The tribes called tlu-mselves after an- imals from which they believed them- selves descended. 158 WH\ FLOWHRS HAVE PERFUMES Where Does a Flower Get Its Perfume? Tlie perfume or smell of the flower comes from within the plant itself. The perfume arises from an oil which the plant makes, and just as there are many kinds of flowers, so almost every flower has a different smell. Of course, flowers helonj^ing to the same family or sjkxmcs are likely to develoj) different smells. The oils produced are what are known as the volatile oils, which means ''flyins^ oils," because, if extracted from the flower and placed in a bottle and the cork left out, they will vanish into the air. \\'ithout this quality we could not, of course, smell them at all. Why Do Flowers Have Perfumes? Man uses these oils to provide him- self with perfumes, but the plant or flower has another purpose than this. The perfume is not made for man's use, but for the use of the plant itself. In the plant and flower world the smell of the plant which is in the flower is a part of the scheme whereby plants re- produce themselves. Every plant in order to reproduce it- self must produce a seed. The flowers are in most cases the advance agent of the coming seed. I'^ach flower produces within itself a little powder called the pollen, but as plants are like people — also male and female — they are depen- dent upon each other for the production of a perfect seed. Some of the pollen from the male plant must be mixed with the pollen of the female plant before a perfect seed results. How Do Flowers Produce Seeds? Naturally, the nearest male plant to a female i)lant may be quite some dis- tance oft'. How, then, is the pollen from the male plant to mix with the pollen of the female ])lant? In some cases it is the wind which blows the pollen pow- der from one to the other, and this thus leaves the development of a perfect seed from a perfect flower open to chance. In the case of ]")erfumed flowers, however, wdiich are mostly low- growing plants, the wind cannot be depended upon. So nature gives to such plants the ])Ower to make the per- fumed oil and the busy bee does the rest. The perfume being a flying oil rises up into the air and attracts the bee. He is gathering honey and visits in turn all the flowers to which he is attracted. He lights on a male flower and gathers in his honey, and inci- dentally accjuires on his legs, without intending to do so, some of the pollen of the male flower. Then he flies about to the next flower, and to others, and sooner or later he will come across a female flower of the same kind as that from which he secured the pollen on his legs. When he thus enters the fe- male flower, the pollen on his legs mixes with the ]iollen of the same kind of the female flower, and quite unin- tentionally the l)ee hel])S thus to make the ])crfect seed. It is not a part of a bee's business to do this carrying. It only happens that he does this in con- nection with his regular business of gathering honey. It is a wonderful thing which may be noted here that the pollen from a male of any flower will not mix with the pollen of the female of any other kind of flower, but that the same kinds only have attractions for each other. Flowers are given these attractive perfumes in order that they may attract the bees and other insects in this way. The plants or flowers which grow closest to the grounrl have generally the strongest and most far- reaching smells. This is so that they will not be overlooked. Why Are Leaves Not All the Same Shape ? Leaves are of different shapes be- cause they belong to different families of plants or trees. They are a good deal like people in this respect. Hardly two people in the world look exactly alike, but there is a distinct family re- semblance in members of the same fam- ily. It is difficult to say just what hap- pens inside the tree to determine the shape of the leaf and that causes them to possess different shapes from others. The shape of the leaf is a mark of identification of the familv to which the WHY SOME RADIATORS ARE LONGER THAN OTHERS 159 tree or plant belongs, just as you can tell from a dog's ears and from other characteristics what his breeding has been. In the case of plants and trees however it is quite probable that the shape and texture of the leaves has been developed as the result of the condi- tions under which the plant grows. A plant or tree throws off oxygen and takes in carbonic acid gas through the surface of the leaves. To tlirive and be healthy is must secure just the proper amount of this food and as the quan- tity of food taken in depends upon the amount of surface exposed through the leaves, each particular tree or plant has developed in its own direction in this respect until this feature of their struc- tures has been adjusted properly to their needs. It is a good deal like the radiation of heat in your home. Why Are Some Radiators Longer Than Others ? When the plumber gets ready to put in the radiators in the home he figures the cubic measurements of the room and then puts in a radiator, the outside sur- face of whose pipes, is in the right proportion to throw oflf sufficient heat to fill the room or heat all the air in the room. It requires a certain num- ber of square inches of radiator surface to heat each cubic foot of air space and a good plumber can figure this to a nicety. If he puts in a radiator how- ever that has not sufficient number of square inches on the outside of the pipes, the room will not be heated prop- erly. ' In the same way, the trees, re- quire that their leaves have a certain amount of square inches of surface space in proportion to the size of the tree, to enable them to do what is re- quired of them and this is arranged by nature so that the trees grow naturally, and no doubt the shape of the leaves hns something to do with this. What Makes Roses Red? All roses are not red. Some are white and others pink or of still another color. The color of the rose, and in fact the color of all flowers is flue to the way they absorb and reflect the sun- light. In the case of the red rose, the something in the plant that determines the color, absorbs all the other colors in the sunlight and reflects the pure red rays and that makes the color of the red rose. You cannot see the color of any flower when it is perfectly dark. That is because they have no color of their own, but only the colors which they reflect when in the sunlight or some other light. The question of col- ors is more fully explained in another part of the book. Why Do Plants and Trees Grow Up Instead of Down? As a matter of fact plants and trees do grow downward as well as up. There is a part of each called the root whose business it is to grow down and take certain things necessary to the life of the tree out of the ground. But the part we see above the ground and which is the part we generally think of only when we think of plants or trees. The tree or plant, in order to grow properly, and eventually produce flow- ers and perfect seeds, must have sun- shine and carbonic acid gas, and it is the business of the leaves and other parts above the ground to get these out of the air for the good of the plant or tree. So they start to grow toward the sun. It is easy to prove how a plant will turn toward the light. Take notice of the plants in the flower pots at home. Set one of them on the window sill inside the window where the sun can shine on it and notice how quickly the leaves and branches will be bent over against the window pane. Turn it com- pletely around tlien so that the plant leans away from the sunlight and watch it for a day or two. Before long you will find that is has not only straight- ened itself completely out but started to lean toward the window glass again so as to get as near the sun as possible. Most plants, if kept where the sun- liglit cannot touch them, will die. The sunlight is a necessary part of their lives. 160 WHAT THORNS ON ROSES ARE FOR What Becomes of the Plants and Flowers in Winter? A f^reat many, in fact the large per- centage of plants, live only during one season. This kind of plant actually dies completely after, in the natural course of growth and flowering, it has pro- duced its seed which is the method by which such plants are reproduced. Other plants only appear to die in the winter. Parts of them, such as th« leaves and flowers actually die, but the roots and stalks of such jilants do not die in winter. The part that represents the life in them goes to sleep and lies dormant until the light and warmth of summer bring forth the leaves and flowers again. The flowers, however, always die and the same flowers never appear again but others just like them appear in their places. Even in hot countries where there is no winter, the plants must go through a period of rest or sleep, although this change is not so marked in plants which grow in these hot countries. How Can Some Plants Climb a Smooth Wall? To get at the answer to this question. we should pick out one kind of plant like the creeping ivy vine. If we examine same as it climbs a brick wall, w^e find that it sends out little shoots which at- tach themselves around the little rough places in the bricks of the wall which, if examined under a microscope are quite large apparently — at least they are large enough for the tiny creepers of the ivy to hold on to. Of course, if there were only one little "shoot" to reach out and take hold of the rough spots in the wall, the vine could not cling to the wall, but the vine puts out a great many of these shoots — which it would perhaps be best to call "dingers" and as each helps a little to hold on, the great number all holding on together enable a quite heavy vine to hang on to an apparently smooth wall. Some vines have actually the ability to send out little suckers which are made on the same principle as the boys' sucker (a circular piece of leather with string attached to the middle with which a boy can pipk up stones) and such plants can cling to and climb up an almost perfectly smooth wall. What Are the Thorns on Roses and Other Plants Good For? The thorns of roses and other plants which have thorns originally grew for the purpose of enabling the [)lants to fasten themselves on to other things thus helping them to climb. Many plants with thorns are permitted to grow now in places where they can use their thorn > for climbing but many others with thorns are cut down by the gardener to make the plants shapely and to make them produce more flowers and less branches, but they keep on growing their thorns just the same. Do Plants Breathe? Yes, indeed, j^lants do breathe. To breathe is just as important to the life of a plant as it is to a boy or girl. Plants do not have lungs like boys and girls and grown up people, but they find it necessary to breathe. You know, of course, that fishes breathe, but they haven't any lungs either, even though they belong to the animal kingdom. Fishes do not, however, breathe the air in the same form as we do because they must use the air which they find in the water. That is why we say fishes drown when on the land. They cannot breathe air in the form in which we are able to use it any more than people can breathe the air in the water. I'reathing, however, is necessary to all living things and the gas which we take in when breathing is oxygen. There is oxygen in the water as well as in the air. Things which live in the air take their oxygen out of the air and things which live in the water get their oxygen out of the water. For this purpose it is necessary for plants and animals that live under the water to have a breathing apparatus especially adapted for getting oxygen out of the water. WHY MILK BECOMES SOUR 161 What Happens When Breathing Occurs ? The act of breathing consists really of two actions. Taking something into the body and expelling something. Every living thing inhales and expels in breathing. We take in oxygen and expel it again but when it comes out it has added something to it and the com- bination or result is carbonic acid gas — so we take in oxygen and expel carbonic acid gas. How Do Plants Breathe? The lungs of a plant, or what the plant breathes with corresponding to our lungs, are located in the leaves of the plant. Under a magnifying glass we can see the lungs of the leaf quite clearly. In addition to this we rcnow that plants breathe, because if we put them in a vacuum where there is no air they die very quickly. The plant needs air or it will suffocate just as any ani- mal will suffocate under similar con- ditions. Plants, however, do not make use of the oxygen as they find it in the air. They live on the carbon which they find in the air mixed with oxygen. \\'hat happens then is this. The plants take in through their lungs in the leaves carbonic acid gas from which they take the carbon and use it as food, and throw off the oxygen which they cannot use. Human beings and other animals take the oxygen into their lungs and use it and c.xpel carbonic acid gas. The resuit is that each kind of life is dependent upon the other. If it were not for the ]*lant life, men and other animals would finfl it difficult perhaps to find sufficient oxygen in the air to keep them alive, and if it were not for the carbonic acid gas which the animals throw off, plants ann other vegetable life would have great difficulty in finding sufficient carbonic acid gas to go around. Why Do Plants Need Sunlight? Most plants, if placed where no light from the sun can reach them, will die very quickly. To prove that a plant needs the sunlight we have only 1o j)lace it in a flark corner of the cellar and notice how soon it dies. In fact if it were not for sunlight there would be no life on earth at all. The plant or tree drinks in sunlight through the sur- face of the leaves. In fact the ability to take in sunlight constitutes the real life of the tree or plant. Leaves grow thin and flat in order that as much sur- face as possible may be exposed to the sunlight. If a leaf were curled up like a hoop only a part of the outside sur- face would be exposed to the sunlight and the amount of life that a leaf could supply to the rest of the tree would be much less. The leaf is so constructed that when the sunlight strikes down upon its green surface, it changes the carbonic acid gas which it drinks in, into its elements, i.e., it takes out the carbon which goes into the body of the plant and combining with other food and water supplied lay the roots causes the plant or tree to grow and then re- turns the oxygen part of the carbonic acid gas to the air. Why Does Milk Turn Sour? The milk turns sour because a little microbe, known as the milk microbe gets into it, and being very fond of the sugar which is in the milk, turns this sugar into an acid. If we could keep milk entirely away from the air after the cow is milked, it would not turn sour, but as soon as it is exposed to the air these microbes which are constantly in the air, drop into the milk. They are alive, although invisible to the naked eye. If when they drop into the nn'lk it is warm enough for them to get in their work so to speak, they fal.l upon the sugar in the milk and turn it into the acid. Their attempt to sour the milk can be over- come by kec|)ing the milk at a low tem- perature in the refrigerator, but as soon as the milk is taken 'ptian civilization. Stone carvings made when Eg}'pt was yet unborn were reproduced in rugs. At what period the loom was first used is impossible to tell. An ancient Jewish legend claims that Naamah, daughter of Tubal-Cain, was the in- ventor of the process of weaving threads into cloth. There are other in- dications that the ancient Hebrews were the first weavers. Mythology also tells of beautiful maidens weaving exquisite patterns for the gods. Most of us are familiar with the story of Jason who set sail on the Argo in search of the Golden Fleece, arrived at the kingdom of Aeetes, won the hand of Medea, the daughter of Aeetes, who eloped with him after he had secured the coveted fleece. The first hands busy at the weaving craft undoubtedly were those of women. Chaldean gossip, repeated in history relates that Sardanphulees, an ancient Greek king, was often seen in woman's garb carding purple wool from which his wives wrought rugs for floor coverings for the palace. Homer shows Helen of Troy setting the tale of her people's war in the woof of her web, and also tells with Virgil of rugs that were laid under the thrones of kings or upon chariot horses. Ancient Hindu hymns show that these people made their textile fabrics studies of great beauty. The woman in the Prov- ♦Pictures and descriptions by courtesy of Hartford Carpet Co. WHAT THE DESIGNS IN RUGS MEAN 163 erbs of Solomon says : "I have woven my bed with cords ; I have covered it with painted tapestry from Egypt." One learns from the writings of Pliny of the large money value of rugs in ancient times. He wrote at length of a vast rug displayed at a banquet of Ptolemy Philadelphius, the value of which was placed at a fabulous sum. A later writer tells of the love of Cleopatra for rich rugs and tapestries that were woven in her palace or in the countries to the East. On the oc- casions of her meeting with Caesar and Antony, the Eg}^ptian queen enveloped herself in a superb rug which she had woven especially for the purpose of showing her renowned beauty to the best advantage. Akhar, emperor of Hindostan, spread a knowledge of the art of weaving throughout India. The earlier phases of the art of weaving may be traced through the land of the Pharaohs to Northern Africa, Southwestern Asia, and finally into the dawn of the Aryan civilization. The loom has not been materially changed, and it may be seen to-day as it was in the time when the priests of Heliopolis decorated the shrines of their gods with magnificent carpets and when Delilah wove the hair of Samson with her web and fastened it with a wooden pin. The ancient weavers at- tained high artistic standards in their fabrics. Pliny tells of Babylonian couch covers that had all the beauty of paintings and sold for great fortunes to the ancient Asiatic kings. In all ages fine rugs have been used for religious purposes. Early writings describe the use of rugs on the holy cars of pilgrimage to Mecca, at the tomb of the prophet at Medinah and throughout the mosques of the Orient. The aljbot Egelric gave to the church at Croyland, before the year 892, two large rugs to be laid before the high altar on great festivals. At later pe- riods rugs were used for similar ])ur- poses in the cathedrals of Southern Europe. The Oriental people ever have been devoted to symbols and naturally wove them into th<'ir fribrir^:. Their t('xtflc<^ were made to reproduce mythological stories in which the fauna and flora of a country figured prominently. There was the symbolism of form, color and animal life, of trees and flowers, of faith, and earthly and heavenly exist- ence. The symbols were made to illus- trate the conflict between light and darkness, the evolution of hfe, the decay of death and the immortality that awaits the blessed in paradise. What Do the Designs in Rugs Mean? Since many of the figures of ancient rug-weaving are retained in modern rug designs, the following list of meanings of ancient Oriental symbols used in rug-weaving may be interesting as a key to the stories that are said to ap- pear in many rugs of Oriental design : Asp — intelligence Bat — duration Bee — immortality Beetle — earthly life Blossom — life Boat — serene spirit Butterfly — soil Crescent — celes- tial virgin Crocodile — deity Dove — love Eagle — creation Egg— life Feather — truth Goose — child Lizard — wisdom Palm tree — im- mortality Sail of vessel — breath Wheel — deity Lion — power Ass — humility Butterfly — benefi- cence of summer Jug — knowledge Ox — patience Hawk — power Lotus — the sun Pine-cone — fire Zigzag — water Leopard — fame Sword — force Serpent — desire Bird — spirit Owl — wisdom Pig — kindness Such are the traditions that the makers of modern rugs must live up to. The art of the centuries has been revealed in the rugs of many nations, and the rug-maker of to-day must up- hold the standards of an art that un- doubtedly takes rank with the great arts. Wliere a valuable painting goes into the home of one millionaire, thou- sands of rugs made from an original design of un(|ueslioned art and beauty go into homes the country over to give warmth, comfort and beauty, delight- 164 HOW OUR GRANDMOTHERS MADE RAG CARPETS ing housewives and imparting a sense of coziness and elegance. According to students of the art of weaving, the perfection of this art was attained about the sixteenth century, after many centuries of slow growth'. Since then weaving as an art has been broadened and given a wider scope by means of processes invented for a cheaper production of rugs in all the beauty of their original designs. But there also has developed a modern school of rug and carpet designing that at a range of prices within the financial reach of people of modest means. It is only a step from the ancient weaving of rugs, with all the color, glamor and romance that attached to rug-weaving in the ancient days, to the manufacture of rugs in America to-day. There is no romance attached to the making of rugs and carpets in America, except the romance of industrial achievement ; but the American rug- maker is as careful of the quality anrl beauty of his product as was the M.^KING THE OLD RAG CARPET. in itself represents no mean standard of art. Many of the less expensive grades of American rugs and carpets, for example, are of designs created by artists of this modern school of weav- ing designs whose work is of a high degree of artistic excellence. A quarter of a century ago many homes had rugs woven by the house- wives with their spinning-wheels, or no floor coverings, except crude cloths made of rags. These homes, of course, were those of families in moderate cir- cumstances, wliich to-day can have their attractive and comfort-giving rugs of the less expensive grades of tapestry carpet, Axminster or of the various other grades of carpet manufactured ancient weaver, and the best standards of ancient weaving have been realized in the manufacture of rugs and carpets in America to-day. Why Did the Ancients Make Rugs? It is only a rug, several yards of woven threads, a design that few can understand — a simple thing, to be sure ; yet what a lot of history and memories and traditions it carries ! Merely a strip of carpet, with strange figures, beautiful though meaningless, a prod- uct of modern invention like many another, some may think. But the story of a rug may go back through many centuries to ancient times of opulent WHY SOME RUGS ARE SO VALUABLE 165 splendor, when wars were waged and kingdoms created and shattered for the beauty of a woman ; when gorgeous palaces were raised and great spectacles of art were shown to inspire the world for thousands of years. Only a rug, but a relic of a rich and glowing past ! For in those distant days of war and pageantry, an era more classic than our own, history and ro- mance were woven into the rug. The patterns and designs told great stories of wars and loves that swept nations away and created great new empires and related vivid accounts of intrigue and tragedy that determined history and inspired the immortal works of poets and dramatists. The rug in the ancient times was also used for re- ligious symbolism, and sacred doctrines were inscribed in the woven figures. Of all the arts none has been as close to the lives and history of the peoples of the earth as the art of weaving. Songs and stories of these peoples and their national achievements have been immortalized through their woven fab- rics. Generations have learned of the great deeds of their forefathers through the historical accounts woven into rugs. And in the days of the early Greeks, Hebrews and Egyptians and on through the succeeding centuries until the middle ages the rug was used as a symbolical part of state, religious and romantic ceremonies. What Makes Some Rugs so Valuable? The reason many rugs are valued at so high a price in money is largely due to the skill of the artist or designer, just as a painting becomes valuable be- cause the artist who painted it has succeeded in producing a remarkable result. The question of rarity also enters largely into the value of rugs. The great artist weavers of the past who worked for love of their art rather than for the money they might secure by disposing of their masterpieces, are dead, and they have had no successors. Then, also, the rug becomes valuable by reason of the amount of time and labor put into it. Many valuable rugs take years to produce, because the artist must do all his work by hand prac- tically and tie his different colored yarns together just so, or the pattern will not come right. These knots may occur every inch or sometimes even less than an inch, and there will be thousands of hand knots in one rusr. MAKING TURKISH KL'GS. 166 THE OLDER THEY ARE THE MORE HIGHLY PRIZED Tu^ nh^vp U a tvnical Chinese rue, containing symbolical emblems. ?hLt an an?ique and is of a class that sells sometimes as high as $5,ooo, its rar,ty of design, beauty in colors, and scarcity enhances its value. This is .„ American maCine-made '"^^r.r^n^ ?eS'Sa™a^k S'.l-ir'h i's WHERE THE BEST PERSIAN RUGS ARE MADE 167 This antique Persian was made in the district of Kurdistan, in Western Persia. The general effect is handsome, although the design is crude. The ground is of a deep rich red, and top colors of d^rk blue and ecru. The most valuable Persian rugs come from Kurdistan, Khurasan, Peraghan and Karman. The most highly prized come from Kurdistan. The pattern does not show a uniform ground of flowers or other objects, but looks more like a field of wild flowers in the spring, which is very appropriate as a design for anything that is to be walked upon. It is astonishing what wonderful artistic ability is displayed by some of the members of these wild nomadic Persian people. The carpets and rugs are woven on a simple frame on which the warp is stretched. The woof, or cross threads, consist of short threads woven into the warp with the fingers and without the use of a shuttle. Then a sort of comb is pressed against the loose row of cross threads to lighten it. The weaver sits with the back of the rug towards him, do that he depends entirely on his memory to produce a perfect pattern. ^b ^^Tf^ <<\\ $^\^? %^-^ ^^' .^fr\^ '4^ iiP \\\4 \w \\i4 w" '^ Khi* "^i^j ; ; - :*r > o : .«> « -:*-•- ft ^"*> « -- * .> <* -s ;«t s. « -s * S '\ \ ; \y ^,}:n-i> On*- KJ-nHV HhW ^n-W* . ,^ S.i3 oj f!L ■£"■-* ^ U- ■*-» ^,* — 1^ p -3 o ^ 5 £ >, "^-^ rt +^ rt u <« o *-'rt'C..o3j^jjF'"";4^0 ' ::; tA -r-. c _ rt — ri .^ ^ -E r- 1- -n SOME DESIGNS STAMPED ON YARN BEFORE WEAVING 173 Jacquard motion of cards each color wanted in the surface of the rug is pulled up in its proper place, the other frame color laying in the back of the rug. The mechanical process is a re- markable sight. As the pattern forms itself from the mechanical devices, the onlooker is struck with the wonder of it. The weave is now completed ; the rug comes out. But it is rough and has to be finished. It is passed through a ma- chine that removes the roughness of the face as a lawn-mower cuts away tlie top-grass. The ends are finished, and the carpet is complete. The pattern of tapestry carpet is obtained by printing the colors to ap- pear in the design on the yarn which forms the face before the weaving is started, by means of large drums. After all rugs leave the weave-shop a force of skilled women examine them care- fully to make sure that there are no defects. Every yard of the annual out- put of carpet and rugs is inspected five times before it leaves the factory. n ■ 1 ^^Mr ijlHS 1 mm LJ9'^ 1 E L^ m EXAMINING AND REPAIRING PACKING FOR SHIPMENT Why Do I Yawn? When you yawn, you do so because you have not been breathing quite prop- erly and for some reason or other your blood supply has not been getting suffi- cient oxygen through the air which has been taken into your lungs. Nature's way, in this instance, is to call for a big intake of air all at one time, and since it is important at such times that a large quantity of air should be supplied to the lungs at once, nature has so arranged matters that certain muscles shall cause you to open your mouth wide and take in as much air as you can at one time, and also has arranged so that it is almost im- possible to keep from yawning when the demand for it is once made.. The yawn is controlled by a part of our nerve structure which looks after the breathing apparatus. The satisfaction we feel after a wholesome yawn is due to the fact that having replied to nature's demand that we bring in more air, our blood secures the oxygen which it needs and we feel the effect of better blood in our arter- ies at once. A peculiar thing about the process of yawning is that one person in a room yawning will quite likely set all or nearly all the others to yawning also. There seems to be no explanation of this excepting that when a number of people arc in one room and one of them begins to yawn, the others do so, not because tliey perceive the first yawn so much as the probable fact that the air in the room has l)ecotne so poor that there is not enough good air for all the ]HM)plc in it, breathing normally, and many of them arc forced to yawn at about the same time. 174 WHEN MAN BEGAN TO LIVE Where Do Living Things Come From? This is a big subject, but a very in- teresting one. To understand it fully we must begin at the very beginning of the world. God made first of all the rocks, the mountains, the sun, the moon, the stars, the. soil, and put the w^ater in the lakes, rivers and oceans. This took a long time, but they had to be there before the living things could begin to be. What is Inorganic Matter? This thing we have spoken of is called inorganic matter, wdiich means "without life," and everything in the world which has no life is called inor- ganic matter. These things do not die, and for that reason do not have to be replaced. The form and appearance of inorganic matter and its location is often changed by man or other causes, but even when man burns the coal which he has dug up out of the ground in the furnace, no part of it is de- stroyed. Some of it is turned into smoke and gas and some of it is turned into ashes, while every other particle which went to make up the coal origi- nally is still in existence. It remains as inorganic matter in some form or other. Where Did Life Begin on Earth? After the inorganic things had been made and the earth was ready for life, the different kinds of living things which we find on the earth began to exist. These are called organic objects, which means objects "with life." The first living things to appear were the bushes, the grass, the garden vege- tables, the flowers, trees, and all the kinds of life which we ordinarily think of as growing things. This" division of living things makes up what we call the vegetable kingdom, and in a general way of classing it is the kind of life which cannot move about from place to place and which has not a sense of feeling, or any of the other senses, seeing, hearing, tasting or smelling. After this division of life had been estabhshed the world was ready for the other and more important form of life — the fishes, the birds, cats, dogs, horses, cows, with others that we call domestic animals, and also the lions, tigers, elephants and others which con- stitute the division of wild animals. This kind of life was given sotne or all of the five senses, but not all classes of animal life possess all these senses. Some of the lower forms of animal life, like the oysters, clams, in the fish fam- ily, cannot see, hear, smell or taste. They can only feel ; others are able to do more of these things, and many have all of the five senses. When Did Man Begin to Live? Man was not created until all the other living things on earth had been started, and he w-as given additional ]jowers so that he might become the ruler of all the other living things, prin- cipally because he was given a brain v;ith power to think, reason and origi- nate. Why Must Life Be Reproduced? Life must be reproduced because living things die. They have power to live only for a certain length of time. The other life in the world is used to provide food for man, and if there were no way of reproducing life it would not be long before man had eaten all the vegetables and the animals too, and w^ould himself then starve to death. To avoid such a calamity God put into each living thing, both vegetables and animals, a power to cause other things of the same kind as itself to grow. This is called the power of re- production. With this power each kind of living thing can bring other speci- mens of the same kind into the world and each kind of living thing can do this without aid from any other kind of life. The trees, the flowers, and other kinds of vegetable life would reproduce themselves without the aid of man, as would also the fishes and other kinds of animal life. Man, however, just to have things conveniently at hand, uses his power over other life to cause his WHY PLANTS PRODUCE SEEDS 175 vegetables to grow near where he hves, and keep the animals which he wishes to use as food in some place where he doesn't have to hunt for them every time he wishes meat for his table. This, however, he does only with the animals which he has domesticated or tamed. When he wants meat from the animals which are still wild he must hunt for them as he used to do. Each kind of life has the power, however, to reproduce only its own kind. If you plant a peach stone you will sooner or later have a peach tree which will bear peaches, and these peaches from the young tree will look and taste just like the peach whose pit or stone you planted. There may be other kinds of fruit trees all about, and also trees which do not bear fruit. All of the trees secure the food upon which they live and grow from the same soil. Even the grass under your peach tree eats the same things as your peach tree, but it remains always true that things in the vegetable kingdom will grow only to be like the thing from which it came. Have Plants Fathers and Mothers? The little trees grow up to be exactly like their fathers and mothers (for they have fathers and mothers), which is something all living things must have. These are not the same kind of fathers, or mothers either, that a boy or girl has, exactly, but they are parents just the same. So far as the trees, flowers and plants arc concerned we call the parents father and mother natures, which is a term used merely to keej) you from confusing vegetable life fathers and mothers with the regu- lar kind. In the vegetable kingdom you cannot always see these father and mother natures, which enable them to repro- duce their kind of life, but everything in tiie vegetable and also in the animal kingdom has tbem. How Do Plants Reproduce Life? In tlie s])ring we ])Ut seeds into the ground and later on jilants grow up where the seeds were planted, and later the flowers come. The seeds contain the baby plants, which come to life, and after bursting the covering of the seed, unfold and grow up into plants if placed in the ground, where they can obtain the proper amount of warmth and moisture to give them a start. Why Do Plants Have Seeds? To get at this subject in the best manner we must study first how plants produce seeds and what happens. The power in a plant to make another plant like it grow comes from the flower. Ordinarily we think of the flowers as beautiful to look at and delightful to smell, but the flowers do not grow for the mere purpose of being beautiful, but are for a more useful pur- pose — to develop a seed which, when planted, will produce another plant. The machinery for producing a per- fect seed is in the flower or blos- som. Every flower has a definite plan of construction. The leaves and colors vary, but the plan for a per- fect flower is always there. The petals which are generally colored are called the croivn. When you pluck off the petals you see a number of green leaves at the bottom where the petals were at- tached. These form what is called the calyx, and help to hold the petals in place. Inside the flower are little stems which grow to the petals. These are called stamens. Every one of these little stems is hollow, and if you split one oi)en you will discover a fine poiv- dcr. This ])owder is called pollen, and is the "father" nature of the ]ilant. \n the calyx, the part we had left after we plucked off the petals, is the "mother" nature of the plant. The main part of the mother nature is the stem of the flower called the ovary, and this is where the seeds grow. These seeds in the ovary, however, will not become ]erfect seeds unless some of the ])()llen from ibc "father" nature of the plant touches tlieni and fertilizes them. At the ])roper age of the flower some of this ])()llen powder passes into the ovary and frrtilizes the seeds and makes them good seeds. This is only one kind of flower, however. In this kind the father and mother natures are in the same flower. In other kinds of plants the father and mother natures are found on ihfTcrcnt parts of the same ])huit. Why Does an Ear of Corn Have Silk? riie corn plant is one of this kind, ^'ou know what it looks like — a tall plant, generally six or seven feet high. The ears of corn grow out of the side of the corn stalk. The ear is covered with husks and out of the end of the ear hangs a bunch of brown silk threads which we term corn silk. Up at the top of the plant you will see the tassel, but you may not have known that this is the flower of the corn plant. The tassel or flower in this case con- tains the "father nature" of the corn plant, and the ear of corn contains the "mother nature." The husks on the outside of the ear of corn protect the grains of corn on the ear inside and keep them tender. The ear of corn is really the ovary of the corn plant, be- cause that is where the seeds grow. You will guess, of course, that the grains of corn on the ear are but seeds of the plant. Were you to examine one of these ears of corn on the plant when it had just started to form you would find no kernels on the cob, but only little marks which indicated where the grains of corn are expected to grow, but if you want to know, then, how many grains of corn were expected to grow on the ear, you could easily tell by counting the little silk threads which you see on the cob and which stick out over the end. There will be a thread of silk for each grain of corn that is expected to grow. Every grain of corn must receive some of the pollen powder from the tassel or father nature at the top of the corn i)lant or it will not develop into a nice large, juicy kernel. How Does the Pollen Touch the Grain of Corn? Before the kernels of corn grow the tassel is in bloom. The wind blows and shakes the pollen powder ofif of the tassel and the powiler falls on the ends of the silk which stick out of the little ear of corn to be. Each thread of silk then carries a little of the pow- der down to the spot on the ear where it is attached and thus the grain of corn receives the fertilizing necessary to develop it into a ripe seed. If you leave the ear of corn alone the kernel will eventually become yellow and hard and can then be planted and will pro- duce other corn plants. Man, how- ever, finds the ear of corn a delightful food, if taken at a time when the seeds are fully grown but not yet ri])ened into perfect seeds. At this stage the grains of corn would not grow up again if jilanted, because they have not yet be- come perfect seeds. Do Father and Mother Plants Always Live Together? We come now to the kinds of plants on which the "father" and "mother" natures are on difi^erent plants of the same kind. At times they will grow side by side, at other times they will be in the same field, but very often they grow at quite a distance from each other. In some instances the near- est father tree will be even miles away from tlie mother tree of the same kind. But in any event the pollen fiom the father nature must reach the mother nature of the plant or tree before a perfect seed can be produced. In cases of this kind the father nature will be on one tree or plant and the ovary or mother nature on another. The wind helps out nature in some of these cases by blow- ing the pollen of the father plant to the ovary of the mother plant. In many other instances the bees and in- sects help. Why Do Flowers Have Smells? \Miere the bees do this it is because the bee has been visiting the flowers in his search for honey. They do not fly from flower to flower for the pur- pose of uniting the mother and father natures of plants, but they help the flowers incidentally while getting the honey for which they are searching. HOW FISHES COME TO LIFE 177 In gathering his honey the busy bee will go all over the father flower and get his legs all covered with pollen pow- der. Sooner or later he comes to a mother flower of the same kind of plant or tree from which he has father pol- len on his legs, and, still bent on gath- ering honey, he incidentally rubs the pollen powder on to the ovary of the mother flower and the fertilization takes place. The wonderful thing about this is that the father pollen of one kind of a plant w-ill not fertilize the mother nature of another kind of plant. To illustrate this, if a bee carrying pollen on his legs from a walnut blos- som visits the mother blossom of a hickory tree the pollen of the walnut \^'Ould not affect the hickory blossom, but would still have the proper effect on the first walnut mother blossom he visited. This is how life in general is re- produced among the plants and trees. Life in the vegetable kingdom has no sense of feeling or any of the other senses, but this kind of life is still true to its own nature and is a wise thing in the plan of creation, because, since all seed will produce only plants like those from which the seed came, man can control the growth of the vege- tables and fruits he needs as food. He knows when he plants corn that he will get corn in return, because perfect seed never makes a mistake. It would mix things up terribly for man if this were not so, because man might then plant one thing and find another thing growing. It would be a sad thing to plant wheat and find thistles growing. In order that seeds may grow they must be planterl under conditions that suit the kind of vegetable life in the seed. Man has to study and learn what these conditions are. If a seed is planted too deeply the sun may not have a chance to warm the grounrl to that depth, and if it is planted too near the surface it may licrome too wvirm and be killed by the ^un. When planted unrler the proper conditions the seerl soon begins to grow. It grows upward toward the sun to get light and air, and it sends roots down into the ground to get food and moisture. The life in the vegetable kingdom is soon able to take care of itself. How Are Fishes Born? The next step in the study of the reproduction of life brings us to the animal kingdom. The first thing we discover in this section is that in the animal kingdom father and mother na- tures are almost always separated. In plants and trees these parent natures are sometimes in the same flower, often separated, but on the same plant, and in other instances on different plants miles apart. What we must remember, then, is that in the case of plants it is given more or less to the chance of wind or other circumstances to bring the parent natures together. In the animal kingdom there are a few cases where the mother and father natures are found in the same living object, as in the oyster and clam fami- lies, one of the lowest forms of animal life. These have but one of the five senses — that of feeling. This class of animals — the cold-blooded animals — in- cludes the fishes, and in most members of this class the father and mother na- tures are separated and in dift'erent bodies. Step by step from now on we enter higher forms of animal life, and tlirough each step we find a greater dift'erence between the father and mother natures, and in the animal king- dom we speak of the father and mother natures as "male and female." In the animal kingdom, too, what we have previously called the seed is known as the egg. Seeds and eggs are the same so far as their usefulness is concerned, but we say eggs in the animal kingdom to distinguish from seeds in the vege- table kingdom. I'^ish have eggs, then, and it is from the eggs that little fish are born into the world and grow to be of eatable si/c. You recognize the eggs of the fish in the "roe," which is eaten as food. Not all fish eggs are used as food, however. In the iish world the eggs are de- velojx'd in the bodv of the female fish. 178 HOW BIRDS LEARN TO FLY Each little round speck in a "shad roe" is one egg, and there are many thou- sands in a single "roe." Each egg will produce a little fish, under favorahle conditions. These eggs develop in the body of the female fish in winter. In the spring, which is the time in which most living things are born, and, there- fore, the time for hatching out fish eggs, all of the fish swim from the tlccp water where they live in w'inter to the places where the water is shallow and ^^'arm, and in these shallow waters the female fish expels the eggs from her body where the sun can get at them and hatch them by warming them. After the female fish has thus laid the eggs, the male fish swims over the eggs as they lay in the water, and expels from his body over them a fluid which is white in appearance and which fer- tilizes the fish eggs. If any of this fluid fails to reach some of the eggs it is not possible for the sun to bring them to life. When the eggs are laid and fertilized the mother and father fishes swim away and they never see their children or recognize them as such, even if they meet them later in life. The parent fish do not act like other fathers and mothers, and they do not need to, be- cause as soon as a baby fish is born he is able to find his own food and needs no help from father or mother to teach him how to find it or enable him to grow into a real fish. Of course, many of the tiny fish are eaten by other fish and not all the eggs which the mother fishes lay hatch into live fish, because, if they did, the waters would be so crowded WMth fish tl-.at there would not be any room for the water. A single female fish will lay millions of eggs in a year, and if each egg developed into a fish there would be far too many. This order of animals, which includes turtles, frogs, etc.. is the cold-blooded class of animal life. They have only part of the five senses. They all can feel and some of the fishes can see and hear, but a great many of them, par- ticularly those kinds which live on the bottom of the ocean, cannot either see or hear, and some members of the fish family cannot even swim. The thing to remember about fishes in connection with the reproduction of life is that the mother fish must select a place which is favorable to deposit the eggs, but after that her responsi- bility ceases. The father merely fer- tilizes the eggs, and then his responsi- ])ility ceases. The little fish look out for themselves as soon as they are born and never know what it is to have a father or mother to look after them. When we study the next higher form of animal life we find that the young ones have to be looked after, and that this becomes more necessary as we ascend the scale of animal life until we reach man, the most intelligent of all animals and yet the most helpless of all at birth. How Birds Are Taught to Fly. The next step brings us to the birds. Before they can look after themselves the little birds must learn how to search for food and the kinds of food good for them. They have to learn the habits of their kind of life. The higher you go in the study of animal life the greater seem to be the dangers which surround the young animals and the longer it takes to teach them how to look after themselves and what to do for themselves. The bird family includes not only the robins, larks, sparrows and pigeons, but also the ducks, geese, and chickens, etc. W^e are all more or less familiar with birds' eggs, and if not we know what a hen's egg looks like. The eggs of the bird family are laid in nests, which is the first sign of home building in the animal kingdom. The birds are the first of the large class of warm-blooded animals. The egg here represents again the reproduc- tive power. The eggs, too, form in the body of the female bird, but are laid in a nest which the parent birds build together. Now this is the first step away from the fish family. The fish looks for a suitable place to lay the eggs and then goes ofif and leaves them. WHAT MAKES THE HOLLOW PLACE IN A BOILED EGG? 179 The birds, however, have to make a nest in which to deposit the eggs. The fish, as you remember, depended upon the warm sun shining on the shallow water to hatch out the eggs, thus de- pending on an outside force to supply the necessary warmth. In the bird family the mother bird must cover the eggs with her own body and keep them warm until they hatch out. Then, too, the father and mother birds feed the young until they are strong enough to fly and find food for themselves, and so the mother and father birds look after their babies until they are old enough to look after themselves. When this time arrives the old birds cease to bother about the young ones altogether. The fishes never act like parents after the baby fishes are born, because the little fish are able to look after them- selves right away. The parent birds are a good deal like fathers and mothers for a time, but only so long as it takes them to teach their little bird children to look out for themselves. Then they forget the children completely. It requires but a few days and no pa- rental care to hatch out a family of baby fishes and no attention at all after birth. It requires several weeks and much patience for the parent birds to hatch out their eggs, and it involves care and attention for several weeks to teach baby birds to take care of them- selves. This being a father or mother in the animal kingdom becomes a greater re- sponsil)ility in every step as we get closer to man, and when we reach man we find him to be the most helpless oflfspring of all at birth, and that it takes more time, care and attention to bring up a human child to maturity than any other animal. What Makes the Hollow Place at One End of a Boiled Egg? This hollow place on the end of the boiled egg (sometimes it shows on the side) is the air which is jait inside of the egg when it is formed so that the little chicken will have air to breathe from the time it comes to life within the egg until it becomes strong enough to break the shell and go out into the world. There is also food in the egg for him. When you boil the egg this pocket of air within the shell, which would have been used up by the chick if the egg had been set to hatch instead of being cooked for breakfast, begins to fight for its space and pushes the boiling egg back and forms the hollow place. The purpose of the air in the egg is a good thing to remember when we come to study the higher forms of ani- mal life from the standpoint of how they reproduce themselves. The mammals are the next higher form of animals. The babies of this class of animals must be fed for sev- eral weeks or months before they are ready to come into the world. A little chicken is ready to come out of the egg almost as soon as it comes to Hfe, and, therefore, needs only a httle air and food before it is strong enough to peck its way out, but the babies of mammals begin to live months before they are ready to come into the world, and they need a great deal of air and food during this time. This class includes the dogs, horses, cows, cats and all other animals in the Zoo and in the woods. The name mammals means the same as "mamma," and in- dicates an animal which must be fed from the body of a female mammal even after it is born. In this class the eggs are retained within the body of the female animal instead of being laid in a nest or some other place, as in animals of lower classes, after being fertilized by the male animal, so that the baby animal may secure its food and air from within the mother's body after the life within the egg is begun. The mother's body supplies the neces- sary warmth to devcloji the life of the little animal in the egg, just as the birds supplied this with their bodies. In the bird class it only takes a few hours to give the little bird sufficient strength to peck his way out, but in the mammal class it is a long time be- fore the l)al)y animal is strong enough 180 IS A\AN AN ANIA\AL? to come out into the world, ami oven after it is born the babies of niaiunials require a great deal of care and atten- tion before they are able to look out for themselves. During this period the animal secures all of its food from the breast of the mother animal. Another reason why the eggs of mammals are retained within the bodies of the females is the need for ])rotect- ing the young animals from enemies. In the animal kingdom each kind of animal preys upon another kind. They attack and devour each other and are constantly in danger. If, then, mam- n-'als laid eggs in nests and sat upon them to hatch them out, the mother animals sitting on the nests would be continually in danger of attack from their enemies. They would either have to flee and subject the nest and its con- tents to the danger of destruction or else stay and fight, and perhaps be de- stroyed. But by carrying her eg;i^ with- in her body the mother mammal is able to move about from place to place and protect her baby. Is Man an Animal? Men, women and children belong to the "mammal" class of animals. The off- spring of the human family is the most helpless of all animals at birth. The young of most kinds of mammals can stand" on their legs shortly after being born, but the human baby requires n-.onths before it can stand up. A baby horse can also walk within a few hours, but human children do not begin to walk until they are more than a year old. Why Cannot Babies Walk as Soon as Born? The human baby has a great many more things to learn than a horse baby before it is safe for him to go about alone. It takes time for the brain to develop, and if a baby could walk be- fore the brain had even partiallv de- veloped it w^ould only get into trouble. This, then, is what we have learned al)Out liic rcj^roduclion of life and the reasons for its being different in dif- ferent classes of life, l^'irst, we had the division of organic life into the vegetable and animal kingdoms. Life in the vegetable kingdom has none of the Jive senses, for plants cannot see, hear, feel, smell or taste. They camiot move from place to place, but remain where they grow until destroyed or re- moved. ( )n tiie other hand, all animal life has at least one of the live senses — f(.eling. The oysters and clams belon.g to this class. Starting with this level of life in the animal kingdom we find that as we go on up through the dif- ferent classes we find each class able to do things which make it superior to the class below it, until we reach the human mammal, who can do most of all. And, further, that since each class as we go up in the scale of life has greater ability to do things than the class beneath it, so in each case the task of the parents in preparing their offspring for their kind of life becomes greater, and the period during which the offspring is learning becomes longer and longer until we reach the human family, in which we find that parents have the greatest responsibility, and the children are the most helpless of all animals, but that in the final result man has a right, on account of his superior qual- ities, to be the ruler of the other crea- tures of the world. What Are Ball Bearings? Some years ago a gentleman in try- ing to find some way to reduce the friction, which is constantly developed to a certain extent, even when the axle is oiled, discovered that if be- tween the axle and the inside of the hub a circle of steel balls were ar- ranged, so that the hub of the wheel did not touch the axle at all, but rested on the little balls which in their turn touched the axle, that a great deal of the friction was eliminated. This j^roved to be a wonderful invention, and when this combination is arranged and oiled, there is harrlly any friction. WHAT MAKES A GASOLINE ENGINE GO ^. .H - .2 « u S^ X >^ fe Si OJ ^ 5 ^ o E i2 c " .5 '- o •" rt fo i/l o o *J t3 1! ^ C C5 > -^ o \- m rt ij w> fcC C ri "rt rt bi) ^ 4^ C H v~ o ;_ C V-, rt (/I 2 o c V- lU . ' wV J2 •c CJD e J rt rt >> 'ii 'ere scared all the time. This is not because they have no blood flowing through the veins and arteries in their faces, but because their sujiply of blood is less than other people's, and some- times because the walls of their arter- ies and veins are so much thicker than the averai'e that the color of the blood 194 WHAT MAKES US SNEEZE does not show through. There are also many people who have so much hlood in their systems all the time, and the walls of whose arteries are so thin, that tliey look at all times as though they might he hlushing. What Makes Me Blush? An}thing that will make your h.eart send an extra supply of hlood into the arteries and veins which supply your face with hlood, will make you hlush. r.mharrassment will do this. So will anger generally, although sometimes ])t.ojile get so angry that the lilood is driven out of their faces. In this case they are so angry that their heart has stopped heating, practically. What Occurs When We Think? When we think the mind is acting on sensations; it is receiving, in conjunc- tion with memories of sensations it has previously received. Sensations as they reach the mind arouse the mind to ac- tivity and, as soon as the sensation is received, the mind begins to compare the new sensation with sensations re- ceived at i)revious times, and by putting things together reaches a conclusion. When you are thinking you are really trying to call upon memory to help you. You know the thought of one thing calls up another, and this leads to some- thing else. This association of ideas is the faculty which enables us to think consecutively and accurately. It is the business of the mind to receive the sensations that enter it and arrange them in their proper jilaccs. That mem- ory of past sensations is the important part of thinking, is proven by the fact that when we have forgotten a thing we are unable to think what it was. Can Animals Think? For this reason if animals have mem- ory they should be able to think. It is now believed that many animals have to a certain extent the power to re- member. A dog will recognize his master even though he has not seen him for years. We might think he does this by his highly developed power of smell, but if Ins master has come from a direction opposite to that from which the dog first sees him, he could not have tracked him by his smell. A dog will recognize his master from (}uite a distance, so he nnist have to a certain extent the ability to remember or the power of associa- tion of ideas, which amounts to the s;ime thing. Again, a horse that once belonged to the fire department, even though now hitched to a milk wagon, will have the impulse to run to the lire when he hears the lire gong. And an old war horse will i)rick u]) his ears as he used to when he hears the bugle call. Why Do I Sneeze? ^ (tu sneeze sometimes when you Itjok r.p at the sun or at a bright light. There does not seem to be any real good ex- l^lanation of why looking at a bright light should make you sneeze. It is due to the connection there is between the nerves of the eyes and the nose. You generally blink if you look at a bright hght suddenly, and the blinking process stirs the nerves inside of the nose to make you sneeze. You know, of course, that the start of the sneeze is inside of your nose. The nose is, besides being the organ of smell, the channel through which we take air into the lungs, when we breathe properly. The nose is lined with mem- branes, back of which are a net of very small nerves which are extremely sen- sitive. The membranes are placed there to catch and hold the impure particles of matter which come into the nose when we take in a breath of air, and sneezing is only one effective way of cleaning out the nose. It is brought on only when some particularly difficult job of nose-cleaning has to be done. Pepper up the nose will make you sneeze quickly, because pepper pro- duces a very great irritation inside the nose, and the nose goes to work at once to get rid of it in the quickest possible manner as soon as the pepper comes in. Cither things have the same effect. Sometimes a cold in the head causes you to sneeze. The sneeze in that event is merely nature's effort to clean out the nose when other efforts have failed. WHAT MAKES THE LUMP COME IN OUR THROATS 195 There are many suggestions for stop- ping a sneeze before it takes place, after you feel it coming on, such as putting the linger on each side of the nose, and many others. But a half sneeze does not -remove the cause of the sneeze, so it is much better to sneeze it out, and many people enjoy the after effects of sneezing so much that they take snuft' into the nose to produce it. What Happens When I Swallow? The muscles of your throat act in the form of a ring when food passes into your throat. The food does not drop directly into your stomach. In other words, the action is not quite the same as when you drop a stone out of the window. When you do the latter, the stone hits the sidewalk or wdiatever is below at the time, with a smash. It \\ould hardly do to have our food drop into the stomach, so the muscles of the throat are arranged to contract in rings A\hich push or squeeze the food down- v/ard, and the food is passed from one ring of muscles to the other. It is just like pushing a ball down into the foot of a stocking that is apparently too small for it to drop down. You put the ])all in the top of the stocking and then by making a ring of your fingers around the stocking you can push the ball down. When you swallow, you start the muscles of your throat to making these rings. The upper ring squeezes the food on to the ring below it and so on down to the stomach. What Makes the Lump Come In My Throat When I Cry? The "lump" which comes up into your throat when you cry is caused by a sort of paralysis of the rings of mus- cles in your throat. The muscles of your throat can make these rings or waves ui)ward also, but it is more dif- ficult ui)ward than downward — pnjl)- ably because of lack of practice, as we say. When you have put something iiito your stf)macli that makes you sick and causes you to vomit, the throat ruisclcs take the matter from yf)ur stomach and bring it back to the mouth in the same way, except, of course, that this action begins at the bottom. Sometimes when you cry, or lose con- trol of yourself in some other way (you know, of course, that in crying you al- ways lose control of yourself, don't you) practically the same eft'ect is pro- duced as when you have something in your stomach that should come out. Crying, or the thing that happens some- times when we cry, makes the throat muscles act just as if we were vomit- ing, and as the action is an unnatural one, when the ring or wave reaches the top of the throat, we feel the lump or ball as we call it. We feel the lump because the throat has been made to go through the motion of eliminating something in an imnatural way, just as your arm will hurt if you pretend to have a ball or a stone in it, and in throwing the imaginary ball or stone, you put the same force into your move- ments as you would if you had an ac- tual ball or stone in your hand and were seeing how far you could throw it. Why Do We Stop Growing? We eventually stop growing because certain of the cells of the body lose their ability of increasing in size and producing other cells. It is one of the marvels of the construction of the hu- man body that this is so and one of the wisest provisions also. At first the cells of the body crave lots of food and increase in size, divide and then the parts go on growing until they become of a certain size, when they again di- vide and each part goes on growing, etc., and thus we grow. A growing boy needs more food than a mature man, because he needs some of it to grow with, while the man only has to keep what growtli he has going, i. e , alive. We say this limit of growth is a wise pT-ovision of nature because if there were no limit to the size we might be- come, we would not know how large to buil'cept, of course, that there are no hu- man beings to be seen. Instead of birds flitting about the tree-tops, fish swim about them, and where the squirrel and rabbit bound through the woods on Ipnd, the great king crab and sea turtle drag their unwieldy forms on the ocean's bottom. Some of the scenes at the bottom of the sea are like fairyland, and in tropical waters are often as beautiful and spectacular as those we see in theatrical pantomines. Deli- cately tinted sea-shells, great trees of snow-white coral, sea foliage of every tint and shape, and deep dark caverns, in which lurk the devil- fishand other otld looking fish. The Diver's Outfit. The armor of to-day consists of a rubber and canvas suit, socks, trousers and shirt in one, a copper breastplate or collar, a copper helmet, iron-soled shoes, and a belt of leaden weights to sink the diver. -ADJUSTING THE TELEPHONE. This enables the diver to talk at all times to those above him. PUTTING ON THE HELMET. It is made of tinned copper, with three glass-covered openings, to enable the diver to jnok out. TELEPHONING FROM THE BOTTOM OF THE OCEAN 203 TESTIXG THE TELEPHONE. E\ cry precaution is taken to see that everything is in order before the diver goes down. The helmet is made of tinned copper, Vv-ith three circular glasses, one in front and one on either side, with guards to protect them. The front eye-piece is made to unscrew and enable the diver t'j receive or give instructions without removing the helmet. One or more outlet valves are placed at the back or side of the helmet to allow the vitiated air to escape. These valves only open outwards by working against a spiral spring, so that no water can enter. The inlet valve is at the back of the helmet, and the air on entry is directed by three channels running along the top of the helmet to points above the eye- pieces, enabling the diver to always inhale fresh air. The helmet is secured lo the breastplate below by a segmental screw-bayonet joint, securing attach- ment by one-eighth of a turn. The junction between the water-proof dress and the breastplate is made watertight by means of studs, brass plates and wing-nuts. A life or signal-line and also a mod- ern telephone enables the diver to com- municate at all times with those above him. The cost of a complete diving outfit ranges from $750.00 to $1,000.00. The weight of the armor and attachments worn by the diver is 256 pounds, di- vided as follows : Helmet and breast- y.late, 58 pounds ; belt of lead weights, 122 j)Ounds ; rubber suit, i<) ])Ounds ; iron-soled shoes, 27 pounds each. THE FINAL TEST. The least error in the adjustment may mean death to the diver. The air which sustains the diver's life below the surface is pumped from above by a powerful pump, which must be kept constantly at work while the diver is down. A stoppage of the ptmip a single instant while the diver is in deep water would result almost in his instant death from the pressure of the v/ater outside. The greatest depth reached by any diver was 204 feet, at which depth there was a pressure of 88^ pounds per square inch on his body. The area ex- posed of the average diver in armor is 720 inches, which would have made the diver at that depth sustain a pres- sure of 66,960 pounds, or over 33 tons. The water pressure on a diver is as follows : 20 feet 8K' lbs. 30 feet i2.>:; lbs. 40 feet ly^i lbs. 50 feet 21^)4 lbs. 60 feet 26j^ lbs. 70 feet 30K' lbs. 80 feet S4H lbs. 90 feet 39 lbs. 100 feet 43K' ll)s. 120 feet 5234 lbs. 130 feet 56><^. lbs. 140 feet C}0^4 lbs. 150 feet 65^ lbs. 160 feet 6(;X| l])s. 170 feet 74 lbs. 180 feet 7>^ ll)s. 190 feet 82 14 lbs. 204 feet 88'^ lbs. 204 THE GREATEST DIVING FEAT The dangers of diving are manifold, and so risky is the calling that there are comparatively few divers in the United States. The cheapest of them command $10.00 a day for four or five hours' work, and many of them get $50.00 and $60.00 for the same term of labor under water. The greatest danger that besets the diver is the risk he runs every time he dives of rupturing a blood-vessel by the excessively compressed air he is compelled to breathe. He is also sub- ject to attacks from sharks, sword-fish, devil-fish, and other voracious monsters cf the ocean's depths. To defend him- self against them, he carries a double- edged knife as sharp as a razor. It is the diver's sole weapon of defense. Just how far back the art of sub- marine diving dates is a matter of con- jecture, but until the invention of the present armor and helmet, in 1839, work and exploration under water was. at best, imperfect, and could only be pursued in a very limited degree. Feats of Divers. Millions of dollars' worth of prop- erty has been recovered from the ocean's depth by divers. One of the greatest achievements in this line was by the famous English diver, Lambert, who recovered vast treasure from the "Alfonso XII," a Spanish mail steamer belonging to the Lopez Line, which sank off Point Gando, Grand Canary, in 26^ fathoms of water. The salvage party was dispatched by the underwriters in May, 1885, the vessel having £100,000 in specie on board. For nearly six months the operations were persevered in before the divers could reach the treasure-room beneath the three decks. Two divers lost their lives in the vain attempt, the pressure of water lieing fatal. The diver re- covered £90,000 from the wreck, and got £4,500 for doing it. One of the most difficult operations ever performed by a diver was the recovering of the treasure sunk in the steamship "Malabar," off Galle. On this occasion the large iron plates, half an inch thick, had to be cut away from the mail-room, and then the diver had to work through nine feet of sand. The whole of the specie on board this ves- sel — upward of $1,500,000 — was saved, as much as $80,000 having been gotten out in one day. It is an interesting fact that from time to time expeditions have been fitted out, and companies formed, with the sole intention of searching for buried treasure beneath the sea. y\gain and again have expeditions left New York or San Francisco in the cer- tainty of recovering tons of bullion sunk off the Brazilian coast, or lying undisturbed in th^mud of the Rio de la Plata. ^ At the end of 1885, the large steamer Imbus, belonging to the P. & O. Co., The la.st look just before going down. Looming up alter a successful trip. 4M^ WHAT HAPPENS WHEN A THING EXPLODES 20.") sank off Trincomalee, having on board a very valuable East-India cargo, to gether with a large amount of specie. This was another case of a fortune found in the sea, for a very large amount of treasure was recovered. Another wreck from which a large sum of gold coin and bullion was re- covered by divers, was that of the French ship "L'Orient." She is stated to have had on board specie to the value of no less than $3,000,000, besides other treasure. A parallel case to "L'Orient" is that of the "Lutine," a warship of thirty- two guns, wrecked off the coast of Hol- land. This vessel sailed from the Yar- mouth Roads with an immense quantity of treasure for the Texel. In the course of the day it came on to blow a heavy gale ; the vessel was lost and went to pieces. Salvage operations by divers, during eighteen months, resulted in the recovery of £400,000 in specie. Humorous scenes do not play much of a part on the ocean's bottom, and the sublime and awe-inspiring are far more in evidence there than the ludi- crous, yet even beneath the waves there are laughable scenes at times. A diver had been engaged to inspect a sunken vessel off the coast of Cuba. Arriving on the scene he discovered a number of native sponge-di\Ters, who descend to considerable depms, diving down from their canoes to the sunken vessel trying to pick up something of value. They paid little attention to the arrival of the wrecking outfit, and did not notice the diver descend, until suddenly what seemed to them to be a horrible human-shaped monster, with an im- mense head of glistening copper and three big, round, glassy eyes, came walking around the vessel's bow and marie a big salaam to them. That was enough. They shot surfaceward like sky-rockets, climbed frantically into their canoes and hurriedly rowed away. What Happens When Anything Ex- plodes? By exjilosives are meant substances that can be made to give off a large quantity of gas in an exceedingly short time, and the shorter the time required for the production of the gas the greater will be the violence of the explosion. iVIany substances that ordinarily have no explosive qualities may be made to act as explosives under certain circum- stances. Water, for example, has caused very destructive boiler explosions when a quantity of it has been allowed to enter an empty boiler that had become red hot. Particles of dust in the air have occasioned explosions in saw mills, where the air always contains large quantities of dust. A flame intro- duced into air that is heavily laden with dust may cause a sudden burning of the particles near it, and from these the fire may be conveyed so rapidly to the others than the heat will cause the air to expand suddenly, and this, together with the formation of gases from the burning, will cause an explosion. It must not be thought, however, that fine sawdust or water would ordinarily be classed as explosives. The term is generally applied only to those sub- stances that may be very easily caused to explode. The oldest, and most widely known, explosive that we possess is gunpow- der, the invention of which is gen- erally credited to the Chinese. It is a mixture of potassium, nitrate, or salt- peter, with powdered charcoal and phur. The proportions in which these substances are mixed vary in different kinds of powder, but they usually do not differ much from the following: Sulphur 10 per cent. Charcoal 16 per cent. Saltpeter 74 per cent. The explosive quality of gunpowder is due to the fact that it will burn with great rapidity without contact with the air, and that in burning it liberates large volumes of gas. When a spark is in- trofhiced into it, the carbon, charcoal, anfl sulphur combine with a portion of the oxygen contained in the saltpeter to form carbonic acid gas and sulphur- ous acid gas, and at the same time the nitrogen contained in the saltpeter is set free in the gaseous form. 'I'his ac- tion takes place very suddenly, and the 206 WHAT SMOKELESS POWDER IS MADE OE volume of j^i'as set free is so much greater than tliat of the jjouder lliat an explosion follows. In the manufacture of gunpowder all that is absolutely necessary is to mix the three ingredients thoroughly and in the proper ])roportions. But to fit the powder for use in firing small arms and cannon it is made into grains of various sizes, the small sizes being used for the small arms with short barrels, and the large sizes for cannon. The reason for this is that if the powder is made in very small grains it all burns at once, and the explosion takes place so sud- denly that an exceedingly strong gun is required to withstand the explosion, while if larger grains are cmjiloyed the ])urning is slower and continues until the projectile has traveled to the muzzle of the gun. In this way the projectile is fired from the gun with as much force as if the explosion had taken ])lace at once, but there is less strain on the gun. What Causes the Smoke When a Gun Goes Off? Powder of this latter kind always produces a considerable quantity of smoke when it is fired, because there is a quantity of fine particles formed from the breaking up of the saltpeter and from some of the charcoal which is not completely burned. This smoke forms a cloud that takes some time to clear away, which is a very objectionable feature. In order to get rid of it, ef- forts were made to j^roduce a substance that would explode without leaving any solid residue, and that could be used in giuis. These efforts were finally suc- cessful, and there are now several brands of smokeless powder in use. What is Smokeless Powder Made Of? The most satisfactory forms of smokeless powder are all made from guncotton or nitrocellulose. This sub- stance, which is made by treating cotton with a mixture of nitric and sulphuric rcids, is a chemical compound, not a mixture like gimpowder ; and when it i.s exploded it is all converted into gases, of which the chief ones are car- bonic acid gas, nitrogen, and water- vapor. To cause the explosion of gun- cotton it is not necessary to burn it, but a mere shock or jar will cause it to de- compose with e.x])losive violence. Of course, sucii a violent ex])losive as this could not be used either in small arms or in cannon, but guncotton can be con- verted into less ex])losive forms which are suitable for use in guns, and the majority , of smokeless powders are made in this way. The methods used in producing the smokeless powders are kept secret by the various countries that use them. What is Nitroglycerine? Another very powerful explosive, which is closely related to guncotton, is nitroglycerine. Tliis compound is made by treating glycerine with the same sort of acid mixture that is used in making giuicotton. It explodes in the same way that guncotton does and yields the same products. It is an oily liquid of yellow color, and on account of its liquid form it is difificult to handle and use. The difificulty in handling nitro- glycerine led to the plan of mixing it A\ith a quantity of very fine sand called infusorial earth. WHien mixed with this a solid mass called dynamite is formed, v.hich is easier to handle and more dif- ficult to explode, but which has almost as much explosive force as nitro- glycerine. A more powerful explosive than cither nitroglycerine or guncotton is obtained by mixing them together. When this is done the guncotton swells up by absorbing the nitroglycerine and becomes a brownish, jelly-like sub- stance that is known as l)lasting gelatin. This is generally considered the most powerful explosive obtainable. What Makes Nitroglycerine and Gun- cotton Explode So Readily? Let us now consider for the moment Avhat it is that makes guncotton, nitro- glyce!-'"e, and blasting gelatin explode so readily. The explanation is found m the presence in them of nitrogen. As WHAT WORRY IS 207 you remember from what you learned about air, nitrogen is an extremely in- active element. It has no strong tend- ency to combine with other elements, and when it does enter into combination with them the compounds formed are almost always easily decomposed. In the compounds that have just been de- scribed a shock causes a loosening of the bonds that hold the nitrogen, and the whole compound goes to pieces just as an arch falls when the keystone is removed. What Is Silver ? Since the earliest time recorded in history, silver has been the most used of the precious metals, both in the arts and as a medium of exchange. Even in the prehistoric times silver mines were worked and the metal w^as em- ployed in the ornamental and useful arts. It was not so early used as money, and when it began to be adopted for this purpose, it was made into bars or rings and sold by w^eight. The, first regular coinage of either gold or silver was in Phrygia, or Lydia, in Asia Minor. Silver was used in the arts by the Athenians, the Phoenicians, the \^ikings, the Aztecs, the Peruvians, and in fact by all the civilized and semi- civilized nations of antiquity. It is found in almost every part of the globe, usually in combination with other metals. The mines in South America, Mexico, and the United States are es- pecially rich. Silver is sometimes found in huge nuggets. A mass weighing 800 pounds was found in Peru, and it is claimed that one of 2,700 pounds was extracted in Mexico. The ratio of the value of silver and gold has varied greatly. At the Christian era it was 9 to I ; 500 A.D. it was 18 to i ; but in 1 100 A.D. it was only 8 to I. In i8g «5V>". c\c> V///// ////////////////^^^ l_OT> gx >v>«*»»T»\ ■^««!iV^«»«> V^TPo g rt '3V>«c\J <~roOT>e\ o;-< :t» -,» ■».» c*Vrv g OoN^'^^ FIGURE I. The Story in a Tunnel How a Tunnel Is Dug Under Water. Fig. I. On the left is a cross section showinq'. in diagram, the back view of a shield. The heavy black circle is the "tail"' or "skin." The small circles within the tail are the hydraulic rams which at a pressure of 5.000 pounds to the square inch force the shield for- ward. The square compartments within the sihield are the openings through which the men pass to dig away the ground. In the middle of the shield is shown the swinging "erector" which picks up the iron lining j)lates and puts them in position. The view on the right is a longi- tudinal section of the tunnel showing the shield and the bulkhead wall across the tunnel with the air locks built into it. The front of the shield ahead of the doors is made with a sharp edge called the "cutting edge" and this makes it easier for the shield to advance in case all the ground in front has not been removed. This view shows how the tail overlaps the last portion of the iron lining. Some distance behind the shield comes the concrete bulkhead wall with the air locks contained in it. There are two shown in the view. The upper one is the emergency air lock, always kept ready so that in case of an accident the men have a means of escape even though the lower part of the tunnel is filled with rushing water or mud. The lower air lock is for the passage of men and materials during ordinar}^ working. This view also shows that all the tunnel ahead of the bulkliead wall is tmder compressed air while the finished tunnel behind the bulkhead wall is under the ordinary or normal air pressure. When the tunnel is finished the air locks and bulkhead walls are removed. FRONT VIEW OF A DRIVING SHIELD 209 This shows the front of one of the shields used on the Pennsylvania Railroad tunnels crossing the North Kiver at New Vork. The cutting edge is clearly seen and the various compartments, each with its door, which divide up the front of the shield. These shields weighed about 200 tons each. HOW TUNNELS ARE BUILT. These notes describe very generally the way' in w.hich tunnels are built through mud and gravel under parts of the sea or large rivers in such a way that the men who build them are pro- tected and as safe as the carjjcnter who is building a house. The way these tunnels are built is called the "shield" way because the ma- chine used is called a shield. It is given this name because it shields the tunnel builders from the water and the mud which are ready at every moment to overwhelm them and kill them. The shield was invented in 1818 by a great Engineer, Marc Isanibard I'ruiiel, who was a P^rcnchman living in J'Jig- land. The idea of the shield came to him as he saw how the sea worm which attacks the wooden piles of docks along the shore bores the holes it makes in the wood. The head of this worm is very hard and can 'bite its way througli the hardest woods. As it goes through the wood its body makes a hard shelly coating which lines the holes which its head has made and prevents the hole from getting filled up. This is the general idea of a tunnel built by a shield. The first shield -was used by Mr. Brunei to make a tunnel across the Thames River at London, F.nglaiul. This is still the biggest tunnel ever built by a shield, although not the long- est, and is still used by railroad trains. This tunnel was begun in 1825 and was finished in 1843, and provides a history of almost unexampled and not-to-be- c.xcelled coura-^c in attacking difficultio-s and skill in defeating them. Since iIr- (la\s of Jirunel many great 210 HOW THE SHIELD IS PUSHED FORWARD This shows the rear cml or tail end of one of the smaller shields, used on the Hudson and Manhattan Railroad tunnels under the North or Hudson River at New York. It shows the skin, the hydraulic jacks within the skin and the piping and valves fur working them. It also shows the doors leading to the front or "face." The erector is not shown, but the circular hole in the middle shows where it would be attached. This shows one side of an air lock bulkhead wall with the air lock in place. The boiler- 1 Tlii» i? .1 rear view of one of the Pennsylvania Tun- nel shields, taken after a length of tunnel had been ike appearance of the lock is clearly visible, completed. All the details of construction are shown, IS well as the door and the pressure gauge but in this case the erector is clearlv seen also. 1 he o tell the air pressure inside the lock. valves which control the erector and the rams which push the shield forward are seen near the top of the shield. The rods across the tunnel are turn-buckles used to keen the iron lining from getting out of shape in the soft mud. These are removed later. The floor and tracks in the bottom are temporary and are used for brinffing materials to and from the shield. WHO INVENTED THE COMPRESSED AIR METHOD 211 improvements have been made in the shield and in the way of working it but the same idea is still there. After the days of Brunei's shield an- other great help was given to tunnel builders by the invention of the use of compressed air to hold back the water which saturates the ground in which the tunnel is being built. The first real invention of compressed air for this purpose was made by Ad- miral Sir Thomas Cochrane who, in 1830, took out a patent for the use of compressed air to expel the water from the ground in shafts and tunnels and, by this means, to convert the ground from a condition of quicksand to one of firmness. This patent covers all the essential features of compressed air working. As suggested above, the thing which compressed air does in a tunnel is to push the water out from all the spaces which it fills in the ground, so that the men who are digging away the ground for the tunnel are working in firm dry ground instead of a mixture of earth and water which will nm into and fill the hole they dig as soon as it is dug. Whenever a timnel is being built be- low a body of water through ground which is porous, or in other words through any ground except solid rock or dense clay, the water fills every crev- ice and space in the ground and is ex-: erting a pressure of about half a pound per square inch above the ordinary pressure of the air, (which is 15 pounds to the square inch) for every foot of depth below the surface of the water ; so that supposing the tunnel is 40 feet below the water the water has a pres- sure of nearly 20 pounds per square inch on every square inch of the sur- face of the tunnel. This pressure causes the water to flow violently into any hole or opening that is made in the ground, and, unless the water is prevented from moving by some means or other, the rr|)ening made would be very quicklv filled with water and also with 'ground as the rush of water will carry tlic sand, gravel (^ir'mud with it. By Cochrane's invention the whole tunnel is filled with air under a pressure equal to the pressure of the water. This compressed air therefore balances the pressure of the water and holds it back from moving, and if the pressure of the air is made slightly greater than that of the water the water is driven back from the tunnels for a short dis- tance so that when the tunnel is being dug the ground instead of being wet is quite dry. This explains the principles of the shield and compressed air way of mak- ing a tunnel. The following describes very shortly how these principles are put to actual use. Most tunnels which are built by shield and compressed air under rivers or arms of the sea are lined with cast iron plates to protect the railway or roadway which is in the tunnel. The tunnel is a circular tube, or shell, and the plates have flanges on all sides which are bolted together. This shell is put into place, plate by plate, by means of the shield which not only protects the workmen and the work under construction, but which helps to build the iron shell. In fact it cor- responds to the sea worm which bores through the wood and lines the hole with a shell. In the case of the tunnel the shell is made of iron. The shield itself consists of a steel tube or cylinder slightly bigger in diameter than the tube or tunnel it is intended to build. The front edge of this shield is made up of a ring of sharp edged castings which form what is called the "cutting edge." Just behind the cutting edge is a bulk- head or wall of steel, in which are open- ings which may be opened or closcrl at will. Behind this bulkhead are placed a number of hydraulic jacks or prcsse.4 arranged around the shield and within it, so that by thrusting against the last erected ring of iron 'lining the whole shield is pushed forward. The rear end of the shield is a continuation of the cylinder which forms the front end, and this part, called the "tail," always f)verlaps the last few feet of the built up iron ihcll. •2\: HOW THE SHIELD CUTS THROLQH THE GROUND This IS a photograph of a model of the Pennsylvania Tunnels to New York City, made for the James- town Tercentenary Exposition of 1907. It is given because it illustrates, as no photograph of actual work could do. the relationship between the shield, the tunnel itself and the air lock. This view shows the rear part of the shield on the extreme left, with the erector picking up an iron plate. It shows a man bringing a car with two of the iron plates up to the shield. Behind this man comes the bulkhead wall with the emergency air lock in the top and the ordinary air lock for passing in and out at the bottom. It also shows the upper platform to the emergency lock along which the men can get to the emergency lock m case of an accident. The diagram, Fig. 1, shows more clearly what is meant. From an in- spection of Figure 1 it is clear that, when the openings in the shield bulk- head are closed, the tunnel is protected from an inrush of either water or earth ; the openings in the bulkhead may be so regulated that control is maintained over the material passed through. After a ring of iron lining has been erected within the tail of the shield, the shield doors are opened and men go through them and dig out enough earth for the shield to. go ahead. The rams are then thrust out thus pushing the shield ahead. Another ring of iron is built up within the tail for which purpose an hydraulic swinging arm, called the "erector," is mounted on the shield face. This erector picks up the plates and puts them into position, one by one, while the men bolt them together. Ex- cavation is then carried on again and the whole round of work repeated, gain- ing every time the jacks are rammed or thrust out a length equal to the length of one ring of iron lining. In- carrying out this -work in ground charged with water the shield is assisted by introducing compressed air as de- scribed before. To use the compressed air thick bulkhead walls of masonrv are This IS auulher vit;\ the air locks are clearl'- shown. san.e model, but showing the front view jt tiie slueld. The doors on THE DANGER WHEN LEAKS OCCUR 213 built across the tunnel behind the shield and into the space between the shield and the bulkhead wall air is pumped, compresses to the same pressure as that of the water in the iground, or in other words the pressure of the air in pounds per square inch is about half the num- ber of feet the tunnel is below the water surface. This dries the ground and simplifies enormously the difficulty of working in it. The diagram, (Fig. 1) shows a bulkhead wall across the tun- nel. In order to pass from the ordinary air outside the bulkhead into the com- pressed air inside it, all the men and the materials have to pass through the "air locks" which are built into the wall. the outside. The door at the end has been tightly closed to prevent the com- pressed air from rushing out. We close the door behind us and are now tight- ly shut in the boiler-like lock. We now open a valve and compressed air be- gins to flow quickly into the air lock and the air gets hotter and hotter, due to the compression of the air. Very likely an intense pain begins to make itself felt in the ears but by swallow- ing hard and blowing the nose it may be relieved. It is caused by the air pressure being greater on the outside of the ear drum than on the inside. If the delicate ear passages are choked, because of a cold or some such reason, They are callerl air locks because they are like the locks on a canal which raise the water from a lower to a higher level or lower it from a higher to a lnrcssure in the air lock has reached that in the working chamber, the door leading to the shield may be oi^cned and wc can pass to the working space and note the work going on. There is no espe- cial bodily sensation to be felt excc])! a slight cxhilaralir)n and it is curious to find that one cannot whistle. On leaving I he compressed air we enter the 214 MAKING THE JOINTS WATER TIGHT c *^ n L. n be -cS rt c 4^'r: ?-= -^ tp „ c n ^ iiC: «j i- .- c 4,— "^ " 5; ^'"^ CJJi f-- S^^ C HJ c c - >-*' ' 4'-*',, Ecn '" 1/1 ^ 1/ C-— •-♦--CD ,.•2 -Sj: -*- . 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The white arrow shows where each shield ends. The platform of one shield on which the man stands corresponds exactly with the platform of the other shield. As may be imagined, it takes very careful and skillful engineering and surveying work, both before the work is begun and while it is being carried out, to enable tunnel shields to meet like this. This part of the art of tunnelling would take an article to itself. air 'lock by the door we left; a valve is turned'^nd the air begins to escape and "the pressure in the air lock begins to go down. As it does so the air be- comes colder and colder and the whole lock is filled with a wet fog due to the chilling by expansion of the air. The air has to be allowed to escape very slowly, as bubbles of air and gas other- wise form in the blood vessels and tis- sues of the body giving rise to the very painful complaint known to tunnel Ijuildcrs as "the bends," and in very serious cases to paralysis and even death. The higher the air pressure the more slowly must one come out into the ordinary air. When the shield has been pushed across the entire length of the water way which has to be tunnelled, and the whole of the iron tu'l>e or shell is in j)lace, a thick lining of concrete is placed inside the iron shell to protect it and make the tunnel stronger. As an added safeguard wherever the tun- nel is in rock, gravel, strong clay or other ground which is not so soft that it does not close tightly in on the outside of the tube, liquid cement is forced by compressed air through holes made in the iron plates for this puri:)Ose. This liquid cement enters every pore or crev- ice in the surrounding ground and when it has set hard it still further protects the iron with a coating of cement. Pieces have been cut out of the iron lining of a tunnel built under the river Thames at London, I^ngland, in 1869, which showed that the iron at all places was as good as the day it was first put in forty years before, and iron put in the lining of the Hudson River Tuniu'l about 1878 when removed after thirty years was in ])erfect condition. This account of tunnelling by shield and compressed air is very sliort and gives no more than a bare statcuicnt of the principles and chief methods of SHIELD AT END OF JOURNE^ THE LAND END OF A GREAT TUNNEL UNDER THE HUDSON 217 HODSON & MANHATTAN R. R. I MIS VH-w IS KivM 1.1 -ii.iv. Iiow <.irii| lU.i .im ii i i. i. i k m ii i , ,. I -iiiulilli- in.iy li.n r {<> Kr lll.nlv li. I.il>> care of the rcf|iiircments of traHic. 'I liis view hIiows tlic three Krcat reinforceil concrete caissons sunk thruueh the earth at Jersey City i.; order to contain the switches and crossings rconired to form the New Jersey connections of the nptowii anrl flowntown tnnnels of the Hndson and Manhattan Railroad. These caissons were sunk tinder air jiressure l)y excavating l)elow litem just as thongh they were tunnels tui'ncd up on end. In sinking these caissons the material iiassed throuKh was water lojjRed' inade Kround, and the hulls ol two sunken canal boats were encountered and had to he cut into |)ieces small enough to be taken out throiii^h the locks. The usual passenKcr rushuiK at high speed in the trains between Jersey Citv and Newark and New York has little idea of the very complicated structure necessary to allow of his iloinR so. The information in this article was suiiplieil by Jacobs & l)avics, Inc., CoiistiltinB Enffincers, .10 rhurch Street, New York, the Kngineers for the Pennsylvania Railroad, Hudson River Tunnels, tlie Hudson and Manhattan Railroad, and many other tunnels in various parts of the world. The illustrations were kindly supplitd by tlie Pennsylvania RailroacI and the Hudson and Manhattan Riilroad. 218 DANGERS OF TUNNEL BUILDING such work. Xothin«; has been saiil of tlic eiii^ineeriiig^ difficulties involved in the desijjn of sucii work, nor of the delicate surveying; work necessarv if one should hope to start two shields a mile or two apart and have theni meet as shown in Fig. 13 like two great glass tumblers placed rim to riin after having travelleil through thousands of feet of every kind of ground. Xothing has been said of the men who work on this most arduous form of subterranean navigation, ho^v they cheerfully face the dark and the water ever threaten- ing above them and the unseen but not less deadly ally, and yet foe. the com- pressed air, with its dreaded result, the bends, or the men on the surface who keep the air compressors running with- out pause or stop day in and day out imtil the work is done so tliat tlicir comrades below may work in safety. Nothing has been said of the curious accidents that are liable to occur as Avhen the air pressure in the tunnel gets too high, overbalances the water pres- sure and blows a hole tliroiigh the river-bed and forms a geyser in the river above. It gives no account of the special difficulties which arise when special conditions are found ; for ex- ample, when the lower part of the tun- nel is in rock and the tipper part is in soft material. In fact it is nothing more than a bare outline but it 'hoped that some, who may not be clear in their minds as to how tunnels are built, may learn some of the first princi])les of this most romantic kind of work from tins bald narrative. Why Do My Teeth Chatter? Your teeth chatter because when you are cold in a way that makes your teeth chatter the little muscles which close the jaw act in a series of cjuick little contractions which pull the jaw up. and then let it fall by its own weight. This is repeated many times and, as the action is quick, the chatter- ing occurs. It is a peculiar thing that this occurs in spite of the will or brain. when, as a mailer of fact, these muscles wiiich operate the jaws are especially under the control of the brain. The chattering is really a spasm caused by the cold, and all spasms act indepen- dent of the will. Cold seems to act on the jaw muscles a good deal like some poisons which cause spasms. Where Did All the Water in the Oceans Come From? No, it did not come from the rivers which empty themselves into the oceans, because the oceans were there before the rivers existed. Part of it comes from the rivers now, but only a little in com]:)arison to all the water there is in the ocean. I will try to tell you simply how all the water got into the ocean. There was a time when there was no water on the earth at all. That was when the earth was red hot, just as it is to-day on the inside, and at that time all the water we have to-day was up in the air in the form of gases. Strange as it may seem to you, if you take two gases, one called hydrogen and the other oxygen, and mix them the right way, they will turn into water, and if you had the right kind of chem- ical apparatus you could take water and turn it into these gases again. When, then, the earth was still all red hot, all of our water was up in the air in the form of these two gases. Then, later on, when the amount of heat on the earth was just right to make these gases mix together, the water came down out of the air in great quantities, and there was so much of it that it completely covered the whole earth and no land was visible. Later on, for various reasons, mountains were thrown up on the earth's surface by great earthquakes, and every time a mountain or a high ])lace was formed there had to be a hole or low place some place else, and the water ran into these low places and stayed there, and that uncovered more of the land, be- cause there wasn't enough water to fill all the holes and cover the land too. •^— ^BTSiW WHERE THE WATER IN THE OCEANS CAME FROM 219 and that is what makes our continents and islands and all of the land we see. There is now about three times as much earth covered with water as there is land. Of course, the sun is always picking up water through what is called evaporation, which means that it is taken into the air in the form of gases. Later it comes down again in the form of rain and falls into the oceans or on the land, where it sinks in, finally find- ing a stream or river, and sooner or later gets back into the ocean again. Why Don't the Water in the Ocean Sink In? This is due to the fact that there is a kind of substance at the bottom of the ocean which the water cannot pene- trate, in spite of the tremendous pres- sure which the great body of deep water exerts. In all places where the bottom of the ocean has a covering \\hich water can sink into it does so, but there are such a few places where this is possible, by comparison, that the amount that gets out that way is not noticeable. This water, if it can keep on going, will eventually reach the in- side of the earth, where it is red hot, and is turned into steam. Where Does the Water in the Ocean G-o at Low Tide? To get to the answer of this you must know something about the tides. The tide is caused by the pull of the moon on the waters in the ocean. The moon revolves about the earth once each day and has the ability to draw up the waters in the ocean toward it, as we have seen in our study of the tides. Now, when it is high tide in one place it is low tide in another. The moon docs not make more water, but Mily jmlls it towarrl it from side to side. When it is low tide where we are the water has simply moved as a body to- ward the place where it is high tide. The tides act a good deal like a see- saw, cxce[)t that they move from side to side instead of u]) and down. When one end of the see-saw goes u]) the other end goes down, and when the "down" end comes up the other end goes down. So the answer to your question really is that at low tide the water which made it high tide a few hours before has gone to some place where it is at that mo- ment high tide. Why Does the Ocean Look Blue at Times and at Other Times Green? Sometimes when we look at the ocean from the pavilion or while on the sand of our favorite bathing beach the water in the ocean looks very beautifully blue, 9nd on other days will look dark green from the same point. Why is it? If you will stop to think that at night when there is no moon or other light the water in the ocean looks black, I think you will soon be on the right track to answer the question yourself. When the sky is blue — the kind of blue we like to see in the sky when we are at the beach — the water in the ocean is blue, because the sea reflects the color of the sky, and when the sky is overcast and gray the color reflected by the sea will be gray also. But, say you, sometimes the water in the ocean is dark green, and yet the sky is never green. Quite true, and I will try to tell you what produces the green color. This happens some- times where the water is shallow, either near the shore or out further where there is a sandbar or other shal- low place. Sometimes at such points the sunlight strikes the water at such an angle that the rays go clear to the bottom and are reflected from that point — the bottom — to our eyes. In such a case the light will be changed through a combination of the color of the bottom at that point and the color of the sky itself at the time to make tbic color green as it is reflected to our eyes from \hv bottom. Why Does Water Run? Water runs because it has not enough of anything in it to make it stick to- gether. In school language we call this stick- 22(J WHAT MAKES WATER BOIL ing-together-thinj^ "cohesion." The principle of cohesion makes all the dif- ference there is, so to speak, between solids, liquids and gases. A brick, a stone, a stick of wood, or a piece of iron and all other solid substances have a certain amount of this property of cohesion, and the particles stick to- gether, enabling us to build buildings and other things which become perma- nent structures. These solid substances are either naturally cohesive or else nian, as in the case of the brick, has brought together certain things with little or no cohesion and made them stick together permanently. In the case of the brick, he takes a quantity of clay, which is cohesive only to a certain de- gree, bakes it in an oven and it becomes hard enough — more cohesive — so that he can pile one on top of the other and make a building. Then he puts sand, mixed with other things — lime and water — between the bricks to hold the bricks together, and makes a struc- ture that will last. Two bricks have no natural cohesion for each other and, therefore, they can only be held to- gether by something that has cohesion within itself and also for the bricks. The lime, sand and water make mortar which is cohesive when properly mixed, while in themselves neither lime nor sand have much cohesive property, and w^ater has none at all. Liquids have little or no cohesion. Water has none, or very little. Syrup has a good deal more, but will run over the edge of a piece of bread and butter if you are not careful. Gases have no cohesive properties at all and, therefore, fly all over the place, through any opening they can find, either at the top of the room or under the crack of the door. They are always trying to get to some place else and will keep moving as long as not confined. Gases can move in any direction. Liquids, however, while they are in- clined to be constantly on the move, can only go in one direction — down hill, and they go down fast or slow if there is a chance, in proportion to the amount of stick-together properties they have. Liquids can never go up of their own accord, excepting in the process of evaporation, and then only when changed into gases. A lake of water will dry up completely by evaporation unless fed by streams of water con- stantly flowing in, because evaporation is constantly taking place wherever water is exposed to the air. What Makes the Water Boil? What we call boiling in the water we see when water is put over a hot fire long enough to make it boil, is the changing of the water from what we generally regard it — a liquid — into gases. Water consists of two gases — hydrogen and oxygen — in fact, two parts of hydrogen gas and one part of oxygen gas when mixed will always make pure water. Now, then, if liquid water is heated to a certain point or temperature it turns into the two gases, oxygen and hydrogen, and' comes to the top of the water, which still re- mains in liquid form, in the form of a bubble and explodes into the air — not a very loud explosion, but still an explo- sion. The process of turning liquid water into gases is a gradual one, and that is why the water does not all turn into one large bubble at once and ex- plode away. If you keep the fire going long enough, all the water in the vessel will explode away into the air, a few bubbles at a time. If you hold a cold plate over the vessel as the bubble ex- plodes you can catch some of these gases in the form of bubbles on the under side of the plate, which are again liquid water. When the water becomes hot enough it turns into bubbles and as bubbles rise that is wdiat makes the boiling you see. When the same gases then come together again in a certain proportion under proper temperature they turn into liquid water. At What Point of Heat Does Water Boil ? The boiling point of water is the temperature at which it begins to pass into the form of gases. This varies in dififerent altitudes. At the sea level the boiling point is at 212° Fahrenheit. On the top of mountains, for instance, WHAT WE MEAN BY FAHRENHEIT 221 w ater would boil at a much lower tem- perature. It would be possible to go high enough in a balloon so that the water would fly from the pan in the form of gas without making the water hot. Also, a mile below the level of the sea it would take many more de- grees of heat to make the water boil. It is said that high up in a balloon you could not boil an egg hard in a pan of boiling water if you kept it in the boiling water for an hour or more, whereas we know that an egg will be hard-boiled if we keep it in boiling water down where we live for more than five minutes. The degree of heat at which w^ater passes away into the form of gases is regulated by the pressure of the air on the water and other things about us. At the average level in the United States where people live the pressure of the air on everything is fifteen pounds to the square inch, and at this pressure water boils only after it reaches a tem- perature of 212° Fahrenheit. As we go up the mountains the pressure be- comes less and less as we go up. At the top of Mount Blanc, which is 15,781 feet high, water boils at 185° Fahren- heit. If we took a balloon from the top of the mountain we would come to a height where there was no air pressure at all. What Do We Mean by Fahrenheit? The name Fahrenheit is used to dis- tinguish the kind of scale most com- p-iOnly used on thermometers in Great Britain and the United States. Gabriel Daniel Fahrenheit, a native of Dantzic, made the first thermometer on which this scale was used, and .it is named after him. In this scale for thermome- ters the space between the freezing point and the boiling point is divided into 180 degrees — the point for freez- ing being marked 32 degrees and the Ijoiling point 212 degrees. Why Can't We Swim as Easily in Fresh Water as in Salt Water? Our bodies are heavier than fresh water, i. e., a bulk of fresh water equal \<, the size of our body would weigli less than our body, so that the first tendency is to sink to the bottom if we find ourselves in fresh water. If man had not learned to swim that is what he would always do, sink to the bottom ; but having learned how to keep from sinking, he is able to swim in fresh water. However, we find that an amount of salt water equal to the bulk of a man in size is heavier than an equal amount of fresh water, although such a bulk of ordinary salt sea water will still weigh less than the man. A man will sink in salt water also if he has not learned to swim or float, but he can keep up with less efifort in salt water, and also swim in it more easily. In a nutshell, then, the answer to this question is that salt water is heavier than fresh water. You can make salt water so full of salt that it becomes heavier than a man. Great Salt Lake in Utah is so salty that one cannot sink in it for this reason. You could drown yourself in it, of course, by keeping your head under, water, but whether in shallow water or deep water you would not sink in Great Salt Lake. Why Do We Say Some Water Is Hard and Other Water Soft ? What we call hard water contains certain salts which soft water does not contain. This salts in hard water is lime or some other salts which the water has picked up out of the ground as it passed through either coming up or going down. On the other hand, we can guess after having been told this much that if we can find any water that has not passed through the ground, and, therefore, not hacl a chance to pick up any salts, we will have soft water. I'roni that point it is easy to guess, then, that rain water must be soft water, and so it is. The water in the cisterns, whicli is rain water, is soft water, and (he kind we get out of llie wells is hard water. We do nol like to wash cither our faces or our clothes in hard water, especially when it is necessary to use soap, because when wo use soap wilh 222 WHERE THE RAIN GOES hard water the soap undergoes chemical change which prevents its dissolving in the water. Therefore, you cannot easily do a good job of washing in hard water. On the other hand it is easy to dissolve the soap in pure rain water or soft water and that is the kind we, therefore, prefer for washing. How Does Water Put a Fire Out? This is at first a puzzling question, because back in your mind is the thought that since hydrogen and oxy- gen are necessary to make a fire burn, it seems strange that water, which is composed of oxygen and hydrogen, will also put it out. A burning fire throws off heat, but if too much of the heat is taken from the fire suddenly the temperature of the fire is sent down so far below the ]-)oint at which the oxygen of the air will combine with it that the fire can- not burn. We speak commonly as though water thrown on a fire drowns it. That is practically what happens. Scientifically what happens is that the water thrown upon the fire absorbs so much of the heat to itself that the tem- ]-)erature of the fire is reduced below the point where oxygen will combine with the carbon in the burning material and the fire goes out. To answer the unasked part of your question at the same time I will say that hydrogen and oxygen when com- bined as water will put the fire out rather than make it burn, more because when these gases take the form of water they are already once burned, and you know that anything, substance or gas, which has already been burned cannot be burned again. It required great heat to make oxygen and hydro- gen combine and form water, and it also takes great heat to separate them again. So they are really burned once before they become water. Where Does the Rain Go? Eventually almost all of the rain that falls runs into the rivers and lakes and later finds its w-ay into the ocean, where it is again taken up into the air by the sun's rays. But many other things happen to parts of the rain which do not find their way into the ocean. In the paved street, of course, where the water cannot sink in, it flows into the gutter and thence into the sewer and on down to the river or wherever it is that the sewers are emptied. You sec, it depends very much on what the earth's surface is covered with at the place -where the rain falls. When it strikes wdicre there is vegetation a great deal of it stays in the soil at a depth of comparatively few feet. If it is soil where trees and other plants grow a great deal of it is sucked up from the ground by this vegetation and given back into the air through the leaves and flowers. Sorne of the rain keeps sinking on down into the earth until it strikes some substance like rock or clay, through which it cannot sink, and then it follows along this until it finds something it can get through and collects in a pool and forms an underground lake, and may cause a spring to flow. Then there are also worms and other forms of animal life in the earth which use up some of the water. But it all gets back into the air eventually to come dow-n some time again in the form of rain. Why Does Rain Make the Air Fresh? The main answ-er to this question must be that the rain in coming dow^n through the air drives the dust and other impurities w'hich are in the air before it, and so cleans the air and m^akes it absolutely clean. In addition to this it is now stated that since very often rain is produced by electrical changes in the air, and that these elec- trical changes produce a gas called ozone, which has a delightfully fresh smell, it is this ozone that makes us say the air has become fresh. The air above our cities is almost constantly filled with smoke, containing various poisonous gases, and these are driven away by the falling rain. Then, too, there is always a greater or less accumulation of dirt, garbage and other things in the cities which give off offensive smells constantly, but which we do not notice always because we become used to them. When the rain comes down it washes the streets and destroys these smells, and that makes the air fresh and delightful to take into the lungs. In the country the air is more nearly pure all the time, because the things which spoil the air in the city are not present. Is a Train Harder to Stop Than to Start? The answer is yes. It is harder to stop a train than to start it, or rather it takes more power. The speed of a train depends upon the motive power. When a train is stopped and you wish to start it, you must apply enough mo- tive power to start it going. There must be enough power to move the Aveight of the train and overcome the friction of the wheels on the track. It is. of course, easier to move a thing that weighs less than a heavier one. If you throw a ball ten feet into the air, it will perhaps not sting your hand Vvhen you catch it on its return ; but, if you throw it one hundred feet into the air, it will sting your hands when you catch it. Besides, it will come down faster the last ten feet of the way than the ball which you threw only ten feet into the air. This is be- cause when movement is applied to anything you add power to it. The ball which comes down from one Imndred feet in the air acquires more power in falling and it takes more power to stop it. A train in motion hr.s not only the power of the weight of the train Ijchind it, but also the ad- ditional weight which the movement of the train has given it. Therefore, it takes more power to stop it than to si art it. To stop a train you must ap- jly the same amount of power as is in the moving train because the j)owcr tc stop any moving thing must always l tlie furnace. With this scrap is charged suflicicnt lime or limestone to make tlic slag, as well as some iron ore to assist in reducing the carbon of the iron. In aliout two or throe hours the required amount of molten iron is brought from the mixer in ladles, and poured into tin- fiirn;icc on top of tlic scr.i]), lime ;ind ore. 236 MOLTEN STEEL BEING POURED LIKE WATER Molten Steel Being Poured Into Ladle. When the scrap has all been melted, a test is taken to determine the amount of carbon remaining in the bath. Iron ore is added from time to time until the carbon in the bath has been reduced to the desired point, and the metal is sufficiently hot to pour. At this point "rccarburizers" (consisting of Ferro-Manganese, Ferro-Silicon, and pig- iron, or coal) are added to get the required composition. The tap hole at the back of the furnace is opened, and the steel is allowed to run out into a ladle, the slag coming last and forming a blanket over the steel in the ladle. Crane Carrying Ingot and Soaking Pit Furnaces. The ladle is picked up by an electric crane and carried over cast-iron moulds, which are set on cars, the steel being poured into the moulds, resulting in steel ingots. A GETTING READY TO MAKE A RAIL 237 sufficient amount of time is allowed for the steel to become chilled or set, when the cars are pushed under an electric stripper, where the moulds are removed from the ingots. After the ingots leave the stripper they are taken to the scales and weighed, and after weighing are put into the soaking pits. The pits get their name from the part they play in the heating of the steel for rolling. When the steel ingot is stripped the outside of the ingot is cool enough to hold the inside, which is still in a liquid state, and the steel is put into the soaking pits to allow the inside to settle into a solid mass, after which the ingot is reheated for rolling. The length of time in the soaking pits depends upon the size of the ingot, as the larger the ingot, the greater length of time is required to set. When the steel is ready for foiling it is taken from the pits by overhead electric cranes, and placed into a dump buggy at the end of a roller line, which leads to the blooming mill. The dump buggy derives its name from the fact that when the ingot is placed into same in an upright position, the buggy, in order to place the ingot into a 4 Itl ,■ - ■m - -:^ IB 1 . • '■ '' € " • "^ w ^r^'-^-^S^^",^-^ '■''"0'R m.\ ■■■>M ^ -. '' -«ir^. ^-.^1 ^ 4^^M - —'~ ^-^ ---- '^K^^sSBS^^' ' ' T7~ i '«*. ■ "-gi ■H».V ) 'h''ii% S '-^? ■^ 1". 2£r ^ ^ 1 w ,. :sipfmsiii| ^* t ^RMMpft> ^Mt^ '■-- ^ The Ingot Becomes a Rail. The bloom dropping out, being sufficiently hot to roll into rails, travels along another roller line to the roughing or first set of rolls. Here the bloom is given five passes in the rolls, and is then transferred to the strand or second set of rolls, where it receives five additional passes; after this operation it is transferred to the finishing or third set of rolls, in which it is given one pass. The bloom has now been converted into a rail, and the rail travels on another roller line to the hot saw, where it is cut into 33-foot lengths, this being the standard length in this country for all rails. The rails when hot are cut by the hot saw to lengths of about 3S f^et 6y2 inches, the allowance of 6J/2 inches being made for shrinkage in cooling. It is difficult to believe that steel shrinks to this extent, but tnis is a fact, and while the rails are cooling on the hotbeds they have the appearance of being animated, as they move first one way and then the other. After the rails are on the hotbed a sufficient length of time to cool, the}'' are taken from the hotbed and placed on a traveling roller line, which takes them to an endless chain conveyor. The statement that rails are put on hotbeds for cooling seems paradoxical, but the hotbeds are so called because the rails are placed on them while hot, and are left there until they have cooled. , ..., The endless-chtin conveyor places the rails mi another bed, from which they are picked up by an electric crane and distributed to the straightening presses, where all burrs (which have been caused by the hot-sawing operation) are removed before the rails are straightened. After straightening they are transferred to drill presses, where they have holes drilled into them for the accommodation of the splice bar, after which they are placed on the loading docks. After being carefully examined by the railfa'! c iiiiiiaii} '> inspectors they are picked up from the loading docks by electric magnets attached to a crane, and are placed in cars ready for shipment. WHY JURIES HAVEiTWELVE MEN 239 Who Made the First Felt Hat? The felt hat is as old as Homer. The Greeks made them in skull-caps, coni- cal, truncated, narrow- or broad- brimmed. The Phrygian bonnet was an elevated cap without a brim, the apex turned over in front. It is known as the "cap of liberty." An ancient figure of Liberty in the times of An- tonius Livius, A.D. 115, holds the cap in the right hand. The Persians wore soft caps ; plumed hats were the head- dress of the Syrian corps of Xerxes ; the broad-brim was worn by the Mace- donian kings. Castor means a beaver. The Armenian captive wore a plug hat. The merchants of the fourteenth cen- tury wore a Flanders beaver. Charles VII, in 1469, wore a felt hat lined with red, and plumed. The English men and women in 15 10 wore close woolen or knitted caps ; tw^o centuries ago hats v.'ere worn in the house. Pepys, in his diary, wrote : "September, 1664, got a severe cold because I took off my hat at dinner" ; and again, in January, 1665, he got another cold by sitting too long with his head bare, to allow his wife'5 maid to comb his hair and wash his ears ; and Lord Clarendon, in his essay, speaking of the decay of respect due the aged, says "that in his younger days he never kept his hat on before those older than himself, except at dinner." In the thirteenth century Pope Innocent IV allowed the cardinals the use of the scarlet cloth hat. The hats now in use are the cloth hat, leather hat, paper hat, silk hat, opera hat, spring-brim hat, and straw hat. What Is the Hottest Spot on Earth? The hottest regions on earth is said to bo' along the Persian Gulf, where lit- tle or no rain falls. At Bahrein the arid shore has no fresh water, yet a comparatively numerous population con- trive to live there, thanks to the cojhous si>rings which break forth from the bottom of the sea. The fresh water is got by diving. The diver, sitting in his boat, winds a great goat-skin bag around his left arm, the hand grasi)ing its mouth ; then he takes in his right hand a heavy stone, to which is attached a strong line, and thus equipped he plunges in, and quickly reaches the bot- tom. Instantly opening the bag over the strong jet of fresh water, he springs up the ascending current, at the same time closing the bag, and is helped aboard. The stone is then hauled up, and the diver, after taking breath, plunges in again. The source of the copious submarine springs is thought to be in the green hills of Osman, some 500 or 600 miles distant. Where Do We Get Ivory? Ivory is a hard substance, not unlike bone, of which the teeth of most mam- mals chiefly consist, the dentine or tooth-substance which in transverse sec- tions shows lines of dififerent color run- ning in circular arcs. It is used exten- sively for industrial purposes and is derived froni the elephant, walrus, hip- popotamus, narwhal, and some other animals. The ivory of the tusks of the African elephant is held in the highest estimation by manufacturers ; the tusks vary in size, ranging from a few ounces in weight to 170 pounds. Holtzapfifel states that he saw fossil tusks on the banks of rivers of Northern Siberia which weighed 186 pounds each. Ivory is simply tooth-substance of exceptional hardness, toughness, and elasticity, due to the firmness and regularity of the dentinal tubules which radiate from the axial pulp-cavity to the periphery of the tooth. How Did Trial by Jury Originate? A jury consists of a certain number of men selected according to law and sworn to incjuire into and determine facts concerning a cause or an accusa- tion submitted to them, and to declare the truth according to the evidence. The custom of trying accused persons before a jury, as practised in this coun- try and Kngland, is the natural out- growth of rudimentary forms of trial in vogue among our Anglo-Saxon ances- tors. The ]>resent system of trial by jury is the result of a gradual growth 240 ANIMALS WHICH FORETELL THE WEATHER under the English Common Law. There is no special reason why twelve is the usual number chosen for a complete jury except the necessity for limiting the number. In a grand jury the num- ber according to law must not be less than twelve nor more than twenty-three, and twelve votes are necessary to fuiil an indictment. The ancient Romans also had a form of trial before a pre- siding judge and a body of judices. The right of trial by jury is guaranteed by the United States Constitution in all criminal cases, and in civil cases where the amount in dispute exceeds $20. A petit or trial jury consists of twelve men, selected by lot from among the citizens residing within the jurisdiction of the court. Their duty is to determine questions of fact in accordance with the weight of testimony presented and report their finding to the presiding judge. An im- partial jury is assured by drawing by lot and then giving the accused, in a criminal case, the right to dismiss a certain number without reason and cer- tain others for good cause. Each of the jurymen must meet certain legal re- quirements as to capacity in general and fitness for the particular case, upon which he is to sit, and must take an oath to decide without prejudice and accord- ing to the testimony. A coroner's jury or jury of inquest is usually composed of from six to fifteen persons, sum- moned to inquire into the cause of sud- den or unexplained deaths. Can Animals Foretell the Weather? Certain movements on the part of the animal creation before a change of weather appear to indicate a reasoning faculty. Such seems to be the case with the common garden spider, which, on the apj)roach of rainy or windy weather, will be found to shorten and strengthen the guys of his web, length- ening the same when the storm is over. There is a popular superstition that it is unlucky for an angler to meet a single magpie, but two of the birds together are a good omen. The reason is that the birds foretell the coming of cold or stormy weather, and at such times, in- stead of searching for food for their young in pairs, one will always remain on the nest. Sea-gulls predict storms by assembling on the land, as they know that the rain will bring earthworms and larvne to the surface. This, however, is merely a search for food, and is due to the same instinct which teaches the swallow to fly high in tine weather, and skim along the ground when foul is coming. They simply follow the flies and gnats, which remain in the warm strata of the air. The different tribes of wading birds always migrate before rain, likewise to hunt for food. Many birds foretell rain by warning cries and uneasy actions, and swine will carry hay and straw to hiding-places, oxen will lick themselves the wrong way of the hair, sheep will bleat and skip about, hogs turned out in the woods will come grunting and squealing, colts will rub their backs against the ground, crows will gather in crowds, crickets will sing more loudly, flies come into the house, frogs croak and change color to a din- gier hue, dogs eat grass, and rooks soar like hawks. It is probable that many of these actions are due to actual uneasi- ness, similar to that which all who are troubled with corns or rheumatism ex- perience before a storm, and are caused both by the variation in barometric pres- sure and the changes in the electrical condition of the atmosphere. Nearest Approach Ever Made to Per- petual Motion in Mechanics. An inventor has patented a double electric battery which seems to come exceedingly near to perj)etual motion. Instead of using the zinc battery, he professes to have hit upon a solution which makes a battery seven times as powerful as the zinc battery, with ab- solutely no waste of material. The power of the battery grows gradually less in a few hours of use, but returns to its original unit when allowed to' rest a few hours. He has two batteries so arranged that the power is shifted from one to the other every three hours. A little machine has been running for HOW PLANTS BREATHE 241 some years in the patent office at New York. Certain parts of the mechanism are constructed of dififerent expansive capacities, and the machine is worked by the expansion and contraction of these under the usual variations of tem- perature. In the Bodleian Library at Oxford there is an apparatus which has chimed two little bells continuously for forty years, by the energy of an ap- parently inexhaustible "dry-pile" of very low electrical energy. A church clock in Brussels is wound up by atmos- pheric expansion induced by the heat of tile sun. As long as the sun shines this clock will go till its works wear out. Mr. D. L. Goff, a wealthy American, has in his hall an old-fashioned clock, \v hich, so long as the house is occupied, never runs down. Whenever the front door is opened or closed, the winding arrangements of the clock, which are connected with the door by a rod with gearing attachments, are given a turn, so that the persons leaving and enter- ing the house keep the clock constantly wound up. Do Plants Breathe? Plants, like animals, breathe the air ; plants breathe through their leaves and stems just as animals do by means of their respiratory organs. When a young plant is analyzed it is found to consist chiefly of water, which is all re- moved from the soil ; there is about 75 per cent or more of this fluid present, and the rest is solid material. Of this latter by far the most abundant con- stituent is carbon, almost every atom of v.-hich is removed from the atmosphere by the vital action of minute bodies con- tained in the green leaves. The carbon is taken into the i)lant as carbonic acid gas. Plants also absorb oxygen, hydro- gen, and nitrogen from the atmos])hcrc in different f|uantities through their leaves, and also by means of their roots. These new proflucts stored arc in turn used in building up the different organs of the i)Iant. Plants give off used-up moisture through their leaves, just as animals perspire through the pores of their skins. Calculations have been made as to the anutunt of water thus perspired by plants. The sunflower, only 3^ ft. high, with 5,616 square inches of surface exposed to the air, gives off as much moisture as a man. What Depth of Snow Is Equivalent to an Inch of Rain? Newly fallen snow having a depth of about 1 1 1-3 inches is equivalent to one inch of rain. A cubic foot of newly fallen snow Aveighs 55^ pounds and a cubic foot of fresh or rain water weighs 62^ pounds or 1,000 ounces. An inch of rain means a gallon of water spread over every two square feet, or about a hundred tons to every acre. The den- sity of snow naturally varies a good deal according to the speed with which it falls. Temperature, also, has much to do with its bulk. In cold, crisp weather, when the thermometer reg- isters several degrees of frost, snow comes down light and dry ; but in moist, cold weather, when the temperature is only just below thirty-two degrees, the snow falls in large, partially thawed flakes, and occupies much less space where it falls than that which reaches the earth during the prevalence of a greater degree of cold. How Are the Stars Counted? Stars are counted by means of the telescope and photography. The As- tronomer-Royal for Ireland, Sir Robert S. Ball, in one of his lectures men- tioned a photograph which had been ol)tained by Mr. Isaac Roberts rci:)re- senting a small part of the constellation of the Swan. The picture is about as large as the page of a copy-book, and it is so crowded with stars that it v;ould puzzle most people to count them ; but they have been counted by a patient person, and the number is about 16,000. Many of these stars are too faint ever to be seen in the greatest of telescopes yet erected. Attempts arc now being made to obtain a munber of similar i)hotographs which shall cover the whole extent of the heavens. The task is indeed an immense one. Assum- ing the plates used to be the same size as that above mentioned, it would re- (juire at least 10,000 of tlicin to repre- 242 HOW FAST DOES THOUGHT TRAVEL sent the entire sky. The counting of stars by the telescope was first reduced to a system by the Herschels, who in- troduced "star-gauges," which were simply a calculation by averages. A telescope of i8 in. aperture. 20 ft. focus, and a magnifying power of iSo, giving a field of view 15 in. in diameter, was used for the purpose. The process con- sisted in directing this instrument to a part of the sky and counting the stars in the field. This, repeated hundreds of times, gave a fair idea of the average nimiber of stars in a circle of 15 in. diameter in all parts of the sky. From this as a basis it is possible to reckon the number of stars in any known area. How Is the Voluine of Sound Measured ? Sound arises from vibrations giving a wave-like motion to the surrounding atmosphere, the wave gradually en- larging as it leaves the source of dis- turbance, while at the same time the motion of the air particles becomes less and less. The simplest method of de- termining the number of vibrations of a sound is by means of Savart's appa- ratus. This consists of two wheels — a toothed or cog-wheel and a driving- wheel. They are so adjusted that the cog-wheel is made to revolve with great rapidity, its teeth hitting upon a card fixed near it. The number of revolu- tions is indicated by a counter attached to the axis of the cog-wheel. Suppose that sound is traveling in the air at the rate of 1,000 ft. per second, and that Savart's wheel is giving a sound pro- duced by 200 taps on the card per sec- ond, it follows that in i.ooo ft. there will be 200 waves or vibrations, and if there be 200 waves in 1,000 ft. each wave or vibration must be 5 ft. in length. The velocity of sound through air varies with the temperature of the latter, but is usually reckoned at 1,130 ft. per second. At What Rate Does Thought Travel? Thought travels iii feet per second, or about a mile and a quarter per minute. Elaborate experiments have been made by Professors Heimholtz, Flersch, and Bonders, to ascertain the facts on this question, the result of which was that they found the process of thought varied in rapidity ill dififerent individuals, children and old persons thinking more slowly than people of middle age, and ignorant people more slowly than the educated. It takes about two-fifths of a second to call to mind the country in which a well- known town is situated, or the language in which a familiar author wrote. \\ e can think of the name of the next month in half the time we need to think of the name of the last month. It takes on the average one-third of a second to add numbers containing one digit and half a second to multiply them. Those used to reckoning can add two to three in less time than others ; those familiar v.-ith literature can remember more quickly than others that Shakespeare wrote "Hamlet." It takes longer to mention a month when a season has been given than to say to what season a month belongs. The time taken up in choosing a motion, the "will time," can be measured as well as the time taken up in perceiving. If it is not known which of two colored lights is to be presented, and you offer to lift your right hand if it be red and your left if it be blue, about one-thirteenth of a second is necessary to initiate the cor- rect motion. What Is the Largest Tree In the World? In San Francisco, encircled by a cir- cus tent of ample dimensions, is a sec- tion of the largest tree in the world — exceeding the diameter of the famous tree of Calaveras by five feet. This monster of the vegetable kingdom was discovered in 1874, on Tule River, Tu- lare County, about seventy-five miles from \'isaHa. At some remote period its top had been broken off by the ele- ments, or some unknown forces, yet when it was discovered it had an eleva- tion of 240 feet. The trunk of the tree was III feet in circumference, with a diameter of 35 feet 4 inches. The sec- tion on exhibition is hollowed out, leav- ing about a foot of bark and several inches of the wood. The interior is 100 WHAT MAKES US FEEL HUNGRY 243 feet in circumference and 30 feet in diameter, and it has a seating capacit)^ of about 200. It was cut oil from the tree about twelve feet above the base, and required the labor of four men for nine days to chop it down. In the center of the tree, and extending through its v.-hole length, was a rotten core about two feet in diameter, partially filled with a sogg)% decayed vegetation that had fallen into it from the top. In the center of this cavity was found the trunk of a little tree of the same spe- cies, having perfect bark on it, and showing regular growth. It was of uniform diameter, an inch and a half all the way : and when the tree fell and split open, this curious stem was traced for nearly 100 feet. The rings in this m.onarch of the forest show its age to have been 4,840 years. Where Did the Term Yankees Origi- nate? This is a word said to be a corrup- tion of Yengees, the Indian pronuncia- tion of Enghsh, or of the French "An- glais," when referring to the English Colonists. It was first applied to the Kew Englanders by the British soldiers as a term of reproach, later by the Eng- lish to Americans generally, and still later to the people of the North by the Southerners. How Far Does the Air Extend? It is, perhaps, generally known that enveloping the earth is a layer of air fifty or more miles in thickness. Just liow thick this layer is we do not know, but we do know that it extends man}'^ miles from the earth. Y'ou may assure yourselves of this in a very simple man- ner by watching the shooting stars that may be seen on any clear night. These are nothing but masses of rocks that give ofT light only when they have been made red-hot by friction with the air in their rapid flight. The fact that we often see these stars while they are still many miles from the earth ])roves to us that the air through which they are passing extends to that height. What Makes Us Feel Hungry? Htmger is a peculiar craving which we are accustomed to sa)^ comes from the stomach. It is the business of the stomach to change such food as we take into it in such a way that the rest of the organs of the body which we have for the purpose can make blood out of it. When you feel the sensa- tion of hunger, it means that the blood- producing system is calling on the stomach to furnish more blood-mak- ing material. The stomach prepares the food for blood production by mix- ing with it certain juices which the stomach is able to supply. As soon as the stomach is then called upon to supply more blood-making material, it goes to work on what is in the stomach and begins mixing things. If, however, there is nothing in the stomach, the craving which we call hunger is produced. It is, therefore, then not altogether the stomach which makes us hungry, but the parts of our body which actually turn the food into blood after the stomach has prepared it To prove this it is only necessary to say that the sensation of hunger will stop if food which is easily absorbed and, therefore, does not need the preparation which the stomach gen- erally gives, is introduced into the sys- tem through other parts of the body, as, for instance, by injecting it into the large intestine, which is a part of the body, the food passes through after it leaves the stomach ordinarily. What Makes Us Thirsty? Thirst is a sensation of dryness and heat which is generally communicated to us through the tongue and throat. The sensation of thirst can be arti- ficially produced by passing a current of air over the membranes which cover the tongue and throat, but thirst is naturally due to a shortage of water in the body. The human body requires a great deal of water to keep it in con- dition, and when the sujiply becomes low a warning is given to us by mak- ing the membranes of the tongue and throat dry. 244 WHERE THE HORIZON IS In connection with thirst, however, as in the case of hunger, where the warning is given by the stomach, thirst will be appeased by the introduction of water, either into the blood, the stomach or the large intestine, with- out having touched either the tongue or throat, which proves that it is not our tongue or throat that is thirsty, but the body itself. What Is Pain and Why Does It Hurt? Pain is the result of an injury to some part of our bodies, or a disturbed condition — a change from the normal condition. Pain is caused by nerves in the body. The network of nerves coming in big nerves from the back bone or spinal chord branches out in all directions, and near the surface of the skin they spread out like the tiny twigs of a tree, covering every point of the body. Some parts of our bodies are more sensitive than others. That is beca'jse the nerves are then nearer the surface or else there are more nerves in that part. The heel is per- haps the least sensitive part of the body, as the nerves do not lie so near the surface there. Pain is not a thing w'hich you can make a picture of or describe in words. Pain is a sensation of the brain caused by a disturbance of conditions in some part of the body. If you cut your finger, you cut certain veins or arteries and also the tiny nerves in the finger. The nerves immediately let the brain know that they are injured, and the brain sets to w^ork to have the damage repaired. But there is a con- gestion right where the cut is. The veins being cut, the blood w^hich would ordinarily flow through them back to the heart, pours out into the cut and the inside of your finger is thus ex- posed to the oxygen of the air, and the action of the air on the exposed part helps to make the pain. It is not your finger, however, that hurts. It is the shock that your brain gets when you cut your finger that hurts. A pain in your stomach is a pain caused by something else than a cut. If the stomach could always digest everything or any amount of stuflf you put in it, you would not have a stomach pain. But sometimes you put things into your stomach through your mouth, of course, that the stomach cannot handle. Or, it may 1)C a combination of a number of things that cause this unusual condition in your stomach. The stomach makes a special efifort to get rid of this trouble- some substance and generally suc- ceeds eventually, but while the fight is going on, it pains or hurts you. Pain is the result of a disturbance of the nerves. It is just the opposite of gladness. We sometimes are so glad we feel good all over. Pain is just the opposite. You can prove that pain is not a real thing but only a sen- sation. Perhaps you have had tooth- ache. You go to the dentist and he kills the nerve or takes it out. After that you cannot have the toothache in that tooth again, because there is no nerve there to telegraph to the brain, even though the cause of the hurt still exists. You cannot feel pain un- less the brain knows about the injury. What Is the Horizon? Of course you know what the hori- zon is. It is easiest to see the horizon at sea when out of sight of land. There, when you look in any direction from the ship to the place where the sea and the sky meet you see a line which, if you follow with your eye as you turn completely around, makes a perfect circle. It looks as though it marked the boundary of the earth. On land it is not easy to see as much of the horizon at one time, because of buildings and trees and hills in the woods and else- where, but if the land were perfectly smooth like the sea and there were no trees or buildings or hills in the w^ay, you could see just as perfect a circle on land as on sea. This proves that the horizon is a movable circle. On land it is where the earth and sky ap- pear to meet, and on water it is v/here sky and water appear to meet. WHY WE HAVE TO DIE 245 How Far Away Is the Horizon? The actual distance of the horizon away from us depends altogether upon the height above the sea level from which we are looking as far as we can. The horizon is always as far away as we can see. At the seashore, where we are practically on a level with the water, we cannot see so far as when we are up on a bluff or hill overlook- ing the sea. The higher we go up straight from a given point the greater the distance we can see up to a certain point and the farther away the horizon will appear. The height of the person looking, of course, figures in this, be- cjiuse when you are at sea level it is only your feet really that are at sea level (if you are standing up straight) and the distance of the horizon is meas- ured from the eye of the person look- ing. A boy or girl of ten would be, say, a little over four feet high, and the eyes of such a person would be about four feet above the level of the sea. At that height the horizon would be about two and a half miles away. If the eyes are six feet above sea level the distance of the horizon will be about three miles, so that prac- tically every one sees a different hori- zon, that is, one that appears at a different distance. A hundred feet above the level of the sea the horizon will be more than thir- teen miles away, while at looo feet altitude it would be 42 miles away, and if you could go a mile into the .'lir the horizon would appear 96 miles from where you are. The higher you go the farther away the circle which apparently marks the joining of the e.'.rth and sky appears. Why Can We See Farther When We Are Up High? Remcinlx-r that tiie earth is round and you will probably be able to an- swer the question yourself. This one. like most (|uestions boys and girls ask, only requires a little thought. The earth, of course, as we have learned long ago, is a globe. When you look out on the land or the sea from a high place you can see more of the earth's round surface before the curve of the earth's surface takes things beyond the range of vision. If you are on a bluff 100 feet high at the seashore and looking toward a point where a ship is coming toward shore, you will be able to see the ship much sooner than if you were at the sea level. In exact words, you actually see more of the earth's surface the higher up you are, because, as you go up your position in relation to the curvature of the earth's surface changes. What Makes lobsters Turn Red? When a lobster is taken out of the lobster trap with which the fisherman traps him, he is green, but when he comes to the table as a choice morsel of food his shell is red. We know that he has been boiled and we know that he goes into the boiling water green and comes out red. This change in the color of the shell of the lobster is the result of the effect of boiling wa- ter on the coloring material in the shell. When the lobster is put in the boiling water the process of boiling produces a chemical change in the color material in the lobster's shell. There is no particular reason why the lobster should turn red, excepting that that is the effect boiling water has on the coloring matter in the shell. Why Do We Have to Die? Death must come to all things that have life. . All matter in the world is either living (animate) or dead (in- animate). Inanimate things do not change. They remain always the same. We can change the form and size of inanimate things, and particles of them even help to make up the bodies of the living things, but what they are made of always remains wiiat it was. Death is one of the things that must occur if we are to contiinie to have w.orc life. 'I'he whole i)lan of living tilings includes the al)ility to re])r()- (luce themselves. I^\'er\- kind of life has the power to produce lil'c like it- self and this process of reproduction is contiiuious. If there were no death, then tile world would soon be crowded with living things to the point where there would be neither room nor food. 246 WHERE WINDOW GLASS COMES FROM X?!- .^-:ak.%; ;*^-v ■J' L Making Plate Glass What Is the Difference Between Plate Glass and Window Glass? How is plate glass made? These questions are asked very frequently. The two products are wholly unlike each other; and we wish to show wherein lies the difference. We shall tell how plate glass is made ; and w^e hope to make it clear that great care, time and expense are involved in its manufacture. The raw materials may be said to be virtually the same in plate glass as in window glass ; the main difference be- ing that in plate glass greater care is exercised in selecting and ])urifying tlie ingredients. Window glass is made with a blow-pipe. The work requires skill on the part of the operator; but the process is quite simple and rapid. And the result is, naturally, a compar- atively ordinary and indifferent prod- uct. On the other hand, the superb quality of plate glass is owing to the elaborate method of producing it. Commercial plate glass was first made in France somewhat more than Pictures herewith by courtesy of I'ittsburgh Plate Glass Co. THE CLAY MUST BE TRAMPLED WITH BARE FEET 247 MIKING SILICA two hundred years ago ; although glass in one form or another 'has been in use for many centuries. Apparently glass was known in Egypt fully four thou- sand years ago. The materials used are silica (w'hite sand), carbonate of soda (soda ash), and lime. Other materials, as arsenic and charcoal, are used in small propor- tions, but the main ingredients are the first three named. Probably it is little imagined that in the production of plate glass, mining is involved in two or more forms (namely silica and coal), also the quar- rying of limestone, the chemical man- ufacture of soda ash on a large scale, the reduction and treatment of fire clay to its right consistency, an elaborate and expensive system of pot naaking; and the melting, casting, roilling, annealing, 'grinding and polishing of the glass. In special uses, as in beveled ])lates and mirrors, two more elaborate proc- esses must be aded — beveling and silvering — all of which are performed imder the direction of e.\y)erts aided by a large amoimt of labor and expensive machinery. I'ots of fire clay take so important a part in the successful manufacture of plate glass that the subject deserves especial notice. The different clays after being mined are exposed to the weather for some time to bring about disintegration. At the proper stage fisely sifted raw clay is mixed with coarse, burned clay and water. This reduces liability of shrinkage and cracking. It is then "P^g'g'ed," or kneaded in a mill ; kept a long time (sometimes a year) in storage bins to ripen; and afterwards goes through the laborious process of "treading." ^Xothing has thus far been found in macliinery by Avhich the right kind of plasticity can be developed as does this primitive treading by the bare feet of men. The clay must be treaded, not once or .twice, but many times. The building of pots is a slow, tedious and time-killing aft'air; but this is most essential. Without extreme care, some elements used in the making of the pots might be fused into glass while undergoing the intense heat of the furnace ; or they might break in the handling. The av- erage j)ot must hold ^about a ton of molten glass, and the average furnace 248 HOW MELTING POTS ARE MADE POT MAKING. heat necessary is about 3,000° Fahren- heit. The work is not continuous. Each workman has several pots in hand at a time, and passes from one to an- other adding only a few inches a day to each pot, so that a proper in- terval for seasoning be given. After completion, comes the proper drying out of the pots; and this is another fea- ture in which the jjreatest scientific care is required. No pot may be used until it has been left to season for at least three months, and even a year is desir- able. And after all this trouble, the pot has but 25 days of usefulness. The pots form one of the heavy items of expense in plate glass manufacture ; and upon their safety great things de- pend. The pot, having been first brought to MIXING THE CLAY, TRAMPLING THE CLAY. HOW THE HUGE PLATES OF GLASS ARE CAST 249 SKIMMING THE POT. the necessary liigh tempera'ture, is filled heaping full with its mixed "batch" of ground silica, soda, Hme, etc Melting reduces the bulk so much that the pot is filled three times before it contains a sufficient charge of metal. When the proper molten stage is reached the pot is lifted out of the furnace by a crane; is first carefully skimmed to remove surface impurities, and then carried overhead by an elec- tric tramway to the casting table This is a large, massive, flat table of iron, having as an attachment a heavy iron roller which covers the full width, and arranged so as to roll the entire length of the table. The sides of the table are fitted with adjustable strips which permit the producing of plates of dififerent thicknesses. The pasty, or half-fluid glass metal is now poured upon the table from the melting pot, and the roller quickly passes over it, leaving a layer of uniform thickness. The heavy roller is now moved out of the way, and then by means of a stow- ing tool the red hot plate is shoved into an annealing oven. All of these stages of the work have to be per- formed with remarkable speed, and by men of long training and experience. The plates remain for several days in the annealing oven, where the temper- ature is gradually reduced from an in- CASTINC, I'l.ATI-. CLASS. 250 HOW THE GLASS PLATES ARE GROUND PREPARING THE GRINDING TABLE. tense heat at first, until at the end of the required period it is no hotter than an ordinary room. When the plate is taken from the annealing- oven it has a rough, opaque, almost undulating appearance on the surfaces. It is only the surface, how- ever, for within it is as clear as crystal. First, it is submitted for careful inspec- tion, so that bubbles or other defects may be marked for cutting out. It then goes to the cutter who takes off the rough edges and squares it into the riglit dimensions ; and thence to the grinding room. The grinding table is a large flat re- volving platform made of iron, twenty- five feet or more in diameter. The ])late must be carried from the anneal- ing oven to the grinding machines, and thence to the racks, by men skilled in the art. Twenty men are required to carry the larger plates of glass, ten on each side, using leather straps and stepping together in perfect time. The lock-step is absolutely essential to pre- vent accident. The grinding table is prepared by being flooded with plaster of Paris and water; then the glass is carefully lowered, and a number of men mount upon the plate and tramp it into place until it is set. After this, greater security is obtained by peg^ging GRINDING THE PLATES HOW MIRRORS ARE MADE 251 with prepared wooden pins ; and then the table is s^et in motion. The grind- ing is done by revolving runners. Sharp sand is fed upon the table, and a stream of water constantly flows over it. After the first cutting by the sand, emer}' is used in a similar manner. The plates are inspected after leav- ing the grinding room, and if any scratches or defects of any kind are found they are .marked. Some of these can be rubbed down by hand. There are also, not infrequently, nicks and fractures found at this stage ; and in such case the plate must again be cut and squared. Afterward comes the polishing, which is done on another special table. The polishing material is rouge, or iron peroxide, applied wdth water, and the rubbing is done by blocks of felt. Reciprocating machin- ery lis so arranged that every part of the plate is brought underneath the rubbing surface. The grinding and polishing has taken away from the original plate half of its thickness, sometimes more. There is no saving of the material ; it has all BEVF.LIN'G PLATES been washed away. When to this waste is added the fact that fully half of the original weight of lime and soda has been released by the heat of the furnace, escaping into the atmosphere in fumes and acids, one may begin to understand something of the cost of converting the rough materials of sand, limestone and soda into beautiful plate glass. In preparing plate glass for mirrors great care must be exercised in tlie selection of the plates. This selection bears reference not only to surface de- fects, but to the quality in general ; de- fects which cannot ordinarily be seen are magnified many fold after the glass has received a covering of silver. In the process of beveling, the plate passes through the hands of skilled w^orkmen of five different divisions, namely : roughers, emeriers, smoothers, white-wheelers and» buffers; and dif- ferent abrasive materials are used in the order indicated by the titles. These materials are' sand, emery, nat- ural sandstone imported from England, pumice and rouge. " The roughing mill is a circular cast- iron disk about 28 inches in diameter, constructed so that the face or top of the mill revolves upon a horizontal plane at a speed of about 250 revolu- tions per minute. The sand is con- veyed to the mill from above through a hopper simultaneously with a stream of water which is played upon the sand to carry it to the mill. The rougher places the edge of the plate upon the rapidly revolving m'ill, and the cutting of the bevel is done by the passage of the sand between the mill and the plate of glass. A bevel of any desired width may be produced. Pattern plates con- taining incurves, mitres, etc., require a practiced eye and gfeat skill upon tlie part of the operator^ When the plate :reaves the rougher's hands the surface of the bevel has been ground so deep by the coarse sand that polishing at this stage is impossible. Consequently, in otder to produce a surface fine enouglv to render it sus- ceptible of a high aim brilliant polish it must go through thd Various treatmeiUs we have mentioned.!-^ The emerier uses a fine grade of eme^' on a mill sinu'lar in construction to' a roughing mill, which takes away considerable of the coarse surface given by the first cutting. Then it goes to the smoother, who re- duces the roughness slowly by using a fine sandstone from l^ngland ; then it goes to the white-wheeler who operates 252 HOW MIRRORS ARE SILVERED an upright poplar-wood wheel usini^ powdered pumice stone as an abrasive ; and then, as a last stage it reaches the buffer, whose method of operation is shown in the illustration. The buffer brings a high polish to the bevel by the use of rouge applied to thick felt which covers his wheel. SILVERING MIRROR PLATES. The plate, after leaving the beveling room, is again carefully examined for surface defects. These defects may con- sist of scratches caused inadvertently by j)ermitting the surface of the plate to come into contact with the abrasive material. These scratches are removed by hand polishing, which must be skill- fully done ; otherwise the reflection will become distorted through over-polish- ing in a given area or spot. The plate is then taken to a wash table where the surface to be silvered is thoroughly washed with distilled water ; after which it is taken to a table that is cov- vered with blankets, and which is heated to a temperature of from 90° to 110°. The blanketing is to protect the plate from being scratched, and also to catch all of the silver waste. The sil- vering solution is nitrate of silver liq- uefied by a certain formula, and is poured over the j^late ; the fluid having an appearance which to the ordinary observer looks hke nothing other than pure distilled water. Within a\ few minutes the silver, aided by a reactory, added prior to pouring, begins to pre- cipitate upon the glass; the liquids re- maining above, and thus preventing air and impurities from coming into con- The two photographs here are of the same building taken under contrasting conditions. 1 he first picture was taken through a window glazed with common window glass. It is an extreme example, to be sure, but of a sort not infrequently seen. The second view shows the same building taken through a window of polished, flawless plate glass. An observing person can see this startling contrast any day as he walks along a residence street. At intervals a front window will be seen which gives a twisted, distorted reflection of the houses or trees on the opposite side: this is window glass. The other kind— the window that gives a sharp brilliant reflection — is plate glass. It is practically impossible to obtain superior reflecting quality from window glass. It can only be had from surfaces which have been ground and polished. WHY THE SKY IS BLUE 253 tact with the silver. Such contact would produce oxidation. After the silver • is precipitated the plate is thoroughly dried, shellacked and painted ; after which it is ready for commercial use. Until about 25 years ago, practically all mirrors were silvered with mercury. There have been two reasons for dis- couraging the use of mercury for sil- vering; one being its injuriousness to the health o.f the workmen. In some European countries stringent laws were enacted, stipulating that men should work only a certain number of hours. Other hygienic stipulations, added to the fact that the use of mercury was already very expensive, have tended to replace that process by the use of nitrate of silver. Why Is the Sky Blue? This question puzzled every one who thought of it for a long time. Even astronomers, the men who make a busi- ness of studying the skies, and other learned men, puzzled their brains about it and searched for the answer long ago, until finally, as always happens when a lot of people study a subject, Professor John Tyndall, a noted scientist of the last century, discovered the answer. The explanation follows : All the light we have is sunlight, which is pure white light. This white light is made up of rays of light of different colors. These rays are red, orange, yellow, green, blue, indigo and violet. It takes all of these different rays of light to make our white sunlight, and when you separate sunlight into its original rays you always produce the rays of light in the above colors and in the same order. This is only true, however, when the sunlight is passed through an object which does not ab- sorb any of its rays. This is the ar- r.'uigcnicnt of the different colors of lij^ht found in the rainbow. The rain- bow is formed by sunlight passing into raindro])s or vapor in such a way as to divide the sunlight into the different colored rays of light. When the rain- bow is formed none of the rays are absorbed by raindrops or vapor through which the sunlight passes. Some of these rays of light are known as short rays and others as long rays. But when sunlight meets other things besides those which make a pure rain- bow, these other objects have the ability to absorb some of the rays of colored light, and they throw off the remainder. When these rays have been thrown oft" those which have been absorbed make many different combi- nations, and thus are produced all of the different colors we know, the vari- ous tints and shades of color, according to composition and size. Now, then, to get back to the color of the sky, which is blue as we know. The sky or air which surrounds the earth is filled with countless tiny specks of what we may call dust — particles of solid things hanging or floating in the air. These specks are of just the size and quality that they catch and absorb part of the rays of light which form our sunlight and throw off the rest of the rays, and the part which has been absorbed forms the combination of color which makes our sky so beauti- fully blue. Sometimes you notice, of course, that the sky is a lighter or darker blue than at other times. This difference is due to the kind and con- dition of tiny specks in the air at the time, and to the direction or angle at which the sunlight strikes these tiny particles. This fact brings up a ques- tion which you have not asked, but which would come naturally as the re- sult of your first. What Makes the Colors of the Sunset? The direction of the sun's rays when they meet these large and small ])ar- ticles in the air has a great deal to do with the combination of colors that result as these objects absorb part of the rays and throw off others. The sky is the most beautiful blue when the sun is high in the sky. lUit when the sun is setting the light has a greater dis- tance to travel through the belt of air which surrounds the earth thAn when it is high up over our heads. You 254 WHAT MAKES THE COLORS IN THE RAINBOW kix)\v that it you stick a pin straight down into an orange it won't go in very far before it is clear through the jKcl, but if you stick the pin into an orange along the edge it will go through a great deal more of the peel than the other way. That is the way it is with the sunset colors. The peel of the orange is a good representation of the belt of air which surrounds the earth. At sunset the light instead of coming straight down through the belt of air, thus meeting the eye through the short- est possible amount of air. strikes the air on a slant, and, therefore, travels through a great deal more air and closer to the earth to reach it, with the resuUs that it meets a great many more of these little specks, besides all the smoke and other things that hang in the air near the ground, and we thus get many more colors, because some of the things in the air absorb some of the rays and others absorb very different rays when the light comes in this slanting way, and that is what makes the different colors in the sunset. For this reason sunsets are often richer and more beau- tiful in color when the air is not so pure, but has much dirt and other matter floating about in it. Are There Two Sides to the Rainbow? Xo, there is only one side to the rainbow. The rainbow is made by re- flection of the rays of sunlight through drops of water in the air, but you can never see a rainbow unless you are between it and the sun. You could r.ever see a rainbow if you were look- ing at the sun, and so if you are look- ing at a rainbow you can be certain that anyone on the other side of it could not see it, because they would have to b^ looking right at the sun. The rain- bow is always opposite to the sun and there can never be two sides to it. Do the Ends of the Rainbow Rest on Land? The ends of the rainbow do not rest on anything. You see, the rainbow is only the reflection of the sun's rays thrown back to us by the inside of the back of the raindroi)S, which are still in the sky after the rain. Of course, if any of the drops of water touched the ground they would cease to be rain- droj)s and, therefore, could not reflect the rays of the sunlight. So, what we think of as the ends of the rainbow do not really exist at all. The rainbow is only a reflection of the rays of sun- light from countless drops of water in the air, which the sun's rays must strike at a certain angle in order to reflect back the light so we can see it. Where the sun's rays do not strike the drops of water at the right angle no light is reflected, and there is the end of the rainbow. What Causes the Different Colors of the Rainbow? The colors of the rainbow, which are always the same, and are shown in this order — red, orange, yellow, green, blue and violet — are sunlight broken up into its original colors. It takes all of these colors in the ])roportions in which they are mixed in the rainbow to make the pure sunlight. These are known as the prismatic colors. As shown in another answer to one of your puzzling ques- tions, the rainbow is caused by the rays of the sun jiassing into drops of water in the air and reflected l)ack to us with one part of the drop of water acting on it in such a way as to break up the pure sunlight into these prismatic colors. When a rainbow appears at a time when there is a great deal of sun- light, you will generally see two rain- bows. The inner rainbow is formed bv the rays of the sun that enter the upper part of the falling raindrops, and the outer rainbow is formed by the rays that enter the under part of the raindrops. In the inner or primary bow, as it is called, the colors beginning at the outside ring of color are red, orange, yellow, green, blue and violet, and being exactly reversed in the outer or secondary bow. The seconflary bow is also fainter. You may sometimes see smaller rainbows, even if it has not been raining, when looking at a foun- tain or waterfall. These are caused in exactly the same way. What Makes the Hills Look Blue Some- times ? This is due to the fact that when the hills look blue you are looking at them at a distance, and there is a long stretch of air between you and the hills. This air is filled with countless par- ticles of dust and other things, and what you see is not really blue hills, but the reflection of the sun's rays from the little particles in the air striking your eye. The color is due to the angle at which the light from the sun strikes these particles, and is reflected back to your eye and partially due to the char- acter of the particles in the air. Do the Stars Really Shoot Down? The answer is "No." We have come to use the expression "shooting stars" commonly, but we should probably be more correct if we said "shooting rocks," for the things we refer to com- monly as "shooting stars" are more like rocks than anything else. If any of the real stars were to fall into the air surrounding the earth we should all be burned up by the great heat de- veloped long before it actually hit the earth, which it would undoubtedly destro3^ The things that fall and leave a streak of light are really only pebbles, stones, rocks or pieces of iron and other substances that fall from some place iiito the earth's air belt. When they strike the air at the speed at which they are falling the friction of the air makes a heat that causes them to be- come luminous, and by far the greater part of them is burned up before they get very near the earth. We call them meteorites. Sometimes, though rarely, one will manage to strike the earth, coming at such great speed and being so large that the air has not been able to burn it u]) comjjletely, and it will strike the earth and sink deep down into the soil. In most museums can be seen such meteorites that have been dug up after striking the earth. These are constantly falling itUo the air surround- ing the earth, but in the day-time their light is not strong enough to be seen while the sun is shining. Will the Sky Ever Fall Down? No, the sky can never fall down, be- cause it is not made of the kind of things that fall. We have become used to thinking of it as the roof of the earth, a great dome-shaped roof, be- cause in our little way of looking at things we compared the earth and what is above it with the houses in which we live. The sky is just space in which the heavenly bodies revolve in their orbits. We cannot really ever see sky. We see only the sun's light reflected by the air belt which surrounds the earth. In this air belt are the clouds which do come closer to the land at times than at others, and this is apt to aid in giving us an incorrect im- pression of this. What Is the Milky Way? The "Galaxy," or "Milky Way," as it is popularly called, is a luminous circle extending completely around the heavens. It is produced by myriads of stars, as can be seen when you look at it through a telescope. It divides into tv.o great branches at one point, which travel for some distance separately and then reunite. It has also several branches. At one point it spreads out very widely into a fanlike shape. Why Do They Call It the Milky Way? The stars in the group are so numer- ous that they present to the naked eye a whiteness like a stream of milk. To produce this efifect there are not hun- dreds of stars, nor thousands of them, but actually millions of them. When you stoj) to tliink that each one of these stars in tlie Milky Way is a sun like our own — some of them smaller, of course, but many of them much larger — you begin to realize how impossible it is for man to form any real idea of the magnitude and wonders of the earth. Here in the Milky Way arc so many suns like our own sun > that they together as we look at them form the j:)articles of a path which makes the circle of the heavens, and yet are so far away that to the naked eye each of them looks to us like only one of countless drops of milk in a very large stream of milk that goes around the whole sky. Why Don't the Stars Shine in the Day- time? The stars do shine in the day-time. If you will go down into a deep well or the open shaft of a deep mine and look up at the sky, of which you can see a circular patch at the top of the well, you will be able to see the stars in the day-time. The moon also shines in the day-time, on some part of the earth. At certain times during the month you can notice that the moon rises before the sun sets, and sometimes in the morning you can still see the moon in the sky after the sun is up. Usually you cannot see either the moon or the stars in the day-time, because the light from the sun is so bright and strong that the light of the stars and moon are lost in the brightness of the sun's rays. When the moon is visible before the sun sets or after the sun has risen it is because the light of the sun is not so bright and strong at the beginning or close of daylight. If you are for- tunate enough some time to witness a total eclipse of the sun you will be able to see the stars in day-time without hav- ing to go down into a deep well or mine shaft. How Far Does Space Reach? Space surrounds all earths, planets, suns, and extends for an infinite dis- tance beyond each of them in all di- rections. It is impossible to measure in terms of human knowledge how far space extends. It is one of the things beyond the comprehension of the human mind, and for that reason man can never know in miles or the number of millions of miles how far it extends. Man has been able to measure the dis- tance from the earth of some of the stars, and some of the nearest of them are millions of miles from the earth. Most of them are hundreds and even thousands of million miles away, and when we stop to tiiink that space ex- tends at least as far on the other sides of the stars as it does on this side, and even beyond that, we can readily under- stand that it is not only imi)()ssiblc to measure space, but also im])ossible to give in words any concej^tion of what its limits might be. There is one word — infinite — which we are forced to use in speaking of the extent of space. Infinite means "with- out end," unbounded, and so man has come to use the word "infinite" in de- scribing the extent of space, and that is as near as any one can describe it. What Does Horse Power Mean? The term "horse power" is used in describing the amount of power pro- duced by an engine or motor. When man made the first engines he needed some term to use in describing the amount of power his engine could de- velop. Up to that time man had used the horse for turning the wheels of his machinery and the horse to him naturally represented the most power- ful animal working for man. When engines came into use they replaced the horses because they were capable of developing many times the power of the horse. In finding an expression which would accurately convey to the mind of another the power of a par- ticular engine, it was natural to say that this engine would do the work of five, ten or more horses, and as this described it accurately and in a way that was entirely clear, it became cus- tomary to describe the power of an engine as so many times the power of one horse. To-day we still cling to the term "horse power" in describing the strength of the engine, although the horse-power unit used to-day is greater than the power of an average horse. To speak of an engine of one horse power to-day means an engine that has the power to lift .^0,000 pounds one foot in one minute. WHERE OUR COAL COMES FROM 257 A COAL BREAKER. Coal is brought in mine cars from several mine shafts and slopes, dumped onto a conveyor that runs on the inclined framework shown at the right of the picture. At the top it is broken in rolls, sorted and sized as it slides through the different screens, pickers, etc., and is finally delivered into railroad cars. The Story in a Lump of Goal How Did the Coal Get Into the Coal Mines? The heavy black mineral called coal, which we burn in our stoves and fur- naces, and use to heat the boilers of our engines was formed from trees and plants of various sorts. Most of the coal wais- formed thousands of years ago at a time when the atmosphere that envelopes the earth contained a much larger proportion of carbonic acid gas than it does now, and the climate of all regions of the earth was much warmer than it now is. This period was known as the carboniferous age, that is, the coal-making age, and its at- mospheric conditions, favored the growth of plants, so that the earth was covered with great forests, of trees, giant ferns, and other plants, many of which are no longer found on the earth. In the warm, moist, and carbon-laden atmosphere of that period the growth of all kinds O'f plants was rapid and luxuriant, and as fast as old trees fell and partially decayed, others grew up in their places. In this way, thick layers of vegetable matter were formed over the soil in which the plants grew. In many places, where these beds were formed, the surface of the earth be- came depressed and the water of the sea flowed over the beds of veg;etable matter. Sediment of various kinds was de- posited over the vegetable matter, and in the course of centuries the sedi- ment was transfonned into rock. After the formation of the covering of sediment, the decay of the vegetable matter was checked, but a slow change 258 MINE WORKERS THAT NEVER SEE DAYLIGHT Underground stable con- structed of concrete and iron, with natural rock roof to avoid danger of fire. Mules are only taken to surface when mines are idle. of another kind was brought about by the pressure of the sedimentary deposits and the heat to which the plant re- mains were subjected. The hydrogen and oxygen which constituted the greater part of the plant substance was driven off and the carbon left behind. This change took place very gradually, through periods so long that we can only 'guess at their duration, but we know that many beds of coal were formed from layers of vegetable matter that were covered up many thousand years ago. The coal first formed and submitted longest to pressure is known as hard coal, or anthracite. It is pure black, or has a bluish metallic luster. Its spe- cific gravity is 1.46; which is about the same as that of hard wood. Anthra- cite contains from 90 to 94 per cent, of carbon, the remainder beinig com- posed of hydrogen, oxygen, and ash. Hard coal may be called the ideal fuel and is especially adapted to do- mestic heating purposes. It burns without smoke and produces great heat. There is no soot deposit upon the walls of chimneys, and in good stoves or furnaces the small amount of gas given off by it is consumed. Anthracite is the least abundant of all the varieties of coal and is much more costly than the other varieties. For this reason it The Mules and their drivers. — An important part of the haulage sys- tem. Mules are kept in stables on surface at this mine and driven in every day through slope or drift. 4 HOW THE SLATE PICKERS WORK 259 Boy slate pick- ers. Coal slides down the chutes. Boys pick out the slate and rock and throw into chute alongside. is not much used in manufacturing. The coal formed later is very dif- ferent in composition and is called bi- tuminous or soft coal. Its name is de- rived from the fact that it contains a soft substance called bitumen, which oozes out of the coal when heat is ap- plied to it. Soft coal contains from 75 to 85 per cent, of carbon, some traces of sulphur, and a larger per- centage of oxygen and hydrogen than anthracite. When soft coal is heated Spiral slate pickers do work of many boys. Coal and rock start together at the top in the small inner spiral. The coal being lighter slides faster, and in going around is carried over the edge into the outer spiral, while the rock con- tinues in the bottom. 260 HOW A COAL MINE LOOKS INSIDE Shaft gate. One of the two cages in the shaft has just brought the men to the surface; the other is at the bottom. Safety gate rest- ing on top of cage covers top of shaft when cage is down, as shown at right. Section showing Anthracite Seams. Coal is shown black ; rock and dirt lighter ; shaft tunnels and workings, white. Upper part of " Mammoth " seam is stripped and quar- ried. Lignite mine in Texas. Loaded mine cars ready to go to surface. Undercutting with pick. The man lying on his side cuts under the coal. A light charge of powder exploded in a drill hole near the roof breaks the coal down in large pieces. in a closed vessel or retort, the hydro- gen and oxygen, in combination with some carbon, are driven off. Soft coal is black, and upon smooth surfaces it is glossy. It lacks the bluish luster sometimes seen in hard coal and is much softer and more easily broken. When handled it blackens the hands more than hard coal does. In this kind of coal are frequently seen the outlines of leaves and stems of plants that en- ter into its formation. Occasionally, trunks of trees with roots extending down into the clay below the bed of coal have been found. Soft coal has a specific gravity of 1.27. It burns with a yellow flame which is larger than the flame from hard coal, but it does not emit so high a degree of heat. Combustion, gen- erally imperfect, gives rise to offensive gases and to black smoke that concen- Unrlcrcutting in seam. A compressed air driven machine undercuts deeper and faster than the man with a pick. ^^M^^^^'m^: 1-4 1^ ■^ ^• 11- ^^ ■: ■ iw ' <-■; ^^^^Pf fi^^^^^KP J m ■ 1 B&' K^-,Ei w^- ■^ OHBB 262 THE DANGERS TO THE MINERS trates in the air and falls to the ground as soot, which blackens buildings, and. in winter, noticeably discolors the snow. The formation of lig-nite has been observed in the timbers of some old mines in Europe. In some of these mines wooden pillars have been sup- porting: the rocks above for four hun- dred years or ilonger, and in that time the pressure of the rocks and other in- fluences acting upon the wood of the pillars have caused it to become trans- formed into a brown substance re- sanbling lignite. This fact tends to confirm the theory of coal formation stated at the beginning of this article. The proportion of carbon in lignite is never above 70 per cent., and the ash indicates the presence of considerable earthy matter. It is chiefly used in those forms of manufacture where a hot fire is not required. In Europe it is used, to some extent, in heating the houses of the poorer classes. Peat is regarded as the latest of the coal formations. In it, the change in the vegetable matter has not extended beyond merely covering it, and subject- ing it to slight pressure. Peat is formed in marshy soils where there is a considerable growth of plants that are constantly undergoing partial decay and becoming covered by water. It consists of the roots and stems of the plants matted together and mingled with some earthy material. When freshly dug out of the bog or marsh in which it was formed there is always a quantity of water in it, the amount being greatest in the peat found nearest the surface and least in that at the bottom of the bed, where the peat is not very different in appearance from lignite. Peat is used for fuel where wood is scarce and coal is high in price. Re- cent experiments in saturating peat with petroleum, have shown that in this way a form of fuel may be produced for which considerable value is claimed. Its manufacture is confined to Southern Rui;sia. "where peat is plentiful and petroleum is cheap. Why Does Firedamp Explode in a Safety Lamp Without Producing an Explo- sion of the Gas With Which the Lamp Is Surrounded? Tlie i)assing of the flame from the lamp to the outside air is prevented by the gauze. This splits the burning gas into little streamlets (784 to each square inch of gauze), which are cooled below the point of ignition, that is, are extinguished by coming in contact with the metal of the gauze, so that the flame does not pass outside the lamj). In some cases the explosion may be so great as to force the flame through the gauze and thus ignite the gas out- side. Are There Any Conditions Under Which it Would Not Be Safe to Use a Safety Lamp? The underground conditions aflfect- ing the safety of the lamp are exposure in air-currents of high velocity by rea- son of which the flame may be blown through or against the gauze, or ex- posure for too great a time to mixtures of air and gas which will burn w'ithin the lamp and thus heat the gauze. The dangerous velocity of air-currents be- gins at about 500 feet a minute, but varies with the type of lamp, some being much less sensitive to air-cur- rents of high velocity than others. Other conditions under which the lamp is not safe concern the lamp itself or the one using it. The lamp is dan- gerous in the hands of inexperienced persons or when the gauze is dirty or broken. If the gauze is dirty, that portion absorbs the heat and may be- come hot enough to ignite the outside gas ; naturally any holes in the gauze will pass the flame. The safety lamp when left too long in air containing much explosive gas may cause an explosion, and it is ex- tinguished by certain unbreathable gases. The electric lamp burns safely regardless of the atmosphere, but gives no warning of poisonous or explosive gases. It is often used by rescue men wearing oxy^gen helmets to enter mines THE LAMP WHICH SAVES MANY LIVES 263 full of poisonous gases after explo- sions. The safety lamp is dangerous when there is a hole in the gauze that will permit the passage of flame to the out- side, or when the gauze is dirty, so that any particular spot may be overheated, or when the velocity of the air is so great that the flame is blown through the gauze, or (generally) when in the hands of an inexperienced person. The unbonneted Davy lamp is not safe where the velocity of the air exceeds 360 feet per minute. The velocity with w^hich the air strikes a lamp car- ried against it is increased by the amount equal to the rate at which the fireboss travels. If he walks at the rate of, say, 4 miles an hour or 352 feet a minute (on the gangways he will usually have to move faster than this to make his rounds on time) he will create by his own motion (and in still air) a velocity practically the same as that at which the unbonneted Davy is considered unsafe. The safety lamp. The sheet iron bonnet or covering of the upper part protects the gauze within from strong currents of air, while the glass permits the light to be diflused. The above is a modem lamp similar to a bonnetted Clanny lamp. History of the Safety Lamp. The safety :lamp. the miner's faitiiful and indispensable companion at his dan- gerous work, has been, heretofore, con- sidered as the invention of the famous ICnglish 'scientist, Humphrey Davy, though the name of George Stephen- son, of locomotive fame, has also been mentioned in this connection. Both came out with their inventions about the same time, but neither of them is Open oil lamp commonly worn on hat. Wick is inverted in spout. the real inventor of the safety lamp ; for there was, as proven by Wilhelm Nie- man, a safety lamp in existence two years before Davy's invention became known. It was not inferior to the latter, but rather surpassed it in illu- minating power. Previous to this, all the precaution employed for the pre- vention of the threatening dangers of firedamp had been quite incomplete. One tried to thoroughly ventilate the mines by fastening a burning torch to a large pole, which was pushed ahead and exploded the gases. This was ex- tremely dangerous work which, in the Middle Ages, was generally done by a criminal, in order that he might atone for his crimes, or by a penitent for the benefit of mankind. The attempt to Acetylene or carbide lamp for caj) or hand. subslituc for the open light pho-sphores- cent su1)stanccs, encased in glass, was not much of a success. An improve- ment was the so-called steel mill, in- vented about 1750 by Carlyle S|)C(l(ling. 264 THE MAN WHO INVENTED THE SAFETY LAMP manager of a mine. This steel mill consisted of a steel wheel which was put into rapid motion by means of a crank. By pressing a firestone against the fast revolving wheel, an incessant shower of sparks was produced giving a fairly good and absolutely safe il- lumination. However, the running ex- penses of his apparatus, which neces- sitated the continual services of one man, were very high ; for instance, the expenditure for light in a coal mine ELECTRIC CAP LAMP AND BATTERY. The safety lamp when left too long in air containing much explosive gas may cause an explosion, and it is extinguished by certain un- breathable gases. The electric lamp burns safely regardless of the atmosphere, but gives no warning of poisonous or explosive gases. It is often used by rescue men wearing oxygen hel- mets to enter mines full of poisonous gases after explosions. near Newcastle in the year 1816 amounted to about $200 per week. Nevertheless, the steel mill was very much appreciated and in use for a long time, only to be slowly supplanted by the safety lamp. At the beginning of the nineteenth century the existing coal mines were worked to the limit and the catastro- phies, caused by firedamp, increased in an alarming manner. In fact the dis- tress was so great that in 1812 a society for the prevention of mine disasters was formed at Sutherland, and the origin of the safety lamp can be traced back to the efforts and labors of this organization. Dr. William R e i d Clanny, a retired ship's surgeon, was probably the first to undertake the task (in the year 1808), which he success- fully finished with energy and skill. He concentrated his efforts at first on the se])aration of the flames from the surrounding atmosphere, but he did not succeed till the latter p^rt of 1812, when he constructed a lamp that seemed to meet all requirements. The report of this invention was submitted to the Royal Society of London, May 20, 1813. and was printed in the min- utes of that academy. The casing of this original safety lamp was closed at the top and bottom, by two open water tanks ; the air was pumped in by means of bellows and, passing in and out, had to go through both these resevoirs which acted as valves, so to speak. The lamp proved to be absolutely safe and was successfully introduced by the management of Herrinigton Mill pit mine. The clumsy parts of this appa- ratus were eliminated by its inventor by various improvements. The so-called steajTi safety lamp was completed in December, 1815, and installed in sev- eral mines. In the meanwhile, two competitors made their appearance. George Stephenson had finished his lamp October 21, 1815. and Davy ]mb- lished his first experiments November 9, 1815, in the Transactions of the Royal Society of London. Clanny's lamp, nevertheless, stood the test in the face of this competition, through its much superior illuminating power, and more particularly as it still continued to burn when the Davy and Stephenson lamps had gone out. To Clanny, there- fore, belongs the distinction, in the his- torv of invention, of having constructed the first reliable safety lamp. WHAT IS THE MOST VALUABLE METAL? 265 What Is a Metal? The oldest known metals in the world are gold and silver, copper, iron, tin and lead. They are to-day still the most useful and widely-used metals. Some of the properties by which we distinguish metals are the following: They are solid and not transparent ; they have luster and are heavy. Mer- cury is an exception to the rule ; it is a liquid, though yet a metal, and there is another, solium, which is solid, though very light. What Is the Most Valuable Metal? If you were guessing you would nat- urally say that gold is, of course, the most valuable of the metals. But you would be wrong. The proper answer to this is iron. We do not mean the pound for pound value, for you could get much more for a pound of gold than for a pound of iron. We mean in useful value — iron is in that sense the most valuable metal known to man. This is true because iron is of such great service to man in so many ways, and it is very for- tunate that there is such a great amount of it available for man's pur- poses. Iron is not generally found in a pure state in the mines. It is gener- ally found compounded with carbon and other substances, and we obtain pure iron by burning these other sub- stances out of the compound. Iron is put upon the market in three forms, which differ very much in their properties. First, there is cast-iron. Iron in this form is hard, easily fusible and quite brittle, as you will know if you ever broke a lid on the kitchen range. In the form of cast-iron it cannot be forged or welded. Next comes wrought-iron, which is fjuite soft, can be hammered out flat or drawn out in the form of a wire and can be welded, but fusible only at a high temi)crature. Third comes steel, the most wonderful thing we produce with iron. It is also mallealjle, which rr.eans that it is caj^ablc of being ham- mered out flat and can easily be welded, and this is the great property of steel — it acquires when tempered a very high degree of hardness, so that a sharp edge can be put on it, and when in that shape it will easily cut wrought- iron. Ordinarily we make wrought- iron and steel from iron that has been changed from its original state to cast- iron. The term cast-iron is generally given to iron which has been melted and cast in any form desired for use. Stoves are made in this way. The iron is melted and then poured into a mold ; while the product out of which wrought-iron and steel are made is technically cast-iron, the term pig-iron is used in speaking of iron which is cast for this purpose. The process by which pig-iron is changed into wrought-iron is called puddling. The object of puddling, \vhich is done in what is called a re- verbratory furnace (which is a furnace that reflects or drives back the flame C'r heat) is to remove the carbon which is in the pig-iron. This is done partly by the action of the oxygen of the air at high temperature and partly by the action of the cinder formed by the burning furnace. When this has been done the iron is made into balls of a size convenient for handling. These are "shingled" by squeezing or ham- mering and passed between rolls by which the iron is made to assume any desired form. Now we come to steel, the most wonderful product or form in which we take advantage of the value of iron. Steel was formerly made from v/rought-iron, so that you first had to get cast-iron, from which you made wrought-iron, and eventually got steel by changing the wrought-iron. Now we make steel direct from ])ig-iron. This is known as the Resscmer process. The most noticeable feature in the chemical composition of the difi"ercnt grades of iron and steel is found in the percentages of carbon they contain. Fig-iron contains the most carbon ; steel the next lowest, and wrought-iron the least. Iron has been known (o nii'ti from early historical times. 'I he smelting of iron ores is not any indication of ad- vanced civilization either. Savage tribes in many parts of the world prac- ticed the art of smelting, even before they could have learned it from people who had become civilized. Why Is Gold Called Precious? Gold is called one of the precious metals because of its beautiful color, its luster, and the fact that it does not rust or tarnish when exposed to the air. It is the most ductile (can be stretched out into the thinnest wire), and is also the most malleable (can be hammered out into the thinnest sheet). It can be hammered into leaves so thin that light will pass through them. Pure gold is so soft that it cannot be used in that form in making gold coins or ill making jewelry. Other substances, generally copper, are added to it to make the gold coins and jewelry hard. Sometimes silver is also added to the gold with copper. The gold coins of the United States are made of nine parts of gold to one of copper. The coins of France are the same, while the coins of England are made of eleven parts of gold to one of copper. The gold used for jewels and watch- cases varies from eight or nine to eighteen carats fine. Another reason why gold is called a precious metal is that it is very dif- ficult to dissolve it. None of the acids alone will dissolve gold, and only two of them when mixed together w'ill do so. These are nitric acid and hydro- chloric acid. When these two acids are mixed and gold put into the mix- ti-re the gold will disappear. What Do We Mean By 18-Carat Fine? We often hear people in speaking of their watches say, "It is an i8-carat case." Others speak of 14-carat watches or 22-carat or solid-gold rings. When you see the marks on a v.^atch-case or the inside of a gold ring they read 18 K or 14 K, or whatever number of carats the maker w'ishes to indicate. A piece of gold jewelry marked 18 K or 18 carats means that it is three- fourths pure gold. In ar- ranging this basis of marking things made of gold, absolutely pure gold is c.'dled 24 carats. Then if two, six or ten twenty-fourths of alloy has been added, the amount of the alloy is de- ducted from twenty-four, and the re- sult is either 22, 18 or 14 carats fine, and so on. On ordinary articles made by jewelers the amount of pure gold used is seldom over 18 carats, or three-fourths. Weddings rings (and these are considered solid gold) are generally made 22 carats fine, that is, there are only two twenty- fourth parts of alloy in them, "Why Does Silver Tarnish? Silver is a remarkably white metal, which is associated with gold as one of the precious metals. It is harder than gold and will not rust, although it will tarnish, which gold will not, when ex- posed to certain kinds of air. The silver tarnishes when it is ex- posed to any kind of air that has sul- phur mixed in it. It ranks below gold a:3 a precious metal for use in making ornaments and is not so costly, be- cause there is a great deal more of it to be found in the world. While silver is somewhat harder than gold, it is still not sufficiently hard to use pure for making coins, so, as in the case of the gold coins, it is mixed with something else — copper — to harden it. Otherwise our dimes and quarters would wear out too rapidly. Our silver coins are made of nine parts of silver to one of copper. The coins of France are in the same proportion, while the silver coins of England are made of 92^ parts of silver to 73/2 parts of copper. German silver coins are made of three parts of silver and one of copper. Why Do We Use Copper Telegraph Wires? One of the characteristics which dis- tinguishes copper is its color — a pe- culiar red. It stands next to gold and silver in ductility and malleability, and WHY LEAD IS SO HEAVY 267 comes next to iron and steel in te- nacity — which means the ability of its tiny particles to hang on to each other. That is why copper wire bends in- stead of breaking when you twist it. But that is not the only reason, al- though an important part of the rea- son, why we use copper for telegraph wires. Copper is an extremely good conductor of electricity when it is pure. So are gold and silver, but we cannot afford to buy gold and silver wires for the telegraph, telephone and other wires, and if we used such wires the cost of the equipment would be so great that we could not afford to have telephones in our homes. But there is a great deal of copper in the world and it is very cheap, and so it makes an ideal element for use in things through which electricity is to pass. When you compound it with other sub- stances it loses some of its conduc- tivity. Copper is used extensively in many ways in the world. This book is , printed, for instance, from copper electrotype plates. The whole business of electrotyping is based on the use of copper. Why Is Lead So Heavy? Lead is a white metal and is noted for its softness and durability. It has a luster when freshly cut, but becomes dull quite soon after the freshly-cut surface is exposed to the air. Lead is the softest metal in general use. It can be cut with an ordinary knife. It can be rolled out into thin sheets, but cannot be drawn out into wire. Lead is a very dense metal, that is, its particles are very compact and there is no room for air to circulate in between these particles. A piece of wood is lighter than a jiiece of lead of exactly equal bulk, l)ecausc the little particles which make up the piece of wood are not very close together, and there is a lot of air in the ordinary piece of wood, while this is not true of the lead. A great deal of lead is used in mak- ing pipes for plumbing. This is be- cause lead pipe is comparatively cheap, although you might not think so when you think of the general conclusions we have been brought to form about plumbers and everything connected with them. Lead pipe is easily bent in any direction also, and is particularly good for use in plumbing for that reason. Another wide use of lead is in mak- ing paints — white lead being the base used in making oil paints. The process of making white lead for paint is quite interesting and pictures of it are shown in "The Story In a Can of Paint" in another part of "The Book of Won- ders." Why Are Cooking Utensils Made of Tin? Tin is the least important of the six useful metals. It is also inferior in many ways to the others in this group of elements, but is tougher than lead and will make a better wire, though not a really good one. It has a white- ness and a luster that are not tarnished by ordinary temperature and is cheap. That is why it is used in making cook- ing utensils, pans, etc., and for roofs. But the pans, roofs, etc., are not pure tin. They are thin sheets of iron coated with tin. Pure tin would not be strong enough for these purposes, so a sheet of iron is first taken to sup- ply the strength and then covered with tin to improve the appearance of the tin pans and keep them from rusting rapidly. What Is Gravitation? Gravitation is the result of the at- traction which every body, no matter what its size* has for every other body. It is a strange force and difficult to explain in plain words. It is what keeps the heavenly bodies in their jxilhs. Every one of the ])lancts is held in its path by gravitation and every object on each of the planets is kept on the planet by gravitation. Wc can come nearer understanding gravi- tation by studying the effect of tlic at- traction of gravitation on our own earth and the obji'cts on it. When you 268 WHAT SPECIFIC GRAVITY MEANS throw a ball or a stone into tlie air il: is the attraction of gravitation that causes it to come back. If this were not so the stone would go on up and up and would keep on going forever. If it were not for this wonderful force you could jump into the air and just keep on going up with nothing to bring you back. Tlie reason you do not pull the earth toward you is because the body or mass with the greater bulk has always the greater pulling power. This is a wonderful force. It can- not be produced nor can it be destroyed or lessened. It just is. It acts be- ^•een all pairs of bodies. If other bodies come between any pair of bodies the attraction of gravity be- tween the two outside bodies is neither lessened or increased, and yet each of the outside bodies will have an inde- pendent attraction or pull on the body which is in between. No particle of time is spent by the transmission of the force of gravity from one body to another, no matter how far apart they may be. The only effect that distance has on the attrac- tion of gravitation is to lessen its fc>rce. Any body which is being pulled through gravity toward another body v.-ould fall toward the center of the attracting body if all the force of at- traction from all other bodies were removed. What Is Specific Gravity? Specific gravity is the ratio of weight of a given bulk of any sub- stance to that of a standard substance. The substances taken as the standard for solids and liquids is water, and air or hydrogen for gases. Since the weights of different bodies are in pro- portion to their masses, it follows that the specific gravity of any body is the same as its density, and we now gen- erally use the term "density" instead of specific gravity. To find, for instance, the specific gravity of a given bulk of silver, we must take an equal bulk of water and weigh it. Then we also weigh the sil- ver. We find that the silver weighs ten and a half times as much as the water, and so the specific gravity of silver is 10.5. If you will bear in mind that water is the standard used for measuring the specific gravity of solids and liquids, and that air or hy- drogen are used as standards for the gciscs, you will always know what the figures after the words specific gravity mean. Why Do We See Stars When Hit On the Eye? We do not really see stars, of course, when we are hit on the eye or when we fall in such a way as to bump the front of our heads. What we do see, or think we see, is light. To understand this we must go back to the explanation of the five senses — sight, hearing, feeling, tasting and touching. Now, each of these senses has a special set of nerves through which the sensations received by each of the senses is communicated to the brain and, as a rule, these special nerves receive no sensations excepting those which occur in their own par- ticular field of usefulness. The eye then has nerves of vision ; the nose, nerves of smell ; the ear, nerves of hearing ; the mouth, nerves of taste, and the entire body nerves of touch. As we have seen then, these special nerves are susceptible of receiving impres- sions or sensations only in their par- ticular field. But, if you should be able to rouse the nerves of smell in an entirely artificial way and give them a sensation, they might easily act very much as though they smelled some- thing. We find this often in the nerves of touch when we think we feel some- thing when we do not. Now, when some one hits you in the eye, the nerves of vision are disturbed in such a way as to produce upon the brain the sensation of seeing light. In other words, you cannot affect the eye nerves without causing the sensation of light, and that is just what happens when some one hits you in the eye. HOW A BOAT CAN SAIL UNDER WATER 269 ARGONAUT, JUNIOR. Experimental Boat, i8< ARGONAUT THE FIRST. Built 1896- 1897. The Story in a Submarine Boat How Can a Ship Sail Under Water? Up to a few years ago the stories we could tell about the ships that sail beneath the water were the creations of the minds of writers of fiction, hke the author of "Twenty Thousand Leagues Under the Sea," but to-day we can read of many actual trips be- neath the water by the brave men who man our sulmiarines. We never dreamed that the great story of Jules Verne would be realizefl in the little but very destructive ships of war which can be seen to-day in tlic naval ports of the nations of the wc^rld. We might have had these submarines long ago but for the fact that the men who were trying to invent them would not give up the secrets which they had discovered. Many men in different ])arts of the world worked on this ])roblem and each discovered one or more things which were valual)le in working out a solution, and if they had all gotten together and compared notes between them they could have produced a submarine boat almost as good as those we have to-day. 270 HOW A SUBMARINE IS SUBMERGED How Does the Submarine Get Down Under the Surface? The first essential in a vessel to en- able it to navigate below the surface of the water is that it be made suf- ficiently strong to withstand the sur- rounding pressure of water, which in- creases at the rate of .43 of a pound for each foot of submergence. A boat navigating at a depth of 100 feet would therefore have 43 pounds pressure per square inch of surface, or 6192 pounds for every square foot of surface. It will readily be seen, therefore, that the first essential is great strength. Therefore, the sub- marine boats are usually built circular in cross section with steel plating riv- eted to heavy framing, as that is the best form to resist external pressure. These boats are built for surface navi- gation as well, therefore they have a certain amount of buoyancy when navi- gating on the surface, the same as an ordinary surface vessel. When it is desired to submerge the vessel this buo)^ncy must be destroyed, so that the vessel will sink under the surface. Now, the submerged displacement of a submarine vessel is its total volume, and, theoretically, a vessel may be put in equilibrium with the w^ater which it displaces by admitting water ballast into compartments contained Avithin the hull of the vessel, therefore, if a ves- sel whose total displacement submerged was 100 tons, the vessel and contents must weigh also 100 tons. If it weighed one ounce more than 100 tons it would sink to the bottom. If it weighed one ounce less than 100 tons it would float on the surface with a buoyancy of one ounce. If it weighed exactly 100 tons it would be in what submarine design- ers specify as being "in perfect equi- librivmi." It is possible to give a vessel a slight negative buoyancy to cause her to sink to, say, a depth of 50 feet and then pump out sufficient water to give her a perfect equilibrium, and thus cause her to remain at a fixed depth w^hile at rest. In practice, however, this is sel- dom done. Most submarine boats navi- gate under, the water with a positive buoyancy of from 200 to 1000 pounds and are either steered at the depth desired by a horizontal rudder placed in the stern of the vessel, or are held to the depth by hydroplanes, which hydroi)lanes correspond to the tins of a fish. They are flat, plane surfaces, ex- tending out from either side of the vessel, and when the vessel has head- way, if the forward ends of these planes are inclined downward, the resistance of the water acting upon the planes is sufficient to overcome the reserve of buoyancy and holds the vessel to the desired depth. If the vessel's propeller is stopped, the boat, having positive buoyancy, will come to the surface. By manipulating either the stern rud- ders or the hydroplanes, the vessel may be readily caused to either come nearer to the surface or go to a greater depth, as the change of angle will give a greater or less downpull to overcome the reserve of buoyancy. The above description applies to nav- igating a vessel wdien between the sur- face of the w'ater and the bottom. Another type of vessel w'hich is used for searching the bottom in locating wrecks, obtaining pearls, sponges, or shellfish, is provided with wheels. In this type of vessel the boat is given a slight negative buoyancy, sufficient to keep it on the bottom, and it is then propelled over the water bed on wheels, the same as an automobile is propelled about the streets. This type of vessel is also provided with a diver's com- partment, which is a compartment with a door opening outward from the bot- tom. If the operators in the boat wish to inspect the bottom, they go into this compartment and turn compressed air into the compartment until the air pressure equals the water pressure out- side of the boat ; i. e., if they were sub- merged at a depth of 100 feet they would introduce an air pressure of 43 pounds per square inch into the diving compartment. The door could then be opened and no water could come into the compartment, as the diving com- partment would be virtually a diving bell. Divers can then readily leave the boat by putting on a diving suit and stepping out upon the bottom. ONE OF THE FIRST PRACTICAL SUBMARINES 271 "protector." 13U1LT I9OI-I9O2, BRIDCKPOKT, CONN. This was the pioneer Submarine Torpedo Boat of the level-keel type, and w.as built in Bridgeport in 1901-1902. It was shipped to St. Petersburg, Russia, during the Russian- Japanese war. From St. Petersburg it was shipped to Vladivostok, 6000 miles across Siljeria, special cars being built for its transport. rw , v.ri^'f^'^- h This picture iiluslratcs the same vessel, also at full speed under engines, with the conning-towcr entirely awash and with the sighting-liood and the Omniscopc alone above water. Notwithstanding the limited areas exposed above the surface, still observation could be had well-nigh continuously cither through tlie dcad-lighls in the sighling-hood or by means of the Omniscopc. In neither condition is it necessary to have recourse to ilcrlrical proi)ulsion — (he boats can still be safely and si)eedily driven as here shown luidrr tluir engines. 272 THE INSIDE OF A SUBMARINE TIIF. "G-t' RKCENTI.V DEI.IVKRF.n TO THE UNITED STATES GOVERN' ME XT. Tlie largest, fastest submarine in the United States and the most powerfully armed submarine torpedo boat in the world. In addition to the usual fixed torpedo tubes arranged in the bow of the vessel, which requires the vessel herself to be trained, the (seal) '"G-i" carries four torpedo tul)es on her deck which may be trained while the vessel is submerged, in the same manner as a deck gun on a surf.i.ce vessel is trained, and thus fired to either broadside, which gives many technical advantages. The above view gives a general idea of the interior of a submarine torpedo boat and the method of operation when running entirely submerged with periscope only above the surface. The commanding officer is at the periscope in the conning tower directing the course of the submarine through the periscope, which is a tube arranged with lenses and prisms which gives a view of the horizon and everything above the surface of the water, the same as if the observer in the submarine was himself above water. The steersman is shown just forward of the commanding officer and steers the vessel by compass under the direction of the commanding officer, the same as w^hen navigating above the surface. In the larger type boats the steersman also has a periscope which enables him to see what is going on above the surface. Below decks two of the crew are shown loading a torpedo into the torpedo tube ; each torpedo is charged with gun-cotton and will run under its own power over a mile and will e.xplode on striking the enemy. The crew live in the com- partment aft of the torpedo room. Aft of this is the engine room, in which art iocated powerful internal combustion engines for running on the surface and electric tootors for running submerged. The electric motors are driven by storage batteries located under the living quarters. Wheels are shown housed in the keel, which may be lowered for navigating on the bottom in shallow water. A diving compartment in the bow permits divers to leave the vessel when on the bottom, to search for and cut or repair cables or to plant mines. A SUBMARINE SAILING CLOSE TO THE SURFACE 273 A sLibmarine running partly submerged with the connnig tower hatch upon, showing the remarkable steadiness of this type of boat in a semi-submerged condition, a thing no otlier craft could safely accomplish. v Another bubniariiie running entirely .subnierged, periscope only showing. The flag is attached to top of periscope to show her position in maneuvers when periscope goes entirely under water. 274 THE EYE OF A SUBMARINE A PHOTOGRAPH TAKEN WITH THE PERISCOPE UNIVERSAL LENS. AN ALL-SEEING EYE FOR THE SUBMARINE Vision under water is limited to but a few yards at best, and hence a sub- marine boat, when submerged, would be as blind as a ship in a dense fog and would have to grope its way along guided only by chart and compass, were it not for a device known as a peri- scope, that reaches upward and pro- jects out of the water, enabling the steersman to view his surroundings from the surface. Of course the height of the periscope limits the depth at which the craft may be safely sailed. Nor can the periscope tube be extended indefinitely, because the submarine must be capable of diving under a ves- sel when occasion demands. But when operating just under the surf ace, where it can see without being seen, the craft is in far greater danger of collision than vessels on the surface, because it must depend upon its own alertness and agility to keep out of the way of other boats. The latter can hardly be ex- pected to notice the inconspicuous peri- scope tube projecting from the water in time to turn their great bulks out of the danger course. The foregoing article describes the type of periscope now in common use on submarines and one of the engrav- ings on this page clearly illustrates the principles of the instrument. A serious defect of this type of instrument is that the field of vision is too limited. The man at the wheel is able to see under normal conditions only that which lies immediately before the boat. SEEING IN ALL DIRECTIONS AT ONCE 275 it is true that he can turn the periscope about so as to look in other directions, but this, of course, involves consider- able inconvenience. On at least two occasions has a submarine boat been run down by a vessel coming up behind it. As long as the submarine has but a single eye it would seem quite essential to make this eye all-seeing ; and since the two lamentable accidents just re- ferred to, an inventor in England has devised a periscope which provides a view in all directions at the same time. This has been attempted before, but it has been found very difficult to ob- tain an annular lens mirror which would project the image down the peri- scope tube without distortion. The accompanying illustrations show how this difficulty has now been overcome. While we will not attempt to enter into a mathematical explanation of the precise form of the mirror lens, it will suffice to state that it is an annular prism. The prism is a zonal section of a sphere with a conoidal central opening and a slightly concave base. All the surfaces, however, are generated by arcs of circles owing to the me- chanical inconvenience of producing truly hyperboloidal surfaces. The lens mirror is shown in section at A in Fig. I. The arrows indicate roughly the course of the rays into the lens and their reflection from the surface B, which is preferably silvered. The tube is provided with two objectives C and D (Fig. 3) between which a condenser E is interposed at the image plane of the lens C. At the bottom of the peri- scope tube the rays are reflected by means of a prism F into the eyepiece. Two eyepieces are employed. One of lower power, G, is a Kelner eyepiece, the purpose of which is to permit in- spection of the whole image, while a high-powered eccentrically placed Huy- ghenian eyepiece, H, enaljles one to inspect portions of the image. The two eyepieces are mounted in a rectilin- ear chamber, /, which may be rotated about the prism at the end of the peri- scope, thus bringing one or other of the eyepieces into active position. The plan view, Fig. 4, shows in full lines the high-powered eyepiece in operative position, while the dotted lines indicate the parts moved about to bring the low-powered cyci)icce into use. A small catch, /, shown in Fig. 2, serves to liold the chamber in cither of these two ])ositions. The high-jx^wered eye- ])icce is mounted on a ])late, A', which may be rotated to bring the eyepiece into position for inspecting any desired portions of the annular image. The parts arc so arranged that wheti the (ye])iece is in lis uppermost position, 276 HOW WE LOOK THROUGH A PERISCOPE riii; I'EUiscoi'E TOP. as indicated by lull lines in Fig. 2, the observer can sec that which is (hrectly in front of the submarine, and when the eyepiece is in its low position, as indicated by dotted lines, he sees ob- jects to the rear of the submarine. With the eyepiece at the right or at the left he sees objects at the right or left, respectively, of the submarine. The high-powered eyepiece is slightly iticlined, so that the image may be viewed normally and to equal advan- tage in all parts. Mounted above a plain unsilvered portion of the mirror is a scale of degrees which appears just outside of the annular image. A scale is also engraved on the j^late K with a fixed pointer on the chamber, making it possible to locate the position of any object and rotate the plate K so as to bring the eyepiece H on it. The scale also makes it possible to locate the ob- ject with respect to the boat. This improved periscope is appli- cable not only to submarine boats but for other purposes as well, such as pliotographic land surface work, in which the entire surroundings may be recorded in a single photograph. The accompanying photograph, taken through a periscope of this type, shows the advantages of this arrangement and gives an idea of its value to the submarine observer when using the low-powered eyepiece. Of course, by using the other eyepiece any particular part of the view may be enlarged and examined in detail. PERISCOPE IN GENER.AL USE. THE UN1VERS.\L OBSERVATION LENS. INSIDE OF A MINE=PLANTINQ SUBMARINE 277 :T' .2 >> = •o s > c c o (U -C ^ a; (t) -*-• u i-i ■ ' < cfl (U u '^ > £ S^^ " _Q :3 (u 5 ^, ^^^ S 3 a "o.S ^f^ OJ u ■ ':;;'o (U (U C > c^-c OJ ^ — 1 tn n 4-1 C TD 3 <» u h— H UJ f) lU a. JIJ u a S (« E (U rt I« x: U C CTi c u> hn <"> c c b "O oj -0 (U oJ c c rt J= be •*H "•^ bfl n !/l n Tl t/i J- x: (LI tj H rrt OJ c <« (U J>i 0. 6 b «j c 0. c u (U > C (U OS Ih c u u. OJ 03 u. 1 rt ^ ^ C ^ ""* Uc c 3 o en > C j:: 3 IM O o , >> aj u O C u "" -o rt , ' o J^ c u dJ x: T1 iJ 1) i/i a, a R E 3 C Ul 3 280 WHO MADE THE FIRST SUBMARINE BOAT? Story of How the Submarine Has Been Developed. It is only within the past twenty years that man has been able to suc- cessfully navigate under the surface of the water. It has been a dream of inventors and engineers for the past three hun- dred years. During the reign of King James I. a crude submarine vessel was built of wood, and was designed to be propelled by oars extending out through holes in the side of the vessel, the water being prevented from coming in through the openings by goat skins tied about the oars and nailed to the sides of the boat, which made a water-tight joint, but at the same time gave flexi- bility to the oars, so that by feathering them on the return stroke they could be manipulated to give head motion. Very little, if any, success could have attended this effort. Nearly a hundred years later a man by the name of Day built a submarine and made a wager that he could de- scend to lOO yards and remain there 24 hours. He built a boat and sub- merged it in a place where there was a depth of 100 yards. He succeeded in remaining the 24 hours, and accord- ing to latest ad^nces is still there, as he never returned to the surface. There is very little information as to the construction of these early craft. The first really serious attempt at sub- marine navigation was made by a Con- necticut man, a Dr. David Bushnell, who lived at Saybrook during the Rev- olutionary War. He built a small sub- marine vessel which he called the "American Turtle," and with it he ex- pected to destroy the British fleet, an- chored off New York during its occu- pation by General Washington and the Continental Army. Thatcher's Military Journal gives a description of this vessel and describes an attempt to sink the British frigate "Eagle" of 64 guns by attaching a tor- pedo to the bottom of the ship by means of a screw manipulated from the interior of this submarine vessel. A sergeant who operated the "Tur- tle" succeeded in getting under the British vessel, but the screw which was tc hold the torpedo in place came in contact with an iron scrap, refused to enter, and the implement of destruc- tion floated down stream, where its clockwork mechanism linally caused it to explode, throwing a column of water high in the air and creating consterna- tion among the shipping in the harbor. Skippers were so badly frightened that they slipped their cables and went down to Sandy Hook. General Wash- ington complimented Dr. Bushnell on having so nearly accomplished the de- struction of the frigate. If the performance of Bushnell's "Turtle" was such as described, it seems strange that our new govern- ment did not immediately take up his ideas and make an appropriation for further experiments in the same line. When the attack was made on the "Eagle," Dr. Bushnell's brother, who was to have manned the craft, was sick, and a sergeant who undertook the task was not sufficiently acquainted with the operation to succeed in attach- ing the torpedo to the bottom of the frigate. Had he succeeded the "Eagle" would undoubtedly have been destroyed and the event would have added the name of another "hero" to history and might then have changed the entire art of naval warfare. Instead of Bushnell being encouraged in his plans, how- ever, they were bitterly opposed by the naval authorities. His treatment was such as finally to compel him to leave the country, but he returned after some years of wandering, and under an as- sumed name, settled in Georgia, where he spent his remaining days practicing his profession. Robert Fulton, the man whose genius made steam navigation a success, was the next to turn his attention to sub- marine boats, and submarine warfare by submerged mines. A large part of his life was devoted to the solution of this problem. He went to France with his project and interested Napoleon Bonaparte, who became his patron and who was the means of securing suf- ficient funds to build a boat which was HOW SUBMARINES WERE DEVELOPED 281 called the "Nautilus." With this vessel Fulton made numerous descents, and it is reported that he covered 500 yards in a submerged run of seven minutes. In the spring of 1801 he took the "Nautilus" to Brest, and experimented with her for some time. He and three companions descended in the harbor to a depth of 25 feet and remained one hour, but he found the hull would not stand the pressure of a greater depth. They were in total darkness during the whole time, but afterward he fitted his craft with a glass window i^ inches in diameter, through which he could see to count the minutes on his watch. He also discovered during his trials that the mariner's compass pointed equally as true under water as above it. His experiments led him to believe that he could build a submarine vessel with which he could swim under the surface and destroy any man-of-war afloat. When he came before the French Admiralty, however, he was met with blunt refusal, one blufT old French admiral saying: "Thank God, France still fights her battles on the surface, not beneath it," a sentiment which apparently has changed since those days, as France now has a large fleet of submarines. After several years of unsuccessful efiforts in France to get his plans adopted, Fulton finally went over to England and interested William Pitt, then chancellor, in his schemes. He built a boat there, and succeeded in attaching a torpedo be- neath a condemned brig provided for the purpose, blowing her up in the presence of an immense throng. Pitt induced Fulton to sell his boat to the I'.nglish government and not bring it to the attention of any other nation, thus recognizing the fact that if this type of vessel should be made entirely success- ful, Fngland would lose her supremacy as the "Mistress of the Seas." Fulton consented to do so, but would not pledge himself regarding his own country, stating 'that if his country should become engaged in war, no l)lcdge could be given that would pre- vent him from offering his services in any way which would be for its benefit. The English Government paid him $75,000 for this concession. Fulton then returned to New York and built the "Clermont" and other steamboats, but did not entirely give up his ideas of submarine navigation, and at the time of his death was at work on plans for a much larger boat. Fulton had a true conception of the result of submarine warfare, and in a letter he says : "Gunpowder has within the last three hundred years totally changed the art of war, and all my reflections have led me to believe that this application of it will, in a few years, put a stop to maritime wars, give that liberty on the seas which has been long and anxiously desired by every good man, and secure to Americans that liberty of commerce, tranquillity, and independence which will enable citizens to apply their mental and cor- poreal facilities to useful and humane pursuits, to the improvement of our country and the happines of the whole people." After Fulton's death spasmodic at- tempts were made by various inventors looking to the solving of the dif^cult problem, but no very serious efforts were put forth until the period of the Civil War, and then a number of sub- marine boats were built by the Confed- erates. These boats were commonly called "Davids," and it was one of them that sank the United States steamship "Housatonic" in Charleston Harbor on the night of the 17th of February, 1864. This submarine ves- sel drowned four different crews, a total of thirty men, during her brief career. At the time she sank the "Hou- satonic" her attack was anticipated, and sharp lookout was kept at all times ; but, notwithstanding their vigi- lance, she succeeded in getting sufti- cicntly close to plant a tor])edo on the end of a sj)ar, and sink this line, new shij) of i4(X) tons dis])lacement. It will be seen from the above de- scription that these vessels, while able to go unen tree, about 30 inches in length, is made to revolve ir what is known as a peeling machine. After a few revolutions the rough outer surface is removed, and thin rolls of smooth-surfaced wood are peeled oft' or veneered. The machine at the same time scores the wood ready for folding by the boxmaking machine. Cut into skillets, i. e., into pieces of the size re- quired for box covers or insides, the ends are next dipped in pink dye to cover the edge of the wood which is not covered by the label. The skillets then go to the box machines, which fold and label them, and after half an hour in a cleverly devised drying chamber they are ready for use. In one room alone sixty machines are labelling and folding the skillets to the number of several thousand gross a day. To see these machines take a strip of wood, push it forward to receive the pasted label, fold it, fasten the joint, wipe off the superfluous paste, and, finally, toss the finished "outside" into a receiving basket, is as fascinating an example of mechanical ingenuity as the industrial world can afford. Are Matches Poisonous? A non-poisonous "strike anywhere" safety match, made from selected, clear, strong cork pine is now made in this country, and is the first satisfactory non-poisonous match. It is also the first match to be endorsed by the coun- try's recognized leaders and authorities in fire prevention and the conservation of human life and property. The Hughes-Esch Anti-White Phos- phorus Match Bill, which became a law during the administration of President Taft, was drafted by the attorneys of the American Association of Labor Legislation, and is the most drastic that our National Constitution will permit. It would be unconstitutional to abso- lutely prohibit the manufacture of white phosphorus matches, but the IIughes-Esch bill obtains the same re- sult, viz. : absolute prohibition by means of excessive taxation. No match man- ufacturer in these days of keen com- petition can afi^ord to pay a tax of ten cents On each box of white phosphorus matches made, and place his factory under government surveillance, for this tax of ten cents is over three times as much as his present selling price to the wholesale trade. As soon as man learned to make fire and light, he began to appreciate how much more comfortable he could be if he could keep his lights burning and to have his light independent of his fire, because it was at times very un- comfortable to sit by a fire on a hot night simply because he wished to use the light which it made. The first schemes devised for lighting purposes merely were the camp-fire torch and the rushlight. With these as a basis, man was enabled to fashion more con- venient forms of lighting. He in- vented the candle and the lamp, and grown "enlightened," boxed his- light in iron and in other metals. Did Candles Come Before Lamps? The candle is in appearance a primi- tive affair, yet there is little doubt that its predecessor was the lamp. Those old Egyptian tombs, which have un- locked many mysteries, held lamps, and through them evidence of ancient burial customs. Lamps played a part in the solemn feasts of the Egyptians, who on such occasions placed them be- fore their houses, burning them throughout the night. Herodotus, in one of his numerous references to Xerxes, alludes to the hour of lamp- lighting, and evidences abound regard- ing the use of lamps among the ancient Greeks. Lamps, indeed, are pictured upon some of their oldest vases, indi- cating the symbolic significance which attached to them. THE EARLIEST FORMS OF LAMPS 295 A French watch tower of the fifteenth century in time of siege. The tower is lighted by means of beacons and is protected by dogs. Ruins of such a tower can still be seen at Godesberger on the Rhine. What Were the Earliest Lamps? It is probable that the earhest lamps were nothing more than convenient vessels, filled with oil and fired by means of rushes. Among the Romans pine splinters, the torch and the flam- beau, supplied light until the fifth cen- tury before Christ, and even when the Roman began to use the lamp, it was by no means common, finding a place only in the homes of the rich, or on special festival days. The custom of burning funeral lights beside the dead before interment is a very old one. Gregory, interpreting its significance for the Christian, says that departed souls, having walked here as the children of light, now walk with ("iod in the light of the living. The Roman, I 'liny, refers to the use of the ])ith of brittle rushes in making funeral lights and watch-candles, which were probably the ancient jjrototype of the old rushlight of England. Again, in speaking of flax, Pliny states that the part of the reed that is nearest to the outer skin is called tow, and is good for nothing but to make lamp-matches or candlewicks. What Were the Lamps of the Wise and Foolish Maidens Made Of? When lamps had come into general favor, better attention was given to their form and construction. The first seem to have been made of baked clay, moulded by hand into elongated ves- sels to contain the oil, and provided at one end with a lip to admit the wick. These are the lamps which artists have pictured in the hands of the wise and foolish virgins, though in the opinion of some scholars they were merely rods of porcelain and iron, covered with cloth and steeped in oil. Another early type, which was less common, presents a simple disc with an aperture in the centre for the oil, and a hole for the wick, at one or both of the sides. Under the Empire, when the light of the lamp had become general, the better ones were made of bronze, orna- mented with heads, animals, and other decorations, attached to the handles, while as life in Rome partook more of luxury and extravagance, gold, silver, or Corinthian brass were the materials, the designs being more elaborate and complicated. Many and beautiful ex- amples of these ancient lamps have been unearthed from the ruins of Her- culaneum and Pompeii. When Were Street Lamps First Used? Dark must have been the lives of those people who, until comparatively recent times, lived, in the absence of sunlight, by the feeble, uncertain light of the primitive illuminants borne by these lamps. And as for street light- ing — that was a luxury but seldom in- dtilged in, and then, not for ])ublic benefit, but to enhance the glory of a potentate, or grace the obsecfuies of some great man. Iwen Rome, at the height of her luxury and beauty, rarely exhibited more than one or two lanterns in her streets. These were suspended 296 THE FIRST STREET LIGHT IN AMERICA over the baths and places of pubHc resort. Occasionally, however, the streets were illuminated during festi- vals and other public occasions, while the Forum was sometimes lighted for eighteenth century the candles were made by dipping the wicks into melted wax or tallow, but about this time an ingenious Frenchman conceived the idea of casting them in metal moulds. The first street light in America. Early in 1795 sever- al large cressets were placed on the corners of BoSiton's most frequented street. Pine- knots were placed in these fire baskets b}' the night watch- a midnight exhibition. With these glit- tering exceptions, and that memorable one when, to satisfy the homicidal im- pulses of a bad emperor, the bodies of Christians were made living torches, Rome was a city of darkness. When Were Candles Introduced? Historical records indicate the preva- lent use of candles in the earliest days of Rome, but these candles were of the simplest sort — mere string or rope which had been smeared with pitch or wax. In the early Christian centuries it was the custom to dip rushes in pitch and coat them with wax, a method of candle-making that was long continued, for it was not until the fourteenth cen- tury that dipped tallow candles were introduced. In the Middle Ages w^ax candles provided the usual means of illumination, and these were made, not by common craftsmen, but by monks, or by the servants of the rich. Until the fifteenth century their use was con- fined to churches, monasteries and the houses of nobles, but the demand for them had become so great that the chandlers of London obtained an act of incorporation. As late as the A part of the "Amende Honorable" of Jacques Coeur before Charles VII of France. It is only within a modern period that the state or city has assumed re- sponsibility in the matter of public lighting, which for the most part had been left to the good will and public spirit of citizens. But in England a A pagan votive lamp of bronze, now in the museum at Naples. THE FIRST OIL LANTERN 297 The first "Reverbere" — oil lantern — with a metal reflector, used to light the streets of Paris. It was invented by Bourgeois de Chateaublanc in 1765, and used until the introduction of gas. proclamation was issued to the effect that every individual should place a candle in each of the lower windows of his house, and keep it burning from nightfall until midnight. Paris was the first city to improve upon this method of street lighting, and in 1658 huge, vase-like contrivances, filled with resin and pitch, were set up in the principal thoroughfares. The no honest man would venture abroad without his torch or flambeau, and as London, Berlin, Vienna, and all leading cities of Europe, were in like case, the darkness of Paris could be borne. But progress had been made, and early in the eighteenth century the Cor- poration of London entered into con- tract with a certain individual to set up public lights, giving him permission to exact a sum of six shillings from every householder whose actual rent exceeded ten pounds. In the middle of the same century the Lord ]\Iayor and Common Council applied to Parliament for power to light the streets of Lon- don better. From the granting of this permission dates improvement in pub- lic lighting. Where Did the Word "Gas" Originate? A Belgium chemist. Van Helmont, coined the word "gas" in the first half of the seventeenth century. The Dutch word "geest," signifying "ghost," suggested the term to him, and his superstitious neighbors hounded him into obscurity for talking of ghosts. Argand got his first sug- gestion for his burner — invented in 1780 — from this style of alcohol lamp, then in general use throughout France. improvement proving, as may readily be seen, both dangerous and exnensive, the falct, so-called, were replaced by the lantern. This was at first simply a rude frame, covered with horn or leather, within which a candle burned. For more than one hundred ye^irs this was the extent of the illumination which the authorities could provide. But of course it was understood that Hanging lamp from Nushagak in South- ern Alaska. It is suspended from the framework of the tent by cords. Oils and fats from northern animals give a clear and steady likdit, and Eskimo lamps are fro(iuontly jir.-ii'-rd l>y travelers. SIX MILLION" CUBIC FOOT GAS HOLDER. Almost every boy and girl has seen the big tank near the gas works, and most of them have wondered what was in it and what it is for. This big tank is a "holder" in which the gas is stored after it is manufactured. The giant holders are reservoirs from which gas is constantly being taken and the quantity on storage constantly replenished, as the ordinary gas plant never ceases manufacturing its product. There is little or no danger of an interruption of the supply by reason of accident, as gas plants are always equipped with duplicate apparatus for emergencies. HOW THE GAS GETS INTO THE GAS JET 299 When Illuminating Gas Was Discovered. How Does Gas Get Into the Gas Jet ? The first practical demonstration of the value of gas made from coal for lighting was made by a Scotchman — Robert Murdock — who in 1797, after some years of experimenting, fitted up an apparatus in the workshop of Boul- ton and W'att, in Birmingham, Eng- land, which successfully lighted a por- tion of that establishment. The ad- vantages of this kind of lighting were so apparent that its use was rapidly extended, although in many instances the people were afraid of it. For a time this kind of lighting was confined to street lights. One of the first great structures to be lighted by gas was Westminster Bridge in London, and great crowds gathered to watch the burning jets nightly. It was difficult to remove from the minds of the peo- ple the belief that the gas-pipes were filled with fire and the jets were only openings through which the flame in the pipes escaped. People sometimes touched the pipes expecting to find them hot, and when the pipes were put in buildings they made sure that they were placed several feet from the walls lest the fire in them set fire to the buildings. The use of illuminating gas for lighting private houses developed quite slowly because of this fear of the fire in the gas-pipes. This was not en- tirely unwarranted, however, because at first the plumbers did not know, as they do now, how to prevent leakage of gas from the pipes. The methods of joining the pipes were oftentimes im- perfect and, not realizing the dangers which would follow leaks, causing ex- plosions, the workmen were often care- less in installing the pipes. The first American house in which gas was used for lighting was the home of David Mellvillc at Newport, H. I. Baltimore, Maryland, was the first American city to use gas for light- ing. It was introduced there in 1.S17. If you hold a cool drinking glass over a burning gas jet for a moment, a film of moisture will form on the inside of the glass and remain until the tumbler becomes warm, and then disappear. Now, then, you will re- member that water is a mixture of oxy- gen and hydrogen, and that when hy- drogen is burned in the air, water is formed. It is also true that whenever water is formed by burning anything, hydrogen is present in it. You see, therefore, that the gas used for lighting purposes must contain hydrogen. Let us now learn something more about what gas is made of. Wet a piece of glass with a little fresh lime water and hold this over the lighted gas jet. In a few moments a change takes place in the water. The water turns somewhat milky. This indicates the presence of carbonic acid gas, and the formation of carbonic acid gas, when burning is going on, means the presence of carbon. From these two experiments we gather that the gas in the jet contains hydrogen and carbon. All kinds of illuminating gas contain these two sub- stances. Sometimes there are small quantities of other substances present, but the value of gas for lighting de- pends on hydrogen and carbon. We have already learned about hy- drogen, but it would be well to re-learn about carbon. Carbon is an element, and an ex- tremely important one, for a large part of the comi)Osition of every living thing is carbon. It is found in more com- pounds than any other element. Almost pure carbon can easily be obtained by heating a ]Mece of wood, in a covered utensil, until it is turned into charcoal. Charcoal, which is black, is composed almost entirely of carbon. It is a very interesting product in all ways ; in con- nection with gas we are particularly interested in the fact that carbon will burn when heated in the air or in oxygen. (harcoal is very much like hard coal, both bcjng formed in practically the 300 WHERE THE GAS IS TAKEN FROM THE COAL GENERATOR HOUSE AND IJS-FT. STACK. In the process of gas making, coal is placed in the generator and heated to an incandescent state, then from the top or bottom steam is admitted and forced through the heated coal, producing a crude water gas which is passed on to the carbureter. In this shell enriching oil is produced, but as the oil and the water gas do not effectually unite, they are passed on to the superheater, where, as its name implies, they are subjected to a high temperature which thoroughly gasifies them into a permanent gas. AN INTERIOR VIEW OF GENERATOR HOUSE. • Pictures on Gas Manufacture by courtesy of the Consolidated Gas, Electric Light and Power Co. of Baltimore. ILLUMINATING GAS MUST BE SCRUBBED 301 .SH.Wl.NO bCKUliliKKh. After passing into the scrubbers the gas is cooled, passed into the scrubbers, and by contact with wooden slat trays, made up like screens; a large portion of the tar is removed from the gas, the tar passing off to large receptacles. 302 HOW ILLUMINATING GAS IS MADE same way. Ages of years ago many large forests of trees were buried under a layer of soil and rocks, during changes that occurred in the earth's surface, and the hot inside earth slowly heated the wood, until almost nothing was left but the carbon. Soft coal was formed in much the same manner, but the process was not so completely finished. Alixed with the carbon in soft coal we find quite a good deal of other substances, of which hy- drogen forms the principal part. This is what makes soft coal valuable in the making of illuminating gas. When soft coal is heated in a closed receptacle a gas is formed which will burn. To show this we have only to take an ordinary clay pipe, put a little piece of coal in the bowl, close the top with wet clay, and put the bowl part of the pipe in the fire. When it is quite hot, a gas will be found coming out of the stem of the pipe, which will, when lighted, burn. The Story In a Gas Jet. Soft coal is heated in large tubes of fire clay called retorts, and the gas that is formed is then collected in a large tank and sent through pipes to our homes after being purified. The part of the coal that is left consists largely of carbon and is what we call coke. While the gas that comes directly from coal will burn if lighted, it is not a desirable gas to burn in our homes, because it contains a number of sub- stances that should be eliminated before it is used for lighting. How the Gas Is Purified. From the clay retorts the gas passes through horizontal pipes containing water. This cools it and takes out of it most of the tar and water vapor that are driven ofif with the gas when formed. These substances settle in the water. The gas then goes through a series of curved pipes, which are air cooled. These pipes constitute what is known as an atmospheric condenser. From these the gas goes into a series of receptacles containing wooden slat trays, made up like screens. These re- ceptacles are called the scrubbers, and they take out of the gas the last traces of tar and some of the other com- pounds found present. The removal of the sulphur is very important, for burning sulphur gives off a gas which is not only extremely impure to breathe, but also injurious to the health. From the scrubbers the gas goes on through pipes to the purifiers — boxes v.'hich contain wood shavings coated with iron rust upon which the sulphur is deposited by chemical action. At the same time the lime absorbs a small quantity of carbonic acid gas, which is formed with the other gases. From the purifiers the gas passes into the great iron tanks, in which it is stored until needed. The gas in the tanks consists chiefly of hydrogen, a number of compounds of hydrogen and carbon, and a small amount of a compound of carbon and oxygen containing less oxygen than carbonic acid gas, known as carbon monoxide. The hydrogen and carbon monoxide burn with a very pale flame, which gives but little light and much heat. The light-giving quality of the gas is found in the compounds of car- bon and hydrogen. W'^hen these burn, the particles of carbon are heated white hot and glow very brightly, making a luminous flame. There are, of course, some impurities in the purified gas. These are com- pounds containing sulphur and am- monia. The quantities of these sub- stances, however, are so small that they are harmless ; but the compounds taken out in the process of purifying the gas are saved, as considerable use is made of them. The water used for washing the gas is heavily charged with am- monia and is, in fact, the chief source of the ammonia sold by druggists. In addition to coal gas made in the way just described, there is another form of illuminating gas, in the manu- facture of which coal is indirectly em- ployed. This gas, known as water gas, because it is formed by the decompo- HOW THE IMPURITIES ARE TAKEN FROM THE GAS 303 PURIFVIXG BOXES. The principal impurity to be removed is sulphur, and this is accomplished by passing the gas through large iron rectangular boxes filled with wood shavings coated with iron rust upon which the sulphur is deposited by chemical action. I ■.', III-. I !■[ . 1 I \\ I % M . M i il'KS. 304 HOW THE METER MEASURES THE GAS y ^^^m Fi/ 1 Fi^ 3 Fi(J. ^. f;5i 4 Gas first enters inlet pipe A (Fig. 3) passing along Ai into covered valve chamber B up through orifice O. It then passes down through two of the valve ports at the same time, ports C and Di (Fig. 2). Before Ci (Fig. 3) has gotten to its extreme opening, the valve on the opposite side has moved to allow gas to pass down port D. On everj^ quarter turn of tangent P ^one port is opening to receivl gas which passes down through the valve ports into the chambers below (see arrows on Fig. 2), which shows the gas passing into chamber F Ihe pressure being greater on the outside of the diaphragm, forces the diaphragni inward and expels the gas from the inside of D2 through D and passes over the cross-bar into the fork channel (see Fi- I). On the other side gas is passing down through port Di (Fig 2) entering diaphragm D3 the pressure being greater on the inside of D3 therefore forces the diaphragm outward and expels the gas from the outside of diaphragm Dj out through port Ci into fork channel same as shm^-n in (Fig. i). All exhaust gas from the chambers below is checked from entering the Sambe^S by the slide valve G and Gi (Fig. 2). Instead of passing into chamber 5 it passes overthe cross-bars between DiEi and CiEi into the fork channels, then to outlet pipe N (Fig. 3) to house pipe. Note : All gas registered must pass through outlet A . HOW THE LIGHT GETS INTO THE ELECTRIC LIGHT BULB 305 sition of water, is produced by passing steam over red hot carbon, in the form of hard coal or coke. When this is done, the hydrogen in the steam is set free and the oxygen combines chem- ically with the carbon, to form the car- bon monoxide, that was mentioned as being present, in small proportions, in ordinary coal gas. This carbon mon- oxide is poisonous, if much of it is breathed, and as it has no odor it is difficult to detect when escaping. A number of deaths have resulted from water gas for this reason, and in some states the laws forbid its use for light- ing purposes. When water gas is used it must be enriched with some other substances before it will yield much light. You have already learned that neither hy- drogen nor carbon monoxide burns with a bright flame, and you will see that water gas must have something added to it to fit it for lighting pur- poses. The substance usually added is the vapor of some light, volatile oil, like gasoline. This vapor is composed of compounds of carbon and hydrogen, and when it is mixed with the water gas it forms a gas that yields a very satisfactory light; and that may be pro- duced more cheaply than common coal gas. There remains one more form of il- luminating gas which has been the sub- ject of much discussion in recent years, namely, acetylene. This is a compound of carbon and hydrogen, in which there is twelve times as much carbon as hydrogen. It has not been discov- ered recently, for it was known early in the nineteenth century, but its pos- sible use for lighting purposes was not considered then. Attention was directed to it a few years ago by the (hscovery of a sub- stance callcfl calcium carbide. This is a comjKjund of carjjon and the metal calcium, formed by heating to a very high tem])erature a mixture of coal and h'me. It has the peculiar property of '1 (composing, when treated with water. The calcium present combines with the oxygen and half the hydrogen of the water, to form commfjn slackcc] lime or calcium hydrate, while the carbon and the remainder of the hydrogen com- bine to form acetylene gas. The gas formed in this way needs no purifications before burning; it can be produced in small generators, and the production can be checked at any time. When burned in the proper form of burner it yields the brightest of all gas flames. For these reasons it is adapted for use in small villages and for lighting single houses. It is also frequently used in magic lanterns, where a strong and steady light is necessary. But the cost of producing acetylene in large quantities is greater than that of coal gas, and it seems ex- tremely unlikely that it will ever be much used for lighting large cities and towns. How the Light Gets Into the Electric light Bulb. The incandescent lamp was invented in 1879 ^I'ld the patents were granted to Thomas A. Edison. There were, however, a number of electrical men who were working on the idea at this time who deserve a great deal of credit for developing the lamp. The incandescent lamp, which is used chiefly for house lighting, consists of a glass bulb from which the air has been exhausted by pumps and chemical processes — in which there is a thin fila- ment of tungsten metal wound on what is called an arbor (as shown in Fig. 4). This filament opposes high resistance to the passage of the current of elec- tricity, and, consequently, is heated to incandescence when a current passes through it. The removal of the air from the bulb prevents the tungsten metal from burning up, as it would do if oxygen were j^resent. IMie filaments of the first lam])s were made of vegetable fibre. The next ile- velo])ment was the cellulose i)roc(,'ss, which is still used in r;ni)()n and niet.il- lized lamps, altliongh a number of ])n)e- esses are used miw which improve the filament considerably. The discovery that tungsten metal could be used in incandesetiit lamps 306 THE DEVELOPMENT OF INCANDESCENT LAMPS Edison's first lamp with a filament of bamboo fibre. The carbon lamp — the old- Standard Mazda lamp — the est form of incandescent highest development of the lamp. incandescent lamp. The Tantalum lamp de- veloped just before the Mazda lamp. Improved Mazda lamp for lighting large areas— the most efficient lamp ever made. WHAT X=RAYS ARE 307 was made in 1906. The first tungsten lamp manufactured in America was made in 1907. The filaments of the first tungsten lamps were composed of two or three short pieces of wire. In 1910, however, a lamp with a continuous tungsten fila- ment was invented which increased the strength of the lamp wonderfully. Mazda is a trade name given to all metal filament lamps made by the prom- inent American lamp manufacturers. The reason that the Mazda lamp is so much more efficient than the carbon filament lamp is because the tungsten filament can be burned at a much higher temperature than the present carbon filament, without seriously blackening the bulb. How Does an Arc Light Burn? In the arc light a current of elec- tricity is made to leap across from the tip of one rod of carbon to the tip of another that is held a short distance from the first. In passihg across the current does not follow a straight path, but makes a curve, or arc, whence comes the name "arc light." In this form of light the carbons are not enclosed in a space from which air is excluded, consequently there is some destruction of the carbon. The light is due to the fact that the air between the tips of the carbon rods opposes a high degree of resistance to the cur- rent, so that the rods become intensely hot at their tips. The high degree of heat causes a slow burning of the car- bon at the tips, and the small particles that burn are heated white hot before they are consumed, thus producing light. In order to keep the light from an arc light uniform in strength, it is necessary to keep the tips of the carbon rods always the same distance ai:)art. This is practically impossible, and, as a result, the arc light docs not produce light that is well adai)tcrl for reading or for other ])ur])Oscs that ref|uire con- stant use of the eyes. The light i)ro- duced by the arc light is very ])Owerful, however, and for that reason it is much used for street lighting. What Are X-Rays? It was discovered by Professor Con- rad Roentgen in 1895, that if a cur- rent of electricity be passed through a certain form of glass bulb, from which most of the air has been exhausted, a disturbance is produced in the ether that bears some resemblance to light waves. For want of a better name to give to a disturbance which was not well understood. Roentgen called his discovery the X-Ray, but it is now fre- quently called in his honor the Roentgen ray. The nature of this disturbance is not yet known, but as it does not afifect the eye it is not light. These rays are produced with a glass vacuum tube and a battery from which a current of elec- tricity is sent through the tube. The wires of the battery are connected with two electrodes, one of which consists of a concave disk of aluminum, and the latter of a flat disk of platinum. The X-rays are discharged in straight lines as shown in the figure. The most strik- ing properties of the X-ray is its power to penetrate m_any substances that are impermeable to light. All vegetable substances, and the flesh of animals, are penetrated by it very readily. Glass, metals, bones, and mineral substances generally are opaque to it! Conse- quently, when a limb, or even the body of an animal, is exposed to X-rays they pass through the fleshy parts, but are stopped by the bones. Certain sub- stances have the property of glowing, or becoming fluorescent, when exposed to the X-ray, and when screens of paper are coated with these substances they form a convenient means of detecting the presence of X-rays. By holding the hand between a tube that is giving off X-rays and a screen of this kind, the bones of the hand will be outlined in shadow on the screen, and the rest of the surface will glow with a greenish light. If a bullet or other piece of metal has become imbedded in the body, it may easily be located, if it is not in a bone, and the extent of an injury to a bone or a joint may be plainly shown. l'V)r this reason the X-ray is now widely used by surgeons. yus HOW MAN LEARNED TO FIGHT FIRE How Man Learned to Fight Fire. When you see the modern fire engine racing through the streets, gongs ring- ing, with the firemen hanging on and the poHce clearing the track, you should remember that it has taken man a long time to learn as much as he has about fighting fire. No sooner did man learn to make fire than he found it necessary to learn how to put it out. The first fire apparatus of record is found in Rome. The Gauls burned the citv in 3'>0 !>. C, each citizen was or- dered to keep in his house a "machine for extinguishing fire." This consisted of a syringe. The first record of an actual machine for putting out fire is by Hero of Alex- andria. This contrivance, a "siphon used in conflagrations." was used in Egypt about a hundred and fifty years before Christ. The first record of what we would call a fire department is also found in Rome. A disastrous fire, occurring in the reign oi Augustus called his atten- tion to the benefit of a regular fire bri- gade would bring. So he organized a fire department. It consisted of seven companies of a thousand men each. The first real fire engines were used in 1633 at a big fire on London Bridge. The first fire" hose was invented by the two \^an der Heydes in 1672. One of the earliest engines used consisted of a tank drawn by two horses, w^hich threw a stream an inch in diameter to a height of eighty feet. An improved engine was invented in 1721 by News- ham, of London, and the first engine used in the United States was made by Xewsham. The first steam fire engine was invented by John Braithwaite, of London, in 1829. Fire alarms came into use in medieval times. It was the custom, in many of the towns to have a watchman stationed on a high building whose duty it was to look for fires. As soon as he saw one, he gave warning by blowing a horn, firing a gun, or ringing a bell. The first London fire department con- sisted of ten men of each ward. The first nnmicipal American fire department was created in Boston in 1678. The fire engine was a hand pump bought in England. The first leather fire hose was made in America in 1808 in Philadelphia. Rubber hose was first made in England at about 1820. How Did Man Learn to Cook His Food? The primitive man lived on raw food — raw flesh, roots, fruits and nuts. There must have been a time when he lived thus because there was a Ume when he had no fires and no knowledge of how to make a fire. There are no records, however, to show when man learned that cooked food was best. It must have come about almost si- multaneously with his knowledge of fire, for the art of cooking goes back to the first knowledge of fire. We do not know either how man learned to make a fire. The earliest nations of which we have any record seem to have been acquainted with fire and certain methods for producing it. Xot onl}^ one but all early nations seem to have been possessed of this knowl- edge. Occasionally travellers have re- ported that people have been founa who w^ere unacquainted with either fire or cooking, but investigation has always proven these reports unauthentic. Cook- ery has always been found in practice where people knew about fire. It is strange how man has lost track of the beginning of his knowledge of fire and cookery, because fire represents the beginning of man's culture and cookery goes hand in hand with it. There are many legendary accounts of how man learned the value of cooked food, all of w^hich are based upon the accidental burning or roasting of ani- mals or birds. Perhaps, therefore, Charles Lamb's "Roast Pig" story, which we read with much laughter in our school readers, was quite accurate from a historical standpoint. Accord- HOW MAN LEARNED TO COOK HIS FOOD 309 ing to the story a man's house burned and he cried more over the fate of his pet pig than about the loss of his house. He kept his pig- in the house you will remember and as soon as the fire died away he rushed into the debris to look for his pet pig, hoping still to rescue him. He found him in a corner and made haste to pick him up and carry him into the open air. But the poor pig had been roasted to a turn and was still hot. The man's fingers went right into the well done roast pig and were burned. With a cry he withdrew his fingers and put them into his mouth to blow on them and thus he secured his first taste of roast pig, which he found so much to his taste that he repeated the operation of licking his fingers. While this is but a story, it is quite likely historically correct as to this dis- covery of the value of cooked food to some of the early nations. No doubt Fire and Cookery were developed to- gether. When man had learned to make fire, he found that it often got beyond his control. Here and there he would set the woods on fire quite without inten- tion perhaps, but with damaging results. He would watch the conflagration and, when it was passed, he would find the baked bodies of deer or other animals which had been overcome by the fire and learned that baked meats were good to the taste and more easily digestible than raw meats. Why Does a Sponge Hold Water? A sponge will hold water because it has, on account of the plan on which it is grown the power of capillary at- traction. The sponge is made up of little hair like tubes. If you take a glass tube, open at both ends and immerse one end in a vessel of water, you will find that the water will rise in the tube to a level higher than the surface of the water in the vessel. The smaller the hole through the glass tube, the higher the water will rise. This is caused by the cohesion of the water against the inside surface of the hole in the tube and causes a i)iill upward. The water is pulled up into the tube be- cause the surface of the tube has a greater cohesive attraction for the water than for the air which was in it and the air is forced out partly. Some liquids, such as mercury will not rise in the same way, but is depressed in a glass tube, since it cannot adhere to glass. Mercury however will run or rise in a tin tube, just as water in a glass tube, because it adheres to the tin. Now a sponge is merely a lot of capillary tubes which have the same power of pulling up the water as the glass tube. The tubes in a sponge are so fine that the water will rise to the entire length of the tubes. In addition, this adhesive quality of water to the in- side of the tubes in the sponge is so strong, that the sponge can be taken entirely out of the water and the water will remain in it. Why Is the Right Hand Stronger Than the Left? The right hand is stronger than the left only in case you are right-handed. If you have the habit of being left- handed, your left hand becomes stronger. If you are truly ambidex- trous, your strength will be the same in both hands. We get our strength by moving the various parts of the body, i. e., by using them. When a little baby stretches his arms and legs and kicks, he is only exercising naturally, making the blood circulate. You can prove that the fact that your right hand is stronger than your left because of the greater use or exer- cise you give it, by tying your right arm close to your side and keeping it in that condition without using it for sev- eral weeks. When you remove the bands which held it tight, you will find your arm has lost its strength and that now your left hand is stronger. If. however, you are left-handed and lie that hand down for the same length of time, your right hand would be the stronger. This shows that the strength we have in our arms and legs, and other parts of the body, is developed by using them ,'ind giving Ihem rational 310 WHY A BARBER POLE HAS STRIPES exercise. Of course, it is possible to over-use a part of the body, but you will notice that nature always gives us a warning by making us tired before we come to the point where further use of that particular part of the body would cause injury. Why Do My Muscles Get Sore When I Play Ball In the Spring? They do this because you have prob- ably not been exercising the particular muscles which you employ in throwing a ball enough in the winter to keep you in good condition. Muscles which have been developed through use or work need more work to keep them in con- dition. In a sense certain of the mus- cles w'hich you employ in playing ball have been treated during the winter very much as if you had tied them down, as we suggested you might do with your arm. You have not been using them — they have not been doing enough work, and they begin to lose their strength when for any period they have not been used enough. The sore- ness that you feel is the natural con- dition that arises when you begin to use a muscle that has been idle for some time. Why Does a Barber's Pole Have Stripes? In early years the barber not only cut hair and shaved people, but he was also a surgeon. He was a surgeon to the extent that he bled people. In early times our knowledge of surgery was practically limited to blood letting. A great many of the ailments were attri- buted to too much blood in the body, and when anything got wrong with a man or woman, the first thing they thought of was to reduce the amount of blood in the body by taking some of it out. The town barber was the man who did this for people and his pole repre- sented the sign of his business. The round ball at the top which was generally gilded represents the barber- ing end of the business. It stood for the brass basin which the barber used to prepare lather for shaving customers. The pole itself represents the staff which people who were having bictod taken out of their bodies held during the operation. The two spiral ribbons, one red and one white, which are painted spirally on the pole, represented the bandages. The white one stood for the bandage which was put on before the blood was taken out and the red one the bandage which was used for bind- ing up the wound when the operation was completed. How Was the Flag Made? The design of our flag was outlined in a congressional resolution passed on June 14, 1777, which stated "that the Hag of the thirteen United States be thirteen alternate stripes red and white ; that the union be thirteen stars, white in a blue field, representing the new constellation." After \'ermont and Kentucky had been admitted to the Union, Congress made a decree in 1794 that after May 1, 1795, "the flag of the United States be fifteen stripes alternate red and white and that the Union be fifteen stars white on a blue field." This made the stars and stripes again equal and it was the plan to add a new stripe and a new star for each new state ad- mitted to the Union. Very soon, how- ever, it was realized that the flag would be too large if we kept on adding one stripe for each new state admitted to the Union, so on April 4, 1818, Con- gress passed a resolution reducing the number of stripes to thirteen once more to represent the original colonies, and to add only a new star to the field when a new state was admitted to the Union. At this time there were twenty states in the Union. Since that time none of the flags of the United States have more than thirteen stripes while a new star has been added for* each state until now we have forty-eight stars, repre- senting the forty-eight states. Why Are Some Guns Called Gatling Guns? A gatling gun is a kind of gun in- vented bv Richard Jordan Gatling In WHY IT IS CALLED A HONEYMOON 311 1861 and 1862 and so it receives its name from its inventor. The original gatling gun had ten parallel barrels and was capable of firing 1,000 shots per minute when operated by hand power. It was discharged by turning a crank and would shoot in proportion to the rapidity with which the crank was turned. It was at first not a huge suc- cess but has from time to time been improved so that the crank is now turned by electric power and about fif- teen hundred shots per minute can be fired with it. How Did Hobson's Choice Originate? As used today, this expression means a choice with only one thing to choose. Tobias Hobson was a livery stable keeper at Cambridge, England, during the reign of King Charles I. He kept a stable of forty horses which he hired out by the hour or day, and was famous in his day so far as a livery stable keeper could be. When you went to Hobson to hire a horse, you had the privilege of looking over all the horses in the stable to de- ride which one you would like to drive, but he always made you take the one in the stall nearest the door. In this way all the horses in the stable were worked in turn and while you might pretend to choose your own horse, you really had no choice — you had to take the one nearest the door or none. As soon as a horse was hired, the other horses in the stable were moved up, each one to the stall next towards the door so there was always a horse in the stall nearest the door. Why Do They Call It a Honeymoon? The word Honeymoon which is com- yionly used to clescriljc the first few weeks after marriage, has always meant the first month or moon after marriage, but does not have any reference to llu- month or moon excepting as that de- scribes a certain period f»f time. The wr)rd ririginated in an f>ld cMistom quite common among ncwlv marricfl couples among the ancient Teutons of drinking a kind of wine made from honey during the first thirty days after being married. In these days newly married couples generally take a trip away from home for a short or longer period after their wedding day and this is called the honeymoon whether it is but a few days or three months or more. The custom of drinking wine made from honey has been abandoned so that the word is now used in an entirely dififerent sense than formerly. Why Is a Horseshoe Said to Bring Good luck? The luck of the horseshoe comes from three lucky things always connected with horseshoes. These consist of the following facts: It is the shape of a crescent; it is a portion of a horse; it is made of iron. Each of these has from time im- memorial been considered lucky. Any- thing in the shape of a crescent was al- ways considered a thing to bring luck. From the earliest times, too, at least since the world knew something of the qualities of iron, iron has been re- garded as a thing to give protection and incidentally that would involve good luck. And lastly the horse, since the days of English mythology, has been regarded as a luck animal. When, then, we had a combination of the three — the crescent, the iron and the horse in one object, it became a true lucky sign in the eyes of the people. Some Wonders of the Human Body. There are said to be more than two million little openings in the skins of ouv bodies to serve as outlets for an ecjiial number of sweat glands. The body contains more than two hundred bones. It is said that as much blood as is in* the entire body pases through the heart every minufe, i.e.. all the blood in llu' liody goes in and out of llic heart once every minute. The lung capacity of the average person is about 32.S cubic inches. With ever\' brealh \ou iidiale ahout 312 HOW THE WORD "NEWS" ORIGINATED two-thirds of a pint of fresh air and exhale an equal amount if you breathe normally. The stomach of the average adult person has a capacity of about five pints and manufactures about nine ])Ounds of gastric juice daily. There are over five hundred muscles in the body all of which should be exercised daily to keep you in the best condition. The average adult human heart weighs from eight to twelve ounces and it beats about 100,000 times every twenty-four hours. The perspiration system in the body has only very small ducts or pipes, but there are about nine miles of them. The average person takes about one ton of food and drink each year. We breathe about eighteen times a minute, which amounts to about 3,000 cubic feet an hour. Where Did the Expression "Kick the Bucket" Originate? The expression originally came from the method used in stringing a hog after killing it. The pig after being slaughtered was hung by by the hind legs. A piece of bent wood was passed in behind the tendons of each of the hind legs and the pig hung up hy this stick of wood much like we hang up clothes with a clothes hanger today. The piece of wood was called a bucket. The ''bucket" part of the expression does not, therefore, refer to a bucket at all but to this bent piece of wood. All are not agreed on this explanation, how- ever, as it does not explain where the "kick" comes in. Many investigators hold to the belief that a man named Bolsover was the first to "kick the bucket" literally and that the expres- sion came from the manner of his death. He stood on a pail or bucket while arranging to hang himself by ty- ing a rope around his neck and to a beam which he could not reach with- out standing on the bucket. A\'hea ready he kicked the bucket out trom under his feet and so succeeded in car- rving out his own wishes and in so do- ing coined a famous expression which still means "to die." How Did the Word "News" Originate? The word "News" which was created to describe what newspapers are sup- posed to print, came from the four letters which have for ages been used as abbreviations of the directions of the compass. In this N stands for North, E for East, S for South and W for West, and in illustrating the points of the compass the following diagram has long been used: N W— — E The earliest newspapers always printed this sign on the front pages of their papers in every issue. This was done to indicate that the paper printed all the happenings from four quarters of the globe. Later on some enterprising news- paper man who may have forgotten the original significance of the letter in the diagram, arranged the letters N. E. W. S. in a straight line at the head of the paper and that is how what w^e read in the papers came to be known as news. Almost one-half the whole number of newspapers published in the world are published in the United States and Can- ada. Who Made the First Umbrella? No one know^s w'ho made the first umbrella but we know that Jonas Han- way of London was the first man to carry one over his head to keep off the rain. Umbrellas seem to have been known as far back as the days of Ninevah and Persepolis, for representations of them appear frequently in the sculptures of those early days. The w'omen of an- cient Rome and Greece carried them but the men never did. Mr. Hanway is said to be the first man who walked in the streets of Lon- don with an open umbrella over his head to keep off the rain. He is said to have used it for thirty years before they came into general use for this pur- pose. HOW MAN LEARNED TO TELL TIME 313 The first picture shows what was probably man's first method of telling time. The principle was the same as that of the sun-dial. It provides to-day an accurate method of telling time. Of course, man in the early days needed to find some other means of noting the passing of time at night, for then the sun cast no shadow for him. His ingenuity taught him to make a candle which was light and dark in alternate rings, and as each section burned he made a mark to record the passing of a certain length of time. Before candles were invented he used a rope in which he tied knots at equal spaces apart and which he burned as shown in the third picture. The Story In a Time Piece What Is Time? Time, as a separate entity, has not yet been defined in language. Defini- tions will be found to be merely ex- planations of the sense in which we use the worrl in matters of practical life. No human being can tell how long a minute is ; only that it is longer than a second and shorter than an hour. In some sense we can think of a longer or shorter period of time, but this is merely comparative. The difference between 50 and 75 steps a minute in marching is clear to us, but note that we introduce motion and space before we can get a conception of time as a succession of events, but time, in itself, remains elusive. In time measures we strive for a uni- form motion of something and this implies equal spaces in equal times ; so we here assume just what we cannot explain, for space is as difficult to de- fine as time. Time cannot be "squared" or used as a multiplier or divisor. Only numbers can be so used ; so when we speak of "the square of the time" we mean some numl)iT wliich we have arbitrarily assumed Id represent it. This becomes plain when we state tli.it in calculations relating to pendidunis, for example, we may use seconds and inches — mimites and feet — (jr seconds 314 MAN'S FIRST DIVISIONS OF TIME and meters — and the answer will come out right in the units which we have assumed. Still more, numbers them- selves have no meaning till they are applied to something, and here we are applying them to time, space and mo- tion ; so we are trying to explain three abstractions by a fourth ! But. happily, the results of these assumptions and calculations are borne out in practical human life, and we are not compelled to settle the deep question as to whether fundamental knowledge is possible to the human mind. What Was Man's First Division of Time ? Evidently, man began by considering the day as a unit and did not include the night in his time-keeping for a long period. "And the evening and the morning were the first day," Gen. I, 5; "Evening and morning and at noonday," Ps. Iv, 17, divides the day ("sun up") in two parts. "Fourth part of a day," Neh. ix, 3, shows another advance. Then comes, "are there not twelve hours in a day," John xi, 9. The "eleventh hour," Matt, xx, i to 12, shows clearly that sunset was 12 o'clock. A most remarkable feature of this 12-hour day, in the New Tes- tament, is that the w^riters generally speak of the third, sixth and ninth hours. Acts ii, 15; iii, i; x, 9. This is extremely interesting, as it shows that the writers still thought in quarter days (Neh. ix, 3) and had not yet acquired the 12-hour conception given tc them by the Romans. They thought in quarter days even when using the 12-hour numerals! Note, further, that references are to "hours" ; so it is evi- dent that in New Testament times they did not need smaller subdivisions. "About the third hour" shows the mental attitude. That they had no con- ception of our minutes, seconds and fifth-seconds becomes quite plain when we notice that they jumped down from the hour to nowhere, in such ex- pressions as "in an instant — in the twinkling of an eye." Before this the night had been di- vided into three watches (Judges vii, 19). Poetry to this day uses the "hours" and the "watches" as symbols. This twelve hours of daylight gave very variable hours in latitudes some distance from the equator, being long in summer and short in winter. The amount of human ingenuity expended on time measures so as to divide the time from sunrise to sunset into twelve ecjual parts is almost beyond belief. In Constantinople, to-day, this is used, but in a rather imperfect manner, for the clocks are modern and run twenty- four hours uniformly ; so the best they can do is to set them to mark twelve at sunset. This necessitates setting to the varying length of the days, so that the clocks appear to be sometimes more and sometimes less than six hours ahead of ours. A clock on the tower at the Sultan's private mosque gives the impression of being out of order and about six hours ahead, but it is running correctly to their system. Hotels in Constantinoj:)le often show two clocks, one of them to our twelve o'clock noon system. Evidently the Jewish method of ending a day at sunset is the same and explains the command, "let not the sun go down upon thy wrath," which we might read, "do not carry your anger over to another day." This simple line of steps in dividing the day and night is taken principally from the Bible because every one can easily look up the passages quoted and many more, while quotations from books not in general use would not be so clear. How Did Man Begin to Measure Time? Now, as to the methods of measur- ing time, we must use circumstantial evidence for the prehistoric period. The rising and the going down of the sun — the lengthening shadows, etc., must come first, and we are on safe ground here, for savages still use i)rimitive methods like setting up a stick and marking its shadow so that a party trailing behind can estimate the dis- tance the leaders are ahead by the changed position of the shadow. Men notice their shortening and lengtht ning shadows to this day. When the shadow HOW TIME IS CALCULATED AT SEA 315 of a man shortens more and more slowly till it appears to be fixed, the observer knows it is noon, and when it shows the least observable lengthen- ing then it is just past noon. Now, it is a remarkable fact that this crude method of deten^iining noon is just the same as "taking the sun" to determine noon at sea. Noon is the time at which the sun reaches his highest point on any given day. time is important, several officers on a large ship will take the meridian pas- sage at the same time and average their readings, so as to reduce the "personal error." All of which is merely a greater degree of accuracy than that of the man who observes his shadow. The gradual development of the primitive shadow methods culminated in the modern sun-dial. The "dial of Ahas" (Isa. xxxviii, 8), on which the The Sun-dial is only an improvement on the stick which cast a shadow which enabled man to tell the time of daj' at any hour. The shadow moves around the dial, falling on the numbers on the circle. How Is the Time Calculated at Sea? At sea this is determined generally by a sextant, which simply measures the angle between the horizon and the sun. The instrument is a[)j)lied a little before noon and the observer sees the sun creeping upward slower and slower till a little tremor or hesitation appears, indicating that the sun has reached his height — noon. Oh! you wish to know if the observer is likely to make a mistake? Yes, and when accurate local sun went back ten "degrees," is often referred to, but in one of the revised editions of the Bible the sun went back ten "stejis." This becomes extremely interesting when we find that in India there still remains an immense dial built with steps instead of hour lines. In a restored flower garden, within one of the large houses in the ruins of Pompeii, may be seen a sun-dial of the Armillary tyj^e, presumably in its orig- inal position. It looks as tf the i)lanc of the e(|uat(jr and the position of the 310 THREK GREAT STEPS IN MEASURING TIME earth's axis must have been known to the maker. Both these dials were in use before the beginning of our era and were covered by the great eruption of Ve- suvius in 79 A.D., which destroyed Pompeii and Herculaneum. Modern sun-dials ditYer only in being more accurately made and a few "curi- osity" dials added. The necessity for time during the night, as man's life be- came a little more complicated, neces- sitated the invention of time machines. The "clepsydra," or water-clock, was probably the first. A French writer has dug up some old records putting it back to Hoang-ti 2679 B.C., but it ap- pears to have been certainly in use in China in iioo B.C., so we will be sat- isfied with that date. In presenting a subject to the young student it is sometimes advisable to use round num- bers to give a simple comprehension and then leave him to find the over- lapping of dates and methods as he advances. Keeping this in mind, the following table may be used to give an elementary hint of the three great steps in time measuring. Shadow time, 2000 to 1000 B.C. Dials and water-clocks, 1000 B.C. to 1000 A.D. Clocks and watches, 1000 to 2000 A.D. Gear-wheel clocks and watches have here been pushed forw-ard to 2000 A.D., as they may last to that time, but no doubt we will supersede them. At the present time science is just about ready to say that a time measurer con- sisting of wheels and pinions — a driving power and a regulator in the form of a pendulum or balance, is a clumsy con- trivance and that we ought to do better very soon. It is remarkable how few are aware that the simplest form of sun-dial is the best, and that, as a regulator of our present clocks, it is good within one or two minutes. No one need be with- out a "noon-mark" sun-dial ; that is, every one may have the best of all dials. Take a post or any straight object standing "plumb," or best of all the corner of a building. In the case of the post, or tree trunk, a stone (shown in solid black) may be set in the ground ; but for the building a line may often be cut across a flagstone of the footpath. Many methods may be employed to get this noon mark, which is simply a north and south line : View- ing the pole star, using a compass (if the local variation is known) or the JJrawing by James Arthur. A form of Sun-dial that is as good to-day as any dial for determining noon. old method of finding the time at which the shadow of a pole is shortest. But the best practical way in this day is to use a watch set to local time and make the mark at 12 o'clock. On four days of the year the sun is right and your mark may be set at 12 on these days, but you may use an almanac and look in the column marked "mean time at noon" or "sun on meri- dian." For example, suppose on the bright day w'hen you are ready to place your noon mark you read in this col- umn 11.50, then when your watch shows 11.50 make your noon mark to WATER CLOCKS FOR TELLING TIME 317 the shadow and it will be right for all time to come. Owing to the fact that there are not an even number of days in a year, it follows that on any given yearly date at noon the earth is not at the same place in its elliptical orbit, and the correction of this by the leap years causes the equation table to vary in periods of four years. The centennial leap years cause another variation of 400 years, etc., but these variations are less than the error in reading a dial. How Did Men Tell Time When the Sun Cast No Shadows? During the night and also in cloudy weather the sun-dial was useless, and we read that the priests of the temples and monks of more modern times "went out to observe the stars" to make a guess at the time of night. The most prominent type after the shadow de- vices was the "water-clock" or "clep- sydra," but many other methods were used, such as candles, oil lamps, and in comparatively late times, the sand-glass. The fundamental principle of all water- clocks is the escape of water from a vessel through a small hole. It is evi- dent that such a vessel would empty itself each time it is filled in very nearly the same time. The reverse of this has been used, as shown in the picture of the Time-boy of India. He sat in front of a large vessel of water and floated a bronze cup having a small hole in its This picture shows the hour-glass or sand-glass. It is really a type of water- clock, being based on the same principle. The upper glass bulb was filled with sand and this sand fell through a little hole be- tween the two bulbs. When the sand had all gone through, the glass was turned upside down and the operation repeated. PImIo l)y James .\rtliur. TIME-BOY OF I.VniA. — WATKU-CI.OCK. The Water-clock consisted of a large vessel filled with water, on the surface of which was placed a smaller vessel, really a gong, with a hole in the bottom. The water grad- ually filled the smaller vessel, and it sank. The Time-boy sat beside the Water-clock and as soon as the vessel sank he fished it out, emptied it, struck the gong- one or more times and set it on the water ugain. 318 A PRIMITIVE TWELVE=HOUR CLOCK bottom in this large vessel, and as the water ran in through the hole the cup sank. The boy then fished it up and struck one or more blows on it as a gong. This he continued and a rude division of time was obtained — while the bov kept awake ! I irav. mu I'r.'iii ilcscription by James Arthur. The "Hon-woo-et-low," Canton, China. Copper jars dropping water. The most interesting of all w^ater- clocks was undoubtedly the "copper jars dropping water," in Canton, China, where it can still be seen. Referring to the picture herewith and reading the four Chinese characters downwards the translation is "Canton City." To the left and still downwards, "Hon-woo- et-low," which is, "Copper jars drop- ])ing water." Educated Chinamen in- form me that it is over 3000 years old. The little open building or tower in which it stands is higher than surround- ing buildings. It is, therefore, reason- ably safe to state that the Chinese had a weather and time station over 1000 years before our era. It is a 12-hour clock, consisting of four copper jars partially built in masonry forming a stair-like structure. Commencing at the toj) jar each one drops into the next downward until the water reaches the solid bottom jar. In this lowest one a float, "the bamboo stick," is placed and indicates the height of the water, and thus in a rude way gives the time. It is said to be set morning and evening by dipping the water from jar 4 to jar i, so it runs 12 hours of our time. What are the uses of jars 2 and 3, since the water simply enters them and drips out again? No information could be obtained, but I venture an explanation and hope the Photo by James Arthur. TOWER OF THE WINDS. This tower is located at Athens, Greece. It was bnilt about 50 B.C. It is octagonal in shape and had at one time sun-dials on each of its eight sides. On top was a bronze weather vane from which it derived its name. THE FIRST MODERN CLOCK 319 reader can do better, as we are all of a family and there is no jealousy. When the top jar is filled for a 12-hour run it would drip out too fast during the first six hours and too slow during the second six hours, or account of the varying "head" of water. Now, the spigot of jar 2 could be set so that it would gain water during the first six hours, and lose during the second six hours, and thus equalize a little by splitting the error of jar i in two parts. Similarly, these two errors of jar 2 could be again split by jar 3 making four small variations in lowest jar, in- stead of one large error in the flow of jar I. This could be extended to a greater number of jars, another jar making eight smaller errors. The best thing the young student could do at this point would be to grasp the remarkable fact that the clock is not an old machine, since is covers onl}^ the comparatively short period from 1364 to the present day. Compared with the period of man's history and inventions it is of yesterday. Strictly speaking, as we use the word clock, its age from De Vick to the modern astronomical is only about 540 years. If we take the year 1660, we find that it represents the center of modern im- provements in clocks, a few years be- fore and after that date includes the pendulum, the anchor and dead beat escapements, the minute and second hands, the circular balance and the hair spring, along with minor improvements. Since the end of that period, which we may make 1700, no fundamental invention has been added to clocks and vv-atches. This becomes impressive when we remember that the last 200 years have produced more inventions than all previous known history — but only minor improvements in clocks ! The application of electricity for wind- ing, driving, or regulating clocks is not fundamental, for the time-keeping is done by the master clock with its pen- dulum and wheels, just as by any grandfather's clock 2cx) years old. 'JMiis Ijroad survey of time measuring does not jjcrmit us to go into miinite me- chanical details. •CORO. WEIGHT. Drawing by James Artliur. Modern clocks commence with De Vick's of 1364, which is the first unquestioned clock consisting- of toothed wheels and con- taining the fundamental features of our present clocks. References are often quoted l)ack to about 1000 A.D., but the words translated "clocks" were used for bells and dials at that date; so we are forced to con- sider the De Vick clock as the first till more evidence is obtained. It has been pointed out, however, that this clock could hardly have been invented all at once; and there- fore it is i)robable that many inventions leading up to it have been lost to history. That part of a dock which does the ticking is calU'd tile "escapement," and the oldest form known is the "Verm." 320 EARLIEST CLOCKS HAD NO DIALS OR HANDS Scattered references in old writings make it reasonably certain that from about looo A.D. to 1300 A.D. bells were struck by machines regulated with this verge escapement, thus show- ing that the striking part of a clock is older than the clock itself. It seems strange to us to say that many of the earlier clocks were strikers only, and had no dials or hands, just as if you turned the face of your clock to the wall and depended on the striking for the time. Photo by James .Arthur. ENGLISH blacksmith's CLOCK. .V good idea of the old clun-ch clocks may be obtained from the pic- ture herewith. Tradition has followed it down as the "I*lnglish Blacksmith's Clock." It has the very earliest ap- plication of the pendulum. The pen- dulum is less than 3 inches long and is hung on the verge, or pallet axle, and beats 222 per minute. This clock may be safely put at 250 years old, and contains nothing invented since that date. Wheels are cast brass and all teeth laboriously filed out by hand. Pinions are solid with the axles, or "stafTs," and also filed out by hand. It is put together, generally by mor- tise, tenon and cotter, but it has four original screws all made by hand with the file. How did he thread the holes for these screws? Probably made a tap by hand as he made the screws. Put the most remarkable feature is the f;ict that no lathe was used in forming any part — all stafifs, pinions and pivots being filed by hand. This is simply extraordinary w'hen it is pointed out that a little dead center lathe is the sim]:)lest machine in the world, and he could have made one in less than a day and saved himself weeks of hard labor. Tt is probable that he had great skill in hand work and that learning to use a lathe would have been a great and tedious efifort for him. So we have a complete striking clock made by a man so poor that he had only his anvil, liammer and file. The weights are hung on cords as thick as an ordinary lead-pencil and pass over pulleys hav- ing spikes set around them to prevent the cords from slipping. The weights descend 7 feet in 12 hours, so they must be pulled up — not wound up — twice a day. The single hour hand is a work of art and is cut through like lace. Public clocks may still be seen in Europe with only one hand. Many have been puzzled by finding that old, rudely made clocks often have fine dials, but this is not remarkable when we state that art and engraving had reached a high level before the days of clocks. Courtesy of Colgate and Company. THE HANDS OF THE LARGEST CLOCK IN THE WORLD — ON THE ROOF OF THE COLGATE FACTORY. This big clock faces the giant office buildings of down-town New York. Its dial is 38 feet in diameter and can be read easily at a distance of three miles, so that passengers on the incoming liners pick out the clock as one of their first sights of New York. The next largest clock (on the Metropolitan Tower) is 26j/> feet in diameter; tha Westminster clock of London, 22^ feet. The great clock weighs approximately 6 tons. The minute hand, 20 feet long, travels at its pomt 23 inches every minute; more than one-half mile each day. The bed of this clock is 4 feet in length, the wheels and gears being made of bronze and pinions of hardened steel. The time train occupies about one-third of the bedplate, and has a main time whgel measuring iSy^ inches in diameter. This train is equipped with Dennison's double three-legged gravity escapement, which was invented by Sir Edmund Becket, chiefly for use on the famous Westminster clock, installed in the Parliament Huildings, in London, England. The use of this escapement is most advantageous for a gigantic clock of this kind as it allows the impulse given the pendulum rod to be always constant, and therefore does not permit any change of power or driving force of the clock to affect its time-keeping qualities. It requires about 6cx) pounds of cast-iron to propel this time train, and the clock is arranged to run eight days without winding. The gravity arms of the escapement are fastened at a point very near the suspension spring, and the arms are fitted with bronze roller beat pins. The dial contains 1134 square feet, or about one thirty-fifth of an acre. The numerals consist of heavy black strokes, 5 feet 6 inches long and 30 inches wide at the outer end, tapering to a point at the inner end. The circumference of the dial is api)roximately 120 feet. The distance from center to center of nunurals is 10 feet, and the minute spaces arc 2 feet. The background on dial is painted white, and in the daytime the black numerals show up distinctly. At night the numerals, or hour marks, are (lesignated by a row of incan- descent bulbs j)laced in a trough 5 inches wide and 5 inches deep. The hands at night are outlined with incandescent electric lights, there being 27 lamjis on the hour hand and 42 lamps on the minute hand. 322 THE MACHINERY WHICH RUNS A BIG CLOCK This picture shows the machinery necessary to operate a large modern tower clock. The mechanism is held in place and confined entirely within a cast-iron structure which is firmly bolted to the floor. The wheels are composed of bronze, the pinions of steel (hardened) and the gears are machine cut. At the front of the clock is a small dial which enables one to tell exactly the position of the hands on the outside dials, and there is also a second hand to permit of very close regulation and adjust- ment. Three ways are provided for the regulation. First by a knurled screw at the top of bed frame. Second by a revolving disc at the bottom of the pendulum ball. Very often by either of these two methods it is impossible to bring the clock to fractional seconds, and in order to permit of a nicety of adjustment there is a cup fitted at the top of the ball so that by inserting or taking out lead pellets, the rating can be brought to absolute time. THE CLOCK IN INDEPENDENCE HALL 323 IXDEPEXDEXCE HALL, PHILADELPHIA NKW YOUK CITV HALL 324 WHERE THE DAY BEGINS Where Does the Day Begin? To understand this subject we must first appreciate that a day as we think of it is a division of time made by man for the purpose of his own reckoning. So far as the beginning of day is con- cerned, it begins at a different place in the world every hour; yes, every minute and every second in the day. As, however, the distance in feet where the day begins from one min- ute to another is so short that we can hardly notice it in such short measure- ments of time, we will look at the answer to the question from hour to hour. When you understand the subject from that point you can your- self see that the day actually begins at a different point of the earth every minute and every second of time. How Much of the Earth Does the Sun Shine on at One Time? The sun is shining on some part of the earth all the time and the shining of the sun makes the difference be- tween day and night. Wherever the sun is shining it is day-time, and where the sun is not shining It is night-time. To illustrate we will make use of an ordinary orange and a lighted gas jet. Let us take a long hat-pin and stick it through the orange from stem to stem. Now hold the orange by the ends of the hat-pin up before the lighted gas jet. You will notice that one-half of the orange is lighted, while the other half is dark. Of course, it is the half of the orange away from the light that is dark. Now, revolve the orange slowly on the hat-pin axis to- ward the light. When you have turned the orange half way round the part that v.as formerly dark is now lighted up and the other part is now dark. Now examine closely and you will see that just one-half of the orange is lighted at one time and the other half is dark. You revolve the orange in front of the light slowly and a portion of the surface of the orange is always coming into the light, while a corre- s])onding portion of it on the opposite side is constantly going into the dark. In other words, whatever the speed at which you revolve the orange toward the light, one-half of it is always light and the other half is always dark. This is exactly what happens in the relation of the earth to the sun every day. One-half of the earth, which is continually revolving on its axis, is fac- ing the sun, and is, therefore, in the daylight, while the other half of the earth's surface is in darkness, because the light from the sun does not strike any portion of it. If the earth did not revolve one-half of it would always be in day-time, while the other half would be continually having night-time. As the earth is always moving or revolv- ing the half where it is day-time is constantly changing, so that the day is beginning on one-half of the earth's surface every second of the day. Actually, of course, then, if you live on the east side of town day begins with you a little sooner than with your chum who lives on the west side of town. We have come to measure the begin- ning of day as sunrise and the begin- ning of night as sunset, wherever we happen to be. For convenience in setting clocks and in measuring time we do not take into consideration these very slight differ- ences in the rising and setting of the sun, but set our clocks all alike in dif- ferent parts of the same town or city to avoid confusion. In fact, in order to overcome the difficulties and confu- sions arising in reckoning the time of the clock in different localities, and still keep the beginning of what we call day-time constant with the hands of the clock, we have agreed upon what we call standard time. We agreed upon this system of fixing standard time be- cause the actual sun time by which people set their clocks up to a few years ago led to so many mistakes in catching trains, keeping engagements and other misunderstandings where the question of time was involved. Then ^\•hcn this system of standard time was adopted the confusion became even worse, and the mistakes and misses more numerous, because some people insisted on setting their clocks to stan- dard time and others insisted on stick- WHERE THE DAY CHANGES 325 ing to the old sun time schedule. So you could never tell by looking at the clock what time it really was unless they put a sign on the clock saying what kind of time they were going by. Finally, however, most of the people came to appreciate that it would be a good idea to use one uniform system of setting the clocks and of having them in harmony in a sense with the other clocks in the world, and the adop- tion of the standard time plan became universal. To make this system practi- cal and effective, certain points about equally distant from each other were selected, at which point Where Is the Hour Changed? the hour would change for all points within that zone. Under this system all timepieces in any one zone point to the same hour. So the clock time changes only as you go east or west. All points on a north and south line have the same time as the zone in which it is located. For convenience in adjusting the time in America the country was di- vided into four east and west zones. The first zone takes in everything on a straight north and south line east of Pittsburg, and is called Eastern time. The second zone extends from Pittsburg to Chicago, and is called Cen- tral time ; the third zone extends from Chicago to Denver, and is called Moun- tain time ; while the fourth zone ex- tends from Denver to the Pacific Ocean. These selections were made because the sun actually rises about one hour later in Pittsburg than" in New York ; one hour later in Chicago than in Pittsburg ; one hour later in Denver than in Chicago, and one hour later on the Pacific Coast than in Denver. Under this plan when it is nine o'clock in New York it is only eight o'clock at Pittsburg and all points in the Cen- tral zone ; seven o'clock in all points in the Mountain zone ; six o'clock in Den- ver and five o'clock in San Francisco. A.s you keep travelling westward you flroj; one hour of the clock time in every zone, and as under this system the earth's east to west distance is divided into twenty- four such zones, if you went west entirely around the world you would lose a whole day of clock time. If, however, you went around the world from west to east in the same manner you would gain a whole day. Where Does the Day Change ? This system of agreeing on fixed places where the hour changes made it necessary to also fix a point where for the purposes of the calendar the day also changes. This imaginary north and south line is fixed upon at i8o degrees west longitude, which would cut the Pacific Ocean in two. This line makes it possible for a person to travel all day before approaching this line and then find himself after crossing it travelling all the next day with the same name for the day of the week. Thus he could spend all of Sunday travelling toward the International Day Line, as this is called, and after cross- ing it spend another Sunday, which would be the next day, going away from it. This would give him the novel experience of having two Sundays on successive days. The same thing would happen if he were travelling to the Day Line on Monday, Tuesday, Wed- nesday, Thursday, Friday or Satur- day. He would live through two suc- ceeding days of the same name in the same week, one right after the other. This would be in going westward. If you were traveling eastward and crossed the International Day Line on Sunday at midnight you would lose a day completely out of the week, for when you woke up the next morning it would be Tuesday. Why Do We Cook the Things We Eat? We have several reasons for doing this. The first and most important reason to us is that the application of heat to food makes it more easy to digest. Other reasons arc that when cooked our food is more palatable; the process of cooking kills all microbes, which, if taken into our bodies alive, would give us diseases, and also it is easier for us to chew food that has been cooked. 326 WONDERS PERFORMED BY ELECTRIC LIFT MAGNET Magnet fpame - Single Point Suspension Twin Conductor. Metaoc rLE.'>t\BLE Conduit. Maqnet CoiL OuTER Pole. \^Maqnet Rex-Ea.se DiaPhram. \^ Inner Pole. Non-Maqnetic Bottom Plate. This picture shows the construction of a successful electric lift magnet. This device, by means of magnetic attraction, fastens itself to practically all kinds of iron and steel without the aid of slings, cables or chains, The Story in a Magnet What Makes an Electro Magnet Lift Things ? The working parts of an electric lift magnet are as follows : A Shell. — This is a steel casting heavily ribbed on the top for strength, and also to assist in radiating the heat- ing effect from the coil. It is usually made circular in shape, the outside rim forming one pole, while the lug in the center forms the other. The coil fits in between these poles, thus making a magnet similar to the ordinary horseshoe type. A Bottom Plate. — The under side of the magnet is closed by a very tough and hard non-magnetic steel plate, in order to protect the coil. As well as being non-magnetic, this plate also has sufficient strength to re- sist the severe wear to which a magnet is necessarily subjected. A Terminal Box. — A one-piece heavily-constructed steel casting bolted to the top of the shell, containing and protecting the brass sockets into which the wires from the coil terminate, forms the Terminal Box. The sockets are made to receive ])lugs placed on the end of the con- ductor wire, by which the magnet is connected with the generator. A Coil. — This consists of a round insulated wire which is passed, while being wound, through a cement-like substance, heavily coating each indi- vidual strand. A low voltage of current is then passed through the coil, a sufficient length of time, to thoroughly dry out and bake the coating. This renders the magnet absolutely fireproof, elimi- nating all danger of short circuiting of the coil. When finished it is well taped to protect the outside wire from becom- ing chafed. The coil is made slightly smaller than the inside dimensions of the shell and the remaining space is filled with an impregnating coinpound, which hardens to the consistency of pitch. This renders the coil thoroughly- waterproof ; also forms a cushion to prevent injury from the severe jars and shocks, received when dropping a magnet on its load. A Controller. — The rapidity with v;hich it is necessary to turn current on and off while operating a magnet, creates what is called a "back kick." Unless this is dissipated quickly it is very destructive to the coil. A special controller dissipates this back kick through a set of resistance coils placed in the controller. By means of an automatic arrangement, connection with these coils is made instantly upon breaking the current be- tween the magnet and generator. A system of control used prevents undue heating of the coil. This enables the magnet to lift as large a load after a long steady run as at the start. What Is a Lodestone? A lodestone is a variety of the min- eral named magnetite which is a nat- ural magnet. The name magnet comes f^'om the name of the mineral mag- netite and this in turn derived its name from the fact that it was first discovered in Magnesia. The word magnet really means the "Stone of ^lagnesia." A lodestone is one of the mysteries of nature. Its properties can more nearly be understood if we examine an artificial magnet, which is generally made in the form of either a straight bar or a shoe. An artificial magnet i=; made of iron. If you dro]) a bar magnet into a box of iron filings, the filings attach themselves to the bar. If you examine it closely you observe tb.at most of the filings attach them- selves to the ends of the bar. There- fore wc call the ends of the bar the poles of the magnet. If you suspeufl a magnetic needle at its center of gravity so that it is ab- solutely free to turn, you will soon find one end of the needle j)ointing north anfl the other south of course. The end whidi is pointed toward the north is called the north ])f)le and thq f)tb(r the south pole. If you have a horse-shoe magnet, you can demon- strate this for yourself. Rub the end of your magnet over a sewing needle and oil the needle so that when you lay it on the surface of a glass of wa- ter it will float. Then look at it closely. You will see the needle slowly turn until finally it becomes quite still. If you have a compass at hand so that you know surely which is north and which is south, you will find one end of the needle pointing north and the other south. You can then place the end of your magnet against the out- side of the glass and draw the needle toward your magnet. Your horse-shoe magnet has its north and south poles close together. If you have a bar magnet and the end of the needle with the eye in it is pointing north, you can drive the needle on the surface of the water away from you by touching the outside of the glass opposite that end of the needle with the north pole of your magnet. On the other hand, if you reverse the experiment and place the south pole of your magnet to the side of the glass, the needle will come toward the magnet. In other words then the like poles of a magnet repel each other and the unlike poles attract each other. Another interesting way to show this is to take two lodestones or two magnets and let a lot of iron filings attach themselves to the ends of them. Then when you have done this, point the two north poles of the magnets or lodestones at each other close together. You will be intensely irterested in seeing how quickly the mysterious something that is in the magnets makes the filings on the two ends of the magnet try to get away from each other. On the other hand \vhen you put a north and south pole together, they form a union of the iron filings. Another strange thing about a mag- net is tiiat if you break it in two, each half will be a complete magnet in it- self with a north and south pole also, and this is true no matter how many times you break it into pieces. l'>om this we learn that each liny ])arliclc' or 328 WHAT A LODESTONE IS / This is a picture of a complete electro magnet. The magnet is attached to the arm of a crane by the loop in the cen- ter and when the magnet then comes in contact with any kind of iron or steel it lifts it as soon as the current is turned on. By making the electric current stronger, greater weight can be lifted. Many tons of mate- rial can be lifted at one time. An electro magnet will do the work of many men at much less cost. In this picture we see the magnet lifting a great weight of miscellaneous pieces of scrap iron. As many as twenty tons can be lifted and transferred from one place to another at one time. WHAT ELECTRICITY IS 329 molecule throughout the bar is a mag- net by itself. Some things can be magnetized while others cannot. JMany substances have not the property of magnetizing other substances when they have once been attracted by a magnet. These are called magnetic substances. They remain magnetized only as long as they are in touch with the magnet; other substances when once magnetized become permanent magnets. Steel and lodestone have this faculty. A com- pc'ss needle is an artificial magnet which becomes a permanent magnet when rubbed with a magnet. What Is Electricity? If you pass a hard rubber comb through your hair, in frosty weather, a crackling sound is produced, and the individual hairs show a tendency to stick to the comb. After being drawn through your hair a few times, you may notice that the comb has become charged with electricity. This electricity is produced by friction. Not only rub- ber but many other substances become electrified by friction, such as a bar of sealing wax rubbed with flannel, or a glass rod rubbed with silk, will show the same qualities, and these simple ex- periments teach us many of the funda- mental facts about electricity. Some simple experiments will be found instructive and interesting. Rub with flannel a stick of sealing wax until it is electrified and then bring it close to a pith ball which should be hung by a silk thread. The pith ball will at once be attracted to the sealing wax, and, if brought quite close, the ball will adhere to the wax for a few moments, and then fly away from it. The ball will now be repelled by the sealing wax instead of being drawn toward it. Now take a glass rod, rub it with a silk cloth after drying it thoroughly. When the pith ball is brought close to the glass rod it also will at first be attracted toward the glass and, if brought in contact with the glass, the pith ball will adhere as before. It will also then fly away in the same way it dirl from the sealing wax. Repeat these experiments with the sealing wax now and you will find the ball will be attached, as it was at first, but if it touches the wax it will again adhere for a moment and then fly away. By using the sealing wax and glass rod alternately and bringing them into contact with the pith ball, you dis- cover that when it is attracted by one, it is repelled by the other, and that, afer it has been in contact with either for a few moments it is no longer attracted by it. We learn thus that the electricity in the glass and the sealing wax are not the same. To distinguish the two kinds of attraction, we say the glass is charged with positive, or vitreous elec- tricity, while the charge on the sealing wax is called negative, or resinous elec- tricity. When the pith ball was touched with the sealing wax, it became filled with negative electricity, and was then no longer attracted by the wax, but was repelled by it and attracted by the glass rod ; but when the ball had been filled with positive electricity, it was repelled by the glass and attracted by the wax. We conclude from th'ese facts that bodies filled with the same kind of elec- tricity repel each other, while bodies filled with opposite kinds of electricity attract each other. When two substances are charged, as we say, with electricity of opposite kinds and are brought into contact, and left so for some time, the two charges disappear, one appearing to neutralize the other. From this, we conclude, and rightly, that any sub- stance not electrified, contains equal amounts both positive and negative elec- tricity. When, therefore, we rub a piece of glass with silk, we are not creating electricity, but only separating the different kinds. The positive elec- tricity adheres to the glas.s, and the negative remains behind, on the silk. In the same manner, when we electrify scaling wax with flamiel the negative kind remains in the sealing wax and the flannel becomes charged with the posi- tive. Whenever a body is electrified 330 WHAT ELECTRICITY IS Magnets are particularly valuable in lift- ing raw material in a steel mill. The red- hot pig-iron, from which steel is made, can be handled easily in this way, whereas it would be impossible to handle same by hand. Sometimes great quantities of iron are broken up by the magnet. A weight of many tons is lifted by the magnet and allowed to fall on the material to be broken up. The weight falls as soon as the current is turned off. n \ \ Pieces of machinery which cannot be lifted by men on account of their great weight and shape are handled easily. WHAT GOOD AND BAD CONDUCTORS OF ELECTRICITY ARE 331 by friction, both kinds of electricity are produced ; it is impossible to produce one kind without the other. You must rub the entire glass rod or bar of sealing wax to electrify the whole of it. If only a part of the glass rod or sealing wax is rubbed, only that part becomes electrified, as may be shown by trying to attract a pith ball with the part that has not been rubbed. If, however, the charged part of the sealing wax is brought into contact with a metal rod resting on,, say, a drinking glass, the rod becomes charged, not only where it is brought into contact, but all over its surface. Substances over which electricity flows readily are called conductors of electricity. All metals are of this kind. Things like glass and sealing wax over v/hich elec- tricity does not flow readily, are called non-conductors, or insulators. Water, the human body, and the earth are good conductors and rubber, porcelain, most resins, and dry air are non-conductors. You have already learned that sub- tances charged with opposite kinds of electricity attract each other, and sub- stances charged with the same kind repel each other. We will try to discover why substances charged with either kind of electricity attract small light objects, such as pith balls, when these latter are not charged with electricity. As we have discovered, all substances which have remained undisturbed have both kinds of electricity present in them, in equal amounts. Now, when an un- charged body is brought near a charged body, the two kinds of electricity in the uncharged body have a tendency to separate. The kind opposite in char- acter, to that on the charged body, is attracted toward the charged body, and the other kind is repelled. Thus, if our bar of sealing wax, charged with, let us say, negative electricity, is brought near a pith ball, the positive electricity in the ball is attracted to the side nearest the scaling wax, and the negative elec- tricity is repelled to the farther side. As the positive electricity on the pith is nearer to the sealing wax than the neg- ative, its attraction for the negative charge, on the sealing wax, is stronger than the repulsion between the negative electricities of the two objects, and con- sequently, the ball is attracted to the sealing wax. If the charged sealing wax is brought near a good conductor, which is supported on some non-con- ducting substance, such as glass, silk, or rubber, over which electricity will not flow, a much more complete separa- tion of the two kinds of electricity oc- curs on the conductor than on the pith ball. If the charged sealing wax is brought near one end of a metal rod so placed, the charge of negative electric- ity upon the sealing wax will attract the positive electricity on the metal, to that end, and will repel the negative electricity to the other end. When a pith ball, hung by the silk thread, is brought close to either end of the metal rod, when the charged sealing wax is near the other end, the pith ball will be attracted toward the rod ; but will not be attracted if placed close to the middle of the rod. This proves that the metal rod is electrified only in the parts near- est to and farthest away from the charged body. The two kinds of elec- tricity neutralize each other at the parts in between. If now we take two conductors and place them end to end, we have for all practical purposes, a single conductor. It has the decided advantage, however, of being easily separated into two parts. When an electrified substance is brought close to one end of such a con- ductor, a charge of one kind is attracted to the near portion of the conductor, and a charge of the opposite kind is repelled to the farther part. By sepa- rating the two parts of the conductor, we learn that one of the ends, which have been in contact, is charged with j)Ositivc and the other with negative electricity. This act of separating the two kinds of electricity upon a conductor by means of a charge upon another body which is not permitted to come into contact with the conductor, is called in- duction, and two charges of electricity 332 WHAT A LEYDEN JAR IS produced in this way are known as in- duced charges. There are other ways in which a charge of electricity may be induced upon a conductor. One end of the con- ductor may be connected with the earth by means of some good conducting ma- terial, and the charged substance brought close to the other end. A charge, opposite in character to the in- itial charge, is attracted to the end of the conductor that is near the charged body, and the electricity of the opposite kind is repelled, through the conductor to the earth. By securing the connec- tion with the earth, while the charged body is near the conductor, a charge is obtained upon the conductor, that is opposite in character to the initial charge. This method of charging con- ductors, by induction, is practically the same as the one first described, for the earth is a conductor of electricity, and corresponds to the more distant part of the two-piece conductor. An instrument, known as the elec- trophorus, is especially designed for the production of electric charges by induc- tion in the manner just described. This instrument consists of a brass plate, on an insulating handle of glass, and a disk of sealing wax, fitted into a brass dish, whose edges rise somewhat higher than the surface of the wax. In using the electrophorus the brass dish, or sole, is placed upon some support that will conduct electricity, and the sealing wax disk is then rubbed vigorously with a piece of flannel, or catskin, which elec- trifies the sealing wax, with negative electricity. The brass plate is then taken by the glass handle and brought close to the charged sealing wax. The charge of negative electricity on the wax attracts a charge of positive elec- tricity to the under surface of the plate and repels a negative charge to its up- per surface. If the charged plate is now brought into contact with the edge of the brass dish the negative charge, on the back of the plate, flows away, through the legs of the dish, to the earth, but the positive charge remains on the under surface, where it is bound, by the attraction of the negative charge on the disk of sealing wax. If the brass plate is now removed, it will be found to be charged with positive electricity. The negative charge upon the sealing wax is not reduced or diminished by its action in charging the brass plate, and it is possible to charge the plate an indefinite number of times by means of one charge on the sealing wax. The charges of electricity, produced in any of the ways that have been described, are necessarily small, and the disturbance produced, when thev are destroyed by bringing oppositely charged conductors together, is very slight, merely a little snapping noise and, perhaps, a small spark, that seems to leap from the positively charged con- ductor to the negatively charged one, when they come very close together. By the use of electrical machines of various kinds, in some of which the electric- ity is produced by friction, and in others by induction, conductors may be charged with much larger quantities of electricity, and the disturbance pro- duced by their discharge is greatly in- creased. The noise produced is louder and the spark much brighter, and leaps from one conductor to the other, while they are much farther apart. It is pos- sible to produce still larger charges of electricity upon conductors if they are arranged so as to form what are called condensers. What Is a Leyden Jar? One of the commonest forms of con- denser is the Leyden jar, which is so named because it was invented at Ley- den, in Holland. This is a glass jar, upon the outside of which is fastened a coat- ing of tinfoil, that covers the bottom of the jar and extends two-thirds of the way up the sides. Inside the jar there is a similar coating of tinfoil, and through the top of the jar, which is usually made of wood, extends a metal rod. On the upper end of the rod, there is a metal ball, and, at the lower end, is attached a chain which runs down to the bottom of the jar and rests upon the inner tinfoil coating. HOW ELECTRICITY WAS DISCOVERED 333 In using the Leyden jar, the ball on the metal rod that runs through the top of the jar is connected with an electrical machine, and the jar is supported upon some conducting material, through which electricity may be conveyed from the outer coating of tinfoil to the earth. If the inner coating of tinfoil is now charged with positive electricity, by means of the electrical machine, it in- duces, upon the outer coating of foil, a charge of negative electricity, which is bound by the attraction of the positive charge on the inside of the jar. At the same time, the positive electricity, on the outer coating of foil, is repelled, through the conducting support, to the earth. The charge that can be communicated to the coating of the foil, inside the# Leyden jar, is greatly increased by the presence of a charge of the opposite kind of electricity, on the coating on the outside of the jar. Each of these charges attracts the other, through the glass of the jar, and serves to bind or hold it. If either coating of foil is re- moved, the charge on the other coating tends to fly off the tinfoil, and will im- mediately do so, if a conductor is brought near. It is because the negative effects of the initial charge, inside the jar, and of the induced charge outside the jar, make it possible to communi- cate, to each coating of foil, a larger charge than it could otherwise be made to receive, that a Leyden jar is called a condenser. When a Leyden jar is disconnected from the electrical machine, two oppo- site charges of electricity are present on it, one inside and the other on the out- side. If the two coats of tinfoil are now connected, by means of a condenser, they will at once neutralize each other, and the jar will be discharged. A jar may be discharged, by simply taking holfl of the tinfoil on the outside of the jar, with one hand, and touching the metal rod, running through the top of the jar, with the other. If you do this, there will be a sudden flow of clectricitv through your body, your muscles will give a sudden jerk, and you will feel a peculiar tingling sensation. In other words, you will have received a shock. It is not necessary, for the hand that does not grasp the jar, actually to touch the rod that runs through the top. If the hand is brought toward the rod, rather slowly, you will see a spark leap across the space between the rod and your hand, while your hand is still some distance from the rod. The greater the distance, across which the spark leaps, the brighter will be the spark, and the stronger the shock produced. This distance is sometimes spoken of as the length of the spark, and it indicates the size of the charges on the tinfoil coatings of the jar. Who Discovered Electricity? It may seem difficult to believe, that the tiny spark and weak snapping noise that are produced when a Leyden jar is discharged, are, in many respects, the same as lightning and thunder, but it is nevertheless true. This was proved by Benjamin Franklin, about the middle of the 18th century, in the following way. One afternoon, when a thunder shower was approaching, he sent up a kite, to the string of which he fastened a large metal key; and to the key, a ribbon of non-conducting silk, which he held in his hand. When the rain had been falling long enough to wet the string thoroughly, it become a good conductor of electricity, and Franklin found that the key had become charged with electricity transmitted from the clouds, along the wet kite string. The non-conducting silk ribbon, that formed the continuation of the kite string, from the key to his hand, was employed to prevent him from receiving shocks from the passage of the electricity, through his body, to the earth. Up to this point, your attention has been directed in charges of electricity. You have been told how they may be produced, what some of their leading properties are, and what effects they produce, when they are discharged. The subject that will now be exi)laiiied to you is that of electric currents. 334 WHAT AN ELECTRIC CURRENT IS What Is an Electric Current? By an electric current, is meant a flow of electricity along a conductor. The flow of electricity, through your body, when you receive an electric shock, is a current, but it lasts only for an in- stant, and it is difficult to learn much about its nature. By the use of various devices, it is possible to produce cur- rents, that will continue as long as we want them, so that we are enabled to study their properties quite thoroughly. One of the oldest and simplest forms of apparatus, for producing electric cur- rents, is that which is known as the voltaic cell. This form of apparatus may very easily be constructed. Pour some water into a glass jar, and add a little sulphuric acid. Now place in the water a strip of -clean zinc and one of clean copper. Do not let the strips of metal touch in the water, but connect them outside the water by means of a piece of wire. When this has been done, a current of electricity will be sent up along the wire and through the water between the two strips of zinc and cop- per. This current is said to flow along the wire from the copper, which Is called the positive pole of the cell, to the zinc, which is called the negative pole. In the liquid in the cell (i.e., the jar), the current travels from the zinc to the copper, thus completing what is called the electric circuit. Whenever the circuit it broken, that is, whenever there is a gap made in the wire con- necting the poles, or anything else is done to destroy the completeness of the path, along which the current travels, the current ceases ; consequently, when it is desirable to stop the current, all that is necessary is to cut the wire con- necting the two strips of copper and zinc. The production of a current of elec- tricity, by means of an apparatus of this sort, depends upon the chemical action of the acid in the water upon the strip of zinc. As long as the acid continues to act upon the zinc, the current is pro- duced, and when the acid ceases to act upon the zinc, the current ceases to flow. If the zinc is clean, the chemical action of the acid ceases, whenever the circuit is broken, and consequently, when the cell is not being used to produce a current, the zinc is not destroyed by the acid. But if the zinc is not clean, small elec- tric currents are set up, within the liquid, between the zinc and the impuri- ties on its surface, and around the points where these impurities lie the acid acts upon the zinc and dissolves it. This ac- tion of the acid upon the zinc, when the circuit is broken, is known as local action, and it is very desirable to pre- vent it, as far as possible. For this purpose the zinc is often rubbed with mercury, whch soaks into the zinc and forms a film on its surface, upon which the impurities float. This treatment of the zinc is known as amalgamation, and it serves to prevent almost all the local action, due to impurities of the zinc. Many other substances, besides zinc and copper, have been found capable of yielding an electric current, when placed in a suitable liquid, and many other fluids, besides water that contains a little sulphuric acid, have been em- ployed to act upon the zinc and copper, or the substances used in their stead. Numerous cells of difl"erent kinds have, therefore, been devised, but, in all of them, the current is produced by chem- ical action. IMost of them contain a liquid of some sort, which is called the exciting fluid, and two solid substances, which are called the elements of the cell. One of these elements is always much more susceptible to the chemical action of the exciting fluid, than the other, and this one is known as the posi- tive element. The other element, upon which the exciting fluid may have no action, is called the negative element. In cells in which the elements are zinc and copper, the zinc is always the posi- tive element. This may seem strange to you, for you have already learned that the zinc is the negative pole of the cell, but, to avoid confusion, you must fix well in your mind the fact that the zinc is not the positive element HOW MAGNETS ARE MADE 335 of a voltaic cell, but its negative pole, and that the copper, which forms the negative element is the positive pole of the cell. The currents produced by the various forms of voltaic cells, vary con- siderably in strength, but none of them are very strong. In order to obtain a stronger current, a number of cells must be used together. Such a collection of cells forms a voltaic battery, and in some instances, as many as fifty thou- sand cells have been used in a single battery. We have already learned in our study of water that it may be separated into its elementary gases by sending an electric current through it. The effect is a chemical one. Water, however, is not the only substance that is decom- posed by electricity ; almost all chemical compounds may be decomposed by the passage of a current through them, pro- vided a current of sufficient strength is used. Another effect of the current is its heating effect. It has been found that ' the passage of an electric current, through any body, is always productive . of a certain amount of heat. The amount of heat produced depends upon the strength of the current of electricity, and the resistance to its passage that is offered by the body through which it travels. This amount is increased by increasing either the strength of the current or the resistance of the con- ductor along which it travels. We have already learned, that some substances allow electricity to pass over them very readily, and are therefore called con- ductors, while substances through which electricity does not flow readily are known as non-conductors. No sub- stance is a perfect non-conductor, for electricity can be made to pass through any substance, if the current is suf- ficiently powerful. Neither is any sub- stance a perfect conductor, for all sub- stances offer some resistance to the pas- sage of an electric current. Those sub- stances that are ordinarily considered good conductors offer varying degrees of resistance to electric currents. For example, a copper wire offers less re- sistance than an iron wire of the same length and diameter. The resistance of a body depends not only upon its material, but also upon its length and size. In conductors of the same material, the resistance is directly proportional to the length of the con- ductor, and inversely proportional to the square of its diameter. This is not surprising, for an electric current bears a strong resemblance to a current of water, in many of its properties, and you know that it is harder to force water through long, narrow pipes, than through short, wade ones. From what has been stated about re- sistance, you may see, that a current will produce more heat, in passing through a long fine wire, than through a shorter and thicker one, and that, of two conductors of the same length and size, but of different material, one may be heated much more by a current than will another. A third effect of the electric current, which has not previously been men- tioned is its magnetizing effect. It is upon this, that some of the most impor- tant effects of electricity depend. By coiling a wire around a bar of iron or steel, and then sending an elec- tric current through it, the piece of iron, or steel, is made to show magnetic properties. By this is meant, as you doubtless know, that the iron will now attract other pieces of iron, or steel, to it. The strength of this attraction depends upon the strength of the cur- rent, and upon the number of turns of wire around the bar. By increasing either the strength of the current, or the nimiber of turns in the coil of wire, around the bar of iron, the strength of its magnetic attraction is increased. When the current is stopped, the mag- netic properties of the iron disappear almost completely. A magnet, that de- pends upon a current of electricity for its magnetic power, is called an electro- magnet. Besides electro-magnets there arc others, which arc called permanent magnets. Flcctro-'magnets are com- posed of soft iron, the softer the better, 336 WHY A BEE HAS A STING and, as soon as the current of elec- tricity ceases to flow around them, their magnetic properties disappear. Perma- nent magnets, on the contrary, are made of steel, and their magnetism is inde- pendent of the action of a current of electricity. No coil of wire is wound around them, and no current is em- ployed to maintain their magnetic prop- erties. A piece of steel may be made to become a permanent magnet, by pass- ing a current of electricity, for a con- siderable time, through a coil of wire wound around it, or by allowing a piece of steel to remain for some time in contact with a strong magnet. When a current of electricity passes through a coil of wire, wound around a bar of steel, it takes longer to magnatize the steel than it would to magnetize iron, but, when the current ceases, the mag- netism does not all disappear from the steel. A portion of it remains, and the steel becomes permanently magnetic. If a thin bar of steel is magnetized, and is then suspended by its middle, so that it can spring freely, it will be found that one end tends to point toward the north, and the other toward the south. Whenever the bar is swimg out of this position, it swings back to it, and if the north end is turned entirely around to the south, it does not remain, but swings back to its former position. This shows that there is a difference in the magnetism at the two ends of the mag- net. To indicate this difference, the north-seeking end of a magnet is called the positive pole of the magnet, and the south-seeking end is known as the negative pole. By suspending two bar magnets, in the manner described, it can be shown that the positive and negative poles of the magnets act like positive and nega- tive charges of electricity. Poles of the same kind repel, and poles of opposite kinds attract, each other. Permanent magnets are usually made in two forms, either straight or horse- shoe shaped. A compass needle, as has been shown, is an example of a straight magnet. The horseshoe vari- ety, which has a little bar of iron, called the keeper, laid across the poles is a common toy. Electro-magnets are sel- dom seen, except in electrical instru- ments or machinery. The pictures shown on the following pages give us a bird's-eye view of some of the won- ders performed by these electro-mag- nets. Tons and tons of material are picked up and held securely by one of these magnets as easily as you can hold on to an apple. Why Does a Bee Have a Sting? The bee's sting is given him as a weapon of defence. Primarily it is for the sole purpose of enabling him to help defend the hive from his enemies. Sometimes when he is attacked away from the hive he uses his sting to de- fend himself. When he does so, he in- jects a little quantity of poison through the sting and that is what causes the inflammation. How Does a Honey Bee Live ? The bee lives in swarms of from 10,- 000 to 50,000 in one house. In the wild state the house or hive is located m h hollow tree generally. These swarms contain three classes of bees, the per- fect females or queen bees, the males or drones, and the imperfectly developed females, or working bees. In each hive or swarm there is only one perfect fe- male or queen whose sole mission is to propagate the species. The queen is much larger than the other bees. When she dies a young working bee three days old is selected as the new queen. Her cell is enlarged by breaking down the partitions, her food is changed to "royal jelly or paste" and she grows into a queen bee. The queen lays 2,000 eggs per day. The drones do not work and after performing their duty as males are killed by the working bees. The female bees do the work of gather- ing the honey. They collect the honey from the flowers, they build the wax cells, and feed the young bees. When a colony becomes overstocked, a new colony is sent out to establish a new hive under the direction of a queen bee. Probably no form of construction is so interesting to everyone as the construction of a huge steamer, a wonderful "city" afloat, with its thousands of passengers, its thousand officers and crew, the tremendous stores of provisions and water, and the precision with which the great ship plows its way from one shore to the other. This picture shows the first work in building a modern steamer, laying the keel and center plate, upon which the massive hull is constructed. The rivets are driven by hydraulic power, noiselessly but firmly. In the new "Britannic"— largest of all British steamers and the newest (1915) modern leviathan— over 270 tons of rivets — nearly three million in all— were required to give staunchness to the steel-plated hull. The cellular double bottom is constructed between the bottom and top of the center plate. A LONGER VIEW OF TUE ABOVE OPERATION. 338 THE CRADLE OF A STEAMSHIP CALLED A "GANTRY VIEW NEAR THE BOW. The "ribs" of the "Piritannic," showing the deck divisions, in outline. The huge "gantry" or cradle of steel, in which "Britannic" was built, cost $1,000,000. THE DOUBLE BOTTOM OF MODERN STEAMSHIPS 339 THE BRITANNIC OF THE WHITE STAR LINE. VIEW OF THE DOUBLE BOTTOM PLATED. THE HUGE STEEL SKELETON OF THE "UKITANNIc'' UEFOKE THE PLATES WERE PLACED ON IT. The plates arc seen piled in flu- foreKroiiiifl. The largest of tlicm arc 36 feet long and wci^di 4'/i Ions each. 340 THE SHIP READY TO LAUNCH NOT A "skyscraper," BUT A FLOATING HOTEL IN PROCESS OF CONSTRUCTION. THE HULL ITSELF IS 64' 3" DEEP, AND FROM THE KEEL TO THE TOP OF THE FUNNELS IS 175 FEEI. THE NAVIGATING BRIDGE IS IO4' 6" ABOVE THE KEEL. READY TO LAUNCH. The '"Britannic" on the ways at Belfast (Harland & Wolff's). The largest gantries ever constructed to hold a ship. THE MACHINERY USED IN LAUNCHING A SHIP 341 FORWARD LAUNCHING GEAR (hyDRAULIC), The snip went from the ways into the water in 62 seconds and was stopped in twice her own length. THF. niJCE HtnX LKFT THK WAYS EASILY AND CREATm ONLY A SMAfl, SPLASH. 342 A CLOSE VIEW OF A SHIP'S RUDDER ** 'RRITANNIC HKI.n IT Tt'ST AFTER THF. r.AfXCTI. "britaxxic." the ioo-tox rudder, the (cexter") tureixe propeller shaft and one of THE "wing" propeller SHAFTS. WHAT A SHIP'S PROPELLER LOOKS LIKE 343 THE COMPLETED SHIP The center (the turhinc) pi'ipi llcr, i6' 6" in (li;inuter, cast of one sohd \)\i.iv of manRanese bronze, 22 tf)ns in weight. Tlic "I'.ritaiinic" like "Olympic," is propelled by two sets of reciprocating engines, tlie exhaust steam from these hcinR rensed in the low- pressure tnrhine, cfTectinR great economy in coal. 'J he two "wing" propellers are 23' (>" in diameter and weigh 3K tons each. 344 WHAT A SHIP'S TURBINE LOOKS LIKE The turbine motor, 130 tons in weight (Parsons type). The steam plays upon the blades with such power that they develop 16,000 horse-power and revolve the propeller (turbine) 165 times a minute. The motor is 12 feet in diameter, 13' 8" long, the blades (numbering thousands) ranging from 18 to 25}^ inches in length. -"^^^ THE IMMENSE TURBINE MOTOR FULLY ENCASED— WEIGHT 420 TONS. HOW A FUNNEL APPEARS BEFORE IT IS IN PLACE 345 fai^WiWmMtJMMKal'. UMiHia't^J?! One of the four immense funnels — without the outer casing. Each is 125 feet above the hull of the ship and measures 24' 6" by 19' o". 34C) WHAT A GREAT STEAMSHIP WOULD ^ I- ^ '■ > S "5 %^'% r- ;3 ID > c •-^ oP^ U , rt r- -^ ^ 4-^ r/5 'CJ (A. Ph i: ij o ^ ed, w of stn Idren' ^'P, ^^ Ti <^ -G rt (/) 5j ,— 71 rt ^ been ins find the i. lasium, a CA) ^oa -o ri C3 rt T* >^ rt ^ J^O ^' ^ 12 ^-3 5r >- o o 5^ ^'-t;i '*^.'^ a. sgg. ID M-H (y . — 1 lyj Pi rt rt 00 rt u- rS <^ o ^ ^^ o rt u O ii c^ v f^ > Iteri tean ars .^X) <1> r- C) .IP, Vi 'V T^ ^- ;; ea iple-s a do -I-' tC n 3 o c"'t:3 some r Line med vT ii (U ly, +-' •si^-S a. >. ^ ^ -^ "TZ CO rt (D c ^ O -.x OS > iL> !- rt r- rt o -M ■*-' >+-. ^ O _ 't: > S ^ C/3 en CJ +J ro flj P> »— I tn-^ « O (« Cm C« "-)•*-' o -^ 01 > CTj CO P* C/i C r- O > . ^ 43 -t-> (Ti 1 1 X. ^ c ^ o rt ,^ -o <■ > airs, one for forming, the other for laying and closing. Each ground has a track to accommodate the machines used and an endless band-rope which conveys the power. At the head of the forming ground stand frames holding the bobbins of yarn. The yarns for each strand first pass through a plate perforated in con- centric circles. This arrangement gives each yarn the correct angle of de- livery into a tube where the whole mass gets a certain amount of compression. As the top truck is forced ahead by the twisting process, the ropemaker by means of Gfreater or less leverage on the "tails" — the loose ropes shown in our picture — preserves a correct ^lay in the rope. The stakes on which the strands rest are removed one by one to allow the top truck to pass, and then replaced to support the rope until the laying is finished and the reeling in of the rope begun. The closing process on cable-laid goods is like the laying except that the twist is reversed. The work now being with three complete ropeS' — frequently very large — a heavier top truck is nec- essary, and this must often be bal- lasted, as shown in our illustration, to keep down the vibration which would otherwise tend to lift the truck off the track. Modern rope-making ingenuity reaches its high-water mark in the com- pound laying-machine where the two operations of forming the strands and .NEAR VIEW OF MACHINE IN ROPE WALK. PREPARING THE FIBER IN ROPE MAKING 359 OPENING 1;ALES UF MANILA FIBER FOR rREPARATlON. rUKPAUATIOX UOOM. Here the filicr is carefully cleaned and cnmbcd by a series of fine loolli inachiniry llirmigli which it passes. 360 COUNTLESS SLIVERS STREAM FROM THE ROPE MACHINE The hanks of fiber are fed by hand into this machine several at a time, where it is grasped by steel pins fitted to a slowly re- volving endless chain. A. second set of pins moving more rapidly draws out the indi- vidual fibers and combs them into a continu- ous form. FOKMATIUN UK SiLl\Ek l-ikST J'.KtAKKK. The operations which follow are very similar. A number of "ropings" are allowed to feed together into a first slowly revolving set of pins and are drawn out again by a high speed set into a smaller sliver, the pins becoming finer on each succeeding machine until the draw frame is reached. Here the fiber is pulled from a single set of pins between two rapidly mov- ing leather belts called aprons. On all of these machines the fiber passes between rollers as it goes oSito and leaves the pins and the sliver is given its cylindrical form by being drawn through a circular opening. A finished sliver must conform to the special size desired for spinning. - •■ jii^ \ ^' m S^ >^4 m «1^ ■L mim^^^m JH SECO.XD BREAKER. DRAW FRAME. A ROPE MACHINE THAT IS ALMOST HUMAN 361 FOUR-STRAND COMPOUND LAYING-M At H INE. laying them into a rope are combined. Up to a certain point this method is more economical than that in which the forming and laying are unconnected. Fewer machines are required for a given output — hence, less floor space and fewer workmen. The time-saving element also enters in. The compound laying machine must, however, be stopped each time that the supply of yarn on any bobbin is so low as to call for a fresh one. This would occur so fref|uently in the case of the larger ropes as to offset the advaiitages just mentioned, hence the machine is used on a limited range of sizes only. 362 AN AVERAGE COIL OF ROPE~1200 FEET As can be seen in the picture, the machine contains a vertical shaft with upper and lower projecting arms which- support the bobbin-flyers — four in number in this particular case. The bobbins within each flyer turn on sei)a- rate spindles, allowing the yarns to pass up through small guide plates and thence into a tube. Each flyer is geared to revolve on its own axis, thus twisting its set of yams into a compact strand. At the same time all the flyers revolve with the main shaft in an opposite direction and form a rope out of the strands as the latter come together in a central tube still higher up. The rope is drawn through this tube by a series of pulleys which exert a steady pull and so keep the proper twist in the rope. From these pulleys the finished product is delivered onto a separately-driven coiling reel, an auto- matic device registering meanwhile on a dial the number of fathoms run. The small reel, seen near the head of the main shaft, holds the small heart rope which is fed into the center of certain four-strand ropes fo act as a bed for the strands. Pure Manila rope is the very best and the most satisfactory for all around use. The character of good Manila fiber is such as to impart to a properly made rope such necessary factors as strength, pliability, and wearing qual- ities. Regular 3-strand Manila rope is uni- versally used for all general purposes. For certain special uses, however, and particularly where the rope is to be used for any kind of sheave work, a 4-strand type of construction will be found the most suitable, as such a roj^e presents a much firmer, rounder, and greater wearing surface than the or- dinary 3-strand. There are many dif- ferent types of 4-strand rope. The picture shown on this page rep- resents a coil of 4-strand Manila called "I]est Fall." This rope is made of carefully selected fiber ; is 4-strand with heart, and is harder twisted than or- dinary goods. Best Falll is adapted for heavy hoisting work, as on coal and grain elevators, cargo and quarry hoists and for pile-driver hammer lines. The standard length coil of rope is 1,200 feet, although extra long lengths are every day made for such purposes as oil-well drilling, the transmission of power, etc., etc. SECTION, CROSS SECTION AND COIL, FOUR AND THREE-FOURTHS INCHES CIRCUMFERENCE. SEC- TION AND CROSS SECTION ONE-HALF ACTUAL SIZE. DIFFERENT KINDS OF KNOTS 363 From Kniglit's American Mechanical Dictionary. 1. Simple over hand knot. 2. Slip-knot, seized. 3. Single bow-knot. 4. Square or reef knot. 5. Square or bow-knot. 6. Weaver's knot. 7. German or figure-of-H knot. H. Two half-hitches, or artificer's knot. 0. Double artificer's knot. 16. .Simi)le galley-knot. II. Capstan or prolonge knfjt. 12. Bowline-knot. 13. Rolling-hitch. 14. Clove-hitch. 15. Blackwall-hitch. 16. Timber-hitch. 17. Bowline on a bight. 18. Running-bowline. 19. Catspaw. 20. Double running-knot. 21. Double-knot. 22. Sixfold-knot. 23. Boat-knot. 24. Lark's head. 25. Lark's head. 26. Simple boat-knot. 27. Loop-knot. 28. Double Flemish knot. 29. Running knot, checked. 30. Croned running-knot. 31. Lashing-knot. 32. Rosette. 33. Chain-knot. 34. Double chain-knot. 35. Double running-knot with check-knot. 36. Double twist-knot. 37. Builder's knot. 38. Double Flemish knot. 39. English knot. 40. Shortening knot. 41. Shortening knot. 42. Sheep-shank. 43. Dog-shank. 44. Mooring-knot. 45. Mooring-knot. 46. Mooring-knot. 47. Pig-tail, worked on tlie end <>f a rope. 48. Shrond-knot. .10. .S.iilor's bind. 50. A granny's knot. 51. A weaver's knot. 364 HOW TO SPLICE A ROPE ??^ ENGLISH SPLICE. For transmission rope. The successive operations for splicing a i)4-inch rope by this method are as follows: 1. Tic a piece of twine (9 and 10, figure 6) around the rope to be spliced, about si.x feet from each end. Then unlay the strands of each end back to the twine. 2. Butt the ropes together, and twist each corresponding pair of strands loosely, to keep them from being tangled, as shown (a) figure 6. 3. The twine 10 is now cut, and the strand 8 unlaid, and strand 7 carefully laid in its place for a distance of four and a half feet from the junction. 4. The strand 6 is next unlaid about one and a half feet, and strand 5 laid in its place. 5. The ends of the cores are now cut off so thoy just meet. 6. Unlay strand i four and a half feet, laying strand 2 in its place. 7. Unlay strand 3 one and a half feet, laying in strand 4. 8. Cut all the strands off to a length of about twenty inches, for convenience in manipulation. The rope now assumes the form shown in b, with the meeting-points of the strands three feet apart. Each pair of strands is now successively subjected to the following operations : 9. From the point of meeting of the strands 8 and 7, unlay each one three turns ; split both the strands 8 and 7 in halves, as far back as they are now unlaid, and "whip" the end of each half strand with a small piece of twine. 10. The half of the strand 7 is now laid in three turns, and the half of 8 also laid in three turns. The half strands now meet and are tied in a simple knot, 11 (c) making the rope at this point its original size. 11. The rope is now opened with a mar- lin-spikc, and the half strand of 7 worked around the half strand of 8 by passing the end of the half strand through the rope, as shown, drawn taut, and again worked around this half strand until it reaches the half strand 13 that was not laid in. This half strand 13 is now split, and the half strand 7 drawn through the opening thus made, and then tucked under the two adjacent strands as shown in d. 12. The other half of the strand 8 is now wound around the other half strand 7 in the same way. After each pair of strands has been treated in this manner, the ends are cut off at 12, leaving them about four inches long. After a few days' wear they will all draw into the body of the rope or wear off, so that the locality of the splice can scarcely be detected. WHY WE GO TO SLEEP 365 Why Do We Go to Sleep? First, of course, we sleep to rest our body and brain. During our wak- ing hours many, if not all, parts of our bodies are active all the time, and with every movement we exhaust or spend some of our strength. Take the case of your arm, for instance. You may be able to move it up and down fifty or a hundred or more times with- out getting tired, according to how strong you are, but sooner or later you will not be able to move it any more — it is tired — the life has all gone out of it and it needs rest, in order that it may become strong again. Every time you move your arm you destroy certain parts of its tissues, which can only be replaced during rest. Every activity of your body has the same experience, and the constant work of the brain in directing the various movements and activities of the body, tires it out too. As soon as this condition occurs, the brain tells the other parts of the body that it is time to rest, and even if we try to keep awake and go on with our work or play, or w^hatever it is we are do- ing, we find sooner or later that it is impossible. If we persist w'e fall asleep wherever w^e happen to be. It is not necessary for all parts of the body to be tired before we sleep. One part alone may be so affected by what it has been doing that it alone causes i:s to fall asleep. Sometimes the eyes become so tired, w^hile we are looking at the pictures in a book or reading, for instance, that we fall off to sleep ("luickly. It is perhaps easier to bring on sleep by making the eyes tired than in any other way. That is why so many peojjle read themselves to sleep. It is such a gradual passing into un- consciousness that you can hardly ever tell where you left off reading. It is said that when we are awake our bodies are continually planning for the time when we shall need sleep and are continually making some little germ which is carrierl to the brain as soon as made, and when there are a sufficient number of these little germs ]:)iled up in the brain, we go to sleep. The process of sleeping then destroys these germs, and when they are de- stroyed we again wake up. Why Do We Wake Up in the Morning? To answer thjs we must go back to the answer to the question, "What makes us go to sleep ?" We go to sleep in order to secure the rest which our body and brain need to build up the parts which have been destroyed dur- ing our active Avork or play. We wake up naturally when we have had sufficient rest. We wake up nat- urally, however, only when the de- stroyed parts of the body have been replaced. Other things may waken us — a noise of any kind, loud or slight, a startling dream or a moving thing that disturbs our sleep — according to how fully we are asleep. It is said that sometimes only parts of the body are asleep ; that we are not always all asleep wdien we appear to sleep, and that we dream because some part of the body is awake or active. This is prob- ably true. Now then, v/hen all of anv- one of us is sleepy, we go into what is called a deep sleep and at such times only something out of the ordinary v/ould awaken us. Gradually, how- ever, various parts of the body become rested and they are said to wake up, and finally wdien all of us is rested, we naturally wake up all over. If you are healthy and sleep naturally, in a [)lace where you cannot be disturbed by noises or movements of others, you should be "wide awake" when your eyes open and be ready to get up at once. If you feel like turning over for another snooze, when it is time to get up, you did not go to bed as early as you should have done, or else some part of you did not get the re(|uire(l amount of sleep it should have had. Where Are We When Asleep? We are just where we lie. It seems to us, of course, because of our dreams when we are asleep tbat we are away off some place else. Often when we w.'ikc up we wonder for a minute or 366 WHAT MAKES US DREAM two where we are, as everything seems so strange to us, and it takes a minute or so for us to remember that we are in our own bed, if that is where we went to sleep. This is because of the dreams we have while asleep. In past times the uncivilized savages in va- rious ])arts of the earth believed that when any of them went to sleep that the real person so asleep actually went away, leaving the body behind ; in other words, that the soul went traveling. They thought this because it was the only explanation they could think of for the dreams they had, since almost invariably the dream was about some other place. Why Does It Seem When We Have Slept All Night That We Have Been Asleep Only a Minute? This is because all our ideas of pas- sage of time are based on our con- scious periods. When we are asleep we are unconscious. It is the same as if time did not pass, and when we wake up the tendency is to start in where we left ofif. We have learned by ex- perience that when we go to sleep at night and wake up in the morning that much time has passed and this uncon- scious knowledge keeps us from think- ing always that we have been asleep but a minute. But if you drop asleep in the day time, no matter how long you sleep, you wake up thinking that you have been asleep only a minute, and sometimes it is difficult to con- vince yourself that you have been asleep at all. Sometimes after being asleep for hours, your first waking thought is a continuation of what your mind was on when you went to sleep. The reason for this, as stated above, is that we cannot keep track of passing time when we are asleep, because we are perfectly unconscious. Why Should We Not Sleep With the Moon Shining On TJs? There is no harm in letting the moon shine on us while we are asleep. This is one of the queer superstitions that has developed in the world. A great many people think that something ter- rible will happen if the moon is al- lowed to shine into the room where tliey are asleep. Not so many believe this as used to do so, thanks to the more enlightened condition of things in the world. To prove to yourself that no harm can come to you through the moon shining into your bedroom qr upon you as you are asleep, you have only to remember that a great many men and very many more animals sleep out under the sky every night and that the moon must shine on them while they are asleep. As a matter of fact, people who sleep out under the open sky are generally in ]:»ossession of more rugged health than people who sleep in beds in closed rooms. So it is rather bet- ter to let the moon shine on you while asleep than not. This belief probably started with some one who had trouble in going to sleep with the moon shining on him, because the light of the moon might have a tendency to keep him awake. It is easier to go to sleep in a dark room than in one that is lighted, be- cause when there is no light there is less about you to keep you awake. What Makes Us Dream? Dreams originate in the brain. The brain has many parts and some parts of it may be asleep while others are not. If all parts of the brain are ac- tually asleep, it is said there can be no dreams. We have dreams about things which seem very natural while we are having them, and which we know would be impossible if we were wholly awake, because those parts of the brain which control the other parts are probably asleep while the dream is tak- ing place, and it is then that we have those fantastic and highly imaginative dreams, for the brain is not under con- trol in every sense. We used to believe that dreams have no purpose, just as now we know that they have no meaning. But it has been discovered that dreams have a purpose in that they protect our sleep. You see, every dream is started by some WHAT GHOSTS ARE 367 disturbance or excitement of the body or mind. Something may be pressing or touching us while we sleep, or a strange sound may start a dream, or perhaps it is some uncomfortable po- sition in which we are lying or trouble in the stomach on account of eating something we should not. Whatever it may be, those things wake up some part of the brain, because if all parts cf the brain were asleep, we could not feel or hear anything. Any such dis- turbance or excitement would natur- ally excite the whole brain and wake us up completely if it were not for dreams. The dream takes care of this and enables the rest of the body and brain to sleep while one or more parts of the brain are disturbed and even perhaps awake. We may perhaps have become uncovered in some way. This would produce a cold feeling and might wake a part of the brain and cause a dream about skating or some other winter amusement or experience, or even perhaps one about falling through the ice, and still we might not be uncovered so much that it would make any great difference. The dream comes and we go on with our sleep v/ithout waking up, whereas if it were not for the dream we would awaken. In other words, dreams are just an- other wise provision of nature which enables us to go right on and get the rest we need, even if our digestion is out of order, or some part of our brain is disturbed through something we read about, or were told of, or we thought of while still awake. Why Do We Know We Have Dreamed When We Wake Up? Because we remember some of our dreams. Sometimes we do not re- m.ember the dreams wc dreamed. This is just like what happens when wc arc awake. We remember some things and forget others. Dreams are a sort of safety valve in our sleep. We dream because not all of our brain is asleep at ihe lime and it is a wise ])rovision of nature that permits the waking ])art of the brain to go on working without dis- turbing the sleep of the other parts of the brain. If a large part of the brain is awake and engaged in making the dream, we are very apt to remember the dream ; but when we dream and cannot remember what the dream was, it is because only a very small portion of the brain was awake and making £ dream. What Causes Nightmare? A nightmare is a dream of what we mi'ght call a vigorous kind. A night- mare is caused by a feeling of intense fear, horror, anxiety or the inability to escape from some great danger. A nightmare is the result of either an irregular flow of blood to the brain or by a stomach that is not in -proper condition. The name for this kind of a dream comes from the words night and mare. The latter word in one of its several meanings indicates an incubus or evil vision, and a dream of an evil vision involving fear or horror came to be termed a mare. Since they occurred generally at night, since most people sleep at night, they became known as nightmares. Nightmares are more common to children than grown-up people because children are more apt to have an uneven flow of blood to the brain and also are more apt to eat the things which put the stomach in a state of unrest which causes nightmares. Grown-up people are more likely to have learned to avoid the abuses of the stomach which are apt to produce nightmares. What Are Ghosts? The idea of ghosts is the result of a mistake of the brain or an attempt to account for something of which wc see the results, but have no actual knowledge. There are no ghosts. There are many forces at work in the world of which we know nothing as yet. Many of the wonderful things that occur in the world are as yet mysteries to the mind of man. livery little while man discovers one of these new forces, and then he is able to un- derstand many things plainly which were up to then surrounded with 368 WHAT CAUSES A HOT BOX mystery and in tlie minds of supersti- tious people attributed to sjiirits or ghosts. Long before we understood as much as we do now of the workings of electricity (and they say we know only a little of its wonders as yet) many of the natural wonders produced by elec- tricity were attributed to ghosts. Most of the marvelous tales of the wonders performed by and visits from ghosts are the result of disturbances ot the brain in the pcoj)le who think they see the ghosts and the results of their work. A creature without imagination does not pretend to see or believe in ghosts. Man is the only animal which pos- sesses the ability to imagine things and so the ghosts w^e hear about are the creatures of the disturbed brains of men. Generally in the ghost stories we hear of, the ghost is described as wear- ing clothes — usually white. A bed sheet thrown over the foot of the bed may appear to a half-awake person as the outline of the figure of a ghost and to one of a highly imaginative tem- perament without the courage of in- vestigation, become forever a real ghost. Usually what is supposed to be a ghost is only a creation of the mind — a vision such as we can develop dur- ing a dream — oftentimes, however, v/hat you look at when you think you see a ghost is an actual something such as the sheet referred to, but which takes the form of the ghost in the brain of the person who is looking at it through eyes that really see it, but out of a brain that for the moment at least is far oft its balance. Why Do Girls Like Dolls? Girls like dolls because they come into the world for the purpose of be- coming mothers and the love which they display for dolls is the mother instinct which begins to show itself early in life. To the little girl the doll is a make-believe child. It satisfies her as long as there are no real babies to take its place, but any little girl will drop her dollie if she is given an op- portunity to play at dolls with a real live baby instead. This is a very in- teresting fact in connection with the human race. Boys sometimes play with dolls, but not so often, and any kind of a boy will give up playing V. itli a doll as soon as a toy engine or some other boy's toy appears for him. A boy has certain mannish instincts which a girl has not. We have many other instincts besides the instinct of parenthood and each of them has its origin in some certain kind of feeling which is born within us and is capable of development along interesting lines. What Makes the Works of a Watch Go ? A watch like any other machine which we have, only goes when power is applied in some form or another. In the case of a watch it is a spring. A spring is an elastic body, such as a strip of steel, as in the case of the watch, coiled spirally which, when bent or forced out of its natural state, has the power of recovering its shape again by virtue of its elastic power. The natural state of a watch spring is to be open flat and spread out to its full length. When you wind a watch you coil this spring, i.e., you bend it out of its natural shape. As soon as you stop winding the spring begins to uncoil itself, trying to get back to its natural shape, and in doing so makes the wheels of the watch which operate the hands go round. The spring then, or rather its elasticity, which always makes an efifort to get back to its nat- ural state, is the power which makes the watch go. Men who make watches arrange the spring and the other ma- chinery in the watch in such a way that it will uncoil itself only at a cer- tain rate of speed. Sooner or later the spring loses its elasticity and then its power to make the watch go. What Makes a Hot Box? When you put oil on the axle, how- ever, the oil fills up the hollows be- tween the little irregular bumps on both the axle and the hub, and makes them both smooth — almost perfectly so. This reduces the friction and keeps the axle and hub from becoming hot and expanding. The less friction that is developed, the more easily the wheel will turn. HOW MOVING PICTURES ARE MADE 369 The Story In a Moving Picture How Are Moving Pictures Made? To begin at the beginning, we must start with the negative stock, or film on which the pictures are taken. This material is very much like the films you buy for the ordinary snap-shot camera, slightly heavier and of more durable quality, to stand the wear and tear of passing through the picture camera and the projecting machine used in exhibition. This film is i^ inches wide and comes in rolls of 200 feet in length. This negative stock has to be carefully perforated, making the holes necessary 'to conduct the film by aid of sprockets through the camera and the projectoscope. To still fur- ther understand this explanation, see illustrations of the negative stock. Having prepared the film in the dark room, we can load the camera in the dark room and proceed to take the picture. In taking an industrial or travelogue picture, after the camera is in readi- ness, is not so much of an undertaking as taking a picture of a drama or com- edy, wherein a jilot and players are concerned. The travelogue or industrial pictures are simply photography, with the additional manipulation of pano- raming or turning the camera, which rcfjuires an expert knowledge, ac- quired from experience and years of study. There is a distinction and a big difference between the ordinary photogra])hcr and the moving ])icture photographer, who is generally known as a "camera-man." A photogra[)her. therefore, though of vast experience, cannot step into a "camera-man's" place and expect to "make good." The latter has to depend entirely upon his special experience and judgment as to light and distance, focusing and gen- eral physical conditions of the moving- picture camera, which is affected by static and other electrical peculiarities of the atmosphere, to be avoided by him. These, and many other points, are convincing evidence that the mov- ing-picture camera is entirely different from an ordinary photographic cam- era. A moving-picture camera and tripod weigh from fifty to one hundred pounds. There are two styles of cam- eras, one which takes a single film and one which takes two films at once, and each lens of the double camera must be equally well focused and every feature to be depicted must be brought within the focus, which gen- erally occupies a radius of 8 feet in width by 10 feet in height. When it comes to taking a photo- play, a drama or comedy, different conditions of a varied nature have to be contended with. To proceed intel- ligently in taking a photo-play, a sce- nario or manuscript is essential. It must be })refaced with a well-written syno])sis of the story involved, cast of characters, scenes to be enacted and a list of properties required in the scenes. The director, or producer, of the play, being furnished with such a guide, ])roceeds to select the actors and actresses (called players) suitable 370 THE EXACT SIZE OF A MOVING PICTURE FILM SCENES FROM OFFICER KATE. for the parts and the filHng of the cast. This being accomphshed, he insists that each one of the players read the scenario in order to be familiar with his or her part and understand the whole play before going into the pic- ture. The director instructs them as to the costumes fitting the parts and then confers with the costumer con- cerning the furnishing of proper dress for each one of the players. The di- rector is ready to go on with the per- formance of the play, and tells his cast to appear for rehearsal at a set hour. At that time he i)uts them through a thorough course of training or re- hearsal, to "get over" and register the meaning of each thought which is to be expressed by their actions. Some- times a scene is rehearsed four to six hours before it is photographed. A one-reel play is generally looo feet in length, and it is very important that the director, if he has twenty scenes, for instance, to introduce within that looo feet, to time the scenes to the RAW NEGATIVE STOCK. PERFORATED NEGATIVE STOCK. Exact size of a Motion Picture Film STAGING A MOTION PICTURE IN A STUDIO 371 length of his fihii; that is, if he has twenty scenes within one thousand feet, each of the twenty scenes must not average more than one minute each. If one should happen to be more than one minute, then he has to con- dense another scene less than one min- ute, in order to bring all within the twenty minutes or looo feet.: eight feet of space, which is really con- fined to that much stage width. Here again is where the camera-man has to watch very carefully, not only the workings of his camera, but the play- ers ; always alert that they are in the picture, and assisting the director by his observations. The size of each pic- ture as taken on the film is ^ by i REIIEAKSING SCENE IN STUDIO The Size of Each Picture on the Film. So you can see from this that it needs very careful rehearsal and nice calculation to bring a well-acted and convincing play wnthin so short a time, to tell the whole story intelli- gently. Having done all this, the di- rector is ready to have the "camera- man" do his part of the work. He draws his lines within the range of the camera, which do not exceed eight or ten feet in the foreground. This is another point to be considered on the part of the director, because all the action has to be carried out within the inch. It is magnified ten thousand times its actual size when we see it on the screen in a place of exhibition. A full reel of lOOO feet shows 16,000 photograplis on the screen during the twenty minutes it consumes in its showing. The future of moving pic- tures is no longer a matter of specula- tion. The business is an established one, and its further developments are only matters of time. The i)ossil)ilities and uses of the animated art are un- limited. Already it is felt in educa- tional, religious, scientific, and indus- trial affairs. Their influence in matters of sanitation and all civic improve- 372 EACH PICTURE IS FIRST EXHIBITED AT THE STUDIO inents, construction and mechanics, is invaluable. As a medium of whole- some entertainment and solid instruc- tion it is unsurpassed. These are merely suggestions of a few phases of its utility and it is only a natural conclusion that it will be so far-reaching in its uplift that it will surpass the expectations of the most sanguine. To (lc\clop, tint and clear the films, The films are finally cleared, to wash them clear of any extraneous chemi- cals or matter which might streak or scratch the films, and avoid any ob- jectionable matter that might mar their appearance when shown on the screen or in the process of handling. As soon as convenient after a fihii is finished it is taken to the exhi])iti(jn rooms, at the studio, where it is thrown onto the screen. It is reviewed first THE DF,Vi:i.OPIN'G ROOM. large tanks of wood or soapstone are used. The films, which are wound upon the wooden frames, or racks, are dipped into these vats, filled with the necessary chemicals and liquids. The films being w'ound on frames enables the developers to examine them with- out handling them. The tinting is done by similar methods to give the necessary tint, coloring in red, sepia, blue, green or yellow, imparting to them the efifect of night, sunlight or evening, whichever the case may be. by the heads of the departments and the directors, and later by i)layers and all those interested in it. The projec- toscopes or moving-picture machines are run by motor, presided over by licensed operators, who are kept on the job continually. These exhibition rooms are called, in the parlance of the studios, "knock- lodeums," for here is where every- thing is criticised. Players' acting and fitness are judged by their appearance and conduct on the screen and deci- THE BOARD OF CENSORS PASSES ON EVERY PICTURE 373 DRYING ROOM. sion given as to their qualifications. The quahty of the photography, de- veloping and the picture as a finished production is here determined by the heads of the concern. Every picture before it is released for exhibition must be passed upon by the Board of Censors. It is run upon the screen and thoroughly inspected, criticised, and every point involved thoroughly weighed as to its effect upon the mind of the general public. If, in their estimation, it is found ob- jectionable in any particular, the ob- jectionable parts are eliminated, and if considered entirely harmful, in its sen- timents or influence, the picture is con- demned. The majority rules in the board's judgment, although it is by no means infallible in its decision. This board is composed of about sixty per- sons, who are appointed by the gov- ernment for their general qualifica- tions, their interest in the general wel- fare of the public, keenness as to morals and uplift of the people at large. They do not receive salaries ; their services are pro bono publico. TAKING A MILITARY SCENE OUTDOOKS. 374 THE STORY IN "PIGS IS PIGS" •f^* "PIGS IS i'iGS." ViTAGRAPH Famous Authors' Series dy Ellis Parker Butler. You Have Seen Pigs, but Never Such Pigs as These. Two of Them Become Eight Hundred Pigs so Rapidly, They Set Bunny Daffy and Almost Ruin the Express Business. Director — George D. Baker. Author — Ellis Parker Butler. CAST. f tannery, an E.vpress Agent John Bunny Mr. Morehouse Etienne Girardot Clerk in Complaint Dcpt Courtland van Deusen Head of Claims Dcpt William Shea Mr. Morgan, Head of Tariff Dept Albert Roccardi President of Company Anuers Randole Prof. Gordon George Stevens After a stremious argument with Flannery, the local Ex- press Agent, Mr. Morehouse refuses to pay the 30c charges on each of two guinea pigs shipped him, claiming they are pets and subject to the 25c rate. Flannery replies, "Pigs is pigs and I'm blame sure them animals is pigs, not pets, and the rule says, '30c each.' " Mr. Morehouse writes many times to the Express Company, claiming guinea-pigs arc not common pigs, and each time is referred to a different department. Flannery receives a note from the Tariff Department inquiring as to condition of consignment, to which he replies, "There are eight now ! All good eaters. Paid out two dollars for cabbage so far." The matter finally reaches the President, who writes a friend, a Zoo- logical Professor. Unfortunately that gentleman is in South Africa, causing a delay of many months, during which time the pigs increase to 160. At last word is received from the learned man proving that guinea-pigs are not common pigs. Flannery is then ordered to collect 25c each for two guinea- pigs and deliver the entire lot to consignee. There are now 800 and Flannery is horrified to find Morehouse has moved to parts unknown. He is about to give up in despair when the company orders him to forward the entire collection to the Main Office, to be disposed of as unclaimed property, in accordance with the ecneral rule. BUNNY FEEDING THE PIGS. Who Made the First Moving Pictures ? The first device which produced the motion-picture effect was nothing but a scientific toy. The idea is almost as old as pictures themselves. This toy we speak of was called a zoctrope. It consisted of a whirling cylinder having many slits in the outside through which you could see by looking into the cyl- inder a picture opposite each slit. The pictures were drawn by hand and the artist aimed to place the pictures within the cylinder in such order that each succeeding one would repre- sent the next successive motion of any moving object in making a movement as near as he could draw it ; when the cylinder was whirled with the slits on a level with the eye, the effect produced was of a continuous moving picture. A great many devices were produced as a result of this toy for presenting the effect of pictures so arranged, but until photography was invented no way was found for making the pictures to be viewed except such as were drawn by artists. But when photography was developed it was possible to get actual successive photographs. The greatest difficulty was found in taking photo- graphs in such quick succession that all of the motions in the moving object were taken without any skipping. This difficulty was for the first time success- fully overcome by Muybridge in 1877. He arranged a row of twenty-four cameras with string trigger shutters, the string of each shutter being stretched across a race track. A mov- ing horse approaching down the track broke the strings as he came to them, thus operating each of the cameras in turn in quick succession and securing a series of pictures of the moving horse within a very short time. There were tv/enty-four pictures to this film when reproduced in the devices then known for projecting pictures, and this method ref|uired one camera for each section of the picture produced. Of course, the length of the series was thus limiterl greatly. About ten years later Le I'rince ar- ranged what he called a multipU' cam- era. This was as a matter of fact a battery of sixteen automatically re- loading cameras in which strips of film were used. Each of the sixteen cam- eras took a picture in turn and then automatically brought another strip of the film into position, so that camera number one took the seventeenth pic- ture, the twenty-third, the forty-ninth, etc., and each of the other cameras took their various pictures in turn. With this camera a film of any re- quired length could be produced. The Le Prince camera was therefore the real parent from which the modern motion-picture camera sprang. The first really modern motion-picture cam- era was built in a single case with a battery of sixteen separate lenses and sixteen shutters. These were oper- ated by turning a crank. The pictures were taken on four strips of film. When the crank was turned the ex- posure was made to each of the sixteen lenses in succession, and when the series was completed the films Vv^ere cut apart and pasted together in a single strip of film, the pic- tures themselves being arranged in the proper order. The principal de- velopment of this camera, as found in the present method of making motion pictures, is the invention of the flexible film negatives ; the transparent support for the print which permits the pic- tures to be projected in enlarged form upon a screen ; and the system of holes in the margin of the film by which the film is held in perfect alignment for projecting the pictures. But a few years ago, then, the mo- tion picture was a child's toy. To-day it forms the basis for not only a very large and profitable business for many people, but a source of amusement and education to millions of peo])le at reasonable prices. To-day the motion- picture business is regarded as one of the world's greatest industries. No corner of the world is so far remote l)Ul the motion-picture man finds his way there, either as rui ex- hibitor or as a producer. Nothing hap- ])ens in the world to-day but the mo- ti()n-i)iclure man with his camera is on the job if it is a happening that can 376 HOW FREAK PICTURES ARE MADE be preserved in motion pictures and worthy of that. The dethronement of kings and the inaugurations of presi- dents are all alike to him. If there is a war, he is found in all parts of the field, and is the first to see the parade when there is a peace jtibilee. Disasters, horrors, heroes and crimi- nals pass before his lens and he gives us a moving panorama of everything that is interesting, in nature, in real life, and in fiction. Taking Motion Pictures a Simple Oper- ation. Motion-picture photography is me- chanically simple and the projection of the pictures on the screen was made possible by the improvement in dry plates which made instantaneous pho- tography successful, together with the invention of the process of using cel- luloid films for negatives. Tvlotion pictures consist of a series of photo- graphs made rapidly and then pro- jected rapidly on the screen. In this way one picture follows another so quickly that the change from one pic- ture to another is not noticed and the movements and actions of the persons or things photographed are reproduced in a life-like manner. Is the Hand Quicker Than the Eye ? There is no question that the hand can be moved so quickly that the eye cannot detect the movement. This is proved by the motion picture when projected on the screen. In moving pictures the quickness of the machine deceives the eye and the transition from one picture to another is done so rapidly that the change is not seen and the apparent movement is contin- uous and unbroken. The film made by the motion picture is a "negative" in which the colors are reversed, the blacks being white and the whites black, exactly as in still photography. The film used in the pro- jection machine is a "positive," in which the lights and shadows have their proper values. The principle and process is exactly the same as in mak- ing lantern slides and window trans- parencies. Does the Film Move Continuously? In making the negative lor the mo- tion picture the film does not move for- ward regularly, but it goes by jumps. It is absolutely still at the moment of exposure. The same is true in pro- jecting the picture on the screen. In most projection machines the film is stationary three times as long as it is in motion, though in some machines the proportion is one in six. In the taking of the picture, the film is really stationary one-half of the time. As pictures are usually projected at the rate of fourteen or sixteen to the min- ute, this means that each separate pic- ture appears on the screen three- fourths of one-sixteenth of a second, or three-sixty-fourths of a second, and How Are Freak Pictures Made? Freak pictures are usually the result of clever manipulation of the camera or the film. Articles or individuals can be made to instantly disappear by stopping the camera while the article i^ removed or the person walks ofif the stage, the other characters holding their pose until the camera is again j)ut in motion. In some films in which a person is thrown from a height or is apparently crushed under a steam roller the effect is gained by the live person walking away after the camera is stopped and a dummy substituted to undergo the death penalty. By projecting the picture at a faster rate than it was taken, excruciatingly comic scenes are sometimes devised. An automobile going ten miles an hour, by speeding up the projection machine, may be made to apparently move at a hundred miles an hour, and by increas- ing in the same way the apparent speed of persons dodging the demoniac auto exceedingly ludricrous effects are had. By mechanical means in combining two or more negatives into one positive a man can be shown fencing with him- self or even cutting his own head off. Pictures i)y courtesy of the Vitagrapli Company. HOW RUBBER TIRES ARE MADE 377 WASH KUUM. The Story in a Ball of Rubber How Crude Rubber Is Treated. Washing. — When the crude rubber arrives at the factory of the rubber manufacturer, it is generally stored in bins in dark and fairly cool store- rooms, where it is kept until ready to be used. The rubber passes directly from the storage bins to the wash- room, where it is cut up into small pieces, put into large vats of warmed water and allowed to soak, in order to soften it sufficiently to be broken down in the machines. It is then fed into a cracker, a machine consisting of two rolls with projections on their sur- faces shaped like little pyramids, the two rolls revolving with a differential, one going considerably faster than the other, and being adjustable, so that they can work close together or with some distance between them. The rub- ber is fed between these rolls and broken down into a coarse, spongy mass. Water flows on to the rubber during the process, bringing down sand, dirt, bark, and the many other CALKNUKK l<()(JM. * These and Ihc following Pictures by courtesy of the Onodyear Tire and Rtil)l)er Co. 378 PREPARING CRUDE RUBBER FOR MAKING TIRES foreign materials which come mixed with the rubber. The rubber is put through this machine a number of times, until it is worked into a uniform condition. Some of the rubbers, like the Ceylons and Paras, will sheet out into a coarse sheet by being put through this machine; others, like the majority of the African rubbers, will fall apart and come dow^n in chunks and have to l)e fed into the machine with a shovel. After the rubber is broken down sufficiently in the cracker, it is next put through a washing machine, which is built very similar to the cracking ma- chine, except that the rolls are grooved or rifled, so that their action is not so severe on the rubber. A large quan- tity of water is kept constantly run- ning over this machine while the rub- ber is being put through, and the rolls work very close together, so that the rubber is finely ground and run out into a thin and comparatively smooth sheet, allowing the water flowing be- tween the rolls to take out practically all of the foreign matter that remains. The rubber is run through this machine a number of times until the experi- enced inspectors in charge are satisfied that it is thoroughly washed. Some types of rubber, such as Manicoba, which have large quantities of sand in them, are washed in a special form of washing machine known as the beater w'asher. This is an endless, oval-shaped trough with a fast-revolv- ing paddle-wheel. In this machine the rubber is submerged in water, after being broken down in the cracker, and the sand is literally knocked out of it by the paddle-wheel. The sand drops to the bottom of the machine, wdiere i*" is drained ofif, while the rubber floats to the top and is there gathered and then put through a regular w^ashing machine for the final sheeting out. Drying. — From the wash-room the rubber goes to the dry-room. Before the rubber can be used in any articles of commercial value, it must be thor- oughly dried, as any moisture in the stock would turn to steam during the vulcanizing process and cause blisters - or blow-holes to form in the goods. There are two ways in which rubber is usually dried. The method mostly used, and which is generally practiced with all the better grades of gums, is to hang the washed strips on hori- zontal poles and space them in aisles, so that air can freely circulate all around the surface of the rubber, the dry-room being kept at a constant tem- perature. To properly dry the rubbers by this metho(l takes from four to six weeks. The other method of drying is by means of a vacuum-drier. Low- grade rubbers which have a compara- tively large percentage of resin in their composition cannot bear their own weight when hung on horizontal poles, but drop off and stick in piles on the floor. Hence, these rubbers have to be dried in a peculiar manner. They are laid in trays wdiich are placed into a large air-tight receptacle. The air i^ then withdrawn from this receptacle and the interior heated by means of steam coils. This allows the water to be evaporated ofif from the rubber at a considerably lower temperature than that at which w-ater boils under atmospheric pressure, and at such a low temperature, and in such a short time, that the rubber is not affected. By this process these rubbers can be dried in a few hours. Mixing. — After the rubber has been thoroughly dried, it is ready to be mixed in proper proportions with the 'various ingredients wdiich are used in rubber compounding, to give the de- sired quality of rubbers for the various products for which they are intended. In order that rubber shall vulcanize, it is necessary to mix with it a certain proportion of sulphur, vulcanizing, or curing, as it is sometimes called, being merely the changing of a physical mix- ture of rubber and sulphur into a chemical compound of these ingredi- ents, by the application of heat. Be- sides sulphur, some of the more im- portant ingredients used in compound- ing rubber are : I Zinc oxide.- — -This toughens the rub- ber and increases its wearing proper- ties and tensile strength. WHY WE DON'T USE PURE RUBBER 379 Barium sulphate. — This stiffens the rubber and adds weight, so reducing the cost. Lithopones. — This whitens the stock and makes it soft, and is used exten- sively in druggists' sundries. Antimony sulphide. — This makes the stock red and is a preservative against oxidation. Litharge. — This has the same action as antimony sulphide, but makes the stock black. White lead. — This hastens the cure and is extensively used in gray and black stocks, and is a good filler or weight adder. Magnesia oxide and carbonate. — These are used as fillers for white stocks. Oxide of iron. — Used for coloring red and yellow stocks. Lime (unslacked). — This hastens vulcanization and chemically removes any water left in the rubber. Whiting. — This is used only as a cheap filler to increase quantity and lower cost. Aluminum silicate. chiefly as a filler. -This is used There are also used in compounding what are known as the various sub- stitutes. These are chiefly linseed oil products and mineral hydrocarbons which are more or less elastic, and act somewhat as a flux. Why Don't We Use Pure Rubber? There seems to be a general impres- sion that the various ingredients which are mixed with rubber are put into the compounds merely to cheapen the product and to lower the grade of the material. This is true in many cases, such as the general line of molded goods, rubber heels, bicycle gri])s, au- tomobile bumjKTS, etc., but in many cases, such as tires, packing, belting, etc., these ingredients are added to toughen the gum, increase its wearing qualities, to make it indestructible when subjected to heat, or to make it soft and yielding so that it can be forced into fabric, etc. In the general process of manufac- ture the sheeted rubber is sent di- rectly from the dry-room to the com- pound-room, where the various ingre- dients are weighed out into proper proportions along with the rubber to make up a batch, and placed in recep- tacles ready to be mixed. The batch is then sent into the mill-room to be mixed into a uniform pasty mass, which is the characteristic uncured, or so-called green, rubber compound. The mixing is done in the mill. This is a very heavy machine, constructed simi- larly to a cracker and a washer except that it is much larger and heavier, and the rolls are perfectly smooth and run closer together. No water at all is used on the batch during the mixing. There are steam and cold water con- nections to the mills which are con- nected with hollow spaces inside the rolls, so that the latter can be kept 'at any temperature desired. The general process of mixing is as follows : First the rubber portion of the batch 13 thrown into the mill and is worked and warmed up until it takes on a very sticky and plastic consistency. When it has arrived at a certain stage of plasticity, the various compounds in the batch, which are always in the form of very fine powders, are thrown in the mill, being worked by the rolls into the rubber. The compounds are generally thrown on, a small amount at a time, until they are all taken up by the rubber. The batch is then al- lowed to go through and through the mill, over and over again, until the mixture is absolutely uniform through- out the whole mass. The consistency of the rubber, during this operation, is such that the batch can be made end- less around one of the rolls of the mill, so that it is constantly feeding itself between the rolls. After the batch is properly mixed, it is cut off the rolls in sheets and 380 PROCESS NECESSARY TO MAKING RUBBER GOODS rolled up and sent to the grccn-stock store-room. In this store-room the compounded, uncured gums are kept in different bins, according to the na- ture of the compound, and are there allowed to season a certain length of time, after which they are delivered to the various dcjiartments of the fac- tory in which they are going to be used. Anotner form in which rubber is used is the so-called Rubber-Cement. Rubber or any of its compounds are readily soluble in naphtha. In this process, the com])Oun(ls, after being milled, are chewed up and washed in specially constructed cement-mills and there mixed with a certain proportion of naphtha which gives a thick solu- tion. Spreading and calendering. — Rubber which is used for the general line of molded goods, solid tires, some kinds of tubing, etc., goes directly to the various departments from the green- stock store-room, while rubber used for boots and shoes, waterproof fab- rics, many of the druggists' sundries, belting, pneumatic tires, inner tubes, etc., has to be sheeted out, and some of it forced into fabric before it goes to the various departments.. This sheeting-out of the gum, as well as applying the rubber to fabrics, is done generally by two methods ; either by spreading a solution of the rubber and naphtha onto the fabric, or by cal- endering the rubber between heavy rolls in a rubber calender. In the spreading process, a machine called a spreader is used. The fabric to which the rubber is to be applied is mounted in a roll at one end of the spreader and from the roll passes through a trough of rubber-cement, and then up over a so-called doctor roll, and under a knife edge, which allows only enough cement to pass through to fill the pores of the fabric. From this knife the cemented fabric passes over a steam drying chest and is then rolled up with a roll of liner cloth to prevent its sticking together. Fabric treated in this manner must be put through the spreader a number of times before it has sufficient rubber on it to be used in the products for which it is intended. For calendering rubber, a machine called a rubber calender is used. This machine is made with three and some- times four heavy rolls, which are capa- ble of very fine adjustment. The rub- ber from the green-stock store-room is first warmed up on a small mixing mill and is then fed between the rolls of the calender, coming through in a thin sheet of required thickness, and is wound up in a liner cloth and sent directly to the departments, where it is used for inner tubes, druggists' sun- dries, etc., where only rubber and no fabric is used. Where the rubber is to be applied to fabric, the fabric is put through the calender rolls with the rubber, and the rubber is literally ground into the fabric. Fabric treated in this manner is known to the trade as friction, and is generally used in the manufacture of pneumatic tires, belt- ing, hose, etc. For boots, shoes, and other special work, calenders are used v/hich are equipped with rolls engraved with the shapes of the soles and other parts of the articles in question, so that the sheet of rubber coming from the machine has imprinted on it the shapes and thickness of the articles for which it is intended. After passing through such of the above processes as are required the rubber is ready to be made up into the various articles known to the rub- ber trade, such as boots and shoes, mackintoshes, waterproof fabrics, for balloons, aeroplanes, tentings, etc., me- chanical goods, such as rubber heels, horseshoe pads, packing, tiling, auto- mobile and other bumpers, artificial fish bait, etc.. druggists' sundries, such as nursing-bottles, nipples, syringes, bulbs, hot-water bottles, tubing, etc. tobacco pouches, rubber belting, golf and other balls, insulated wire, fire and garden hose, inner tubes, tires, and the many other commodities into the man- ufacture of which rubber enters. HOW AUTOMOBILE TIRES ARE MADE 381 How Are Automobile Tires Made? From the calender room of the rub- ber factory the stock is received in the automobile tire department, in the form of large rolls of rubber-coated fabric, and in rolls of sheeted rubber of virions thicknesses and widths. The edge so arranged as to be always set at 45 degrees with the edge of the table. This method of cutting is grad- ually being put aside by the use of the bias cutter, an extremely up-to-date machine having jaws which ride up to the end of the fabric and pull it for TRADIXl. K(l(lM. rubber-coated fabric is first cut into strips of proper widths so that the edges will extend from bead to bead over the crown of the tire. These strips are always cut on the bias, gen- erally at a 45-degree angle, with the edge of the roll, and were formerly all cut on a cutting-table, a table about 50 feet long and 6 feet wide, covered with sheet metal. The cutting was done by two men, each having a knife and each cutting half-way across the cloth along the edge of a straight- a certain distance under a knife set at a 45-degree angle, the knife being set to cut just when the jaws have arrived at the limit of their motion. The ac- tion is repeated so that the machine cuts about eighty strips a minute. These strips are fed onto a series of belts which carry them to where they are placed, by boys, into a book having a leaf of common cloth between each strip of gum fabric, to prevent the strips from sticking together. The majority of automobile tires to- CUKJNG K(J()M^ — SOLID TIKI'S. 382 MAKING A PNEUMATIC TIRE CURING ROOM, FIRST CURE — PNEUMATICS. SPREADER ROOM. HOW THE TREAD OF A TIRE IS MADE 383 day are machine built, but there are still a great many built by hand and this is the process we shall describe first. In this process the books of fabric are laid up and spliced into proper lengths to go around the tire and allow a proper lapping for the splices. The proper number of these laid-up pieces, or plies, as they are called, are placed together with cotton cloth between and taken to the tire builder. The tire builder mounts the core, upon which the tire is to be built, on the building stand, generally ce- menting it so that the first ply of fab- ric will stick in place. The first ply is is placed in the so-called tire-building machine. The tire core is mounted on a stand attached to the machine, so that it can be revolved by power, and the fabric is drawn onto the core from the spindle under a certain defi- nite tension. The tire-machines roll the fabric down by power, and the beads are put into place before the tire and core are removed from the machine. Thereafter the process is the same as in the case of the hand-built tires. After the cover rubber is in place the tire is ready to have the tread applied. The tread is made up inde- TKtAD L.WING KUOM. then stretched onto the core and spliced, rolled down with a hand roller onto the sides of the core, and trim- med with a knife at the base. The following plies are put on and rolled down in the same manner, the beads being put in at the proper time, ac- cording to the size and the number of plies to be used. After all the pHes have been put onto the core the so- called cover rubber is put on. This cover rubber is generally a sheet of rubber about one-sixteenth of an inch thick or more, and of the same com- pound as the rubber on the fabric. In the case of the machine-built tire, the result is the same, but the stock is handled as follows: After the rub- ber-coated fabric has been cut on the bias cutter, the strips are s])liced and rolled uj) in rolls on a spindle which pendently of the tire by laying up nar- row strips of rubber, in different widths, in such a way that the center of the tread is thicker than the edges. In the case of the so-called single-cure tires, which are wholly vulcanized at one time, this tread is applied to the tire directly after the cover, a strip of fabric called the breaker-strip gener- ally being ])laced underneath, and tiie building of the tire so completed. In the general method of curing, the tire is allowed to remain on the core, and is either bolted up in a mold and put into an ordinary heater, or it is laid in a mold and put into a heater press, where the hydraulic pressure keeps the two halves of the mold forced together during the vulcanizing process. After the vulcanizing is com- pleted, the tire is removed from the 384 HOW THE INNER TUBES ARE MADE mold, the inside is painted with a French talc mixture, the tire inspected and cleaned, and so made ready for the market. In some methods of cur- ing, instead of the tire being put in a mold, it is init into a so-called toe- mold, which is virtually a pair of side flanges only reaching up as high as the edges of the tread on the side of the tire. After the flanges are fastened into place, the whole is cross-wrai)ped, the cross-wrapping coming in direct contact with the tread. The tire in this condition is then put into the heater and vulcanized, giving the so- called wrapped tread tire. Still an- and just wide enough to make a tube of proper cross-section diameter wdien the two long edges are folded over and fastened together with rubber cement. These two long edges are cut on a bevel so that they make a good lap seam. The tube is then pulled over a mandrel of proper size and a thin piece of wet cloth rolled around it, and then it is spirally cross-wrapped with a long, narrow piece of wet duck for its entire length. The whole is then put into a regular heater and the tube vulcanized. After vulcanizing the wrapping is removed and the tube stripped from the mandrel, turning PXEIMATIC-TIRE ROOM — SHOWI.NLI T1RE-I3UILI)IXG M.ACHINES. Other form of curing is to inflate a kind of canvas inner tube inside the tire and place the whole in a mold. This is known as the air-bag mold process. How Are Inner Tubes Made? Inner tubes for ])neumatic tires may be classed under three headings, ac- cording to the methods used in their manufacture, viz., seamed tubes, rolled tubes, and tube-machine tubes. By far the greater number of tubes come under the first two headings. For seamed tubes, the rubber is taken from the calender in the form of sheets from one-sixteenth to three-sixteenths of an inch in thickness. These sheets are cut into strips of proper length the tube inside out, so that the smooth side which is vulcanized next to the mandrel appears outside, and the rough side showing the marks of the cross-wrapping is inside. The valve hole is then punched in the tube, the valve inserted and the open ends of the tube bulTed down to a feather edge. The tube in this state passes to the splicers, who cement the buffed ends and splice them together, placing one open end within the other, making a lapped seam around the tube about 2y2 inches long. The cement used in splicing is generally cured by an acid which chemically vulcanizes the rubber without the application of heat. The tube is thus finished and ready for the market. Rolled tubes are made from WHAT RUBBER IS 385 WRAPPING ROOM — PNEUMATICS. very thin sheet rubber by rolHng same over a mandrel of proper size, until the required number of layers of thin rubber have been rolled on to give the tube the desired thickness. The tube is then wrapped, cured and spliced, in exactly the same manner as a seamed tube. What Is Rubber? Crude rubber is a vegetable product gathered from certain species of trees, shrubs, vines and roots. Its character- istic peculiarities were early recog- nized by the natives of the tropical countries in which it is found. Records of the earliest travelers in these coun- tries show that the natives had used various articles, such as receptacles, ties, clubs, etc., made from rubber, but it was not until about 1735 that rubber was first introduced into Europe. In civilization rubber was first used for pencil erasers and in waterproof cloth, and finally in cements. Vulcanizing, or the curing of rubber, was not dis- covered until 1844, and thereafter the development of the rubber industry was very rapid, especially in Great Britain. There are many kinds and grades of rubber, and to-day these can be di- vided into two chief classes, wild and cultivated. PNEUMATir-TIRK ROOM, SHOWINC, TIRE FINISHINC. 386 HOW THE CRUDE RUBBER IS SECURED Cintlicring Rubber in South America. I. Tapping Axe. 2. Tin Cup to Catch the Rubber Milk. 3. The Beginning of a Rubber "Biscuit." 4. A Palm Nut. Tapping Ihe Trees in Japan. How the Rubber Looks when it comes to Market. Carrying Balls of Crude Rubber Making Balls of Crude Rubber. to Native Market. Pictures herewith by courtesy of The B. F. Goodrich Company, Ltd. WHERE RUBBER COMES FROM 387 What Is Wild Rubber? The first class, or wild rubbers, are collected from trees which have grown wild and where no cultivation proc- esses whatsoever have been used. These rubber-producing trees, shrubs, etc., are found mostly in Northern South America, Central America, ^Mexico, Central Africa and Borneo. The finest rubber in the world is Fine Para, and is gathered in the Ama- zon regions of South America. This rubber has been gathered in practically the same way for over a century. The natives go out into ihe forests and, selecting a rubber tree, cut "V"-shaped grooves in the bark with a special knife made for the purpose, these grooves being cut in herring-bone fashion diagonally around the tree, with one main groove cut vertically down the center like the main vein in a leaf. The latex, or milk-like liquid, of the tree, from which the rubber is taken, flows from these veins and down the center vein into a little cup which the natives place to receive it. After the little cups are filled they are gathered and brought into the rubber camp, and there the latex is coagulated by means of smoke. This is done by the use of a paddle which is alternately dipped into a bowl of the latex and then revolved in the smoke from a wood or palm-nut fire. This smoke seems to have a preservative efifect on the rubber as well as drying it out and causing it to harden on the paddle, each successive layer of the latex caus- ing the size of the rubber ball or bis- cuit to increase. When a biscuit of sufficient size has been thus coagulated it is removed from the paddle and is ready for shijjment to countries where rubber products are manufactured. Para rubber is sold in three grades. Fine Para, which is the more carefully coagulated or smoked rubber; Medium i'ara, which is rubber gathered and smoked in the same way as I^^ine, but which has had insufficient smoking, and, therefore, more subject to dete- rioration due to oxidation, etc. ; and Coarse Para, which is rubber gathered from the drippings from the rubber tiees after the cups have been re- moved. This latter grade has gener- ally a large percentage of bark and other foreign substances mixed with it, and is subject to even more dete- rioration than is Medium Para, as it is oftentimes not smoked at all. Another important grade of rubber coming from South America is Cau- cho. This tree grows similar to the Para trees and the rubber is gathered in a similar manner, but is cured by adding to the latex some alkaline solu- tion and allowing the whole to dry out in the sun. The value of this rub- ber can be greatly improved by better methods of coagulation. From Central America and Mexico comes the Castilloa rubber. This rub- ber is gathered from trees in a very similar manner to Para, and is coagu- lated by being mixed with juices which are obtained by grinding up a certain plant which grows in the Cas- tilloa districts. After being mixed with this plant juice, the Castilloa is spread out in sheets on bull hides, where it is allowed to dry in the sun, after which the rubber is rolled up and is ready for shipment. Castilloa is gathered mostly from wild trees, but in Mexico it has recently been cul- tivated to some extent. From Mexico we also get Guayule. This rubber is obtained from a certain species of shrub, the shrub being cut down and fed into a grinding or peb- ble mill where the branches are crushed and ground and mixed with water, and the rubber, which is con- tained in little particles all through the wood, is worked out, being taken from the pel)ble mills in chunks as large as a man's fist. From Central Africa and from Bor- neo come the so-called African gums, such as Congo, Soudan, Massai. La- pori, Manicoba, Pontianic. etc. Some of these rubbers are gathered from trees, but most of them from vines and roots, and the methods of coag- ulation are varied. Practically all of them arc dried out in the sun. These rul)l>ers are all of lower grade than the Para rubbers of South America. 388 WHERE CHOCOLATE COMES FROM BAGS OF CACAO BEANS. The Story in a Stick of Chocolate Where Does Chocolate Come From? Perhaps no other one thing is so well known to boys and girls the world over as chocolate. Yet there was a time, and not so many years ago, as we figure time in history, when there, were no cakes of chocolate, or choco- late candies to be had in the candy shops, no chocolate flavored soda water or chocolate cake. To-day quite a panic w^ould be started if the world's supply of chocolate were cut off. Chocolate is obtained from cacao, which is the seed of the cacao tree. It is quite often called cocoa, although this is not quite a correct way of spell- ing the word. The cacao tree grows to a height of sixteen or eighteen feet when cultivated, but to a greater height when found growing wild. The cacao pod grows out from the trunk of the tree as shown in the picture, and is, when ripe, from seven to ten inches long and from three to five inches in diameter, giving it the form of an ellipse. When you cut one of these pods open, you find five compartments or cells, in each of which is a row of from five to ten seeds, which are imbedded in a soft pulp, which is pinkish in color. Each pod then con- tains from twenty-five to fifty seeds, which are what we call "cocoa beans." The cacao tree was discovered for us by Christopher Columbus, so that we have good reason to remember him aside from his great discovery of America. The discovery of either of these would be fame enough for any one man, and it would be difficult for some boys and girls to say just which of the two was Columbus' greater discovery. Columbus found the cacao tree flourishing both in a wild and in a cul- tivated state upon one of his voy- ages to Mexico. The Indians of Peru and Mexico were very fond of it in its native state. They did not know the joy of eating a chocolate cream, but they had discovered the qualities of the cacao bean as a food and had learned to cultivate it long before Co- lumbus came to Mexico. Columbus took some of the cacao beans back with him to Spain and to DIFFERENCE BETWEEN CHOCOLATE AND CACAO 389 VIEW OF COCOA BEANS IN BAG AND COCOA-GRINDING MILL. this day cacao is much more exten- sively used by the Spaniards than by any other nation. The first record of its introduction into England is found in an announcement in the Public Ad- vertiser of June i6, 1657, to the effect that: "In Bishopgate Street, in Queen's Head Alley, at a Frenchman's house, is an excellent West Indian drink called chocolate, to be sold where you may have it ready at any time and also unmade, at reasonable rates." Of course, by the time America be- came settled the people brought their taste for chocolates with them. What is the Difference Between Cacao and Chocolate? When the cacao seeds are roasted and separated from the husks which surround them, they are called cocoa- nibs. Cocoa consists of these nibs alone, whether they are ground or un- ground, dried and powdered, or of the crude paste dried in flakes. Chocolate is made from the cocoa- nibs. These nibs are ground into an oily paste and mixed with sugar and vanilla, cinnamon, cloves, or other flavoring substances. Chocolate is only a product made from cocoa-nibs, but it is the most important product. CACAO CRACKING MILL AND SHELL SEPARATOR. WHAT COCOA BUTTER IS WHERE THE SHELLS ARE SEPARATED FROM THE BEAN. \XD SHELL SEPARATOR. COCOA MILL. MILL IN WHICH THE BEANS ARE ROASTED. What Are Cocoa Shells? There are other pro(kicts which are obtained from the cacao seed. One is called Broma — which is the dry pow- der of the seeds, after the oil has been taken out. Cocoa shells are the husks which surround the cocoa bean. These are ground up into a fine powder and sold for making a kind of cocoa for drink- ing, although the flavor is to a great extent missing and it is, of course, not nearly so nourishing as a drink of real cocoa. What is Cocoa Butter? The oil from the cacao seeds, when separated from the seeds, is what we call cocoa butter. It has a pleasant odor and chocolate-like taste. It is used in making soap, ointments, etc. COCOA ROASTER. HOW CACAO BEANS GROW 391 COCUA TREE WITH FRIIT K.\()W\ AS COC(JA PODS, WHICH CONTAIN THE COCOA BEANS. How is Cacao Gathered? When the cacatj jxjds ri])cn on the troi)ical ])lantatioiis, where the chmatc is such that they can he ^rown success- fully, the native lahorer cuts off the ripened jjods as we see hini (loinj,^ in the picture showing ihe i)0(ls on [\\v tree. He does this with a scissors-like arranj^cment of knives on a long pole. As he cuts off the pods he lays them on the ground and leaves them to dry for twenty- four hours. The next day they are cut o|)en, the seeds taken out and carried lo the place where they .ire cured or sweated. In the proi'css of cni"in<; or sweat- 392 HOW CHOCOLATE IS MADE ing, the acid which is found with the seeds is poured off. The beans are then placed in a sweating box. This part of the process is for the purpose of making the beans ferment and is the most important part of preparing the beans for market, as the quality and the flavor of the beans and, there- fore, their value in the market, de- pends largely upon the ability of who- ever does it in curing or fermenting. Sometimes the curing is done by placing the seeds in trenches or holes in the ground and covering them with earth or clay. This is called the clay- curing process. The time required in curing the cacao beans varies, but on the average requires two days. When cured they are dried by exposure to the sun and packed ready for shipping. At this time beans of fine quality are found to have a warm reddish color. The quality or grades of beans are de- termined by the color at this stage. CHOrOLATP: MILL. How Chocolate is Made. W'hcn the cacao beans arrive at the chocolate factory they are put through various processes to develop their aroma, palatability and digestibihty. The seeds are first roasted. In roasting the substance which develops the aroma is formed. The roasting is accomplished in revolving cylinders, much like the revolving peanut roast- ers, only much larger. After roasting the seeds are transferred to crushing and winnowing machines. The crush- ing machines break the husks or "shells," and the winnowing machine by the action of a fan separates the shells from the actual kernel or bean. The beans are now called cocoa-nibs. These nibs are now in turn winnowed, but in smaller quantities at a time, during which process the imperfect pieces are removed with other foreign substances. Cacao beans in this form constitute the purest and simplest form of cacao in which it is sold. The ob- jection to their use in this form is that it is necessary to boil them for a much longer time, in order to disintegrate them, than when they are ground up in the form of meal. For that reason the nibs are generally ground before marketing as cacao or cocoa. Another form in which the pure seeds are prepared is the flaked cocoa, 'i'his is accomplished by grinding up the nibs into a paste. This grinding is done in a revolving cylinder machine in which a drum revolves. In this process the heat developed by the fric- tion in the machine is sufficient to liquefy the oil in the beans and form the paste. The oil then solidifies again in the paste when it becomes cool. What we know as cakes of choco- late are made from the cocoa-nibs by CHOCOLATE FINISHER. PROCESSES IN CHOCOLATE MAKING 393 CHOCOLATE MIXER. heating the mixture of the cacao, tween heavy rollers to get a thorough sugar and such flavoring extracts as mixture and finally poured into molds vanilla, until an even paste is secured, and allowed to cool. When cool it can This paste is passed several times be- be taken from the molds in firm cakes CHOCOLATE MIXINC AND HRATINd MACHINE. and wrapped for the market. This is the way Milk Chocolate is made. The difference in the taste and consistency of milk chocolate depends upon how many different things the chocolate maker adds to the pure cocoa-nibs to ])roduce this mixture. Often sub- stances such as starchy materials are added to make the cakes more firm. They add nothing to the quality of the chocolate. Chocolate-covered bonbons, choco- late drops, and the many dift'erent kinds of toothsome confections are prepared in the American candy fac- tories, as we all well know. The choco- late covering of this confectionery is generally put on by dipping the inside of the choice morsel in a pan of liquid chocolate paste and then placing the bits in tins to allow them to cool and harden. ^ A great many of the choicest bits of confectionery are now produced by machines entirely. These machines are almost human, apparently, as we see them make a perfect chocolate bonbon which is delivered to a candy box all wrapped for packing. These wonder- ful machines thus give us candy which has not been touched by the hands of any one prior to the time we thrust our own fingers in the brightly-deco- rated box and take our pick of the assortment it offers. WU£1<£ XHK l.NJJUMDLAL PIECES Ul- CONFECTIUN . ARE WRAPPED. THE TALLEST BUILDING IN THE WORLD 395 1N(;, m;\v ^■()KK ( iiv This building, the tallest in the world, is cniiipiK-d with 26 Rcarless traction elevators. Two of the elevators run from the first to the fifly-first floor with actual travels of 679 feet op inchen and f.79 feet lu'/i inches, respectively. There is also a shuttle elevator which runs from the fifty-first to the fifty 1 .iirth floor. Total height of huilding from curb to base of flagstaff, 792 feet. 396 HOW AN ELEVATOR GOES UP AND DOWN How Does an Elevator Go Up and Down ? Ordinarily, when we think of an elevator we think merely of the cage or car in which we ride up or down. But the car is really only the part which makes the elevator of service to man, and from the standpoint of the machinery, is a relatively unimportant part of the equipment. There are two principal types of elevators used to-day; the hydraulic, which is worked by water under pressure, and the electric, which is worked by electricitj' through an electric motor. The latter type, because of the tendency towards the general use of electricity in recent years, has largely super- seded the hydraulic, and, as when you think '^^BBi^ " J^ of elevators you probably have in mind those you have seen in some huge skyscraper, we shall look at one of these. What are the Principal Parts of an Elevator ? The most advanced type of elevator to-day is called a Gearless Traction Elevator. In this elevator the principal parts are a motor, a grooved wheel on the motor shaft called a driving sheave and a brake, all mounted on one cast-iron bed-plate ; a number of cables of equal length which pass over the driving sheave and thence around another grooved wheel called an idler sheave, located just below the driving sheave, and to one end of which is attached the car or cage, and to the other end a weight called a coun- terweight; also a controller which governs the flow of electric current into the motor and thereby the speed, starts and stops of the elevator car. Although the controller, motor, brake and sheaves are usually placed way at the top of the building out of our sight, they are really very important parts of the elevator. The cage or car in which we ride is held in place by tracks built upright in the elevator shaft, and the counterweight at one side of the shaft travels up and down along two sep- arate upright tracks. When the car goes up the counterweight on the other end of the cables goes down an equal distance. The counterweight is used to balance the load of the car and to make it easier for the motor to move the car. Electricity is the power that makes the car go up or down. The operator in the car moves a master switch — in one direction if he wishes to go up, in the other direction if he wishes to go down. This master switch sets the electro-magnetic switches of the con- troller at the top of the hatchway into action, electrically, and the controller in turn allows the electric current to flow into the motor. The motor then begins to revolve, gradually at first, and then faster, turning the driving sheave with which it is directly connected. As this driving sheave revolves, the cables passing over it are set in motion, and the COMPLETE GEARLESS TRACTION c^r and counterweight to which they are ELEVATOR INSTALLATION. attached begin to move. THE PRINCIPAL PARTS OF AN ELEVATOR 39: Af/iq/^fT Bfi/i/re ZW/i^V^ Sf/£//K£ Why Does Not the Car Fall? Of course, the question of safety is a very important one in any elevator, and you wonder what would happen if the cables broke. You think of this especially when you are going up in one of the big skyscrapers — where the elevators sometimes travel to a height of 700 feet. It can be truthfully said that on every modern elevator there are safety devices which should make it practically impossible to have a serious accident, due to the fall of the car. Every elevator is equipped with wedging or clamping devices which automatically grip the rails in case the car goes too fast either up or down. These gripping devices can be adjusted to work at any speed that is desired above the regular speed. It is not at all prob- able that all the cables will break at once, because there are usually six of these, and any one of them is strong enough to hold the car if the others break ; but even if they all should break the gripping devices on the rails will operate and hold the car safely, just as soon as it starts down at great speed. Suppose that the car should descend at full speed, but not sufficiently fast to work the rail-gripping devices, it would be brought to a gradual rest at tDU/t s^eft^^- the bottom of the hatchway, because of the oil-cushion buffer against which it would strike. This is a remarkable in- vention, with a plunger working in oil in such a way that a car striking it at full speed will come to rest so gradually that there is scarcely any shock. You have perhaps seen a clever juggler on the stage throw an ordinary hen's egg high into the air and catch it in a china dish without cracking it. He does it by putting the dish under the falling egg just at the right moment, and bring- ing the dish down with the egg at just the right speed, so that eventually he has the egg in the dish without crack- ing it. The trick is in calculating the rate of speed of the falling egg accu- rately and adjusting the insertion of the dish under the falling tgg to a nicety. The oil-cushion buffer in the modern elevator works in very much the same way. If it were not for the genius which has made possible these new types of elevators we could not have the high buildings. The elevators in the Wool- worth Building are the latest type in modern elevator construction. In this one building alone there are 29 ele- vators, and when you are told that the general arrangement of electric elevators in the United States "op^ng for gearless installed by a single company represent a total of 525,000 horse-power, you will have some idea of the power re- quired to operate elevators all over the country. traction elevator stallation. 398 WHAT THE AIR WEIGHS Does Air Weigh Anything? Air is very light, so light that it seems to have no weight at all; but, if you will think a minute you will see that it must have some weight, because birds tiy in it and balloons can be made to float through it. It has been found that one hundred cubic inches of air at the sea level weighs, under ordinary conditions, about thirty-one grains. This seems a very small weight, but when we remember the thickness of the atmospheric envelope over the earth we see that it must press quite heavily upon the earth's surface. There is a very simple instrument called a barometer, which is used for measuring the amount of this pressure. The name means pressure-measure. Another striking feature of air is its elasticity, and this explains something that is noticed by -all mountain climbers. On a high mountain, it is difficult to get enough air to the lungs, though one breathes rapidly and deeply. The rea- son is, that the air at the foot of the mountain is compressed by the weight of that above it, and consequently the lungs can hold more of it than of the air on the mountain top, which has less weight resting upon it and is, there- fore, not so much compressed. On ac- count of the ease with which it is com- pressed, we find that more than half of all the envelope of air that surrounds the earth is within three miles of the surface. When air is chemically analyzed it is found to consist of a number of sub- siances mingled together, but not chem- ically united. These include nitrogen, oxygen, argon, carbonic acid gas, water vapor, ozone, nitric acid, ammonia, and dust. Oxygen is the most important of these constituents, for it is the part that is necessary to su])port life. Yet, not- withstanding its importance, it forms cnly about one-fifth of the entire bulk cf the atmosphere. Oxygen is a very interesting sub- stance and many striking experiments may be performed with it. If a lighted candle is thrust into a vessel filled with oxygen, it burns very much more ra])- idly and brilliantly than in air. A piece of wood with a mere spark on it bursts into flanu' and burns brightly when thrust into oxygen, and some things that will not burn at all in air, can l)c made to burn very rapidly in oxygon. For example, if a piece of clock spring be dipped in melted sulphur and then ]uit into a jar of oxygen, after the sul- phur has been set on fire, the steel spring will take fire and burn fiercely. The heat produced is so great that dro]:)S of molten steel form at the end of the s])ring, and falling on the bottom of the jar, melt the surface of the glass where they strike. The other two substances found in pure air, nitrogen and argon, are very much alike. They make up the remain- ing four-fifths of the air, and are very dififerent from oxygen in nearly every respect. Nitrogen and argon resemble oxygen m being colorless, odorless, and taste- less gases ; and they are of nearly the same weight as oxygen, argon being a little heavier and nitrogen a little lighter; but here the similarity ends. Oxygen is what we call a very active substance. As we have seen, it causes things to burn very much more rapidly in it than in air. Nitrogen and argon, on the contrary, jiut out fire. If a lighted candle is put into a jar of nitro- gen or argon its flame will be extin- guished as quickly as if put into water. We must now consider the im])uri- ties found in air. Of these the most important is carbonic acid gas, or, as it is frequently called, carbon dioxide. It is always produced when wood or coal is burned, and is, of course, constantly being poured out of chimneys. It is also produced in our lungs and we give ofif some of it when we breathe. It is colorless, like the gases found in pure air, has no odor or taste, and is consid- erably heavier than oxygen or nitrogen. In its other properties it is much more hke nitrogen than oxygen, for when a candle is put into it the flame is ex- tinguished at once. To find out w^hether air contains carbonic acid gas, it is only necessary to force it through a little WHY THE MOON TRAVELS WITH US 399 lime water, in a glass vessel, and watch what change takes place in the water. Fresh lime water is as clear as pure \vater ; but after forcing air containing carbonic acid through it, it becomes turbid and milky. If the turbid water is allowed to stand for a time, a white powder will settle to the bottom, and if Vv'e examine this powder, we find it to be very much the same thing as chalk. While it is true that air generally con- tains only a very small portion of car- bonic acid gas, there are some places in which it is present in such large quan- tities as to render the air unfit for breathing. The air at the bottom of deep mines and old wells often has an unusually large proportion of this gas, which, because of its great weight, ac- cumulates at the bottom, and remains confined there. The presence of a dangerous quantity of the gas in such places may be detected by lowering a candle into it. Why Does the Scenery Appear to Move When We Are Riding in a Train? When you sit in a moving train looking out of the window it appears as though the fields, the telegraph poles and everything else outside were moving, instead of you. This is be- cause our only ideas of motion are ar- rived at by comparison, and the fact that neither you nor the seats of the car or any other part of the inside of the car is changing its position, leads you to the delusion that the things out- side the car are moving and not you. If you were to jmll down all the cur- tains and the train were making no noise at all, you would not think that anything was moving. It would ap- pear as though you were motionless just as everything in the car appears so. When you turn then to the win- dow, and lift the curtain you carry in the back of your mind the idea of be- ing at rest and that is what makes it ajjpear as though the fields and every- thing outside were moving in an op- ])Ositc direction. This is ]>art1cu1arly noticeable when you are in a train in a station with another train on the next track. There is a sense of motion if one of the trains only is moving and you feel that it is the other train, because you are surrounded by objects in the car which are at rest, and when you look out at the other train with this half con- sciousness of rest in your mind, it ap- pears as though the other train were moving when as a matter of fact it is your train. If the delusion happens to be turned the other way, it will ap- pear as though you are moving and the other is still. It depends upon what cause the impression starts with. Why Don't the Scenery Appear to Move When I am in a Street Car ? If you are in a street car in the country and moving along fast you will receive the same impression, es- pecially in a closed car, because you are looking out of one hole or- one window. In an open car you do not receive the same impression because your range of vision is broader. You can and do, although perhaps uncon- sciously, look out on both sides and the impression your mind gets through the eyes is not the same. If you were to pull down all the storm curtains in a moving open street car, and then look out of one little crack, you would tliink the outside was moving. But if you stop to remember that you are moving and not the things outside the car, then the impression vanishes. In the city, of course, your brain is so thoroughly impressed with the fact that houses and pavements do not move, and the cars move so much more slowly, that it is difiicult to make yourself believe otherwise. The im- pression is more difficult always when you are moving through or past ob- jects with which you are perfectly familiar. It is all, of course, a ques- tion of impressions. Why Does the Moon Travel With Us When We Walk or Ride? The moon does not really tnivcl with ns. Il only seems to do so. 'i^ic moon is so far away that when we 400 THE MAN IN THE MOON walk a block or two or a hundred, we cannot notice any relative difference in the relative positions of the moon and ourselves. When a thing is close at hand we can notice every change in our position toward it, but when it is far away the change of our position toward it is so slight that it is hardly perceptible. A very good way to il- lustrate this is to ask you to recall the last time you were in a railroad train looking out at the scenery in the coun- try. The telegraph poles rush past you so fast you cannot count them. The cows in the pasture beside the railroad do not seem to go by so fast. You can count them easily. The tree farther over in the next field does not appear to be moving but slightly, while the church steeple which you can see far in the distance, does not go out of sight for a long time — in fact, seems almost to be moving along with you. The moon is just like the church steeple in this case, except that it is so much farther away that it seems to travel right with you. It is all due to the fact as stated at the beginning of ;his answer, that the relative positions Df yourself and the moon are only slightly changed as you move from place to place, so slight in fact as to appear imperceptible. Is There a Man in the Moon? The markings which we see on the face of the moon when it is full can by a stretch of the imagmation be said to form the face of a man. On some nights this face appears to be quite distinct. If, however, we look at the moon through a telescope, we see distinctly that it is not the face of a man. Through a very large telescope we can see very plainly that the marks are mountains and craters of extinct volcanoes. It just happens that these marks on the moon, aided by the re- flections of the light from the sun, which gives the moon all the light it has, make a combination that looks like a face. Does the Air Surrounding the Earth Move With It? This is one of the old puzzling ques- tions which many a high-school stu- dent has had to struggle with to the great amusement of the teacher who asks for the information and such other scholars who have already had the experience of trying to solve it. To get at the right answer you have merely to ask one other question. If the air does not revolve with the earth, why can't I go up in a balloon at New York, and stay up long enough for the earth to revolve on its axis beneath me, and come down again when the city of San Francisco appears under the balloon, which should be in about four hours? If that were possible, travel would be both rapid and com- fortable, for then we could sit quietly in a balloon while the earth traveling beneath us would get all the bumps. No, the atmosphere surrounding the earth moves right along with the earth on its axis. If it were not so, the earth would probably burn up — at least no living thing could remain on it — since the friction of the surface of the air against the surface of the earth would develop such a heat that nothing could live in it. Why Does Oiling the Axle Make the Wheel Turn More Easily? If you look at w^hat appears to be a perfectly smooth axle on a bicycle or motor car through a powerful mag- nifying glass, you will find that the surface of the axle is not smooth at all, as you may have thought, but covered with what appear to be quite large bumps or irregularities in the surface. If you were to examine the inside of the hub of the wheel in the same way, you would find that it also is like that. Now, when you attempt to turn a wheel on the axle without oil, these little irregularities or bumps grind against each other, producing what we call friction. As friction de- velops heat, the metal of the axle and the hub expand and the wheel gets stuck. WHY A FIRE IS HOT 401 What Made the Mountains? There is no question but that at one time the surface of the earth was smooth, i. e., there were no big hills and no deep valleys. That was before the mountains were made. The earth was a hot molten mass that began to cool off from the outside inward. It is still a hot molten mass inside today. The outside crust became cooler and cooler and the crust became deeper and deeper all the time. Then when there would be an eruption of the red-hot mass in- side, the earth's crust would be bulged out in some places and sucked in in others and would stay that way. The bulged out place became a range of mountains and the sucked in place be- came a valley. This process went on happening over and over again until the crust of the earth became firmly set. Volcanos caused some of these erup- tions, as also did earthquakes. There are today gradual changes occurring which to a certain extent change the outside surface of the earth, and it is possible that new mountain ranges will be produced in this way. What Makes the Sea Roar? The roar of the sea is a movement of the sea which causes the same kind of air waves or sound waves that you make when you shout, excepting that, of course, the vibrations do not occur so quickly in the sea and, therefore, the sound produced is a low sound. It is no different in any sense than the same noise would be if the same air waves could be produced on the land away from the water. Why Is Fire Hot? When a fire is lighted it throws off v/hat we call heat rays or waves. These waves are very much like the waves of light which come from a light or fire or the air waves which produce sounds. The rays of light and heat which come ftom the sun are like the rays of light and heat from a fire. Heat is of two kinds — heat proj)er which is resident i'l the body, anrl rarliant heat which is the kind which comes to us from the sun or from a fire. This radiant heat is not heat at all, but a form of wave motion thrown out by the vibrations in the ether. The heat we feel is the sen- sation produced upon our skins when it comes in contact with the waves cre- ated by the fire. Heat was formerly thought to be an actual substance, but we know now that radiant heat is known to be the energy of heat trans- ferred to the ether which fills all of space and is in all bodies also. The hot body which sets the particles of either in vibration and this vibrating motion in the form of waves travels in aU directions. When these vibrations strike against our skin they produce a heat sensation ; striking other objects these vibrations may produce instead ot a heat sensation, either chemical action or luminosity. This is determined by the length of the vibratory rays in each case. V/hen I Throw a Ball Into the Air While Walking, Why Does It Follow Me? When you throw a ball into the air while moving your body forward or backward, either slowly or fast, the ball partakes of two motions — the one up- ward and the forward or backward mo- tion of your body. The ball possessed the motion of your body before it left your hand to go up into the air because your body was moving before you threw it up, and the ball was a part of you at the time. If you are moving forward up to the time you throw the Ijall into the air and stop as soon as you let go of the ball, it will fall at some distance from you. Also if you throw the ball up from a standing position and move forward as soon as tiie ball leaves your hand the ball will fall behind you, j)rovided you actually threw it straight up. Of course, you know that the earth is moving many miles per hour on its axis and that when you throw a hall straight into the air from a standing I)osition, the earth and yourseh' as well as the ball move with the oarlh a long 402 WHY SOME PEOPLE ARE DARK AND OTHERS LIGHT distance before the ball conies down a^ain. The relative position is, how- ever, the same. We get our sense of motion by a comparison with other ob- jects. If you are in a train that is moving swiftly and another train goes by in the opposite direction moving jusr as fast, you seem to be going twice as fast as you really are. If the train on the other track, however, is going at the same rate of speed and in the same di- rection as you are, you will appear to be standing still. Going back to the ball again, you will find that it always partakes of the mo- tion of the body holding it in addition to the motion given when it is thrown up. What Good Are the Lines On the Palms of Our Hands? It cannot be said that the lines on the pc.lms of our hands are of any great service to us. Indeed it is doubtful if they are of any value in themselves, out- side of the possible aid they may be in helping us to determine the character of the surface of things which we grasp or touch. It is possible that they aid in some slight degree in this way. There is little doubt, however, that they are a result of the \vork the hands are constantly called upon to do rather than contrived for any particular service. The habitual tendency of the fingers in grasping and holding things throws the skin of the palms into creases which through frequent repetition make the lines of the palms permanent in several instances. The peculiarities of these lines or creases in various individuals as to de- tails and length and variations is the chief basis of the so-called science of palmistry. What Makes Things Whirl Round When I Am Dizzy? The medical term that describes this condition of turning or wdiirling is ver- tigo, which means in simple language "to turn." There are two kinds of dizziness — one where the objects about us seem to be turning round and round and the other where the person who is (l^'zzy seems to himself to be turnhig round and round. One cause of this is due to the fact that when you are dizzy the eyes are not in complete control of the brain and the eyes moving independently of each other look in different directions and ])roduce this tUiuing efifect on the brain, since each eye then sends a different impression to the brain instantly. The principal cause of the sense of dizziness is^ however, the httle organ which gives us our power to balance and which is located near the ears. Sometimes this organ becomes diseased and peo]>le affected in this way are al- most continually dizzy. Whenever this organ of balance is disturbed we lose our idea of balance and the turning sen- sation occurs. It is easy to make yourself dizzy. All you do is to turn round a few times in the same direction and stop. In doing this you disturb the little organ of bal- ance and things begin to turn a])])ar- ently before your eyes. If you turn the other way you right matters again or if you just stand still matters will right themselves. There is no great harm in making yourself dizzy and very little fun. Why Are the Complexions of Some People Light and Others Dark? This difference in the complexions of people is due to the varying amounts of pigment or coloring material in the cells of which the skins of all animals is made up. Very light people have very little pigment; very dark people, those with dark eyes and black hair, have a great deal of this coloring ma- terial in their cells. A great many people are neither light or very dark. They have less than the dark-complex- ioned people and more than the light- complexioned people. When the hair turns gray it is because the pigment has disappeared. As this is due to the loss of this coloring material, dark-complex- ioned people turn gray sooner than light-complexioned people. The struc- WHY MOST PEOPLE ARE RIQHT=HANDED 403 til re of the skin showing how these cells are made in layers can be seen by ex- amining the skin with a microscope. What Makes Me Tired? Men were wrong for a long time in their conclusions as to what produced the tired feeling in us. We know now that every activity of our body registers itself on the brain. When we move an arm or leg a great many times we soon feel tired. Every time you move your arm the movement is registered in the brain, and after a number of these movements are regis- tered the tired feeling in the arm ap- pears. It is said that every movement of any part of the body really produces certain defective cells and that these accumulate in the blood. When these reach a certain number the tired feeling takes possession of us, and when we rest, the blood under the guidance of the brain, goes to work and rebuilds these defective cells. We know that a change takes place in the blood when we become tired because, if you take some of the blood from an animal that shows unmistakable signs of fatigue and inject if into an animal that shows no tired feeling at all, the second animal will begin to show signs of fatigue even though it is not active at all. We used to think that being tired in- dicated that our bodies were in need of food and that the way to overcome it was to eat a big meal. We did not stop to think that even when we are hungry the human body has sufficient food sup- ply stored up to keep it going for days without taking in new food. Of course, this mistake was made because we knew that our power and energy came as a result of the food we took into our systems, but this belief was exj^loded when it was found that a really tired person could hardly cligest food while tired, anrl that it is best for ])cc)plc who are very tired to eat only a light meal. Why Are Most People Riqrht-Handed? Most pcfjpic are right-handed because they are trained that way. Being right- handed or left-handed depends largely on how we get started in that connec- tion. When we are young we form the habit generally of being either right- handed or left-handed, as the case may be. Most people correct their children -when it appears they are likely to be- come left-handed, as we have come to think that it is better to be right-handed than left, and that is the reason why most people are right-handed. As a matter of fact, if we were trained per- fectly, we should all be both right- handed and left-handed also. Some people are so trained and, when we refer to their ability to do things equally well with both hands and wish to bring out this fact, we say they are ambi- dextrous. It is not natural that one hand should be trained to do things while the other is not. Why Are Some Faculties Stronger Than Others ? All of our senses are capable of being developed so that our ability along these lines would be about equal. The trouble is that we soon begin to develop one or more of our faculties in an unusual manner at the expense of the develop- ment of others. Many people have a keener sense of observation than others because they have had more and better training along that line. It is a pity that more attention is not given to the development of the power of observa- tion in children, because it is one of the most valuable accomplishments that we can possess ourselves of. With the sense of observation developed to the highest degree, many of the other facul- ties need not be developed so strongly because, if we notice every thing that it is possible for us to see, we do not b.ave the need of thf dcvelopnicnt of other powers to the same extent. It is said tliat it would be possible to so train an infant and bring him up to maturity with all his faiulties de- xc'loprd and in j)ractically an even way. If wi' (h(\ ih.it we would have a won- derfully iiilclligrnt being. 404 HOW CHINA IS MADE Glazing plates. Decorating china cups. The Story in a Cup and Saucer Many different kinds of raw materials are required to produce the clay from which china is formed, and these in- f^redients come from widely separated localities. Clays from Florida, North Carolina. Cornwall and Devon. Flint from Illinois and Pennsylvania. Bo- racic acid from the Mojave Desert and Tuscany. Cobalt from Ontario and Saxony. Feldspar from Maine. All these and more must enter into the mak- insT of every piece. Grinders lor lazing materials. These materials are reduced to fine powder and stored in huge bins. Be- tween these bins, on a track provided for the purpose, the workmen push a car which bears a great box. Under this box is a scale for weighing the ex- act amount of each ingredient as it is put in, for too much of one kind of clay or too little of another would seriously impair the quality of the finished china. From bin to bin this car goes, gather- ing up so m.any pounds of this material and so many pounds of that, until its load is complete. Then it is dumped into one of the great round tanks called "blungers," where big electrically Mill for pulverizing materials. driven paddles mix it with water until it has the consistency of thick cream. Flrom the Hungers this iliquid mas,s passes into another and still larger tank, called a "rough agitator," and is there kept constantly in motion until it is released to run in a steady stream over the "sifters." These sifters are vibrating tables of finest silk lawn, very much like that HOW THE DISHES ARE SHAPED 405 used for bolting flour at the mills. The material for china making strains through the silk, while the refuse, in- cluding all foreign matter, little lumps, etc., runs into a waste trough and is thrown away. From the sifters the liquid passes through a square box-like chute, in which are placed a number of large horseshoe magnets, which at- tract to themselves and hold any par- ticles of harmful minerals which may be in the mixture. After leaving the magnets the fluid is free from impurities, and is dis- oharjged into another huge tank called the "smooth agitator." While the fluid is in this tank a number of paddles keep it constantly in motion. Pressing the water from the clay. From the smooth agitator the mix- ture is forced under high pressure into a press where a peculiar arrangement of steel chambers packed with heavy canvas allows the water to escape, fil- tered pure and clear, but retains the clay in discs or leaves weighing about thirty pounds each. From the presses this damp clay is taken out to the "pug mills," where it is all groimd up to- gether, reduced to a uniform consist- ency, and cut into blocks of convenient size. It is now ready to use. Auto- matic elevators carry it to the work- men upstairs. The exact process of handling the clay differs with articles of different shapes-. Some are molded by hand in jjlaster of paris molds of i)roper shape, while others are formed by machine. To make a plate, for example, the work- man takes a lump of clay as large as a teacup. He lays this on a flat stone, and with a large, round, flat weight, strikes it a blow which flattens the ma- terial out until it resembles douo:h rolled Molding Dishes. The racks to the left are full of molds on which the clay is drying. otit for cake or biscuits, only instead of being white or yellow it is of a dark gray color. A hard, smooth mold ex- actly the size and shape of the inside of the plate is at hand. Over this the workman claps the flat piece of damp clay. Then the mold is passed on to another workman, who stands before a rapidly revolving pedestal, common- ly known as the potter's wheel. On this wheel he places the mold and its layer of clay. He then pulls down a lever to which is attached a steel .Molding sugar bowls and covered dislics. scraper. As the plate rapidly revolves, this scraper cuts away the surplus clay, and gives to the back of the plate its proper form. The plate, still in its mold, is placed on a long board, to- 406 HOW CHINA IS DECORATED ^ethcr with a nunihcr of others, and shoved into a rack to dry. One work- man with two helpers will make 2,400 platfs i«cr day. It is fascinating to watch the niolders' deft hands at work >wiftly chans^ing a mass of clay into licrfec'tly formed dishes. Such skilled workmen are naturally well paid. L Interior of a kiln showing how the "saggers" are packed for firing. When the clay is sufficiently dry, the plate is taken from its mold, the edge smoothed and rounded, and any minor defects remedied. It is then placed in an oval shaped clay receptacle called, a "sagger," together with about two dozen of its fellows, packed in fine sand, and placed in one of the furnaces or kilns. Each kiln will contain-. on an average two thousand saggers. When the kiln is full the doorway is closed and plastered with clay, the fires started, and the dishes subjected to ter- rific heat for a period of forty-eight hours. The fuel used is natural gas. piped one hundred miles from wells 2.000 feet deep. Natural gas gives an intense heat, and yet is always under perfect control — features which are vital in producing uniformly good china. When the plate is taken from the kiln after the first baking, it is pure white, l)ut of dull, velvety texture, and is known as bisque ware. In order to give it a smooth, high finish, the plate is next dipped into a solution of white lead, borax and silica, dried, placed in a kiln and again baked. W hen it is taken out for the second time it has acquired that beautiful glaze wdiich so delights the eye. In this condition it is known as "plain white ware," and is finished, unless some decoration is to be added. Most peo[)le are surprised to learn that the greater part of the gold which adorns dishes is ]>ut on by a simple rubber stamp. Two preparations of gold are used. One is a commercial solution called "liquid bright igold," the other is very expensive, and is simply Taking the di.-hes from a kiln. gold bullion melted down with acids to the right consistency. Decorating in colors is now done al- most exclusively by decalcomania art transfers. These are made princii)ally in Europe. After the gold and colors are ap- plied, the China must again go through the oven's heat for a period of twelve hours. Then the piece finished at last, is ready to grace your table. The dull grav clay has become beautifully fin- ished china, which will delight alike the housekeeper and her guests. How Do Birds Find Their Way? The most interesting phase of the movement of animals from place to place is found in the flight of birds during the spring and fall. In the spring the birds come north and in the fall they go south. This is called "mi- gration" and the reason given for the ability of some birds to come back every year to build a nest in the same ttee is usually attributed to the "in- stinct of migration," and yet that is more a statement of fact rather than an explanation of the wonderful ability of the birds to do this. How Does a Captain Steer His Ship Across the Ocean ? Man, the most intelligent animal, can also find his way about, but he has had to learn to do this step by step. When an explorer first travels into the unexplored forest, he carries a compass which tells him in what di- rection he is traveling, but this is not suiftcient to tell him the exact path he came and return the same way. In order that he may do this, he must make marks on the trees and other objects to find his way back. When these marks are once made, other men can follow the path by their aid, and eventually a path becomes worn so that men can find their way back and forth without the aid of the marks especially. A trained ship captain can take his ship from any port in the world to an- other port. He can start at New York City and in a given number of days, according to how fast his ship can travel, land his passengers and cargo in the port of London or Johannesburg, South Africa, or at any desired port in China, Jaj)an or any other country. But he cannot do this by any kind of instinct. He takes his directions from information that was furnished him by some one who went that way before him — some other captain of a vessel who made marks in his borjk of his position in relation to the sun and stars, 'i'his is i)ractically the same as the traveler in the forest who raadc marks on the trees to make a map of the way back and forth. Even with these charts, compasses and other guiding marks, however, man, even though he is the most intelligent of all the animals, makes very grave mis- takes and sometimes brings disaster upon himself and the lives in his care. Why the Birds Come Back in Spring? The birds, however, have no charts or compasses to guide them. We do not know as yet absolutely what it is that enables the bird to find its way back and forth to the same spot year after year. As nearly as we have been able to ascertain, the birds after they mate and build their first nest and bring up their first family, develop a fondness for that particular spot which is much the same as the instinct in man which we call the "homing in- stinct." Man becomes attached to one particular spot which he calls home and wherever he is thereafter, he is very likely to think of the old locality when he thinks of home, and there are very few of us but have yearnings to go back to the old "home locality" every now and then. The environment in which a bird or human being is brought up generally becomes to a greater or less extent a permanent jxirt of him in this sense. Why Do Birds Go South in Winter ? We know why birds go south in the winter. The necessity of finding food to live upon has everything to do with that. As food grows scarce' towards the end of summer in the farthest northern places where birds live, the birds there must find food elsewhere, 'i'hey naturally turn south and when they find food, they have to divide with the birds living there. The re- sult is that soon the food becomes scarce again and both the new-comers and the old residents, so to speak, arc forced to seek places where food is plentiful. So both of these flocks, to use a short term, fly away to the south until they find food again and en- cfiunter a third l1ork or group of tlic 408 WHY BIRDS SING bird family crowding the locality and exhausting the food supply. So in turn each flock presses for food upon the one in the locality next further to the south until we have a general move- ment tn the south of practically all the birds until they reach a point where the food sup])ly is sufiticient for all for the time being. Why Don't the Birds Stay South? The result of all this is that the south-land is crowded with birds of all kinds and the food supply is enough for all. But soon in following the laws of nature in birds, as in other living things, comes the time for breeding. The south-land is warm enough for nesting and hatching, but it is so crowded that there wouldn't Le enough food for all the old birds and the little ones too and so the birds begin to scatter again. Just think of what would happen in the south-land if all the birds that stay there in the win- ter built their nests there and brought up a new family. A bird family will average four young birds, so that if all the bird families were born and raised in the south the bird population would quickly multiply itself by three and there would be the same old ne- cessity of traveling away to look for food. To avoid this the birds begin to scatter to their old homes before the breeding season begins. How Do They Find the Old Home? The return of the birds to their old homes and how they find their way back to the same spot every year, to do which they must sometimes travel thousands of miles, is one of the most marvelous things in nature and has not as yet been satisfactorily deter- mined. The nearest approach we have to a satisfactory answer to this is that birds do have a memory, that they can and do recognize familiar objects, and that their love for the old home causes them to fly to the north until they recognize the landmarks of their former habitation. In this it is said that the older birds — those who have gone that way before — lead the flocks and show the way. There is no doubt that birds have a more perfect instinct of direction than man. They can follow a line of longi- tude almost perfectly, i.e., ihey can l)ick out the shorter Mv.te by instinct, and this is, of course, a straight line. 'J'hey just keep on going until they come to the familiar place they call b.ome and then they stop and build their nests. That it is not memory and sight of places alone that guides the birds is shown by the fact that some birds when migrating fly all night wdien there is no light by which to recognize familiar objects. Why Do Birds Sing? The song of the birds is a part of the love-makjng. The male bird is the "singer," as we call them at home, when we think of the canary in the cage near us. The male bird sings to his mate to charm her and to fur- ther his wooing. This wooing goes on after the eggs have been laid in the nest and while the mother bird is keeping them warm until they hatch out, but almost instantaneously with the birth of the little birds, the song of the male bird is hushed. Take the case of the nightingale. For weeks during the period of nest-building and hatching he charms his mate and us with the beautiful music of his love song. But as soon as the little nightingales come from the eggs, the sounds which the male nightingale makes are changed to a gutteral croak, which are expressive of anxiety and alarm, in great contrast to the song notes of his wooing. And yet, if you were at this period — just after the birds are born, and when his song changes — to destroy the nest and con- tents, you would at once find Mr. Nightingale return to his beautiful song of love to inspire his mate to help him build another nest and start all over again to raise a family. What Causes an Arrow to Fly? It is caused by the power generated when you bend the bow and string of WHAT MAKES SNOWFLAKES WHITE 409 the bow and arrow out of shape. The bow and string have the quahty of elasticity which causes a rubber ball to bounce. When you force anything elastic out of shape, this quahty in it makes it try to get back to its natural shape quickly. In doing this it acts in the direction which will take it back to its normal shape most quickly. The arrow is fixed on the string in a way that will not interfere with the bow and string getting back to its shape and, when they bounce back, the ar- row goes with it. The real cause for the arrow's flight, however, comes not from the bow, because the bow cannot put itself out of shape, but comes from the person who causes it to be out of shape and, therefore, the per- son who pulls the string back really causes the arrow to fly. Why Do Children Like Candy? Children crave candy because the sugar which it contains largely is in such a condition that it is the most suited of all our foods for quick use by the body. It is actually turned in- tri real energy within a few minutes after it is eaten. All the things we eat are for the purpose of supplying energy to our bodies to replace the energy that our daily activities have dissipated. Nature takes the valuable parts of the foods we eat and changes them into energy. The waste parts she throws off. Many things we eat have little real value as food and many also nature has to work upon a long time before their food value is available in energy. Sugar, however, represents almost en- ergy itself. Children are, of course, more active than grown-ups. They are never still. They are, therefore, almost always burning up or using up their energy. They arc also, therefore, almost al- ways in need of food that can be made into energy, and as sugar docs this al- most more quickly than any other food, nature teaches the children to like candy or sweets. Why Does Eating Candy Make Some People Fat? Eating as much as one can of any- thing at any time will produce fat, provided you do not do sufficient physical work or take enough exercise to counteract the effect of generous eating. When you see a person who eats a great deal and is growing fat, you may know that he or she is not taking sufficient bodily exercise to work off the energy produced by the body from the food that has been eaten. When this happens the energy in the form of fat piles up in various parts of the system. Candy will do this more quickly than any other thing we eat because it contains so much sugar and because sugar is so easily changed by our system into usable en- ergy. You generally find a fat person who eats much candy to be a lazy person. What Makes Snowflakes White? A snowflake is, as you are no doubt aware, made of water affected in such a way by the temperature as to change it into 'a crystal. Water, of course, as you know, is perfectly transparent. In other words, sunlight or other light will pass through water without being reflected. A single snowflake also is partially transparent, i.e., the light will go through it partially, although some of it will be reflected back. When a drop of water is turned into a snow- flake crystal, a great many reflecting surfaces are produced, and the white- ness of the snowflake is the result of practically all of the sunlight which strikes it being reflected back, just as a mirror reflects practically all the light or color that is thrown against it. If you turn a green light on the snow, it will reflect the green light in the same way. When the countless snow crystals lie on the ground close to- gether, the ability to reflect the light is increased and so a mass of snow crystals on the gnnuui look even whiter than one single snowflake. 410 THE USES OF PAINS AND ACHES What Makes the White Caps on the Waves White? In telling why the snowflake is white we have ])ractically already an- swered this (|ucstion also. Instead of little crystals formed from the water, the foam produced by the waves of the ocean are tiny bubbles which have tlie same ability to reflect the light as the snow crystals. What Good Can Come of a Toothache? Very few of us realize that an ach- iiig tooth is a good thing for us, pro- viiled we have it attended to and the ache removed. Any one who has had toothache will hardly agree that there can be a blessing attached to this ex- cruciating pain. But the good comes from the warn- ing it gives us of the condition of our teeth on the inside of our mouths. The arrangement of the interior of the mouth and the use we make of it in passing things into our systems, favors very much the development and in- crease of microbes, and when they once get in they are difficult to re- move. It is said that the greatest per- centage of cases of stomach trouble come from teeth which are in bad con- dition and that a very large percentage of people who have bad teeth are in grave danger oT blood poisoning or other troubles due to the microbes. When these microbes lodge in the mouth, they find conditions favorable to their development when there are bad teeth, and spread through the sys- tem. How Can Microbes Spread Through the Body? The various parts of the body, in- cluding the gums, are connected by a lymphatic tissue, which is practically a series of canals. If the teeth are not properly attended to ?nd kept in good condition, both as to cleanliness and re- pair, the microbes or germs collect on the gums and teeth, and increase in numbers. Soon the mouth is over- populated with microbes and are jmshed oiT the gimis or teeth into the lymphatic canals, wdiere they succeed in developing a disease in your body. Now the ache in the tooth becomes a blessing very promptly if it begins soon after the tooth begins to decay, because in that event the dentist is visited and the tooth filled or j^ulled. Therefore, while it hurts terriljly, it niight be well to remember that a toothache is a timely warning of dan- ger which, if not heeded, will likely (ievelop into something quite serious. What Causes Toothache? The ache comes when the tiny nerve at the heart of the toota is exposed to the air. When the tooth begins to de- cay, it starts to dc so generally from the outside, and after the decaying process has gone far enough, it reaches the nerve in the tooth, which aches when exposed to the air. The ache is the signal w^hich the nerve sends to the brain that there is an ex- posure and a cry for help. Of What Use Are Pains and Aches ? All pains and aches are helpful in sounding a warning. A headache may be the result of improper sleep and rest and, therefore, warns us to take the needed rest or sleep. A pain in the stomach is only nature's way of telling us that we have been unwise in our eating and drinking. As a mat- ter of fact, short though our lives are, they would probably be still shorter, on the average, if it were not for pains and aches, because without these warnings w^e would never have sense enough to stop doing the things we should not do if we lived normally. What Causes Earache? Earache is caused by the nerves in the ear being affected by something either from within or without which produces a swelling of the parts im- mediately adjacent to the nerves in the ear, and which press against the nerves ; as the nerves cannot go any place else they send a warning to the brain that they are being crowded and pressed against. The ])ain you feel is the nerve in the ear warning the brain that something is wrong in the ear. What Is Soap Made Of? Soap is not a ver)- modern product, although we have rarely read of soap in olden times. As long ago as two thousand years, the Germans had an ointment which was made in practically the same way as we now make soap. A soap factory was engaged in making soap in France in 1000 A. D. Even before soap was manufactured, people knew that that ashes of some plants, when mixed with water, gave it a peculiar, smooth, slippery feeling, and added to the cleansing qualities of water. Although they did not know it, this was due to the soda of potash which was in the ashes. Pure soda and potash both have excellent qualities for cleaning, but are likely to injure the skin, and other things coming in con- tact with them. Soap is made by boiling together oil or fat and "caustic" soda or potash. Caustic soda is a substance made from sodium carbonate by adding slaked lime to a solution of it. The slaked lime con- tains calcium in combination with hy- drogen and oxygen, and is known in chemistry as calcium hydrate. When calcium hydrate is added to a solution of sodium carbonate, the sodium pres- ent combines with the oxygen and hy- drogen to form a compound, variously called sodium hydrate, sodium hydrox- ide, or caustic soda. A similar com- pound of potassium is formed when the same kind of lime is mixed in a solution of potassium carbonate. In both cases the calcium is converted into calcium carbonate, which is not soluble in water and settles to the bottom ; but the caus- tic soda or potash is dissolved. The word "caustic" means to burn, lioth will burn the skin if allowed to touch the skin for a short time. The fats used for making soap con- sist of glycerine, in chemical combina- tion with what are called fatty acids. When these fats are boiled with caus- tic soda, or caustic ])otash, the fat is decomposed ; the fatty acid combines with the soflium or j)Otassium to form soa[) and the glycerine is left uncom- bined. In modern soap factories the manu- facture is carried on in large iron ves- sels. Some fat and oil are put into the vessel and a little lye, which is really caustic soda or potash, is added and the mixture boiled. The fat and the lye combine very quickly and form a whitish fluid. More lye is now added and the boiling continued. This process is repeated until nearly all the oil or fat has combined with the lye. If yellow laundry soap is being made, some rosin is put in, and this gives the yellow color. If toilet soap is being made, common salt it put in instead of rosin. The addition of the salt has the effect of separating the water and the gly- cerine from the soap. The soap rises to the surface and is skimmed off. As soon as the separation is complete, and the soap is then cut or pressed into cakes afer it has become hard. Soaps referred to above are the ordi- nary hard soaps. In making soft soaps no salt is added to separate the soap from the liquid. As the water and glycerine do not separate from the soap, the entire mixture remains of a soft consistency. Soft soap is also made with a lye, that is obtained from wood ashes. The ashes are placed in barrels and water poured upon them. The water drips down through the ashes in the barrel and dissolves the potash contained in them, making lye or caustic potash. This lye is then in liquid form and is mixed and boiled with grease or fat to make soap. There are many different fats used in soap making. Palm oil is perhai:)s the most common, but tallow, olive oil, cotton seed oil, and many other fats are used. The hardness of the soap varies with the kind of fat and lye used. Palm oil or tallow soap is very hard, and other oils are sometimes mixed with it to soften it. These are the main facts connected with the making of soaps. 1'liere may appear to be dilTercnt kinds all of which look and smell dilTi'iintly. The differ- ence in them is largely due to the pres- ence of different perfumes and coloring matters. 412 HOW MEN LEARNED TO SEND MESSAGES INDIAN sE.NUINO MlisbAtjE WITH SMOKE SIGNALS. The:^HK^ Indians found their system of smoke signals quite effective in sending messages from place to place. With a good burning fire before him, and a blanket or shield at hand, the Indian was equipped to send his messages. The code consisted of the varying kinds of smoke clouds produced. These were made large or small by covering the fire at intervals with the blanket or shield, thus making interruptions of various lengths in the rising clouds of smoke. By dropping moss or other things into the fire, he made the smoke clouds either light or dark at will. eo u^ k f cy (pRCiS The Story in a Telegram How Man Learned to Send Messages. From the time when man had learned to protect himself from the beasts of the forest, and thus was able to move about more freely, and live by himself rather than remain with the tribe, he has found it necessary to send messages. One of the most interesting of the early methods for sending messages was the Indian way of smoke signal- ling with the simple equipment of a fire mth its rising column of smoke and a blanket or shield. Messages were sent, relayed, received and an- swered, at points hundreds of miles apart. Among savages still found in remote parts of the earth this and other primitive methods are still in use. In the wilds of Africa to-day at points where the electric telegraph service has not yet penetrated, the natives by the simple method of beat- ing drums, which can be heard from one relay point to another, are able to send the " news of the day " across the country with marvellous rapidity. In some parts of South America, the natives long ago discovered that the ground is a good conductor of sound and send their messages almost at will, making their signals by tapping against poles which thcy have planted in the ground at various points and which constitute both their sending and receiving instruments. The Signal Corps in the army u.ses flags for sending messages, where the telegraph is not available, the flags being of diflfcrent colors, and the signals are produced by waving the flags in diflerent ways. The army heliograph is also used as a telegraph line — a mirror which reflects the sun's rays in a manner understood by a pre- arranged code. These and other sim- THE FIRST MESSENGER BOY 413 THE OKEEK RUN'XEK. In this picture we see the Greek Runner on the last leg of his journey and the man to whom he is to deliver the message waiting for him. This method of sending messages was not very fast, although the runners were picked because of their speed and endurance. Here we see the fast riders of the I'oiiy 'I'elcj^raph, which increased the speed of delivering messages quite a good deal, but, of course, there was danger of losing tlie message to enemies or through accident, so that it might be difficult under such circumstances to send u secret message or to even be certain that it would arrive at destination. 414 IT IS EASY TO CALL A TELEGRAPH MESSENGER ilar methods are merely elaborations of devices developed and used by the savages as a solution of the ever present need of sending a message to some other point. The great Marathon runner was nothing more or less than a telcgra]jh messenger hastening with his written message, from the man who delivered it to him, to its destination, and his work was harder than that of the messenger boy to-day, for he not only had to deliver the message him- self to its destination, but had to run fast all the way or lose his job. The messenger on foot finally gave way to the Pony Telegraph, which not only shortened the time necessary to deliver a message, but marked the beginmng of a system. How Does a Telep-am Get There? The ne.xt time \-our daddy takes you down to the office, ask him to show you the telegraph call box. When you see it, you will perhaps not think that by merely pulling down the little lever you can so start things going that, if you wish, you can cause men who are on the other side of the earth to RINGING THE CALL BOX. MESSENGER UOVS WITH BICYCLES W.MTING THE ( All, « ^ i? ^ : 1 1 Here we see the messenger calling at the office from which the call box registered a call and receiving the telegram to be taken by him to the central office to be put on the wire. work for you in a few minutes, and to make little instruments all along the way which, with their other equip- ment, have cost millions of dollars, click, click, click at your will. Sooner or later during the day your father will be wanting to send a tele- gram. He steps to the call box, pulls the little lever and goes back to his desk. In a few minutes, some- times before you realize it, the little blue-coated messenger appears and When the messenger gets back to llie olliie, lie liands the message to the receiving clerk who stamps it, showing the exact time received and sends it by pneumatic tube to the operating room. 416 BEFORE THE TELEGRAPH SERVICE IS POSSIBLE AND says " Call? " Father hands him a telegraph blank on which he has written the message, the messenger takes off his cap, puts the message inside and the cap back on his head and away he goes on his bicycle as fast as his legs can pedal, to the central office, to which point you follow him to see what he does with the message. If you had been at the telegraph office instead of your father's office, you would have seen one of these boys start off on his wheel to get the mes- sage your father wished to send . When the little lever on the call box is pulled down, it is pulled back by a* spring which sets some clock work • going which sends a signal over the wire on a circuit which runs out from a regis- ter at the main office. The register has a paper tape running through it, and the signal from the call box appears as a series of dots on the tape. The clerk knows from the number and spacing of the dots that it was your father that called and not some other business man whose box might be on the same circuit. We have now followed the telegram to the point where it is to start on its real journe}'. Here we see the operator preparing to send the message. He first must " get the wire." By this is meant to get a through connection to the town where the message is to be de- livered. Each office along the line has a signal. The other operators can hear the call, but since it is not their signal, they pay no attention. Almost immediately, however, the operator at the delivery point hears the signal He signals back "II" and repeats his own office call, which means " I hear you and am ready." The message is then ticked off, until finished and the operator at the delivery point signals " O. K.," together with his personal signal, which means he has received the whole message and has it down on paper. Here we see the operator at the delivery office. She has translated the dots and dashes as they came to her over the wire into plain words on a regular telegraph blank, putting down the time received, the amount to be collected, if it is a " collect " message, or marking it " Paid " if it was so sent. She has handed it to one of the blue-clad messengers in her office who starts off at once to deliver it. The operator has also made a copy of the message for the office files. THE TELEGRAM ARRIVES AT DESTINATION 417 Here we see the messenger delivering the telegram to the person to whom it is addressed. It may be good news or bad new^s for the person receiving it, but it is all in the day's work for the messenger boy. But let us see how many people have to work to deliver the message. We have followed it through from the original call box. First there was the messenger who came for it, then the receiving clerk, the sending operator and the operator who receives it and last of all the messenger boy who delivered it. This does not take into account the men who must look after the many miles of wires, the machinery which supplies the current, or the great army of "^^" '^h° ^re constantly laying new wires so that you can send a telegram from almost anywhere to any other place. The Operators you have seen work- ing in these pictures are Morse opera- tors. They send the message by Morse Code in dots and dashes which are sent over the wire as electric impulses. At the other end the message is read by listening to the clicks the sounder makes as it receives these same electric impulses. This is the simplest way of telegraphing. The number of messages sent be- tween two big cities in a day is tremendous — ^many more than cotild be transmitted over one Morse wire. Many wires would be needed. But wire costs money, so ingenious men set to work to find some way to send more than one message over a single wire at the same time. They suc- ceeded. There is now the duplex telegraph, which sends a message each way simultaneously over a single wire, the quadrujjlex, which sends two mes- sages each way simultaneously over a single wire. Last but not least there is the multiplex, which sends four messages each way simultaneously over a single wire. This seems almost unbelievable, but it is done. In the case of the duplex and quad- ruplex, the different messages are sent by currents of different strength, and by changing the direction of the current. Receiving instruments are designed so as to separate the mes- sages by being affected only by the currents of certain strength or polarity, as the direction of flow is termed. It can easily be seen that by these ingen- ious devices, the telegraph company saves many thousands of dollars in the miles and miles of wire, and hun- dreds of telegraph poles which would be required if all the messages had to be sent over a simple Morse wire, one message only upon the wire at a time. V*-' _jl«i?SW- In this picture we see the interior of fi telegraph office along the line of a railroad. The operator has her hand on the " key " or sending instrument. At her left in a stand called the resonator, is the receiving instrument called the " sounder " which icks off the message. In front of her is an instru- cnt called the " relay." Current from two of e batteries goes through the key when it is pressed ■iwn, through the relay and out on to the wires I the pole line, then through the relay of the I- eiving operator at the other end, (see picture !i opposite page) through 'his key and through two • '.re batteries to the ground. The earth forms the ixturn wire of an electric circuit when both keys are " closed " or pressed down. You know all electricity has to flow in a closed circuit. The " sounder " has to make good strong clicks to be understood, and the current after it has gone through miles of wire and ground may not be strong enough so the sounder is put on a local circuit of its own, with a sjn riril battery. [In this circuit is a contact maker v.hu h is part of the relay. When the key is fjresscd aown and current flows over the wires on the poles and through the relays, the magnets of the relay pull on a little piece of metal called the " armature," which makes a contact and closes''the local sounder circuit, so current from the single local battery can Pow up through the magnets of the sounder and back to the battery. This makes the sounder click. When the key is re- leased, the relay armature is pulled back by a spring and breaks the circuit of sounder, which then em.its another click. By the number and duration of the clicks and the time between them, the receiving operator knows the meaning of the signal. The Morse Code, which is used throughout the United States, is shown on the next page. SENDS MESSAGES THOUSANDS OF MILES INSTANTANEOUSLY 419 TvrORSE TELEGRAPH CODE TTers r^lor-s>e Mumercils A F gures r-iorse B _-.. 1 • •— ^. C _. . 2 ..._.. D — -- e> ..._-. E - ^ ....__ F ..^. s «» ^ — G ^^. H "7 "• S J — - — - 9 .^ .. K ^ a^B L .^^ M ^^ N ^ , O , . P O Pcjrictua tions 3 ... . D.^.od T t Colo-^ _- . U ; S>«rr..coloO V ... Co^-'^o ._.— . w . \ 1 ^ r» f-*-o^o ♦ 1 or^ — - -^■ X e.»clar»ic»*«o^ •^^^- Y . . . . - T'-octtoo Lir>« " 420 THE INVENTOR OF THE TELEGRAPH The multiplex telegraph is truly a marvellous invention. It has been de- veloped by the engineers of the Western Union Telegraph Co. working with the engineers of the Western Electric Company. The principle on which this instrument works is that if sepa- rate instrmnents are given connection with the wire one after the other during very short intervals of time, the effect is as though the wire were split up, and each instrument works just as if it alone were on the wire. Not only does the multiplex telegraph thus send four messages in one direc- tion and four messages in the opposite direction, simvdtaneously over a single wire, thus keeping no less than six- teen operators employed on one wire, four sending and four receiving at each end, but each message instead of being sent by the ordinary Morse key, is written upon a typewriter keyboard at one end of the line and appears automatically typewritten at the other end. If you live in a big city, go into one of the larger branch ofhces of the Western Union Telegraph Co. and ask to see printing telegraph. Most of the large branch offices communicate with the general operating department in the cit}* by means of what they term " short line printers," which are instruments on which the message is written upon a typewriter keyboard and appears typewritten at the other end. Who Invented the Electric Telegraph? It is hard to say just how the tele- graph originated in the mind of men. We have already shown how the sav- ages sent signals over distances by means of the smoke rising from his fire. Every boy and girl has used a little mirror, held in the sun to flash a bright spot here and there. This principle has been used by the army to signal at distances. The sun's rays are flashed from a small minor, long and short flashes indicating the dashes and dots of the Morse tele- graph code. Progress towards the perfection of ^^Hf^ /y ' '^^1 Wk ^' M ^H m^ PROFESSOR S. F. B. MORSE, INVENTOR OF THE TELEGRAPH. the electric telegraph began with the first researches of scientists into the natural laws which govern that great natural agent, electricity. Clever, painstaking men, stud^nng and experi- menting for the love of the work, dis- covered bit by bit how to control the force. Stephen Gray with his Leyden jars, which stored up a charge of elec- tricity, inspired Sir William Watson to experiment, and he sent current from one jar to another two miles away. The First Suggestion of the Electric Telegraph. For a long time no one thought that this opened the way for the mak- ing of a useful servant for man. In 1753 this thought occurred to an un- known man in Scotland, who wrote a letter to a newspaper suggesting that messages be sent by electric currents. One of his schemes was that there should be a light ball at the receiving end of the wire which would strike MEN WHO INVENTED TELEGRAPHS ALMOST SIMULTANEOUSLY 421 a bell when it felt the electric impulse come over the wire from the Leyden jar, and by devising a code depending upon the number of strokes of the bell and the time between them, he sug- gested that njessages could be sent and interpreted. Some believe this man to have been a doctor named Charles Morrison of Greenock, Scotland. Who- ever he was, he suggested a method which comes very near to being that in use to-day. The difficulty with proceeding on this suggestion was that the current from the Leyden jar was static elec- tricity, which has not the strength nor can it be controlled as can the cur- rent of low potential which is used to-day. Volta discovered this new and more stable form of electricity and many different men labored in- vestigating what could be accom- plished with it. The names of Sir Humphry Davy and Michael Fara- day are inseparably connected with this advance. It was Oersted's and Faraday's discovery of the connection between electricity and magnetism, and how an electric current may be made to magnetize a piece of iron at will, that really opened the way for the invention of the telegraph we know to-day. The First Real Telegraph. But before the much greater prac- tical value of Volta's current was dis- covered, one man developed a real telegraph which worked with electric- ity of the static kind, produced by friction. This man was named Sir Francis Ronalds. He worked along the lines laid down by the unknown Scotchman, whom we have supposed to be Charles Morrison. The machine he built and operated in his garden at Hammersmith utilized pith balls, which actuated by the charge of static electricity sent along the wire caused a letter to appear before an opening in the dial. When jjcrfectcd he offered it to the British Government, who refused it. They were very stupid in their refusal, for they said " tele- graphs are wholly unnecessary." Sir Francis Ronalds' invention cost him much care, anxiety and money. He lived to see the more practical voltaic current taken up by others and put to successful use. Being unselfish he rejoiced that others should succeed where he had failed. Two Men who Invented our Telegraph almost Simultaneously. The telegraph, working on the elec- tro-magnetic principle, as used to-day, was developed almost simultaneously on the two sides of the Atlantic Ocean. In England Sir Charles Wheatstone and Sir William Fothergill Cooke worked out a practical method and instruments, which with few changes, are in use to-day. Cooke was a doctor and had served with the British anny in India. Wheatstone was the son of a Gloucester musical instrument maker. The latter was fond of science and experimented continually with elec- tricity and wrote about it and other scientific subjects. As a result of his work he was made a prof essor at King's College. There he conducted impor- tant researches and tests, among which was one which measured the speed at which electricity travels along a wire. So Cooke, who was a doctor and a good business man, entered into partnership with the scientist Wheat- stone, and together they completed their invention. It was first used in 1838 on the London and Blackwall Railway. At first it was expensive and cumbersome, using five lines of wire. Later this number was reduced to two, and in 1845, an instrument was devised which required but one wire. This instrument, with a few minor changes, is the one in use to-day in li)ngland. While these two men were working in ii^ngland, an American artist, vS. F. B. Morse, was studying and experi- menting in the United States along his own lines but with the same end in view, namely to jjroduce instruments which would satisfactorily .send mes- sages over a wire by electricity, 422 FIRST TELEGRAPH LINE FROM BALTIMORE TO WASHINGTON An American, however, is given the honor of First by Slight Margin. Morse was bom in Charlcstown, Massachusetts, in 1791. He was gifted as an artist, both in painting and sculpture, and in 181 1 went abroad to England to study. While on a voyage from Havre to America in 1832 he met on board ship a Dr. Jackson, who told him of the latest scientific discoveries in regard to the electric current and the electro-magnet. This set Morse to thinking and after three years' hard work on the problem he produced a telegraph which worked on the principle of the electro-magnet. With the apparatus devised by Morse and his partner Alfred Vail, a message was sent from Washington to Balti- more in 1844. There has been some question as to whether Morse or Wheatstone first invented a workable telegraph. As will be evident from this history, the telegraph in principle was a gradual development, to which many minds contributed. To Morse, however, the high authority of the Supreme Court of the United States has given the credit of being the first to perfect a practical instrument, saying that the Morse invention " preceded the three Euro- pean inventions " and that it would be impossible to examine the latter without perceiving at once " the de- cided superiority of the one invented by Professor Morse." Uncle Sam Helped Build the First Telegraph Line. At the time Morse's Recording Tele- graph was invented there were, of course, no telegraph lines in any part of the world, with the exception of the short lines of wire put up by in- vestigators for experimental purposes. To remove the obscurity as to the pur- pose to be served by the telegraph was the first problem which presented itself to Morse and his backers. In 1843 ^^ appropriation was secured of $30,000 from the U. S. Government, with which a line was built from Wasli- ington to Baltimore. This was buih and operated by the Government for about two years, but the Government refused to purchase the patent rights. So the owners of the patents endeavored to get the general jmblic interested in the telegraph as a commercial under- taking and gradually companies were founded and licensed to use the in- vention. By 1851 there were as many as fifty different telegraph companies in opera- tion in different parts of the United States. A few of these used the devices of a man named Alexander Bain, which were afterwards adjudged to infringe the Morse patents, and one or two used an instrument invented by Royal E. House of Vermont, which printed the messages received in plain Roman letters on a ribbon of paper. This at first seemed to have an advan- tage over that of Morse, which re- ceived the message in dots and dashes, in the Morse Code, and these had to be translated and written out by an operator before they could be delivered. However, as time went on, the opera- tors came to read the Morse messages by the sound of the dots and dashes, instead of waiting to read the paper tape having the dots and dashes marked on it, and finally the record- ing feature was given up and the sounder, or instrument which simply clicks out the message, came into gen- eral use. In the early days, the possibility of the business were little understood and many telegraph companies failed. April 8, 1851, papers were filed in Albany for the incorporation of the New York and IMississippi Valley Printing Telegraph Co. This com- pany, which soon afterwards changed its name to Western Union, was des- tined to absorb the various companies throughout the country until it, in time, operated the telegraph lines over practically the entire United States, and has its blue sign in nearly every town and hamlet in the country. AN EXPENSIVE EQUIPMENT NECESSARY TO=DAY 423 OPERATING ROOM. In large cities like New York and Chicago, the operating rooms are very large. For instance, the main operating department of the Western Union Telegraph Co. in New York City has looo operators. This picture shows an operating room. The men and women sit in opposite sides of long tables. On the tables are the keys and sounders by which they send and receive the messages. Each operator has a typewriter, or " mill," as he calls it, on which he writes off the message as it comes to him over the wire. MAIN SWnclIUOARU. The picture shows a main switchboard in a InrKe operatinR room. Tf) this come the ends of the wires from other cities, and to it arc connected the wires from the instruments in front of the ()i)erators. By putting pIuRS, attached to each end of a wire, into the sockets in th<; board, any wire can be connected with any operat- ing position, or several local circuits can be connecte .m,;," ..In iwiii;; the ^vnv whicli is uscfl in paying out the cable. Away in the bow arc the l>ig slicavcs over wliich the cable goes into the sea. Nearer is a dviianioiiietcr vvhi(.h measures the tension on the cable. 432 HOW THE CABLE IS DROPPED INTO THE OCEAN \ Here we see the cable on the lead, as it is called, passing over the big bow sheave from which it dives into the depths of the sea. THE CABLE ARRIVES ON THE OTHER SIDE 433 course outlined, paying out the cable as she goes. The vessel must pay out more than a mile of cable for every mile she travels because there must be enough slack allowed at the same time to provide for the unevenness of the bottom of the sea. For this purpose the amount of cable paid out must be measured. This is done by the paying-out machine, which is shown in one of the pictures. The difference between the speed of the ship and the amount of cable paid out gives the amount of slack. Too much slack would also be bad, so that it is a very pretty problem to pay out just enough and both the speed of the vessel and the rate of paying out the cable must be watched carefully. One of the greatest wonders accom- plished by the ingenuity of man is the ocean telegraph, by which we flash messages back and forth under the sea between the continents and completely around the world. Hardly had the telegraph become an established fact, before Professor Morse, who made the telegraph practical, expressed the belief that a telegraph line to Europe by means of a wire laid on the bottom of the ocean was easily possible at some future time. Mr. Cyrus W. Field, the first to lay an ocean cable successfully, heard him and in his own mind said " Why not now?" The idea fixed itself so thor- oughly in his resolute mind that he soon said to himself " It shall be done," and went to work, and labored in- cessantly through twelve years of fail- ure and discouragement before he accomphshed his task, which was a great compliment to this giant of American stick-to-it-iveness. While many doubted the feasibility of the project and others thought it the dream of a disordered brain, Mr. Field found many who believed in him and his idea and who loaned him their financial support for the undertaking. Landing the shore end of a cable. The cable is supported on ^^veral boats and this picture shows the inshore boat with the end of the cable reaching the beach with the seas breaking over her. 434 THE MEN WHO MADE THE OCEAN CABLE POSSIBLE THE PIONEERS OF THE FIRST OCEAN CABLE. American genius had not at that time asserted its supremacy in me- chanics and so the first cable had to be made in England ; so Mr. Field ordered one long enough to stretch from the west coast of Ireland to the eastern point of Newfoundland. English cap- italists subscribed the money and the United States provided the vessel in which to store and from which to drop the cable into the ocean. Upon the first attempt to lay the cable, ever\^ thing went along nicely for six days, and then suddenly the cable broke when three hundred and thirty-five miles had been laid, and many said it could not be done. Mr. Field, however, full of American pluck and determination, said " We will try again." A second attempt was made with two ships, the U. S. S. "Niagara" and H. M. S. S. "Agamemnon." Each ship carried half the cable and they traveled in company to the middle of the ocean. There the two pieces of the cable were spliced together and the ships started for the shores in oppo- site directions. Again, however, when only a little of the cable had been paid out — a little more than one hundred miles in fact^the cable broke and both ships were forced to return to England. In his third attempt the cable was finally laid clear across the ocean and fastened at both ends. When tried it was found to work successfully and Queen Victoria and President Buchanan were able to exchange greetings upon the achievemnt of a wonderful work. The people celebrated the event on both sides of the ocean, but in the midst of the festivities, while a message was being flashed, something happened to the cable — what, we have never been able to learn — and the cable was silent, forever. Nothing daunted, however, Mr. Field by his great courage induced his backers to buy him another cable and the "Great Eastern" sailed upon what was to be a most successful mission. Starting from the American side with the greatest steamship then known in charge of the previous cable, the other end was successfully landed at Hearts Content, Ireland, on July 27, 1866, in perfect working order, and the ques- tion of the ocean telegraph was solved. HOW CABLES ARE REPAIRED 435 Here is a buoy which is anchored to the cable. The cable ship will pick it up and haul up the cable to the surface for inspection and perhaps it will have to be repaired. In this picture we see a portion of a cable which has been fouled by the anchor of a ship and badly damaged. Note how the wires are bunched. The cable splicers will go to work on this and put in a new piece of cable, after which it will be let down into the sea again. Three grapnels uscfl fi^r jjicking up a caJjlo from the bed of the ocean. (Jn tiie left is a common graj^nel. In the middle is a special grapnel known as 'i'rotl-Kingsford. On tlie right is the orrlinary cutting grapnel. Note the knives on the shaft and the insides of the (jrongs. 436 POWERFUL ENGINES NEEDED ON CABLE REPAIR SHIPS Here are the powerful engines which are used for picking up a cable which has to be raised from the bottom of the sea for inspection or repair. In this picture we see men at work splicmg a cable which has'been picked up out of the depths of tlie sea and found to be damaged. THE SHIP WHICH HELPED IN LAYING THE FIRST CABLE 437 Here is one of the machines used for armoring the cable. By armoring is meant winding steel wires around and around the cable to protect it from being cut by sharp rocks on the bottom or by deep sea animals like the teredo, which might attack it. The "Great Eastern" which was the first ship to carry a cable across the Atlantic Ocean. This is a section of a telephone cable, known as a " bulge." It contains inductance coils to offset what is called the condenser capacity of the cable, which would otherwise cause the talking to become blurred. 438 THE DOTS AND DASHES WHICH FLASH ACROSS THE SEA Making repairs to a cable where it comes out of the sea on to a bold rocky shore. Note how the cable is wound with chain to protect it from the rocks. Facsimile of Continental Moree Alphabet as Signalled .\croits the Atlantic «nd Copied on Tape by Siphon Recorder Instrument at the Receiving Station. Signals Enlarged for Purposes of this lUustrat ion. CONTINENTAL MORSE CODE SIGNALS USED IN CABLE WORKING A.I_PMABET: A B C D E: F G .5* <" '^ I/. o S o o o o Oh O O ^ O ?. gJ5 tjD-w n) x! b w Ji O M — E S J- OH :>, i, . ^---r c o 4) — o o o o o c o o o o o q q q q in o "^ O N t^ ro fO -M « .H.S a a -c t,fl >- O e "^ ♦^ C o °:S>'oi_K£!>,c gS4)«5i Tit^o" go rt C 4) 2 C T) •r 3 rt " -' "O <-• -(J CJ .^ '« ci, QC 00 go; ' (U V 'S*5o & *- lU u ^, (/' ^ 4> cii ii) 4jJi: t) 4> •r 3 rt H J: u I. 4) rt'a Q 4J 4> 4> V (U 4J 4> 4J 4; 4> E-g e EE B ^ u rt rt rt oj Qw QQQQ CYLINDERS BIG ENOUGH FOR MEN TO SIT DOWN IN 441 ^ , .S O M D O 442 THE LOCOMOTIVE ENGINEER'S WORK ROOM Here is a picture of one end ot the boiler of this giant locomotive. It would take a man more than seven feet high to bumj) liis head in tlic middle of it while standing on his feet. This shows a picture of the engineer's cab oi one of these great railroad niacliiiies. We are accustomed to see the levers and other machinery for operating the engine ri' The masts for the cavalry wire- less sets are so attached that they can be loaded and unloaded with the utmost rapidity; a complete station can be erected or dismantled in less than ten minutes. The gasoline engine which sup- plies the power for operating a cavalry wireless station is fitted to the saddle frame and is light enough to be carried by one horse. THE WIRELESS IN THE ARMY How High Do Wireless Masts Have to be? The towering masts of the Marconi Trans-Oceanic stations are often sup- posed to rise to their great height, so that an antennae will be raised above the obstructions between. If this were necessary, two wireless stations sepa- rated by the Atlantic would have to have masts one hundred and twenty- five miles high to rise above the cur- vature of the earth. The path of the wireless waves, however, is not in a straight line, but follows the curva- ture of the earth. Scientists explain this by saying the rarefied air above the earth's surface acts as a shell enclosing the globe. The speed of wireless messages is placed at 186,000 miles per second. A wireless message will thus cross the Atlantic in about one-nineteenth of a second — a period of time too small for the human mind to grasp. In other words, the wireless flash crosses in a fraction of a second a distance that the earth requires five hours to turn on its axis and the fastest ships take nearly a week to cross. The longest distance over which a wireless message can be sent is not definitely known; the present record was made in September, 19 10, by Marconi from Clifden, Ireland, to Buenos Aires, Argentina, a distance of 6700 miles. THE WIRELESS PREVENTS ACCIDENTS AND SAVES MANY LIVES 449 O M c-S o< ^ S o - - C-- I- rtJ^S o •^ C ^- p W jS c/i §o 450 HOW THE WIRELESS IS INSTALLED ON FAST TRAINS RAILROAD WIRF.LESS. — ANTENNA ON CARS. WIRELESS STATION ON TRAINS. WIRELESS STATION IN U. S. ARMY 451 City side of Scranton station, Laclcawanna R.R., showing aerial of wireless which comma nicates with trains. WIRELESS KECEIVINU STATKJN I.N L. S. ARMY. I'huiu by Sicfano 452 THE MAN WHO INVENTED WIRELESS TELEGRAPHY Gugliclmo Marconi, Inventor of wireless telegraphy. The Man Who Invented Wireless Teleg- raphy. Communication without wares for thousands of miles across oceans, from continent to continent, is a far cry from sending a wireless impulse the length of a kitchen table. That is the develop- ment of twenty years. To i^roperly trace the development of wireless telegraphy, however, it is necessary to go back eighty-three years to when, in 1831, Michael Faraday discovered electro-magnetic induction between two entirely separate cir- cuits. Steinheil, of j^lunich, too, in 1838, suggested that the metallic por- tion of a grounded electrical circuit might be dispensed with and a system of wdreless telegraphy established. Then, in 1859, BowTnan Lindsay demon- strated to the British Association his method of transmitting messages by means of magnetism through and across the water without submerged wires. In 1867 James Clerk Maxwell laid down the theory of electro-mag- netism and predicted the existence of the electric waves that are now used in wireless telegraphy. Dolbear, of Tufts College, in 1836, patented a plan for establishing wireless communication by means of two insulated elevated plates, but there is no evidence that the method proposed by him effected the trans- mission of signals between stations separated by any distance. A year later Heinrich Rudolph Hertz dis- covered the progressive propagation of electro-magnetic action througli space and accomplished the most valuable work in this i^eriod of speculation and experiment. Just twenty years ago, at his father's country home in Bologna, Gugliehno Marconi, then a lad just out of his 'teens, read of the experiments of Hertz and conceived the first wire- less telegraph apparatus. This was completed some months later and a message in the Morse Code was trans- mitted a distance of three or four feet, the length of the table on which the apparatus rested. Satisfied that he had laid the founda- tion of an epoch-making discovery young Marconi pursued his experi- ments and filed the first patent on the subject on June 2, 1896. Further experiments were carried on in London during that year and at the request of Sir WiUiam H. Preece, of the British Post Office, official tests were made, first over a distance of about 100 yards and later for one and three- quarter miles. ' During the year following Mr. Mar- coni gave several demonstrations to the officials of the various European governments and communication was established up to 34 miles. In July of this year, 1897, the first commercial wireless telegraph company was incor- porated in England and the first Mar- coni station was erected at the Needles, Isle of Wight. On June 3, 1898, Lord Kelvin visited this station and sent the first paid Marconi gram. A month later the events of the Kingstown Regatta in Dublin were reported by wireless teleg- raphy for a local newspaper from the steamer " Flying Huntress." In August of that year the royal yacht "Osbom" was equipped with a wireless set, in order that Queen Victoria might com- municate with the Prince of Wales, who was at Lady^vood Cottage and suffering from the results of an acci- dent to his knee. For sixteen days, constant and uninterrupted communi- cation was maintained. Then on PREPARING TO SEND MESSAGES ACROSS THE OCEAN 45:^ This photograph shows how wireless mes- sages are prepared for direct transmission across the ocean. The dots and dashes of the telegraphic code are punched on tapes by skilled operators, thus insuring accuracy and a permanent record of each message. Five or six operators, and sometimes more, are steadily preparing these tapes, which are pasted together and run through a machine which operates the key at each perforation. A speed of lOO words a minute is thus ob- tained. Christmas Eve was inaugurated the first lightship wireless service, messages being sent from the East Goodwin lightship to the lighthouse at South Foreland. Three months later the first marine rescue was effected through this instal- lation. The steamship " R. F. Mat- thews " ran into the lightship and lifeboats from the South Foreland station promptly responded to the wireless appeal for aid. The most important wireless event abroad dur- ing the year 1899 was the establishing of communication across the English Channel, a distance of thirty miles. The American public next learned something of Marconi's invention, for in September and October of that year wireless telegraphy was employed in reporting the International yacht races between the "Shamrock" and the "Co- lumbia" for a New York newspaper. At the conclusions of the races, the naval authorities requested a series of trials, during which wireless messages were exchanged between the cruiser " New York " and the battleship " Massa- chusetts " up to a distance of about 36 miles. On leaving America, Marconi fitted the liner " St. Paul " with his apparatus and when 36 miles from the Needles Station, secured wireless re- ports of the war in South Africa. These were printed aboard the vessel in a leaflet called " The Transatlantic Times," the first of the chain of wire- less newspapers now published daily on practically all passenger steam- ships. Six field wireless sets were dis- patched to South Africa about this time and were later of considerable service in the Boer War. The year 1900 brought the first commercial wireless contracts. By agreement with the Norddeutscher Lloyd, Marconi apparatus was installed on a lightship, a lighthouse and aboard the liner "Kaiser Wilhelm der Crosse." On July 4th the British Admiralty entered into a contract for the instal- lation of Marconi apparatus on thirty- In tlie funil oi this pielurc is seen the automatic transmitter with the message perforated tape running through. This is one of the smaller wireless equipments; much larger ones ;ire used at tlie new Marconi stations. 454 WORLD WIDE USE OF THE WIRELESS two warships and shore stations and the erection of the high power station at Poldhu was commenced. Work on similar station at Cape Cod was begun early in 1901 and on August 12th the famous Nantucket Island and Nantucket Hghtship stations opened to report incoming vessels by wire- less. Heavy gales in September and November ^vrecked the masts at both Poldhu and Cape Cod stations and these were replaced by four wooden towers, 210 feet high. Important experimental work was then shifted to St. John's, Newfoundland, and on December 12th and 13th, signals were received across the Atlantic from Poldhu. This to Marconi was a great achievement and the forerunner of the present day trans- atlantic ser\ace. But with the an- nouncement that the long dreamt of feat had been accomplished a flood of vituperation from scientific men was let loose. It was nonsense; it was deliberate deception; the reading was in error, were among the com- ments. Another prank of the " yoimg man with a box," one scientist termed it. It is amusing now to recall this extraordinary treatment, but it was hardly so amusing to the young in- ventor, then in his twenty-seventh year. But in spite of the skepticism, de- velopments followed rapidly from then on and in 1902, the year in which the American Marconi Company was es- tablished, full recognition to wireless telegraphy was given by the various governments. The wonderful growth of the Marconi system within the last twelve years is well known to all and does not require detailing. But in view of its youth as an industry and its inauspicious beginning, a glimpse into what the present day Marconi system comprises may be interesting. More than 1800 ships are equipped with Marconi wireless and its shore stations are landmarks in practically every country on the globe. Press and commercial messages are transmitted daily from continent to continent direct. Shore to ship and ship to shore busi- ness each year runs into millions of words. Marconi wireless within seventeen years, has become an absolute neces- sity in the maritime field, an invaluable aid in others. Regular communica- tion has been established with icebound settlements and desert communities, and official running orders transmitted to moving railway trains. Its service is dependable under all conditions and embraces activities and locations inac- cessible to any other telegraph system. Continuous service is maintained and wireless messages for all parts of the world at greatly reduced rates are received at any Western Union Office. The direction finder and wireless compass are recent Marconi inventions. A wide variety of types of Marconi equipment are designed for the mer- chant marine, warships, submarines, pleasure craft, motor cars and rail- road trains; also portable signal corps sets, apparatus for aircraft, cavalry sets, knapsack sets and high-power installations for trans-ocean communi- cation. How Does a Fly Walk Upside Down? There is a little sucker on the end of each of the fly's feet which makes his foot stick to the ceiling or any other place he walks, and which he can control at will. It is made very much like the sucker you have seen with which a boy can pick up a flat stone — a circu- lar piece of rubber or leather with a string- in the middle and more or less bell shaped underneath. A boy can pick up a flat stone with this kind of a sucker by pressing- the rubber or leather part down flat on the stone and then pulling gently on it by the string. W^hen he docs this he simply expels the air which is between the leather part of the sucker and the stone, which creates a vacuum and the pressure of the air on the out- side part of the leather enables him to pick it up. The fly has little suckers like these on each of his feet, and they act automatically when he puts his foot down. Of course the sticking power of each foot is adjusted to the weight of HOW MONEY ORIGINATED 455 the fly, just as the sticking or lifting power of the boy's sucker is regulated by the weight of the stone or other ob- ject he tries to pick up. If the weight of the object is sufficient to overcome the sticking power which the vacuum creates, the stone cannot be lifted. What Is Money? It is quite difficult to give a broad definition of money that will be under- stood by all, for in different ages and lands many things have been used as money besides the coins and bills which we think of only when we think at all what money is. Anything that passes freely from hand to hand in a com- munity in the payment of debts and for goods purchased, accepted freely by the person who oft'ers it without any refer- ence to the person who offers it, and which can be in turn used by the person accepting it to give to some one else in payment of debt or for the purchase of goods, is money. This is rather a long sentence and perhaps difficult to understand, and so we will try to ana- lyze what this means. If some one oi- fered you a pretty stone as money in payment of a debt, it would be as good as anv kind of money if you in turn could pass it on to any other person to whom you owed a debt or In payment of something you bought. The stone might appear to you to be valuable but it would not be good money unless you could count on every one else in the community accepting it at the same value. If everybody accepts it at the same value, it is as good as any kind of money. So that anything which is ac- ceptable to the people in any community as a unit of value to pay debts, is good money, provided everybody thinks so and accepts it that way. In this case, then any kind of substance might be- come money provided it was used and accepted by everyone. Why Do We Need Money? We need money for the sake of the convenience which it provides in mak- ing the exchange of one kind of wealtli for anotlicr and as a standard of value. When a community has adopted some- thing or anything which is regarded by all of the people as a standard of value, all of the difficulties of trading disap- pear. Who Originated Money? The earliest tribes of savages did not need money because no individual in the tribe owned anything personally. All the property of the tribe belonged to the tribe as a whole and not to any particular person. Later on, when dif- ferent groups of savages came into con- tact with each other, there arose the custom of bartering or exchanging things which one tribe possessed and which the other tribe wanted. In that way arose the business of trading or of what we call doing business, and soon the need of something by which to measure the values of different things arose. Some of the old Australian tribes had a tough green stone which was valuable for making hatchets. Mem- bers of another tribe would see some of this stone and notice what good hatchets could be made from it — better hatchets than they had been able to make. Nat- urally they wanted it so much that it became very valuable in their eyes and so they came wanting to buy green stones. But they had nothing like what we could call money today. They had, however, a good deal of red ochre in their lands which they used to paint their bodies. They got this red ochre out of the ground on their own lands just as the other tribe got green stones out of its ground, and those who owned the green stones which were good for making hatchets, wanted some red ochre very much, and so they traded green stones for red ochre. The green stones then took on a value in them- selves for making exchanges for vari- ous commodities, and before long be- came a kind of money inside and out- side the community so that when they wanted to obtain anything, the price was put by the merchant as so many green stones and he accepted these in payment for goods given in ex- change. Tie was willing to do this be- 456 WHY WE USE METALS FOR COINING cause he knew he could use them in making trades for almost anything he might want, provided he had enough of the green stones. So you see these green stones of the Australian tribe became a rudimentary kind of money, just because a desire had arisen to pos- sess them ; and the red ochre was actual money in the same sense, for when this tribe found that other tribes would value this red ochre, they began getting the things they wanted and paying for them in red ochre. But the "unrt of value" had to be developed to make a currency that was elastic. It required something that could be carried about easily — in fact it had to be something small enough so a number of units of value could be carried about w^ithoiit too much trouble. The Indians of British Columbia solved this difficulty of making an elastic currency by adopt- ing as a unit of value a haiqua shell which they wore in strings as orna- mental borders of their dresses — and one string of these shells was worth one beaver's skin. These shells then were real money and one of the earliest forms of it. The skins of animals were long used by savage tribes as money. The skins were valuable in trading and a man's fortune was reckoned by the number of skins he owned. As soon as the ani- mals became domesticated, how-ever, the whole animal replaced the skin as the unit of value. This change un- doubtedly came because a whole animal is more valuable than only its skin. The first skins obtainable however were worn by wild animals — the kind that the people could not deliver to someone else alive and whole. But when the animals became domesticated, which meant that man tamed them and kept them where he could control them at will, the skin and the wild animal ceased to be a unit of value because it was an uncertain kind of money. Among domestic ani- mals, oxen and sheep were the earliest forms of money — an ox was considered worth ten sheep. This idea of using cattle as money was used by many tribes in manv lands. We find traces of it in the laws of Iceland. The Latin word pecunia (pecus) shows that the earliest Roman money was composed of cattle. The English word fee indicates this also. The Irish law records show the same evidence of the use of cattle as money and within recent years the cattle still form the basis of the cur- rency of the Zulus and Kaffirs. When slavery became prominent many lands adopted the slaves as the unit of value. A man's wealth was reckoned by the number of slaves he owned. Then, when the practice of agricul- ture became more common, people used the products of the soil as money — maize, olive oil, cocoanuts, tea and corn — the latter is said to pass current as actual money in certain parts of Nor- way now. They used these products of the soil for money even in our own country. Our ancestors in Maryland and Virginia before the Revolutionary War, and even after, used tobacco as money. They passed laws making to- bacco money and paid the salaries of the government officials and collected all taxes in tobacco. Other early forms of money were or- naments and these serve the purpose of money among all uncivilized tribes. In India they used cowrie shells — a small yellowish-white shell with a fine gloss. The Fiji Islanders used whales' teeth ; some of the South Sea Island tribes used red feathers ; other nations used mineral products as money — such as salt in Abyssinia and Mexico. Up to this point we have talked about the things used as money from the standpoint of primitive forms of monev. Today the metals have practically driven all these other crude forms of money out. Metallic Forms of Money. The use of metals as money goes far back in the history of civilization but it has never been possible to trace the his- torical order of the adoption of the various metals for the purposes. Iron according to the statement of Aristotle was at one time extensively used as money. Copper, in conjunction with iron, was used in early times as money in China; and until comparatively a short time ago was used for the coins of smaller value in Japan. Iron spikes were used in Central Africa and nails in Scotland ; lead money is now used in Burmah. Copper has long been used as money. The early coins of England were made of tin. Finally, however, came silver and silver was the prin- cipal form of money up to a few years ago. It was the basis of Greek coins introduced at Rome in 269 B. C. Most of the money of Medieval times was composed of silver. The earliest traces of gold used as money is seen in pictures of ancient Egyptians "weighing in scales heaps of gold and silver rings." Why Do We Use Gold and Silver as Money Principally? There are a good many reasons why gold and silver have become almost uni- versal materials for use as money. Per- haps this will be better understood if these reasons are set down in order. 1st. It is necessary that the material out of which money is made should be valuable, but nothing was ever used as money that had not first become desir- able and, therefore, valuable as money. This is only one of the incidental rea- sons for taking gold and silver for coin- ing money. 2nd. To serve its purpose best, money should be easy to carry around — in other words, its value should be high in proportion to its weight. The absence of this quality made the early forms of money such as skins, corn, tobacco, etc., undesirable. It was difficult to carry very much money about. Imagine the skin of a sheep worth a dollar, say, and having to carry ten of them down to pay the grocer. To a certain extent this difficulty occurred with iron and copper money and in times when they used live cattle it was a pretty expensive job to pay your debts because, while the cattle could move, it was still expensive to drive them from place to place. A man who accepted a thousand cattle in payment had to go ro some expense in getting them home. Then it was expensive to have money when live cattle were used because the cattle, of course, had to be fed and from that point of view the poor man who had no money was better off than the rich man who had money. When cattle were used as money it cost a lot to keep it. Our kind of money doesn't eat any- thing in fact, if you put it in a savings bank, it will earn interest money for you. But when cattle were used as money it cost a great deal to keep them and so it was worse than not earning any interest. 3rd. Another quality that money should possess is divisibility without damage and also the quality of being united again. This quality is possessed by the metals in every sense because they can be fused, while skins and precious stones suffer in value greatly when they are divided. 4th. The material out of which money is made should be the same throughout in quality and weight so that one unit of money should be worth as much as any other unit. This could never be true of skins or cattle as the difference in the size of skins is very great sometimes, and a small skin from the same animal could not be worth as much as a large one, or a skin of an animal of inferior quality so valuable as a very fine one. 5th. Another quality which money should possess is durability. This re- quirement made it necessary to use something else besides animals or vege- table substances. Animals die and vegetables will not keep and so lose their value. Even iron is apt to rust and through that process lose more or less of its value. 6th. The materials out of which money is made should be easy to dis- tinguish and their value easy to deter- mine. For this reason such things as precious stones arc not good to use as mnncy because it takes an expert to 458 HOW THE NAME UNCLE SAM ORIGINATED determine their value and even they are not always certain to be correct. 7th. Then a very important quality that the material out of which money is made is tliat its value should be steady. The value of cattle varies very greatly and, in fact, most of the ma- terials out of which the first currencies were made were subject to quick change in value in a short time. The value of gold and silver does not change excepting at long intervals. Gold and silver are both durable and easily recog- nizable. They can be melted, divided and united. The same is true of other metallic substances, but iron as stated is subject to rust and its value is low; lead is too soft. Tin will break, and both of them and copper also are of low value. Gold and silver change only slowly in value when the change at all; they do not lose any of their value by age, rust or other cause ; they are hard metals and do not, therefore, wear. Their value in proportion to the bulk of the pieces used for money is so large that the money made from them can be carried without discomfort and it is almost impossible to imitate them. Who Made the First Cent? \'ermont was the first state to issue copper cents. In June, 1785, she granted the authority to Ruben Har- mon, Jr., to make money for the state for two years. In October of the same year, Connecticut granted the right to coin 10,000 pounds in copper cents, known as the Connecticut cent of 1785. Massachusetts, in 1786, established a mint and coined $60,000 in cents and half cents. In the same year, Xew Jersey granted the right to coin $10,000 at 15 coppers to the shilling. In 1781 the Continental Congress directed Rob- ert Morris to investigate the matter of governmental coinage. He proposed a standard based on the Spanish dollar, consisting of 100 units, each unit to be called a cent. His plan was rejected. In 1784, Jefferson proposed to Congress, that the smallest coin should be of copper, and that 200 of them should pass for one dollar. The plan was adopted, but in 1786, 100 was substi- tuted. In 1792 the coinage of copper cents, containing 264 grains, and half cents in proportion, was authorized ; their weight was subsequently reduced. In 1853 the nickel cent was substituted and the half cent discontinued, and in 1864 the bronze cent was introduced, weighing 48 grains and consisting of 95 per cent, of copper, and the remainder of tin and zinc. How Did the Name Uncle Sam Orig- inate ? The name Uncle Sam is a jocular name long in use for the Government of the United States. Shortly after the war of 1812 was de- clared, Elbert Anderson of New York State, who was a contractor for the army, went to Troy, New York, to pur- chase a quantity of provisions. At that place the provisions were inspected, the oi^cial inspectors being two brothers named Wilson — Ebenezer and Samuel. The latter w-as very popular among the men and was known as "Uncle Sam Wilson" and everybody called him that. The boxes in which the provisions were packed were stamped with four letters, E. A. for Elbert Anderson, and U. S. for United States. One of the men engaged in making the inspection asked another of the workmen who happened to be a jocular fellow, what the letters E. A. U. S. on the boxes stood for. He said in reply that he did not know but thought they probably meant Elbert Anderson and Uncle Sam Wilson, and that they had left off the W which would stand for Wilson. The sugges- tion caught on quickly and as such things often do, the joke spread rapidly so that everybody soon thought of the name "Uncle Sam" whenever they saw the letters U. S. on anything or in any place. The suit of striped trousers and long tailed coat and beaver hat in w^hich Uncle Sam is now always represented in pictures, was the inspiration of the famous cartoonist. THE WORLD'S BREAD LOAVES 459 Egypt 2500 B.C. Unleavened Bread 2000 B.C. Pompeii 50 AD. Palestine "%'lA -3 Endland Modern American Loaf m' '"•"'^^iJiiMiii^S^ Endland .^^'rs Austria Germany Balkan States 460 WHERE BREAD COMES FROM a. I ,,^ m .^ ^MM ai 1^ , '1 --^.^^ ^J^H HARVESTING WHEAT. The Story in a Loaf of Bread Why is Bread so Important? The history of bread as a food reads like a romance. It has played an im- portant part in the destinies of man- kind and its struggles through the ages to perfection. The progress of nations through their different periods of development can be traced by the quality and quantity of bread they have used. No other food has taken such an im- portant part in the civilization of man. To a large extent it has been the means of changing his habits from those of a savage to those of a civilized being. It has supplied the peaceful pursuits of agriculture and turned him from war and the chase. It is an interesting fact that the civilized and the semi-ci\'ilized people of the earth can be di\4ded into two classes, based upon their principal cereal foods: the rice eaters and the bread eaters. Even,' one admits that rice eaters are less progressive, while bread eaters have always been the leaders of civili- zation. It is an interesting fact that just as Japan is changing from a rice-eating nation to a bread-eating nation she is asserting her power. Any one who stops to consider the history of nations will see that this matter of what we eat is the one ques- tion of vital importance. Bread is one of the earliest, the most generally used and one of the most important foods used by man. With- out bread the world would not exist without great hardship. On bread alone a nation of people can exist, and to sit down to a meal without it causes us to feel at once that something is missing. What Was the Origin and Meaning of Bread ? Bread is baked from many substances, although when we think of bread, we usuallv think of wheat bread. It THE DIFFERENCE IN GRAHAM AND WHOLE WHEAT BREAD 461 is sometimes made from roots, fruits and the bark of trees, but generally only from grains such as wheat, rye, com, etc. The word bread comes from an old word hray, meaning to pound. This came from the method used in preparing the food. Food which was pounded was said to be brayed and later this spelling was changed to bread. Properly speaking, however, these brayed or ground materials are not really bread in our sense of using the term tmtil they are moistened mth water, when it becomes dough. The word dough is an old one meaning to " moisten." This dough was in olden times immediately baked in hot ashes and a hard indigestible limip of bread was the resiilt. Accidentally it was discovered that if the dough was left for a time before baking, allowing it to ferment, it would when mixed with more dough, swell up and become porous. Thus we got our word loaf from an old word lifian, which meant to raise up or to lift up. When Was Wheat First Used in Mak- ing Bread? It is not clearly known when or by whom wheat was discovered, but it seems to have been known from the earliest times. It is mentioned in the Bible, can be traced to ancient Egypt and there are records showing that the Chinese cultivated wheat as early as 2700 B.C. To-day it .supplies the principal article for making bread to all the civilized nations of the world. The origin of the wheat plant is said to have been a kind of grass which is given a Latin name Mgilops ovata by the botanists. Will Wheat Grow Wild? This is a question that has puzzled the world's scientists for more than two thousand years. From time to time it has been reported by investiga- tors in various parts of the world that here and there wheat has been found growing wild and doing well, but every time a further investigation is made. it develops that the wheat has been cultivated by some one. There is as yet no evidence for believing that wheat will grow in a wild state. What is the Difference between Gra- ham Flour and Whole Wheat? Graham flour from which Graham bread is baked is made from unbolted flour. The process of bolting flour, which is described in one of the fol- lowing pages, consists briefly in taking out of it all but the inside of the grain of wheat. When this has been done, we have pure white flour. In making Graham flour ever>^ part of the grain of wheat is left in the flour, and ground up flnely. Many people think that Graham flour is made from a special grain called Graham, but this is not true. It is said that Graham bread is not so good for j^ou because it contains the outside covering of the wheat grain or bran which is composed of almost pure silica, the same substance of which glass is made, and cannot therefore be good for us. Whole wheat flour is made from the whole grain of wheat from which the outside covering or bran has been separated. It contains everything but the bran and is therefore the most nutritious flour made. The grain of wheat has several coverings of bran coats, the outer one of which is the one composed of silica, and which is not valuable as food. Underneath this husk - are found the inner bran coats, which contain the gluten. Gluten is a dark substance containing the flesh-fonning or nitrog- enous elements, which are valuable in muscle building. The inside or heart of the grain of wheat consists of cells filled with starch, a fine white mealy powder which has little value as food, but is a great heat producer. Sometimes in making whole wheat flour, the heart of the grain is also removed, making a pure gluten flour. The name whole wheat for flour is not accurate, therefore, for Graham flour is made of the whole wheat grain, while " whole wheat " flour is made of only certain parts of the grain of wheat. 462 HOW FLOUR IS MADE Wheat conditioners for tempering the wheat before being ground by the corrugated roller mills. How is Flour Made? In threat factories the raw material is frequently taken in at one end and comes out of the opposite end as a finished locomotive, a Pullman palace car, or a pair of shoes. There is no such progression in making flour. The wheat comes in at one place as a plain Spring or Winter wheat and at another goes out as flour, but in the process parts of it may go from top to bottom of the big mill 30 times. Instead of a factory where everything moves along from hand to hand or machine to machine, the flour mill is like a human body — a huge framework like the bones, with thousands of carrying devices, " eleva- SEPARATING THE WHEAT FIBER AND GERMS 463 Purifier for separating the fiber, germ, and other impurities from the semolina (grits) before it is finally crushed or ground into flour by smooth roller mills. tors," " spouts " and " conveyors," like the veins and arteries of the blood- carrying system. Stop up a vein of wheat, the mill becomes clogged, and finally must shut down if it cannot be mechanically relieved. It is an intricate and intensely interesting process, the result of year-to-year experience. Scouring that Suggests a Dutch Kitchen. From the storage bins the wheat is drawn off through conveyors to the first of several cleaning processes, the " separators," where the coarse grain which naturally comes with the wheat, such as com and oats, and imperfect kernels of wheat, is taken out. After this general cleaning the grain goes to the " scouring machine," which is an interesting device — a rapidly revolving cylinder with what are called " beaters " attached. The grain is thrown against perforated iron screens Any clinging dirt is loosened, and a strong current of air passing through the cylinder is constantly " calling for dust," as the miller aptly expresses it, and carries the impurities away as dust and dirt. Indeed, the cleaning process seems to be a constant one from the time the wheat enters the mill until the flour is made. Having been cleansed, the wheat is now ready for the rolls except for a " tempering " process, which is to prepare the grain, so that the out- side of the wheat may be taken off without injury to the inside or kernel. Then as the grain i)asscs to the rolls there begins a gradual reduction of wheat to flour which is most intricate. The first sets of rolls arc corrugated and so adjusted as to " break " each grain of wheat into 12 to 15 parts. The "breaking" process goes on through five different sets of rolls. 464 GRINDING THE WHEAT FOR MAKING FLOUR Corrugated roller mills for grinding the wheat after it has been cleaned. Wooden spouts for conveying the difTerent products, bran and partly ground wheat, from one machine to another. THE FLOUR IS READY FOR BAKING 465 Gyrating sifter for separating the bran particles from the flour and semolina. The Big Bolters with Silken Sieves. Closely allied with the rolling process is the bolting process, which, working hand in hand with it has made modern flour making so perfect. The bolting process consists of a series of sieves — a sifting of the broken grain so that it is finally, after repeated breaking and sifting, a flour. The bolter machine contains a number of sieves covered with silk bolting cloth with varying mesh or number of threads to the square inch. This bolting machine, moving rapidly, makes from 8 to lo different separations of the material. From rolls to bolters, from bolters to Ijurifiers, from purifiers to rolls, over and over, the process continues, until five different grades of " middlings " have been selected by the mechanical hands of the millers. The purifier is still another step to the process. It is a machine having eight sieves of different mesh. The " middlings " flow down over the different sieves in a thin sheet, a current of air meantime drawing all impurities out. With this purifying process completed, the mate- rial is ready for the smooth rolls. The Mill Tries to Catch Up with the Bins. When the flour is made it is conveyed to large round bins — five sheets of hard wood pressed together. These bins are being filled all the time and being emptied all the time, the mill being about seven hours behind the capacity of the bins, so that from start to finish the modem flour mill is a tremendously busy place. Underneath the bins and connecting with them arc the flour packers — automatic devices which pack a 2>h- -pound paper sack as accurately as a 196-pound barrel. The filled i)ackages are sent down " chutes " to the shijj- ping floor. There they go to wagons or through other chutes to boats. 466 WHERE LEAD PENCILS COME FROM The Story in a Lead Pencil Why Do They Call Them Lead-pencils? The lead-pencil so generally used to- day is not, as its name would imply, made from lead, but from graphite. It derives its name from the fact that prior to the time when pencils were made from graphite, metallic lead was employed for the purpose. Graphite was first used in pencils after the dis- covery in 1565 of the famous Cumber- land mine in England. This graphite was of remarkable purity and could be used without further treatment by cutting it into thin slabs and encasing them in wood. Who Made the First Lead-pencils in America ? For two centuries England enjoyed practically a monopoly of the lead-pen- cil industry. In the eighteenth cen- tury, however, the lead-pencil industry had found its way into Germany. In 1761, Caspar Faber, in the village of Stein, near the ancient city of Nurem- berg, Bavaria, started in a modest way the manufacture of lead-pencils, and Nuremberg became and remained the center of the lead-pencil industry for more than a century. For five generations Faber's descendants made lead-pencils. Up to the present day they have continued to devote their in- terest and energy to the devlopment and perfection of pencil making. Eber- hard Faber, a great-grandson of Cas- ])ar Faber, immigrated to this country, and, in 1849, estabhshed himself in New York City. In 1861, when the war tariff first went into effect, he erected his own pencil factory in New York City, and thus became the pio- neer of the lead-pencil industry in this country. Since then four other firms have established pencil factories here. Wages, as compared to those paid in Germany, were very high, and Eber- hard Faber realized the necessity of creating labor-saving machinery to overcome this handicap. Many auto- matic machines were invented which greatly simplified the methods of pen- cil making and improved the product. To-day American manufacturers sup- ply nine-tenths of the liome demand and have largely entered into the com- petition of the world's markets. What Are Lead-pencils Made of? The principal raw materials that enter into the making of a lead-pencil * Courtesy of The Scientific American. 1 ■1 1 I 1 M 1 ■'/■j^ i ! 1 1- T ■ : • ■ k \ 1 ffl *9H^^I li li 1 FIG. I. FIG. 2. FIG. 3. Fig. I shows the shape in which the cedar slats arrive at the factory. These slats after grading are boiled in steam to remove what remaining sap there may be in the wood. The slats are then dried in steam-drying rooms. Then the next step is grooving and gives the results shown by Fig. 2. Now the wood is ready to receive the "leads" (which you will remember are a mixture of graphite and clay), which are placed between two slats sandwich fashion, glued, put in forms that hold them over night under a thousand pounds pressure. Fig. 3 shows the leads laid in one of the grooved slats. are graphite, clay, cedar and rubber. Although graphite occurs in com- paratively abundant quantities in many localities, it is rarely of sufficient pur- ity to be available for pencil making. Oxides of iron, silicates and other im- purities are found in the ore, all of which must be carefully separated to insure a smooth, serviceable material. The graphites found in Eastern Si- beria, Mexico, Bohemia and Ceylon are principally used by manufacturers. How Are Lead-pencils Made? The graphite, as it comes from the mines, is broken into small pieces, the impure particles being separated by hand. It is then finely divided in large pulverizers and placed in tubs of water, so that the lighter particles of graphite float off from the heavier par- ticles of impurities. This separating, in the cheaper grades, is also done by means of centrifugal machines, but the results arc not as satisfactory. After separation, the graphite is filtered through fdter-presses. What Makes Some Pencils Hard and Others Soft? The clay, after having been sub- jected to a similar process, is placed Pictures by courtesy Joseph Dixon Crucible Co. 468 WHAT MAKES SOME PENCILS SOFT AND OTHERS HARD FIG. 4. FIG. 5. Fig. 4 shows a prospective view of the block as it appears when taken out of the form; the leads can be seen in the end. These blocks are fed to machines which cut out tile pencils in one operation. An idea of this operation is given by Fig. 5, which shows a block half cut through. The pencils come out quite smooth, but are sand- papered to a finer finish before receiving the tinishing coats. The finer grades of pencils are given from seven to nine coats of varnish before being passed along for the next process. Fig. 6 shews a pencil after it has been machined and before it has been varnished and stamped. in mixers with the graphite, in propor- tions dependent upon the grade of hardness that is desired. A greater proportion of clay produces a greater degree of hardness; a lesser propor- tion increases the softness. Furthermore, the requisite degree of hardness is obtained by the subsequent operation, viz., the compressing of the lead and shaping it" into form ready to be glued into the wood casings. A highly compressed lead will produce a pencil of greater wearing qualities, an important feature in a high-grade pen- cil. Hydraulic presses are used for this purpose; and the mixture of clay and graphite, which is still in a plastic condition and has been formed into loaves, is placed into these presses. The presses are provided with a die con- forming to the caliber of the lead de- sired, through which die the material is forced. The die is usually cut from a sapphire or emerald or other very hard mineral substance, so that it will not wear away too quickly from the fric- tion of the lead. The lead leaves the press in one continuous string, which is cut into the lengths required (usually seven inches for the ordinary size of pencil), is placed in crucibles, and fired in muffle furnaces. The lead is now ready for use, and receives only a wooden case to convert it into a pencil. HOW THE ERASER IS PUT ON A PENCIL 469 Where Does the Wooden Part of a Lead-pencil Come from? The wood used in pencil making must be close and straight grained, soft, so that it can readily be whittled, and capable of taking a good polish. No better wood has been found than the red cedar, a native of the United States, a durable, compact and fra- grant wood to-day almost exclusively used by pencil makers the world over. The best quality is obtained from the Southern States, Florida and Alabama in particular. The wood is cut into slats about 7 inches long, 2^ inches wide, and ^ inch thick. It is then thoroughly dried in kilns to separate the excess of moist- ure and resin and to prevent subse- quent warping. After this the slats are passed through automatic grooving machines, each slat receiving six semi- circular grooves, into which the leads are placed, while a second slab with similar grooves is brushed with glue and covered over the slat containing the leads. This is passed through a molding-machine, which turns out pen- cils shaped in the form desired, round, hexagon, etc. The pencils are now passed through sanding machines, to provide them with a smooth surface. How is the Color Put on the Outside of the Pencil? After sand-papering, which is a necessary preliminary to the coloring process, when fane finishes are desired, the pencils are varnished by one of sev- eral methods. That most commonly employed is the mechanical method by which the pencils are fed from hop- pers one at a time through small aper- tures just large enough to admit the pencil. The varnish is applied to the pencil automatically while passing through, and the pencils are then de- posited on a long belt or drying pan. They are carried slowly a distance of about twenty feet, the varnish de- posited on the pencils meanwhile dry- ing, and are emptied into a receptacle. When sufficient pencils have accumu- lated, they are taken back to the hop- per of the machine and the operation repeated. This is done as often as is necessary to produce the desired fin- ish. The better grades are passed through ten times or more. Another method is that of dipping in pans of varnish, the pencils being suspended by their ends from frames, immersed their entire length and withdrawn very slowly by machine. A smooth enam- eled effect is the result. The finest grades of pencils are polished by hand. This work requires considerable deft- ness ; months of practice are necessary to develop a skilled workman. After being varnished, the pencils are passed through machines by which the accu- mulation of varnish is sand-papered from their ends. The ends are then trimmed by very sharp knives to give them a clean, finished appearance. Stamping is the next operation. The gold or silver leaf is cut into narrow strips and laid on the pencil, where- upon the pencil is placed in a stamping press, and the heated steel die brought in contact with the leaf, causing the latter to adhere to the pencil where the letters of the die touch. The sur- plus leaf is removed, and, after a final cleaning the pencil is ready to be boxed, unless it is to be further em- bellished by the addition of a metal tip and rubber, or other attachment. How is the Eraser Put On a Pencil? In this country about nine-tenths of the pencils are provided with rubber erasers. These are either glued into the wood with the lead, or the pencils are provided with small metal ferrules threaded on one end, into which the rubber eraser-plugs are inserted. These ferrules are made from sheet brass, which is cuj)ped by means of power presses, drawn through subsequent op- erations into tubes of four- or five- inch lengths, cut to the required size, threaded and nickel-plated. 470 WHERE COTTON COMES FROM Courtesy of Doubleday. Page & Co. A SOUTHERN COTTON FIELD The Story in a Bale of Cotton Where Does Cotton Come From? We get cotton from a plant ^vhich grows best in the warm climate of our Southern States. Cotton has been known to the people of the world for a long time. Before the birth of Christ people knew about cotton. They thought it was wool which grew on a tree instead of a sheep's back. No other plant is of such value to man as cotton. We should learn something about a plant that is used by man in so many ways as cotton. ' The cotton plant of our Southern States is a small shrub-like annual about four feet high. The flowers of the cotton plant are white at first but change to cream color and then are tinged with red. This change takes place over a period of four days when the petals drop off and leave what is called a "boll" in the calyx of the flower. This boll, which is to contain the cotton, is really the seed container of the cotton plant and keeps on grow- ing larger until it is about as big as a hen's egg. When it is fully grown or ripe the boll cracks and the seeds and fibrous lint burst forth. The bolls are then gathered and taken to a cot- ton gin, where the seeds are separated from the lint and the Hnt prepared for weaving. The boll is divided into from three to five sections. Each section contains a quantity of Hnt and seeds. When the boll is fully grown the covering of each of the sections cracks and opens up, revealing the contents. It is just like opening the door of each section and having the contents burst out. When these bolls burst open, there is no more beautiful sight in the world than to look out over a cotton field and see the colored people — the "cot- ton pickers" — busy at their work pick- ing oft' the bolls. ^Mien the crop is gathered and ginned, the lint is packed into bales and taken to the cotton mill, where it is made into cloth. One of the most in- teresting industrial processes in the world is to see the bale of cotton go into a cotton mill and come out a piece o^ cotton goods. THE COTTON ARRIVES AT THE MILL 471 BALES OF COTTON AT LiilluN MILL OPENING MACHINES. The bales are opened, and the cotton is thrown into the large hoppers at the front of these machines, which open and loosen the fibers, work ont Inmps and remove the grosser impurities, such as dirt, leaf, seed and trash. A strong air draft carries off the dust and foreign particles, and lifts the cotton through trunks to the floor above. LAPPER MACHINES. In these machines, known as P>reaker and Finisher Lappers, more of the trash and impurities is beaten out of the cotton, and the lint is carried forward and wound into rolls of cotton bat- ting, known as laps. Several of these are doubled and flrawn into one so as to get the weight of each yard as uniform as possible. 472 FIRST STEPS IN MAKING COTTON CLOTH CARD ROOM. In tlicsc machines, known as Revolving l-"lat Top Cards, the cotton passes over revolving cyl- inders clothed with wire teeth, and the ril)crs are comhed out and laid parallel with each other. They are delivered at the front of the machine as a filmy web, which is gathered together and formed into a soft downy ribbon or rope, known as card sliver. This is automatically coiled and delivered into cans. PRAWIXG FRAMES. To insure uniformity in weight, so that the yarn when spun shall run even, the card slivers are doubled and drawn out, redoubled and again drawn out, somewhat in the manner of a candy maker pulling taffy, only here the process is continuous. Six strands of the card sliver are fed in together at the back of the drawing frames, pulled out and delivered as one ; and the process repeated. This produces a sliver more uniform in weight, and in which the fibres are more parallel. SLUBBERS. The sliver from the drawing frames is taken to machines called slubbers, where again the fibers are drawn out, and the strand of cotton, now much finer and known as slubber roving, is given a bit of twist to hold it together, and is wound on large bobbins. PUTTING THE COTTON FIBER ON BOBBINS 473 , •? ^ O 3 (U"tl •s 2 tn O "3 IJ ^ dJ <_, ui O . ,, <« u rt n •- h:£ c c - w ound of cotton yarn should make y/2 yards of sheeting, or 3-)4 yards of muslin, or 9/^ yards of lawn, or 7/^ yards of calico, or 53^ yards of gingham, or 57 spools of thread. 478 HOW THE MUSIC GETS INTO THE PIANO Picture by courtesy Browne & Howell Co. CHRISTOFORI PIANO FROM THE METROPOLITAN MUSEUM OF ART, NEW YORK CITY. The Story in a Piano What is Music? Music is one kind of sound. All sounds, whether musical or not, are the result of sound waves in the air. They travel almost exactly like the waves of the water. They go in circles in all directions at the same speed and will go on forever unless they meet something that has the ability to stop them. If you drop a pebble into the exact center of a basin of water, you will see the ring of waves produced start from the point where the ]')ebble entered the water and travel to the sides of the vessel, which stop them. Also the pebble as it falls into the water will make ring after ring of waves. When you shout or ring or strike one of the keys of the piano you start a sound wave or a series of them, which you can hear as soon as the sound wave strikes your ear. When the series of waves is regular the sound produced is a musical sound, and when the sound waves are not regular in length we call it some other kind of a sound. Acting on the knowledge so learned, man has devised numerous instruments with which he can produce musical sounds, such as the piano, phonograph, and many others. Who Made the First Piano? The first real piano was made by Bartolomeo Christofori, an Italian. He invented the little hammers by the aid of which the strings are struck, giving a clear tone instead of the scratching sound which all the previous instruments produced. It took two thousand years to discover the value of the little hammers in making clearer notes. His first piano was made in 1709. The word by which we call the instrument pianoforte has, however, been traced back as far as 1598, when it is said to have been originated by an Italian named Paliarino. The first piano made in America was produced by John Behnud, in Philadelphia, in 1775- How Was the Piano Discovered? The piano is a stringed musical in- strument. The name pianoforte comes from two Italian words meaning soft and loud, and is accurately descriptive of the piano because the notes can at will be made soft or loud. The piano is a development of the simplest form of making regular sound vibrations by snapping or hammering a string of some kind which is stretched tight and fastened at both ends. We must go far back into history to find the earliest traces of stringed instruments, and even then we do not know where and when they originated, for there seem to be no records which help us to trace their origin. We know that the Eg}^ptians as far back as 525 B.C. had stringed instruments, but we only know they had them — not where they got them or who made them. There is a legend that the Roman god Mercury, while walking along the Nile after the river had overflowed its banks and the land had again become dry, stubbed his toe on the shell of a dead tortoise. He picked it up to cast it aside and acci- dentally touched some strings of sinew with his finger. These strings were only what remained of the once live tortoise. At the same time Alercury heard a musical note and, after vainly trying to find a cause for the musical sound, twanged the string again and discovered the music in tightly- stretched strings. He set about mak- ing an instrument, using the tortoise shell for the sound box and stretching a number of strings of sinew across it. This is only a legend, of course, but if we examine the early musical instru- ments of the Greeks, which was the lyre, we always find the representation of a tortoise upon it. Other nations, such as the early Chinese, the Persians, the Hindus and the Hebrews, had stringed instruments much resembling the lyre. In the tombs of the great rulers of Egypt are found representations of harps, and one harp which had been buried in one of the tombs for more than 3000 years was actually found to be in good con- dition. Wherever we search among the rec- ords of early nations we find evidence that they were familiar Avith the music obtainable from playing upon stringed instruments, but we have never been Picture by courtesy IJrowne & Howell Co. DULCIMER. 480 THE FIRST STRiNGHD MUSICAL INSTRUMENT able to discover what people or what persons first learned that music could be produced with such instruments. The harp was probably the first practical stringed instrument. Its music was produced by picking the strings with the fingers or with a piece of bone or metal. The next step was the ])saltery, which was produced in the ^Middle Ages. It was a box with strings stretched across it and represented the first crude attempt at using a sounding board. A larger instrument which came about the same time and was very like wliich picked the strings. The elder ]:>ach composed his music on the clavi- chord, his favorite instrument, and that is why the music written by Bach is full of soft and melancholy notes. The clavichord produced only such notes. The next steps brought the virginal, spinet and harpsichord. The strings on all three were of brass with (luills at the key ends for picking the strings. The virginal and spinet were very much alike. The harpsichord was larger and sometimes was made with two keyboards. These instruments had notes covering four octaves only. Picture by courtesy Browne & Howell Co. CLAVICHORD. the psaltery, was the dulcimer. Both were played by picking the strings with the finger or a small piece of bone or other substance. Then came the keyboard, first used on stringed instruments in what is called the clavicytheriiim. This con- sisted of a box with cat-gut strings ranged in a semitriangle. On the end of each key was a quill, which picked the string when the key was operated. After this came the clavichord. It was built like a small square piano without legs. The strings were made of brass and on the end of each key was a wedge-shaped piece of brass The arrangement of the strings in the harpsichord provided one stej) nearer to our piano. It had five oc- taves of notes and there were at least two strings to each note instead of only one, as in previous instruments. Why Do We Have Only Seven Octaves On a Piano? Why Not Twelve or More Octaves? Ordinarily the longest key-board of the piano has seven octaves and three notes in addition, or 52 notes, not counting the sharps and flats. An oc- tave you, of course, know consists of the seven notes C D E F G A B. WHY OUR PIANO HAS ONLY SEVEN OCTAVES 481 Picture by courtesy Browne & Howell Co. SPINET. Every eighth note is a repetition of the one seven notes below or above. The reason that there are no more notes or octaves on the piano is that if we extended the key-board either way one or two octaves more, we shonld not be al)le to hear the notes strnck on the keys. There would be sound produced, or course, but the vibrations would be too fine for the human ear to hear. It is said that the range, of the human ear does not go beyond somewhere be- tween eleven and twelve octaves. Picture by courtesy Browne S: Howell Co. UPRIGHT HARPSICHORD. (From the Metropolitan Museum of Art, New York City.) 7. 1 P'^i^^^,^^.::.^^ . ^» Picture by courtesy Browne & Howell Cc QUEEN Elizabeth's virginal. 482 HOW THE MUSIC GETS INTO THE PIANO Photo by Kohlcr & Campbell Piano Co. PUTTING ON THE SOUNDING BOARD. The nist operation in producing the piano is to make a wooden frame or back on which is attached first the sounding board, then the iron, harp-shaped frame to which the strings are fastened. i he tones of the piano are produced by felt-covered hammers striking the strings. The sounding board, which is made of wood, magnities the tones. riiis picture shows the mechanics glueing the sounding board to the back. Photo by Kohler & Campbell I'iano Co. FASTENING THE STRINGS. The strings are hitched on to pins in the iron frame at its lower end and fastened at the upper end by a rnetal pin or peg driven into the back. The peg is square on top, so that it can be turned with a tuning hammer or wrench in order to tighten or slacken the strings, which is the operation of tuning the piano. THE LITTLE HAMMERS WHICH STRIKE THE PIANO STRINGS 483 to by Kohler &. Campbell Piano Co. BUILDING THE CASE AROUND THE SOUNDING BOARD. As soon as the sounding board with its iron frame and strings is complete, the outside case is built up around it, the front being left open to receive the action and key-board. C aiii|>..i.il I'lano Co. ATTACHING THE LITTLE HAMMERS THAT STRIKE THE STRINGS. Ill this picture the workmen are placinjj the action and keys, to which are attached the little wooden felt-covered hammers, which will strike the strings and produce the tones. It took a great many years for our musical instrument makers to hit upon the idea of using these little hammers, and thus make the piano a perfect instrument. 48-4 RI£QULATINCj the ACTION OF THl: PIANO I'hulo by Kohler & Campbell I'iano Co. REGULATING THE ACTION AND KEYBOARD. This picture shows the piano partly assembled and the workmen adjusting each little black and white key to the proper touch. ino Co. ruLISHING AND FINISHING. The piano is now complete except for polishing and tuning. The tuning is left to the last. The tuner must have a good ear for music. With his key he tightens or loosens each of the pegs to which the wires are attached until it is perfectly in tune and all in harmony. The piano is now ready to play upon. How Sounds Are Produced. If you look closely at a tuning fork, or a piano string, while it is sounding, you can see that it is swinging rapidly to and fro, or vibrating. Touch it with your finger and thus stop its vibration and it no longer produces sound. The only difference that you can discover in the fork or string when sounding and when silent is that when you stop the motion it is silent and when it vi- brates it makes a sound. From this we learn that the sounds are due to the vi- brations of sounding bodies. This has been proven by the examination of so many sounding bodies that we believe that all sounds are produced by vibra- tions. The question that next presents it- self is, how the vibrations affect our ears, so as to produce the sensation of hearing. This may be made clear by a very simple, but striking, experiment. If a bell w^hich has been arranged to be rung by clock-work is suspended under the receiver of an air pump, and the air pumped out, the sound of the bell will grow faint as the quantity of air in the receiver decreases, and finally will stop completely. By look- ing through the glass of the receiver, however, the bell may be seen ringing as vigorously as at first. We learn thus that the air around a sounding body plays an important part in the trans- mission of the vibrations to our ears. The way in which the air acts in trans- mitting the vibrations is as follows. At each vibration of the sounding body, it compresses, to a certain degree, a layer of air in front of it. This layer, how- ever, does not remain compressed, for riir is very elastic, and the compressed air soon expands, and in doing so com- jjrcsses a layer of air just beyond it. This layer expands in its turn, and com- ])rcsses another layer still further from the body. In this way waves of com])res- sion are sent through the air, at each vibration, in all directions from the vi- brating body. It must not be thought that particles of air travel all the way from the vibrat- ing body to the ear when a sound is heard. Each particle of air travels a very short distance, never any further than the vibrating body moves in mak- ing a vibration, and the movement of the air particles is a vibratory one, like that of the sounding body. But the par- ticles of air near the sounding body communicate their vibrations to other particles, further from that body, and these, in turn, to others still further away, so, while the particles of air themselves move very short distances, the waves produced by their vibrations may be made to travel a considerable distance. The size of a sound wave ordinarily is very small, but sound waves are sometimes made of such size and strength as to strike our ears with a force sufficient to rupture the ear drum. Such large and forceful waves come during explosions, such as the dis- charges of cannon or the explosions of large quantities of gunpowder under any conditions. What Is Sound? From what has already been said, you will probably answer that sounds are waves in the air, which produce the sensation of hearing. This is cor- rect, but sound is not limited to vibra- tions of the air. Other elastic sub- stances can be made to vibrate in the same way, and iihe waves so produced when conveyed to our ears, produce the sensation of hearing. If you put your ear under water and then strike two stones together in the water you will hear a sound as readily as you would in air. .Sound waves may be transmitted by solid bodies also, and some of these are better for this purpose than air or liquids. Perhaj^s you have tried the experiment of placing your ear against one of the steel rails on a railroad track to listen for the coming of a distant train. If you have tried this, you know that a soimd that is too faint, or is made too far away, to be heard through the air, can ca.sily be heard through the rail. In view of the fact that other sub- stances th.'in air can be thrown into waves that will afifect the sense of hear- ing, we may define sound as vibrations in any elastic object, that produces the sensation of hearing. The definition is sometimes called the physical definition of sound, in contra- distinction to the physiological definition of sound which is given as the sensa- tion produced when vibrations in elas- tic substances are conveyed to our ears. You will see then that sound when re- ferring to the physical definition is what makes sound known in the phys- iological definition. The term sound alone, without qualifications, may have either meaning, and therefore state- ments concerning sound may be mis- leading, unless we are exact in explain- ing the sense in which the word is used. Hovsr Fast Does Sound Travel? When a sound is made close to us, it reaches our ears so quickly that it seems as though it took no time to travel ; but when a gun is fired by a person at a distance, you will notice that after you see the flash of the gim, a little time elapses before the sound reaches your ear. It takes a little time for the light from the flash to get to your eyes, but a very short time, which you cannot appreciate. Sound travels much more slowly and the time it takes to travel a few hundred yards is no- ticeable. Accurate measurements of the speed of sound have been made, and it has been found that sound usually travels in air at a speed of about eleven hundred feet a second. The speed is not always the same, however, for a number of circumstances may cause it to vary. In air which is heated, the speed at which sound travels in it is increased because hot air expands. At the freezing point, sound travels through the air at the rate of 1,091 feet a second, and for every increase in tem- perature of one degree of heat, the speed is increased about thirteen inches a second. Accordingly at 68° F. the speed would be approximately 1,130 feet a second. Sounds also travel faster in moist air than in dry. In other gases the speed of sound transmission may be greater or less than in air. I'^or example, in hydrogen gas, which is much lighter than air, sound travels nearly four times as fast as it does in air. On the other hand, in car- bonic acid gas, which is heavier than air, sound is transmitted more slowly. In liquids, which are always heavier than air, you would naturally think that sound would travel more slowly than in air, but this is not true. Liquids are less compressible than gases and this causes the speed with which sound is transmitted in them to be increased. In water sound travels about four times as fast as in air. What Are the Properties of Sound? Sounds dififer from each other by the extent to which they possess three qual- ities, namely ; intensity, pitch and qual- ity. The intensity of any sound that we hear depends upon the size of the waves that reach our ears. The size of a sound wave gradually decreases, as the wave travels from its starting point, consequently the intensity of a sound depends upon the distance from the point at which the sound was produced. We know this from experience and if we think of the matter for a moment we will see why it is so. At the start of a sound wave, only a small quantity of air is afifected, but for every inch it travels the quantity of air to which the wave is conveyed becomes larger, and the intensity of the waves must grow correspondingly smaller, just as when a pebble is dropped into water, the ripples produced by it are highest at the point where the pebble struck the water, and grows lower and lower as their circle widens. It has been found possible to meas- ure the intensity of a sound wave, at different distances from the point from which it started, and from these meas- urements it has been learned that the decrease in the open air, follows a fixed rule that is stated thus : the intensity of a sound wave at any point is in- versely proportional to the square of its WHY WE CAN HEAR THROUGH SPEAKING TUBES 487 distance from its starting point. This rule is called "the law of inverse square," and it means that if the inten- sity of a wave be measured at two points, distant say one hundred, and two hundred yards, respectively, from the starting point of the sound, the intensity of the sound at the first point will be found to be four times as great as at the second point. Why Can You Hear More Easily Through a Speaking Tube? We have seen that the decrease in intensity of a sound wave as it travels through the air, is due to the fact that the quantity of air set in motion by it is constantly increasing. But, if a wave is conveyed through a tube containing air, the quantity of air to which the vi- brations are communicated does not in- crease as the wave travels forward, and theoretically there is no decrease in in- tensity. W^hen a wave is actually trans- mitted in this way, however, it is found that there is some decrease in intensity on account of the friction of the par- ticles of air against the sides of the tube ; but the decrease from this cause is much slower than that which occurs in the open air, and consequently sounds can be heard at much greater distances through tubes than through the open air. Tubes for speaking pur- poses are frequently used to connect different parts of the same building, and if the tubes are not too crooked they serve their purpose very well. Pitch is that property of sounds that determines whether they are high or low. The pitch of a sound depends upon the number of vibrations a sec- ond which the body that produces it makes. The sound of an explosion has no pitch because it makes but one wave in the air. The sound made by a wagon on a pavement has no definite pitch, for it is a mixture of sounds, in which the number of vibrations per second is not the same. Pitch is a property of continuous sounds only, and it is ap- parent chiefly in musical sounds, by which we mean sounds in which the vi- brations are continuous and regular. In music, however, pitch is very im- portant. In a musical instrument, the parts are so arranged that the sounds produced can be given any desired pitch, and it is by controlling the pitch that the pleasing effect of musical sounds in large measure is produced Sounds of low pitch are produced by bodies making but a few vibrations a second while high-pitched sounds are made by bodies that vibrate rapidly. Quality, may be defined as that prop- erty of sounds which enable us to dis- tinguish the notes produced by differ- ent instruments. Two notes, one of which is produced upon a piano, and the other upon a violin, may have the same pitch and be equally loud, yet they are easily distinguishable. The difference in them is due to the presence of what are called overtones. What Is Meant By the Length of Sound Waves ? The length of a sound wave em- braces the distance from the point of greatest compression in one wave to the same point in the next. This depends upon the pitch for if a sounding body is making one 'hundred vibrations a sec- ond, by the time the one hundredth vi- bration is made, the wave from the first vibration will have travelled about eleven hundred feet from the starting point, and the remaining ninety-eight waves will lie between the first and the one hundredth. In consequence of this, the wave length for that 'particivlar sound will be about eleven feet. If the sounding body had made eleven hun- dred vibrations a second by the time the first wave had travelled eleven hun- dred feet, there would have been eleven hundred waves produced, and the wave length for that sound woud be one foot. The wave lengths of sounds i)ro(luced by the human voice usually lay between one and eight feet, though some singers have produced notes having wave lengths as great as eighteen feet, and others have reached notes so high that the wave length was only about nine inches. 488 WHAT A SOUNDING BOARD DOES When a tuning fork is struck, it produces a sound so faint that it can scarcely be heard unless the fork is held near the ear ; but if the end of the fork is held on a box or table, the sound rings out loudly and seems to come from the table. The explanation of this is very simple. When only the fork vibrates, it produces very small sound waves, because its prongs are small and cut through the air. But when it is set on a box or table, its vi- brations are communicated to the sup- port, and the broader surface of the box or table sets a larger mass of air in vibration, and so amplifies the sound of the fork. When a surface is used in this way to reinforce the vibrations of a small body, and thus produce sound waves of greater volume, it is called a sounding board. Many musical instru- ments, like the violin and the piano, owe the intensity of their sounds to sounding boards, Avhich reinforce the vibrations of their strings. Columns of air, like sounding boards, serve to reinforce sound waves. Un- like sounding boards, however, they do not respond equally w^ell to a large number of different sounds. They re- spond to one sound only, or to several widely different ones. This may be shown as follows : Take a glass tube about sixteen inches long, and two inches in diameter, and after thrusting one end of it into a vessel of water, hold a vibrating tuning fork over the other end. By gradually loavering the tube into the water a point will be reached at which the sound becomes very loud, and as this point is passed the sound gradually dies away again. By raising the tube again the sound is again made loud when the tube reaches a certain point. This shows that to reinforce sound waves of a cer- tain vibration frequency, the column of air in the tube must be of certain length. Let us now see -why the waves pro- duced by the tuning fork are reinforced only by a column of air of a certain length. When the prongs of the fork make a vibration, a wave of air is pro- duced which enters the tube, goes down to the water, is reflected, and comes back toward the fork. Now, if the reflected wave reaches the fork at the precise moment when it has completed one-half of its vibration and is about to begin upon the second half; it will strengthen the wave produced by the second half of the vibration ; but if the reflected wave reaches the fork before or after the beginning of the second half of the vibration, it will not reinforce it. At the downward movement of the lower prong of the tuning fork, a wave of compression is sent down into the tube, and is reflected at the surface of the water. In order to reinforce the wave produced by the prong when it moves upward, the reflected wave must reach the fork just at the time that the prong reaches its normal position and before it starts upon the second half of its vibration. Not only do columns of air tend to reinforce notes having a certain rate of vibration, but all elastic bodies have a certain rate at which they tend to vi- brate, and when sounds having the same rate of vibration are produced near them, these bodies will vibrate in sympathy with them. If the sounds be kept up long enough, the sympathetic vibrations in objects near them some- times become so great that they can easily be seen. Goblets and tumblers made of thin glass show this property very strikingly. When the proper notes- are sounded the glasses take up the vi- brations, and give a sound of the same pitch. If the note is loud, and is con- tinued for some time, the vibrations of a glass sometimes become so great that the glass breaks. Large buildings, and bridges also, have rates at which they tend to vibrate, and this fact is the foundation for the old saying, that a man may fiddle a bridge down, if he fiddles long enough. Musical Instruments. By musical sounds, are meant sounds that are pleasant to hear, and their com- bination in such a way that their eflfect WHAT PITCH IS IN MUSIC 489 is agreeable produces music. Any in- strument, therefore, that is capable of producing pleasing sounds may be called a musical instrument, and music is sometimes produced by very odd de- vices ; but by musical instruments we ordinarily mean instruments that are especially designed to produce musical sounds. The number of such instru- ments that have been invented is enor- mous, but all of them may be divided into comparatively few classes, only two of which are of much importance. The two classes, only two of which are of much importance. The two classes referred to are stringed instruments and wind instruments. Stringed musical instruments are those in which the sounds are produced by the vibration of a number of strings, and are generally reinforced by a sounding board. The strings are ar- ranged in the instruments in such a way that the pitch of the sound produced by each string shall bear relation to the pitch of those obtained from the other strings. As long as this relation ex- ists, the instrument is said to be in tune, and when the relation is destroyed, the instrument is out of tune, and the music produced by it is apt to contain what we call discords. The conditions that determine the pitch of sounds produced by strings can be very easily discovered by experi- ment. Thus, by taking two pieces of the same wire, one twice as long as the other, and stretching them equally, you will observe on striking them that the shorter one yields the higher note. If their vibration frecjuencies are meas- ured it will be found that the shorter string has a vibration frequency just twice as great as that of the longer string. From this we conclude that when two strings of the same size (and material) are stretched equally taut, their vibration frcfpiencies are inversely f>roportional to their lengths. By now taking two pieces of wire, of the same size and length, and stretch- ing them so that the tension of one is four times as great as that of tlie other, we shall find that the vil)ration fre- quency of the tighter string is just twice as great as that of the looser. Thus, we see that the vibration frequency de- pends upon the tension applied to a string, and, that in strings of the same size and length, the vibration frequen- cies are proportional to the square roots of their tensions. Now taking two strings of the same length, but with the diameter of one twice as great as that of the other, and stretching them equally, we shall find that the vibration frequency of the smaller string is twice that of the larger ; which shows that when the lengths and tensions of two strings are equal, their vibration frequencies are inversely proportional to their diam- eters. In constructing stringed instruments, advantage is taken of each of these con- ditions that affect the vibration of strings, and the requisite pitch is se- cured in a string by choosing one of convenient length and diameter, and by stretching it to just the right tension. When a string is plucked in the middle, it vibrates as a whole, and its rate of vibration, or vibration frequency, is determined by the three conditions that have just been discussed; but if a finger is laid on the string, lin the middle, and the string is plucked be- tween the middle and the end, the string will vibrate in halves, and the middle point will remain at rest. If the string had been touched at a point one-fourth of the length from the end it would have vibrated in fourths, and there would have been three stationary points. When vibrations are set up in a string, with nothing to prevent the free vibration of the whole string, it first vibrates as a whole, and the sound pro- duced is known as the fundamental tone of the string; but very soon smaller vibrations of segments of the string be- gin, first of halves of the string, then of thirds, and then of fourths. These smaller vibrations produce sound waves that blend with the fundamental tone and are known as overtones. The com- bined sound of the fundamental tone and the overtones is called a note. Tiie 490 WHY RED MAKES A BULL ANGRY overtones present in notes that have the same fundamental tone are not the same when the notes are produced by different instruments, and, consequent- ly, the sound of notes of the same pitch is not the same on different instruments. This difference in notes of the same pitch has already been mentioned, but the way in which overtones are pro- duced was not explained in connection with it. In wind instruments the sounds are produced by the vibrations of columns of air in pipes. In the orc^an, whicli is probably the best example of a wind instrument, the vibrations are usually produced by causing a current of air to strike a sharp edge, just above the open- ing of the pipe, as is done in a common whistle. A portion of the air current is deflected into the organ pipe, and it sets up vibrations in the air within the pipe. The pitch of the sound produced by an organ pipe is determined by the length of the pipe. A pipe that is open at both ends, called an open pipe, pro- duces a sound that has a wave length twice as great as the length of the pipe ; and if the pipe is open at one end only, a closed pipe, the sound produced has a wave length twice the length of the open pipe. Hence it will be seen that a closed pipe produces a sound that has the same pitch as that produced by an open pipe that is twice as long. Talking Machines. The phonograph, graphophone, gram- ophone, sonophone, and other talking machines, furnish one of the best proofs of the wave theory of sound, because their invention was based upon that theory. The first talking machine was that invented by Thomas A. Edison and called by him the phonograph. The others merely show the principle of the phonograph applied in different ways, and need not be separately described. The reasoning that led Edison to in- vent the phonograph was that if the sound waves produced by the human voice were allowed to strike a thick disk of hard rubber or metal, they would cause the disk to vibrate in a certain way, and if the disk were again made to vibrate as it had done under the influence of the voice, the sounds of the voice would be reproduced. The difificult part of the task of making a talking machine was in finding a way to make the disk vibrate again as it did under the influence of the voice This, however, was finally accom- plished, providing the disk with a needle, that rests on a cylinder of hard wax. which turns slowly under the point of the needle while the sound waves are striking the disk. The vi- brations of the disk cause the point to indent the surface of the wax so as to produce a groove of varying depth on its surface. After the vibrations of the speaker's voice have been recorded in this way on the surface of the wax cylinder the needle can be made to re- trace its path, and will cause the disk to vibrate as it did under the tones of the speaker's voice. These last vibra- tions of the disk produce sound waves similar to those of the voice, but their amplitude is less and the sound is not so loud. Why Does Red Make a Bull Angry 1 It is very doubtful if a red tlag really makes a bull more exited or more quick- ly than a rag of any other color or any other object which the bull can see plainly but does not understand. Con- ceding for the moment that red excites a bull more than any other color, the answer to the question will be found in the statement that anything unusual which the bull sees has a tendency to make him angry and the thing which he can see at a distance more quickly will start him going most quickly. He can see a red rag better perhaps than almost any other color. There may be something about the color which excites him just as some notes on the piano will worry some dogs, but there is no way of studying the bull's anatomy to determine why red should excite him more than any other color, if that is so. HOW A KEY TURNS A LOCK 491 What Happens When the Knob is Turned ? All of that portion of the lock which is shown above the round central post is operated by the knob, the spindle of which passes through the sciuare hole. Before the knob is turned, the parts are in the position shown in figure 2, with the latch bolt protruding. Turning the knob to the left gives the position shown in figure i, the upper lever in the hub pushing back the yoke, which in turn pushes back the latch bolt. When the hand is removed, the springs cause the parts to return to the position shown in figure 2. Turn- ing the knob to the right also retracts the latch bolt, as shown in figure 3, by means of the lower lever on the hub. The spiral spring on the latch bolt is lighter than the one above it. This gives an easy, lively action to the bolt, with very little friction when the door is closed, while the heavier spring above gives a quick and positive action of the knobs. What Happens When the Key is Turned ? All of that portion of the lock which is shown below the round central post is operated by the key. The square stud is attached to the bolt, and in figure i, it is seen that the projections on the flat tumblers prevent the stud from moving forward, holding the bolt in retracted position. When the key is turned as shown in figure 2, it raises the tumblers releasing the stud, and then pushes the bolt out, the tumblers falling into position as shown in figure 3, with the projections again engaging the stud and preventing the bolt from moving until the key is turned backward, again raising the tumblers and releasing and re- tracting the bolt. How Key Changes Are Provided. There are three ways in which keys are made individual to the locks they fit. a. By changing the shape of the keyhole. This may be done shorter or longer, wide or narrow, straight or tapering and with projections on the sides which the key must fit, making it difficult or impossible for keys of a dift'erent class to enter the lock. In the lock shown, a projection on the keyhole will be noted, fitting a groove in the bit of the key. h. By wards attached to the lock-case. The two crescent-shaped wards seen near the key in figure 2 illustrate this feature. Similar wards arc placed on the lock cover. These fit into the two notches shown on the key bit in figure 4, and their shape and position are varied at will. c. By changes in the tumblers. There are five flat tumblers in the lock shown, and their lower edges fit into the end of the key bit. By varying their height, changes in the cutting of the key are made necessary. The security of a lock depends very largely upon its being so made that no key will operate it e.xcept the one which belongs to it, and this is obtained by guarding the keyhole by means of a, by preventing the wrong key from turning by means of h, and by still further limitations by means of c. Iwr.. ■S- 492 HOW A CYLINDER LOCK WORKS The Cylinder Lock. FIGURE 2. FACE OF CYLINDER LOCK. Door locks of the highest grade of security are made with a locking cylinder, which contains tumblers in the form of miniature bolts which make it impossible to operate the lock except with the key to which it is fitted. This is screwed into the lock-case through the side of the door, with the lever on the inner end engaging the end of the bolt in the lock, so that as it is moved it either retracts or "throws" the bolt as desired. I'^igure I shows all the parts of a modern master-keyed lock. Figure 4 shows a broken view of the cylinder with all parts in position. Figure 3 shows a simpler form used when the master key is not desired. Figure 2 shows the front, the only part which is visible when the lock is in use, with its keyvi'ay of tortuous shape which will not admit flat-picking tools. When the lock is assembled, the pin tumblers project through the shell, the master cylinder and the key plug holding all parts firmly bolted or fastened together. When the proper key is inserted, the tumblers are raised until breaks" in all of them coincide with the surface of the key plug, releasing it and permitting the key to turn it. If any one of the five tumblers is .002 inch too high or too low, the key will not turn; so that no key except the one made for the lock can be used. In the master-keyed lock, the master key causes the breaks to coincide with the outer surface of the master ring. It is thus possible to have a master key which will fit any desired number of locks with the individual or change keys all different from each other and from the master key. The balls reduce friction to such an extent that a key has been inserted and withdrawn for a million times with- out affecting the accuracy of the lock. INTERIOR OF CYLINDER LOCK WITHOUT M.\STER KEY. FIGURE 4. INTERIOR OF MASTER-KEYED CYLINDER LOCK. WHERE SALT COMES FROM 493 Where Does Salt Come From? Salt is one of the things with which we come in contact with daily; perhaps more than any other. With the excep- tion of water, probably no one thing is used more by all civilized people than salt. You have already learned in our talk on elements the difference between a mere mixture of substances and a chem- ical compound. You remember that when some substances are only mixed together, they do not lose their identity. In a compound the substances are al- ways combined in fixed proportions and the properties of the compound are often very different from those of the things that make it. Common salt is made of two substances, that are not at all like salt, and are very different from each other. One, sodium, is a soft, bluish metal, and the other is chlorine, a yel- lowish-green gas. The chemical name for salt is sodium which is derived from the two names sodium and chlor- ine. Sodium and chlorine are both what we have learned to call elements. An element being a substance which can- not be separated into substances of dif- ferent kinds. There are now known about seventy such elements. All the substances around us are composed of these elements along, or chemically united in different compounds, or simply mixed together. Most of them, however, are mixtures, not of separate elements, but of compounds. The soil imder our feet is a mixture of com- ])0unds. Water is also a compound. l\ire compounds very rarely occur naturally. Salt is sometimes found al- most pure ; but generally is mixed with so many other things that we have to take them out to get absolutely pure salt. For practical every-day use it is tmnecessary to purify the salt. Salt is found in large quantities in the sea water, in which it is dissolved with some other substances. It is also found in salt beds, formed by the dry- ing up of old lakes that have no out- lets ; salt wells, that yield strong brine ; and salt mines, in which it is found in hard, solid, transparent crystals, called rock salt. Rock salt is the purest form in which salt is found and, to prepare it for market, it is merely neces- sary to grind it or cut into blocks. The greatest deposit of salt in the world is probably that at Wielizka in Poland, where there is a bed 500 miles long, 20 miles wide, and 1,200 feet thick. Some of the mines there are so extensive that it is said some of the miners spend all their lives in them, never coming to the surface of the earth. A trip through these mines is interest- ing. In one of them can be seen a church made entirely of salt. The salt supply of the United States is obtained chiefly from the salt wells of Michigan and New York, the Great Salt Lake in Utah, and the rock-salt mines of Louisi- ana and Kansas. In the arts and manufactures, the most important uses of salt are in glaz- ing earthenware, in extracting metals from their ores, in preserving meats and hides, in fertilizing arid soil, and also, as we shall presently see, in the manufacture of soda. Of equal import- ance, perhaps, is its use in food. Most people think it not only lends a pleas- ant flavor, but is itself an important ar- ticle of diet. It is certain, that all people who can obtain it use salt in their food, and where it is scarce, it is con- sidered one of the greatest of luxuries. Soda is of interest to us, not so much on account of its use in our households, as because it plays on extremely impor- tant part in two industries that contri- bute greatly to our comfort, viz., the manufacture of glass and soap. Soda is not found naturally in great abundance, as salt is, but is generally made from other substances, l-'ormerly it was made almost entirely from the ashes of certain plants. One, known as the Salsoda soda-])Iant, was formerly cnltivatcrl in Si)ain for the soda con- tained in it, and the ashes, or Barilla, as thev were called, were soaked in water to dissolve out the sodc. Now, however, the world's soda supply is pro- duced from common salt by two proc- esses, known from the names of their inventors as the Leblanc and Solvay processes. In the Leblanc process the first step is to treat the salt, or sodium chloride, with sulphuric acid. As a result of this, a compound of sodium, sulphur, and oxygen, called sodium sulphate is formed, together with another acid containing hydrogen and chlorine, and called hydrochloric acid. This acid is driven oflf by boiling, and the sodium sulphate is left. The next step in the process is to con- vert the sodium sulphate, or "salt cake," into soda, or, to give it its chem- ical name, sodium carbonare. This change is brought about by mixing the salt cake with limestone and coal and heating the mixture. Just what changes go on \vhen this is done, are not known, but the chief ones are j^robably the fol- lowing: the coal, which consists for the most part of an element called carbon, takes the oxygen out of the sodium sul- phate, and unites with it to form car- bonic acid gas, leaving a compound of sodium and sulphur called sodium sul- phide ; this acts on the limestone, which is composed of a metal, calcium, in combination with carbon and oxygen, and causes the sulphur in the sodium sulphide to combine with the calcium, forming calcium sulphide, while the sodium combines with the carbon and oxygen and forms the desired com- pound, sodium carbonate. After the heating, the resulting mass which con- tains calcium sulphide, sodium carbo- nate, and some unburned coal, and is known as "black ash," is broken up and treated with water. This dissolves the sodium carbonate, leaving the rest un- dissolved, and when part of the water is evaporated crystals containing sodium carbonate and water are formed. By heating these the water may be driven oflf, and the sodium carbonate left be- hind as a white powder. The Solvay, or ammonia soda, proc- ess consists in forcing carbonic acid gas through strong brine, to which a considerable quantity of ammonia has been added. \\^hen this is done, crvs- tals are formed in the brine, which are composed of a compound of hydrogen, sodium, carbon, and oxygen, and are called sodium bicarbonate. This sub- stance, which is the soda we sometimes use in baking bread, is decomposed by heating, into water and sodium carbo- nate, the soda used for washing. The Leblanc process was formerly used almost altogether for making soda ; but in recent years the Solvay process has come into extensive use, and it is said that now more than half the soda of the world is made in this way. Where Do All the Little Round Stones Come From? The little round stones you are think- ing of are really pebbles which have been worn smooth and round by being rubbed against each other in the water, through the action of the waves on a beach, or the running water of brooks and streams. This sort of rock is called a water-formed rock. Some of them have travelled many miles before they are found side by side on the shore or in a large mass of what we would call conglomerate rock. But whenever you see a round smooth rock or pebble you may be quite sure that it was made round and smooth by the action of water. You sometimes see large rocks made of small stones of various colors and sizes. You can often find a large rock of this kind standing by itself. If you examine it carefully, you will find it consists of an immense number of small stones of different sizes and of a vari- ety of colors, all fastened together as though with cement. This kind or rock is called conglomerate. We know two kinds of conglomerate rock, one, quite common, in which the little stones are round and smooth, and another, not seen so often, in which the stones are sharp. The latter sort is sometnnes called breccia, to distinguish it from the former, which is called true pudding stone. WHAT THE CAUSE OF SHADOWS IS 495 What Is Clay? Clay is the result of the crumbling of a certain kind of rocks called feldspars. When feldspar is exposed to the action of the weather, it crumbles slowly at the surface and the little fragments com- bine with a certain amount of water, forming clay. Pure clay is white and is used in the manufacture of china and porcelain. The common clay that we usually think of when we think of clay, is generally yellowish, but there are many different colored clays. Most of these colors, particularly those of red clay, yellow clay and blue clay, come from the iron which is present in the clay. Clay which contains iron is use- ful for making bricks. Bricks are made from clay by first softening the clay and pressing it in molds, the size of a brick. When dried for a time in the sun they are put into an oven and baked in great heat and they become quite hard and generally red. Most of the clay from which bricks are made turns red when baked, whether blue, yellow or red, be- cause the iron which is in the clay is generally turned red when subjected to heat. For making porcelains it is desirable to use the kinds of clay which contain nothing that melts when heated to a high degree. Clays which contain sub- stances which melt in strong heat are, therefore, not good for making por- celains. There is a pure white clay called Kaolin which is very excellent for this purpose. Clay out of which we make firebrick for lining stoves and fireplaces is free from substances which melt. Several kinds of clay are good for making paints. Where Do School Slates Come From? Slates such as arc used in school ana as roofing material are formed of clay, which has been hardened under pres- sure and heat. When this occurs it does so because a number of layers of clay, one on top of the other, have at some- time been subjected to great heat and pressure within the earth with tiie re- sult that the clay is pressed into very thick layers and changed in color by the heat and becomes hard. There are many kinds of slate. Some of the slate, as found in slate mines, is used to make roofs over buildings and for this purpose they are cut to shapes very much like wooden shingles. They are easily broken, however, as slate is very brittle. Slate is used in many other ways be- sides for roofs and school slates. Some- times it is made into slate pencils but, since paper has become so cheap, com- paratively few slate pencils are used in the school room today. What Causes Shadows? Where anything through which rays of light cannot pass intercepts the light rays coming from a luminous body, the light rays are turned back in the direc- tion from which they come and the part on the other side of the object which in- tercepted the light goes into shade and a shadow results. A shadow then is pro- duced by cutting off one or more light rays. We notice shadows when the sun is bright in the dav'time and at night when we walk along the streets lighted partly by street lamps. The shadows we see in the daytime are caused by our cutting off and throwing back some of the light rays which come from the sun. These are not so dark as the shadows we see at night because the rays of light from the sun are so bright and are re- flected from so many other objects to the side and in back of us. When, however, we are walking along a dimly lighted street and come to a street lamp the shadows our bodies cause are quite black. The night shad- ows are darker because the source of ligiit is less intense and the objects to the side of and in back of us (if we are walking toward the light) do not reflect so much of the light rays as they do of the sun's rays in the daytime. 496 WHAT HOLDS A BUILDING UP? DRIVING THE HOLLOW STEEL PILES TO EED ROCK. The Foundation of a Sky Scraper How Hollow Steel Piles, Compressed and Concrete Are Employed to Make a Foundation Rapidity of building construction is of primar}' importance in every city of metropolitan size. When real estate is sold at the rate of several hundred dollars a square foot it is self-evident that time is indeed money. The delay of a few days in completinj^ a struc- ture may deprive the owner of the chance of earning thousands in rental money. Because of the excessive depth of an open caisson, the completion of a foimdation may be delayed for months. Hence the building may not be com- pleted until the renting period has passed and the owner must wait an PILES ARE DRIVEN DOWN TO SOLID ROCK 497 entire year before he can expect any financial return on his investment. Because rapidity is so essential in city building construction the method of first sinking an open pit to rock in providing a foundation has been displaced to a large extent by a system in which heavy hollow steel piles are" employed in clusters to support a build- ing. The hollow piles are driven through quicksand to rock, cleaned out and iiltimately filled with concrete. In this method of constructing foundations, which is illustrated, hollow steel piles are driven in the well-known manner down to solid rock. The steel pile sections vary in length from 20 feet to 22 feet, and in diameter from 12 inches to 24 inches. If the ground is to be penetrated to a depth greater than 22 feet, the sections of piling are connected by means of a sleeve in such manner that a watertight joint is fonned. Under a pressure of 150 pounds to the square inch a jet of com- pressed air is then employed to blow out the earth and water contained within the shell. A spouting geyser of mud rising sometimes to a height of 150 feet, and occasional large pieces of rock blown up from a depth of 40 feet below the ground, bear testimony to the terrific force of the air blast. When the shell has been completely cleaned out by means of the blast of compressed air, the exposed rock can be examined by lowering an electric light. Steel sounding rods are em- ployed to test the hardness of the rock and to detect the difference between soft and hard bed rock. After the piles in each pier have been cleaned out, they must be cut off at absolutely the same height — sometimes a very difficult task when there is little room. The oxy-acetylene torch is used for the 'lilE PILES Akl. Al;i>l-I IV, 1..M \-l V.I) ll.l-.l L(>,\(,. 11- i.KKAl Ul-.rrilS AUK TO UK KKAflllCI) SECTIONS OF PILING ARE JOINIiD TOGETHER HY MEANS OK A SLEEVE. 498 CUTTING STEEL PILES WITH A HOT FLAME After the piles in each pier have been cleaned out they must he cut off at exactly the same ■i);ht — sometimes a very iiuult task when there Utile room. The oxy- ■L-lylene torch Is used r the purpose, the iitcnsely hot flame out- ing off the steel almost ike butter. PILE BEING CUT TO PROPER LEVEL BY MEAN'S OF OXY-ACETYLENE TORCH. PILES ARE NEXT FILLED WITH CONCRETE 499 A CLUSTER OF PILES, CLEANED OUT, FILLED WITH CONCRETE AND CUT OFF FLUSH BY MEANS OF THE OXY-ACETYLENE FLAME. purpose, the intensely hot flame cutting off the steel almost like butter at the exact elevation desired. The hollow shell is next filled with concrete reinforced by means of long two-inch steel rods, sometimes fifty feet in length. On clusters of these concrete-filled piles, the weight of the building is supported. That this method of constructing foundations is indeed rapid, the story of the work at 145-147 West Twenty- eighth Street, New York City, proves. Rock was located 38 feet below the curb. The material above it was clay and water-bearing sand. Structural steel was due in three weeks, but the completion of the cellar was still ten days off. The steel pile foundation method offered the only solution of the problem. Specifications were drawn which called for eighty-five 1 2-inch steel piles, driven to rock, blown clean by compressed air, and filled with con- crete, reinforced with 2 -inch rods. Despite various obstructions on the ground (shoring of neighboring build- ings and the like) the driving was started on June 30th. The excavator was still taking out his runway while the rear half of the lot was completely driven. After he had left the ground a compressor was set up, and the first pipe was blown on July 7th. Three days later all driving and cleaning had been completed. During the fol- lowing two days all the piles were filled and capped. In a word, the entire foundation had been completed three days before the expected arrival of the steel. Such rapid work is not unusual with the steel foundation method. On an- other contract, work was completed not in the three months stipulated, but in exactly one month and a half, during which brief time all the excava- tion had been done, including sheeting, shoring, pile-driving, the mounting of concrete girders to carry the wall and CONCRETE PILES WHICH HAVE BEEN SUNK TO ROCK BOTTOM AND IN WHICH TWO-INCH STEEL RODS HAVE BEEN INSERTED TO ACT AS REIN- FORCEMENT FOR THE CONCRETE WHICH WILL EVENTUALLY BE POURED IN. 500 BLOWING OUT MUD AND ROCK WITH COMPRESSED AIR THE STEEL PILE IS EASILY FORCED EVEN THROUGH THE SOFT UPPER LAYERS OF BED ROCK. SOMETIMES VERY LARGE PIECES ARE BLOWN UP INTO THE AIR BY THE BLAST OF COMPRESSED AIR. capping of the piles ready to receive the grillage. Sometimes difficulties are encoun- tered which would prove all but insumiountnble nnd ccrtainlv hoDclcsslv expensive with other methods. Thus in carrying out the one contract, water was found 12 feet from the curb. Two running streams had intersected at that ])oint. The piles were simply sunk through the stream to rock bottom without any difficulty. The excessive cost of open-pit work has sometimes made it impossible to build twelve or fourteen-story buildings in many sections of the city of New York. The steel pile has, however, made steel building constniction profit- able. The carrying capacity of a steel pile is enormous. On a single 12-inch steel pile one hundred tons can be safely maintained. Piers containing sixteen piles have been used, and loadings up to 1300 tons are not unusual. Naturally the question arises: Do the steel piles deteriorate in time? The question has been answered over and over again by the piles themselves. After a service of fifteen years the steel foundation piles were removed from the site of a building which now stands at the northwest corner of Wall and Nassau streets, in New York City. They showed practically no deterioration. The oxidation on the outside was almost negligible. CLEANING OUT A HOLLOW STEEL PILE BY MEANS OF COMPRESSED AIR A GEYSER OF MUD ALWAYS APPEARS. HOW THE WATER GETS INTO THE FAUCET 501 L...- A DRIVEWAY ALONG THE TOP OF THE OLIVE BRIDGE DAM. The Story in a Glass of Water How Does the Water Get into the Faucet ? It is easy for you boys and girls who live in the city to run into the kitchen or bathroom v^hen you are thirsty and by a simple turn of the faucet tap secure a glass of cool and refreshing water, but did you ever stop to think how many men must constantly work and how great and perfect arrangements must be made before it is possible to supply a great city with water to drink, to bathe in, and for cooking and washing? No one who has never had the expe- rience of being in a town or city from which the water supply has been cut off, for a day or a number of days, can realize how necessary water is in our daily lives. We are so used to having all the water we want at any time that we even complain when in summer we are asked to drink water which is not iced. Drinking ice-water is very much of a haVjit. In tropical countries where there is no ice, people drink the water just as they find it, and if you were to go there and drink the waters for a few days, you would soon find that the water slakes your thirst even when quite warm, so it is not the ice in the water that quenches your thirst, but the water itself, and the ice-water is not good for you, as the doctor will tell you, because it chills the stomach. Where Does Our Drinking Water Come from? The best way to find out where the water in the faucet comes from is to follow it back to its source. Let us see. Here we are in the kitchen and you have just had a drink of water taken from the faucet above the sink. The faucet, you will notice, is attached to a small pipe which is fastened to the wall back of the sink. We look under the sink and see that the pipe goes through a hole in the floor, so we reason that the water must come from the cellar. Let us go down cellar and see. Yes, here is the little pipe that comes down through the floor under the sink and we follow it along the wall toward the front of the house, and well, well, there it goes right out through the stone foundation of the house. So we conclude that the water comes from somewhere outside of the house, and that the little pipe'^we have been following is only a means of getting it from the outside into the house. We now mark the place in the wall where the pi])c goes through and run around to the front of the house to see where it comes out, but we don't see it. It must be Ijuried in tjie ground, so we get a sj^ade and pick and begin to dig a hole in the ground, and pretty soon we find the little pipe pointing straight out toward the street. Wc 502 HOW A BIG DAM IS BUILT BUILDING OLIVE BRIDGE DAM TO FORM THE ASHOKAN RESERVOIR. The great Ashokan reservoir is situated about fourteen miles west of Kingston on the Hudson River. Its cost is $18,000,000, and it will hold sufficient water to cover the whole of Manhattan Island to a depth of twenty-eight feet. The water is impounded by the Olive Bridge dam, which is built across Esopus Creek, and also by the Beaver Kill and the Hurley dikes, which have been built across streams and gaps lying between the hills which surround the reservoir. THE OLIVE BRIDGE DAM, 465O FEET LONG, 200 FEET HIGH. The dam is a masonry structure 190 feet in thickness at the base, and 23 feet thick at the top. The surface of the water when the reservoir is fixll is 590 feet above tide level. The total length of the main dam is 4560 feet, and the maximum depth of the water is 190 feet. The area of the water surface is 12.8 square miles, and in preparing the bottom it was neces- sary to remove seven villages, with a total population of 2000. Forty miles of highway and ten bridges had to be built. In the construction of the dam and dikes it was necessary to excavate nearly 3,000,000 cubic yards of material, and 8,000,000 cubic yards of embankment and nearly 1,000,000 cubic yards of masonry had to be put in place. The maximum number of men employed on the job was 3000. keep on digging the dirt away, and thus open a Httle trench from the house to the middle of the street and when we get there after a great deal of digging we find our little pipe attached to a larger pipe which seems to run along the ground in the middle of the street; so we are still in the dark as to where the water comes from, excepting that so far as our own home is concerned we know that it gets into the house through a little pipe which is attached to a big pipe in the middle of the street. By this time we know we have a big job on hand. We are pretty tired of digging by this time, so we call in all the boys and girls in town to help us dig so that we may see where these pipes come from, and we have a regular digging carnival. We follow the big pipe along our own street until we come to the comer. Here we find that our larger street pipe is connected with a still larger pipe, so we think we had better follow the larger pipe. We keep on diggihg, getting more of the boys and girls to help, and we follow that big pipe right out to the edge of town where we see it runs into another stone wall which you knew all the time was the reser- voir, but concerning what it was for you were perhaps never quite clear. Right near the place where the pipe goes in is a stairway which leads up to the top of the wall, so the whole crowd of boys and girls climb the steps and you are at the top of the reservoir; and there spread out before you, you see a big lake surrounded with a stone wall and you see where the water comes from — the reservoir — at least so you think. But you are wrong. You really haven't come anywhere near the source of the supply. For soon as you walk around the broad top of the wall which surrounds your rescrv^oir, you meet a man who asks you what you want, and you tell him that you have been finding out where the water in the faucet came from, but having found out you thought you would go back home. The man smiles at you, but, as he is good-natured and sees you are really trying to find out where the water comes from, he tells you that since you have gone to all the trouble of digging up the streets to follow the pipes, you might as well learn all about it. He first tells you that the reserv^oir is not really the place where the water comes from but only a tank, so to speak. He explains to you that most of the faucets in the city are higher than the real source of the water, which is out in the country miles away, and as water will not run up hill, it is necessary to keep the city's daily supply in some place that is higher than the highest faucet in the city, so that it will force its way into and fill to the very end all of the large pipes in the streets and the small pipes which go into the houses, so that the water will come out just as soon as you turn the faucet. Then he takes you over to a large building near the reservoir which you have always called the water works, but never knew exactly what it was for. He takes you into a large room where there is a lot of nice-looking machinery working away steadily but quietly, and tells you that these are the great pumps which lift the water from the great pipes which bring it from far away in the country, into the reservoir we have just seen, from which the water runs into and fills all of the pipes into the city. He also tells you that in some cities it is impossible to find a place to build a reservoir which is higher than the highest places in the city. In such places, the pumps in the water works pump the water direct into the city water pipes and force the water to the very end of all the pipes and keep it there under pressure all the time. From the pumping station he takes you down stairs in the water works and shows you the huge pipe which brings the water to the water works from the country. It is quite the largest pipe you ever saw. You see it is not really an iron pipe, but built of concrete, which is quite as good. You will be surprised to have our friend, the water- works man, tell you that three average-sized men could stand up on each other's shoulders inside the great pipe. 504 HOW THE BIG PIPES ARE LAID THROUGH THE COUNTRY OLIVE BRIDGE DAM; ESOPUS CREEK FLOWING THROUGH TEMPORARY TUNNEL. PLACING THE 9^ FOOT STEEL PIPES. A HUGE UNDERGROUND RIVER 505 Our water-works man sees how earnest you are in seeing just where the water comes from, so he proposes that we go find out. We go outside and there is an automobile all ready to go and we jump in and the machine starts off along quite one of the nicest roads you were ever on. Soon you exclaim, " Why, this is the aqueduct road," and so it is. The great pipe through which the water comes to the city is an aqueduct and they have built the road right over the place where the aqueduct runs. Away we go as fast as the car can carry us, some- times ten, or twenty or perhaps fifty miles, according to what city you are in. The city goes as far as it must to find a supply of pure water and plenty of it and spends millions upon millions The water is ^conducted from Ashokan reservoir as a huge, underground, artificial river The aqueduct is nipety-tvvo miles in length from Ashokan to the northern city line, and it should be explained that it is built on a gentle grade, and that the water flows through this at a slow and fairly constant speed. The aqueduct contains four dinstict types: the cut-and-cover, the grade tunnel, the pressure timnel, and the steel-pipe siphon. The cut-and-cover type, which is used '■>n fifty-five miles of the aqueduct, is of a horseshoe shtipe and measures 17 feet high by 17 tVet 6 inches wide, inside measurements. It is built of concrete, and on completion it is cov- eted in with an earth embankment. This type is used wherever the nature of the ground and the elevation allow. Where the aqueduct intersects hills or mountains, it is driven through them in tunnel at the standard grarle. There are twenty-four of these tunnels, aggregating fourteen rniles in length. They are horseshoe in shape, 17 feet high by 16 feet 4 inches wide, and they are lined with concrete. When the line of the aqueduct encountered deep and broad valleys, they were crossed by two methods: if suitable rock were present, circular tunnels were driven deep within this rock and lined with concrete. There are seven of these pressure tunnels of a total length of seventeen miles. Their internal diameter is 14 feet, and at each end of each tunnel a vertical shaft connects the tunnel with the grade tunnel above. If the bottom of the valley did not offer suitable rock for a rock tunnel, or if there were other prohibitive reasons, steel siphons were used. These are 9 feet and 1 1 feet in diameter. They arc lined with two inches of^ cement mortar and arc imbedded in concrete and covered with an cartli embank- rnent. There are fourteen of these pipe siphons of a total length of six miles. At present one pipe suffices to carry the water. Ultimately three will be required for each siphon. 506 THE REAL SOURCE OF THE WATER of dollars to make its supply of water good and certain. Occasionally we come to a little stone house along the way where we can go down and see the sides of the great stone pipe. After a while, however, we find our aqueduct road comes to an abrupt stop before another great stone wall. It is the great dam which has been built out there in the country to fonn one end of a great tank that catches and holds the waters from the creeks and rivers that flow into it. Usually the dam is built up right across a river. They simply build the dam strong enough to stop the river from going any further. Then, of course, the water piles up on the other side of the dam and occasionally this tank, which is simply another huge reserA'oir, gets so full that the water flows over. It does not really over- flow the top of the dam, because under- neath the top the engineers have left openings here and there for the water to get through. If it were not for these loopholes, so to speak, the great wall of water within the reservoir, piled against the dam, would break down the wall no matter how well built, by the great pressure it exerts. We are now near to the real source of the water. We take a trip around the top of the great reservoir. Around at the other end we find what looks like a river, excepting that there isn't any current to speak of. It is a river, but a much deeper one than it would have been but for the dam which has been built across it, and originally its surface was quite far down in a valley. Sometimes man makes his water dam at one end of a lake, which has been formed by streams flowing into a valley which has no opening for the water to run out of. In these cases the lake will be high up in the hills and man simply builds his dam at one end, lets the end of his aqueduct into the bottom of the lake and the water flows. In other cases he picks out a valley where there is no lake at all, builds his dam and then drains the water which he finds in small lakes higher up in the hills into the one THROL-GH THIS CH.\MBER THE FLOW OF WATER TO THE AOlEnrCT IS REGULATED. DIGGING A HOLE UNDER A RIVER 50i DIAMOND DRILL BORIXG A HORIZONTAL HOLE IIOO FEET BELOW THE HUDSON RIVER. HUDSON RIVER SIPHON, IIOO FEET BELOW THE RIVER. Of the many siphons constructed, by far the most interesting and difficult is that which hoj been completed beneath the Hudson River. The preliminary borings made from scovys in the river showed that great depths would have to be reached before rock sufficiently solid ar J free from seams was encountered to withstand the enormous hydraulic pressure of the w£.ter in the tunnel. After failing to reach rock by the scow drills, two series of inclined bor- ings were made from each shore, one pair intercepting at aljout goo feet depth and the other at about 1500 feet. Both showed satisfactory rock, and accordingly a shaft was sunk on each shore, to a depth of approximately iioo feet, and then a horizontal tunnel was driven conncct- inc: the two. It is of interest to note that because of the enormous head, whicli must be measured frf;m the flow line far above the river surface, the pressure in the horizontal tunnel reaches over forty tons per square foot. 508 THE HIGHEST BUILDING IN THE WORLD UPSIDE DOWN This picture shows the depth to which the pipes which carry the water through the city must some- times be sunk in order that it will be certain to re- main in place. To illustrate this in connection with the depth of the water tunnel in one place in the city of New York, our artist has taken the liberty of turning the Woolworth Build- ing upside down. Even this build- ing, which is the tallest business building in the world, and is 792 feet high, would not penetrate the water tunnel, at the point shown, which is at the CHnton Street shaft at the west bank of the East River. « WHAT IS CARBONIC ACID? 509 big valley and makes a very large lake. But the water in the lakes comes originally from the creeks, rivers or springs which run into it, and so we will follow our original river back into the hills. Here and there along its course we find a little stream flowing into our river and, as we go up higher and higher into the hills, we find our river getting smaller and smaller. Now it is only a creek and, if we go far enough, we find its source but the tiniest kind of a tinkling brook with the water dripping almost noiselessly between the rocks as it makes its path down the side of the hill. There is the source of the water in the glass you have just enjoyed.] What is Carbonic Acid? It was formerly called fixed air, and is a gaseous compound of carbon and oxygen. It is procured by the pro- cesses of combustion and respiration, and hence is always present in the air, though in minute quantity. Plants live upon it and absorb it into their tissues ; they abstract and assimilate its carbon, and return its oxygen to the atmosphere in a pure condition. It is also present in spring water, and often in quantities, so that it sparkles and effervesces ; it is also produced during the processes of putrefaction, fermentation, and slow decay of animal and vegetable sub- stances in presence of air. It is largely employed by the manufacturers of aerated bread and aerated waters. Under a pressure of about 600 pounds it liquefies, and when allowed to escape through a small jet it rap- idly evaporates and causes intense cold, so much so as to become frozen. It does not support burning. The gas derived from it, carbon dioxide, is in- visible, and is heavier than air by one half, and has a pungent odor and slightly acid taste. In a pure state the gas cannot be respired, as it supports neither respiration nor combustion. When the portion in the atmos])here is increased to a considerable extent, as happens sometimes, it endangers life. The familiar "rising" of bread is brought about by carbonic acid gas escaping through and permeating the dough, making it light and porous. In this form it is known as yeast or as baking powder. We see its uses also in the chemical fire-engine. In some parts of the world large quantities of carbonic acid gas are con- stantly issuing from openings of the earth's surface. Two such places are the famous Poison V^alley of Java, and the Grotto del Cane, near Naples, in Italy. The former is a small valley about a half a mile around and about thirty-five feet deep, in which the air is so loaded with carbonic acid gas that animals entering it are killed in a few minutes. Even birds that fly over the valley are overcome if they do not rise high above it. The Grotto del Cane, or Grotto of the Dog, is a small cavern in the crater of a volcano. A stream of carbonic acid gas flows constantly into the grotto, but the level of the gas does not reach the height of a man's mouth. When the same air is breathed over and over again, the quantity of carbonic acid in it is increased so much, that it may become as deadly as the air in the Poison Valley. Two other gases that may generally be found in air are ozone and ammonia. The first is merely a form of oxygen that is produced by the passage of lightning through the air. After severe thunderstorms, it is said to be present, sometimes, in sufficient proportion to give to the air a slightly pungent odor. It is more active chemically than is the ordinary form of oxygen, and conse- quently has a stimulating effect upon animals. Ammonia, or hartshorn, as it is some- times called, from the fact that it was formerly obtained by distilling the horns of harts, or deer, is almost always present in the air in small quantities. It is produced chiefly by the decay of ani- mal and vegetable matter, especially the former. Though present in the air in very small quantities, it is of much value to the plant world, because it con- tains nitrogen in a form in which it can be readily absorbed by plants. All plants contain some nitrogen, which is essential to their growth, but the 510 VARIOUS GASES FOUND IN AIR greater part of the nitrogen in the air is not in such form that it can be ab- sorbed by them. They must obtain their supply from the soil, which usu- ally contains some nitrogen in a form that may be taken up by plants, and from the ammonia in the air. The lat- ter is not taken directly out of the air by the plants, but the rains falling through the air absorb the ammonia and carry it to the soil, from which it is taken up into the plants by their roots. Besides the gases that have been mentioned, there is present in the air, at all times, a small quantity of water- vapor, which is, in many ways as im- portant to mankind as is the oxygen it- self. The quantity of water in the air ib not always the same. As a rule, the quantity is greater in warm air than in cold, and is less over land than over water. Frequently the air feels damp in cold weather, and dry in hot weather, and it is natural to suppose that there is more vapor in the air on the damp day than on the dry one. This, how- ever, is not always true. There is usu- ally more moisture in the air on a warm summer day than on a cold day in win- ter, though the winter day may seem m.uch more moist. You will be able to understand why this is so by compar- ing the air to a sponge. If we fill a sponge with water, and squeeze it gently, a httle water will be forced out of it. If we then remove the pres- sure on the sponge. When the air cools, will appear dry on the surface, but there will still be water in it, and on being squeezed harder than before it will again become moist on the surface and more water will be forced out of it. Now cold has an efifect upon moisture- laden air very much like that of pres- sure on the sponge. When the air cools, some of the moisture is forced out of it. and the air seems damp. When it warms again, the air seems dry, though there is still water-vapor in it. It seems dr}^ because it can absorb more water-vapor, just as the sponge seems dry after you cease to squeeze it, though it still contains water. From this we see that the air does not always seem moist when there is much water-vapor in it, nor dry when there is only a lit- tle. It feels moist when there is as much water-vapor present as it can hold, and dry when it can hold more than it al- ready has. And we also see that in hot weather the air can hold much more moisture than it can in cold weather, so that whether the air feels dry or moist, there is generally much more water-vapor in it in hot weather than in cold. It is easy to see that, over water, the air naturally takes up more moisture than over land, because there is so much more water there to be transformed into vapor. Over the surface of seas, lakes and rivers, water is continually being converted into vapor by the process of evaporation, and this vapor is absorbed by the air. Let us now consider the solid par- ticles floating in the air, the dust that is seen dancing in the path of a sun- beam. Whenever we examine the air, these small particles are found, even on the tops of mountains, and at points so high above the earth that they have been reached only by balloons. Of course, there is very much less dust high above the earth than near the sur- face, where the winds are constantly stirring up the loose soil, and throwing into the air small particles of every kind. In cities, where factory chim- neys are continually pouring out clouds of smoke, and the ])eople and vehicles are constantly disturbing the dust of the streets, the air always contains more dust than does the air of the country. In order that we may breathe air, the oxygen in it has been mixed with four times as much nitrogen and argon, which must be inhaled with the oxygen, though they have no more efYcct on the body than the water you take with a strong medicine to weaken it. The oxy- gen, however, has a very important ef- fect upon the body, and if we compare the air we exhale with that we inhale we find considerably less oxygen in the former than in the latter. In place of the oxygen, the air has received car- bonic acid gas. It may seem very strange to say that there is burning go- HOW PLANTS EAT CARBONIC ACID 511 ing on in the body, but that is very nearly what takes place. The chief dif- ference from coal-burning is that in the body the process goes on so slowly that it does not make the body very hot ; but when we set fire to coal, the process is much more rapid, and a large amount of heat is produced in a short time, so that the coal becomes very hot. The jjroducts of breathing and of coal-burn- ing are the same, carbonic acid gas be- ing the chief one. When coal is burned it disappears, together with some of the oxygen of the air, and in their stead we have carbonic acid gas. When a breath is taken some of the material of the body disappears, as does some of the oxygen of the air, and in place of them carbonic acid gas is found. If we could weigh the coal burned and the oxygen that disappears in the burning of it, and could then weigh the car- bonic acid gas that is produced in the burning, we should find that the latter weighs just as much as the coal and the oxygen together. So, too, if we could v.'eigh the oxygen that disappears from the air we breathe, and also find the weight of the material taken from our bodies by breathing, we should find that the two together weigh just as much as the carbonic acid gas given off in our breath. In neither case is any- thing absolutely destroyed; the sub- stances resulting from the change weigh just as much as those that took part in it. Having learned that a quantity of oxygen disappears every time we take a breath, every time we build a fire, it would seem that in the thousands of vears during which men and animals have been living on the earth, all the oxygen would have been exhausted and nothing left in its place but carbonic a^id gas. That, however, is impossible, v.s the carbonic acid gas is used up al- most as fast as it is produced ancl the oxygen is returned to the air in its stead. All trees and ]jlants, from the great redwood trees of California to the smallest flowers that dot the fields, need (Tirbonic acid gas to keep them alive and to make them grow. Their leaves have the power when the sun shines on them to take up carbonic acid from the air and to return oxygen in exchange, In this way you see that the balance is kept just as it should be. The oxygen needed by animals of all kinds is fur- nished by the plants, and the carbonic acid required by plants is thrown off in the breath of animals. Is It a Fact that the Sun Revolves On Its Axis? It is a proved fact that the sun re- volves on its axis. All parts of its surface, however, do not rotate with the same velocity. The rotation of the sun dift'ers from that of the earth in this respect. This constitutes the visible proof that the physical state of the sun is different from the earth's, although they are composed of similar chemical elements. The earth, being covered with a solid crust, and being also, as recent inves- tigation demonstrates, as rigid as steel throughout its entire globe, rotates with one and the same angular velocity from the equator to the poles. If you stood on the earth's equator you would be carried by its daily rota- tion round a circle about 25,000 miles in circumference. If you stood within a yard of the North or South Pole you would be carried, by the same motion, round a circle not quite 19 feet in circumference. And yet it would require precisely the same time, viz., twenty-four hours, to describe the 19-foot circle as the 25,000-mile one. What Is the Most Usefully Valuable Metal ? If you were guessing you would naturally say that gold is, of course, the most valuable of the metals. But you would be wrong. The proper answer to this is iron. We do not mean the pound for pound value, for you could get much more money for a pound of gold than for a yjound of iron, but we mean in useful value; — iron is in that scn.se the most vakial)le metal known to man. This is so because iron is of great ser- vice to man in so many different ways, and it is very well that there is so great a quantity of it for man's use. 512 WHERE DOES TOBACCO COA\E FROM? GROWING TOBACCO UNDER CHEESECLOTH. The Story in a Pipe and Cigar* Where Did the Name Tobacco Origi- nate ? It is now generally agreed that the word tobacco is derived from " tobago," which was an Indian pipe. The tobago was Y-shaped, and usually consisted of a hollow, forked reed, the two prongs of which were fitted into the nostrils, the smoke being drawn from tobacco placed in the end of the stem. The island of Tobago, contrary- to the belief of many, did not furnish the name for tobacco, but on the other hand, it was given that name by Columbus, owing to its resemblance in shape to the Indian pipe. How Was Tobacco Discovered? While tobacco is now found growing in all inhabited cotmtries, it is a native of the Americas and adjacent islands. Its discover}- by ci^■ilized man was coincident with the discover},- of this continent by Christopher Columbus in 1492. Columbus and his adventtirous sailors foimd the native Indians using the weed on the explorer's first visit to the new world. Investigation has established that the plant was first used as a religious rite and gradually became a social habit among the natives. Columbus and his CastiUan successors carried the weed to Spain. Sir Walter Raleigh took it to England, Jean Xicot, whose name is immor- talized in nicotine, introduced it to the French; adventurous traders brought the seed to Turkey and Syria, and Spanish argosies carried it west- ward from Mexico to the Philippines and thence to China and Japan. Thus within two centuries after its discovery tobacco was being cultivated in nearly every country- and was being used by ever\' race of men. Where Does Tobacco Grow? While tobacco is a native of the Americas, it is a fact that it -^-ill grow after a fashion almost an}-\\-here. Mil- ton Whitnev, Chief of the Division of * CopjTight by Tobacco Leaf Publishing Co. WHERE HAVANA TOBACCO IS GROWN 513 Soils, United States Department of Agriculture, in his bulletin on tobacco soils says tobacco can be grown in nearly all parts of the countn,- even where wheat and com cannot econom- ically be grown. The plant readily adapts itself to the great range of climatic conditions, will grow on nearly all kinds of soil and has a comparatively short season of growth. But while it can be so universally grown, the flavor and quality of the leaf are greatly influenced by the conditions of climate and soil. The industn,- has been very highly specialized and there is only demand now for tobacco possessing certain qualities adapted to certain specific purposes. ... It is a curious and interesting fact that tobacco suit- able for our domestic cigars, is raised in Sumatra, Cuba and Florida, and then passing over oiu* middle tobacco States the cigar type is found again in IMassa- chusetts, Connecticut, Pennsylvania, Ohio and "Wisconsin. . . It is sur- prising to find so little difference in the meteorological record for these several places diuing the crop season. There does not seem to be siifficient difference to explain the distribution of the dif- ferent classes of tobacco, and 3'et this distribution is probabh' due mainly to climatic conditions. . . . The plant is far more sensitive to these meteorlog- ical conditions than are our instnmients. Even in such a famous tobacco region as Cuba, tobacco of good quality can- not be grown in the immediate vicinity of the ocean or in certain parts of the island that would otherwise be con- sidered good tobacco lands. This has been experienced also in Siimatra and in our own country', but the influences are too subtle to be detected b>' our meteorological instniments. . . . Under good climatic conditions, the class and type of tobacco depend upon the character of the soil, especially on the physical character of the soil upon which it is grown, while the grade is dependent largely upon the cultivation and curing of the crop. Different types of tobacco are grown on \\'idely different soils all the way from the coarse sandy lands of the Pine Barrens, to the heavy, clay, limestone, com and . wheat lands. The best soil for one kind of tobacco, therefore, ma}^ be almost worthless for the staple agri- cultural crops, while the best for another type of tobacco may be the richest and most productive soil of any that we have. Havana tobacco, which means all tobacco grown on the island of Cuba, possesses peculiar qualities which make it the finest tobacco in the world for cigar purposes. The island produces from 350,000 to 500,000 bales annually, of which 150,000 to 250,000 bales come to the United States for use in American cigar factories. The best quality of the Cuban tobacco comes largely from the Vuelta Abajo section, although some very choice tobaccos are raised also in the Partidos section. Remedios tobaccos are more heavily bodied than than others and are used almost ex- clusively for blending with our domestic tobaccos. While there are innimierable sub-classifications, such as Semi- Vueltas, Remates, Tumbadero, etc., the three general divisions named above, Vuelta Abajo, Partidos and Remedios, embrace the entire island. If a fourth general classification were to be added, it would be Semi-Vueltas. The ^"uelta Abajo is grown in the Prov- ince of Pinar del Rio, located at the western end of the island. It is raised practically throughout the entire prov- ince. Semi-\'ueltas are also grown in Pinar del Rio, but the trade draws a line between them and the genuine Vueltas. Partidos tobacco, which is grown principally in the ProA-ince of Havana, differs from the ^"'uelta Abajo in that it is of a much lighter quality. The Partidos country is famous for its production of fine light glossy wrappers. Tobacco from the foregoing sections is used principally in the manufacture of clear Havana cigars. Some of the heavier Vueltas, however, are also used for seed and Havana cigar pur- poses. Remedios, othenA-ise known as Vuelta-Arriba, is grown in the Pro\4nce of Santa Clara, located in the center of the island. This tobacco is taken almost entirely by the United States and Europe and is used here for filler purposes, principally in seed and Hav- 514 HOW TOBACCO IS PLANTED ana cigars. Its general characteris- tics are a high flavor and rather heavy body, ^Yhich make it especially suitable for blending with our domestic tobaccos. Havana tobacco is packed and marketed in bales. Preparing the Seed Beds. The first step is the preparation of the seed beds. For these beds low, rich, hardwood lands are selected. The trees are cut down and the wood split, converted into cord wood and piled up to dry. About the middle of January this wood is stacked up on skid poles and ignited. The ground is thus cleared by burning, the fires being moved from spot to spot until a sufficient area is cleared. By this process all grass, weeds, brush and insects are eradicated. The ground is then dug up with hoes and. cleared off and a perfect seed bed is made. The tobacco seed is first mixed with dry ashes in the proportion of about a tablespoonful of seed to a gallon of the ashes, and about this quantity is sowed over a square rod of land. This amount is calculated to supply plants enough for one acre of ground, but the farmers usually double the planting as a precaution against emer- gencies. After the seed beds are sowed they are covered over with cheesecloth as a means of protection, and they are carefully weeded and watered until the leaves have attained a length of about four inches. They are then ready for transplanting, which operation begins about the middle of April. Fertilization. In the meantime, the tobacco-grow- ing areas have been prepared by plow- ing and fertilizing. The matter of fertilization has been the subject of much study and many experiments, and it has been definitely established that cow manure is one of the best for this purpose. This natural fertilizer is distributed on the fields at the rate of ten to twenty two-horse loads to each acre. In addition to this from two hundred to three hundred pounds of carbonate of potash, and from two thousand to three thousand pounds of bright cottonseed meal are employed. The total cost of this fertilizer amounts to about $120 per acre. Planting. After the fertilizer is well plowed into the land the ground is laid off into ridges about four feet apart, made by throwing two one-horse furrows to- gether. These ridges are about two feet in width and are flattened on the top so as to make a level bed for the young plant. The farmer then meas- ures off ai^d marks these rows at inter- vals of 16 to 18 inches. At each mark he makes a small hole, and after pour- ing in a pint of water the plant is care- fully set. Machine planters are used for this purpose to a limited extent. Care of the Growing Crop. The growers usually calculate on finishing their planting about the first of June. The young plants are then closely watched and are hoed and cultivated at least once a week. They are also supplied with sufficient water to keep them alive and growing. At this stage of the proceedings, the planter begins to look out for worms. The butter worm is one of his greatest enemies. This is a small green moth that lays its eggs in the bud of the plant and turns into a worm two days later. To stop the ravages of this insect, it is customary to use a mixture composed of some insecticide mixed with com meal. A small pinch of this mixture is inserted at regular intervals in the bud of each plant imtil the plant is nearly grown. When the tobacco is about three feet high, all such leaves as were on the plant when it was first set out are picked off and thrown away. About this time the crop is usually threatened by another enemy known as the horn worm. This is a large, mouse-colored moth, w^hich swarms over the field about sun-down, and deposits green eggs about the size of a very small bird shot, on the back sides of the leaves. HOW THE TOBACCO IS HARVESTED 515 f . ;"'-^?f?^ ^Jjt 1 m^^^^^^^M Slii ■■\^^. -j^"- m~ MIm|S^^f^mK^B m^ FfiH^Uy^H!^y|BBR^. *f^W' ^ hMj^-j^i A FIELD OF FINE HAVANA. This is a very ravenous insect and unless carefully watched it will devour every leaf of tobacco, leaving nothing but the stalks standing. It is removed by picking off and by insecticides. Harvesting. About sixty to ninety days after setting, the bottom leaves on the plant are ripe and the grower is able to remove from three to four on each stalk. This is called priming. The primer detaches each leaf carefully and places it face down in his left hand, inspecting it at the same time to see that no worms are carried to the barns. Upon accumulating a handful, he places them in baskets that are lined with burlap to prevent injury to the leaf, and the filled baskets are either carried or hauled to the barns. About this time the plants have begun to bud out at the top, and this bud, with a few small leaves around it, is Vjrokcn off. This process is called topping, and is done for the purpose of confining the development of the plant to the leaves below. After lo])ping, the priming of the tobacco is ccjntinued for about three weeks, and until all the upper leaves of marketa])le value have been harvested. In the meantime, the suckering has to be looked after, which is the removing of the small branches that have a tendency to grow out of the main stalk .of the plant. In the barns the leaves are placed on long tables, behind which stand the stringers. They string the leaves, each separately, on strong cotton twine, about thirty leaves to a string, spaced about an inch apart. If this is not done carefully and accurately, several leaves may become bunched together and the cure will thereby be impaired. It is attention to this detail which pre- vents the defect known as pole-sweat. These strings are tied at either end to a tobacco lath, and the lath is hung upon two poles. These poles are placed in courses in the barn, at spaces of two feet, one above the other. Here the tobacco undergoes its pre- liminary, or bam cure, and during this period the grower is constantly on the anxious seat, having to open A M()0E':RN CUHAN TOHAC CO I'LANTATION. 516 HOW TOBACCO IS CURED and close his curing houses according to the changes in the weather, and to look closely after the ventilation of his crop in order to avoid the develop- ment of stem rot and other afflictions with which the tobacco is threatened at this staerc of the proceedings. A STAND OF TOBACCO IN EACH HAND. Bulk Sweating. In due course of time the laths are taken down, the strings removed and the leaves are formed into hands and tied with a string. The tobacco is then packed temporarily in cases and delivered at the fermenting house, where it is put into what is known as the bulk sweat. This consists of uniform piles of tobacco covered over with blankets, and which are frequently " turned " in order that they shall cure evenly and not become too dark in color. From the bulk sweat the tobacco goes to the sorting tables, where it is divided into numerous grades of length and color. It is then turned over to the packers, who form it into bales. How is Tobacco Cultivated? As the young plants spring up and begin to grow, they are thinned out, watered and cared for until along in October or November, and as soon as the weather becomes settled for the season, the little seedlings are trans- planted into the field. Some growers use shade, but most of the tobacco is grown in the open. The plants are placed in rows, very much as com is planted, only farther apart. The plants are carefully protected from weeds and insects, and in December the early tobacco is ready to be harv^ested. Here the mode of procedure differs accord- ing to the discretion of the grower. The plan universally in vogue until recent years was to cut the plant down at the base of the stalk. Lately, however, the more scientific growers harvest their tobacco gradually, pick- ing it leaf by leaf, according as they ripen and mature. The tobacco is then allowed to lie in the field until the leaves are wilted. The stalks (or stems, according to the method followed) are then stiiing on cujes or poles, so that the plants hang with the tips down. The tobacco is then allowed to hang in the sun until it is dry and later carried into the bams, where the poles are suspended in tiers until the bam is fiill. Tobacco bams everywhere are constructed with movable, or rather, adjustable, side and end walls which permit of a constant adjustment of the ventilation. While hanging in the bam the tobacco undergoes its pre- liminary cure and changes in color from the green of the growing plant to a yellowish brown. The climatic changes have to be carefully studied d-uring this process. If the weather is extremely dry it is customary to keep the bams closed in the daytime and to open the ventilators at night. HOW CIGARS ARE MADE 517 It is generally desirable to keep the tobacco fairly dry while it is under- going the bam cure. After a few weeks, and when the hanging tobacco has reached the proper stage of matur- ity, a period of damp weather is looked for so that the dry leaves may be re- handled without injury. When the desired shower comes along the tobacco is stripped off the poles and placed in pilon — that is, in heaps, or piles, on the floors of the barns and warehouses, each pile being covered with blankets. Here, being in a compact mass, it undergoes the calentura, or fever, by which it is pretty thoroughly cured, the color changing to a deeper brown. After about two weeks in the piles it is sorted, tied into small bundles or carrots, and these in turn are packed in bales. After being baled the tobacco, if allowed to remain undisturbed, under- goes a third cure, by which it is greatly improved in quality. It is then ready for the factory. ing tobacco from the direct rays of the sun. Thus the ripening process is slower, causing the leaves to grow larger and thinner and less gummy; and being thinner and less gummy, they are of a lighter color when finally cured. This method is employed by some growers in cigar-leaf districts, such as Cuba, Florida and Connecticut. A TOBACCO BAKN'. The Shade-growing Method. The shade-growing method is one of the institutions of modem tobacco cultivation. The principle is this: The sun, shining on the tobacco plants, draws the nutrition from the earth, and the plant ripens quickly, the leaves having a tendency to be heavy-bodied and not very large. To defeat these results and produce large, thin, silky leaves for cigar-wrapper purposes, the grower sometimes covers his field with a tent of cheesecloth or with a lattice- work of lathing which protects the grow- TAKING TOBACCO FROM BALES. How Are Cigars Made? While many labor-saving devices have been introduced in all branches of tobacco manufacture, it is a curious fact that in the production of the best grade of cigars, namely, the clear Havana, the work is done entirely by hand. In fact, it may be said that in the process of manufacturing fine cigars exactly the same principles are followed as those of two centuries ago. There has been much improvement in the artisanship of the worker, of course, but no rudimentary change in method. 518 THE GREAT CARE NECESSARY IN SELECTION In the manufacture of snuflf, chewing and pipe tobacco, cigarettes and all- tobacco cigarettes, machinery plays an important part; and mechanical de- vices are also used extensively in the production of five-cent cigars and in the still higher priced grades of part- domestic cigars, such as the seed and Havana. Some of these appliances are almost human in their ingenuity. But in fashioning the tobacco of Cuba into cigars that are perfect in shape, in fomiation and in all the qualities that go to make a good cigar, there is no substitute for the human hand. Upon opening a bale of tobacco the workman takes each carrot out sep- arately, shakes it gently to separate the leaves, and then moistens it, either by dipping it into a tub of water from which it is quickly removed and shaken to throw off the surplus water or else by spraying it with a blower. It is left in this condition over night, so that the leaves may absorb the moisture and become uniformly damp and pliable. The tobacco is then turned over to the strippers, who remove the midrib from each leaf, at the same time sep- arating the wrapper from the filler. From this point on the treatment of the wrappers and fillers is different. The half leaves suitable for fillers are spread out and placed one on top of the other, making what are called books. These books are placed side by side, closely together, on a board, and a similar board is placed on top of the tobacco to hold it in position. Later, it is packed into barrels, the tops of which are covered with burlap, and there it undergoes a fermentation. It is usually allowed to remain in this condition for ten days or two weeks, when it is rehandled and inspected, and if found to be in the right condition, it is placed on racks, where it remains until it is in just the proper state of dryness to be ready for working. The wrapper leaves, after leaving the hands of the stripper, are taken by the wrapper selector, who sits, usually, at a barrel, and spreads out each leaf, one on top of the other, over the edge of the barrel, assorting them as to size, color, etc., into several different piles or books. Each of these piles is divided into packs of twenty-five each, and each lot of twenty-five is folded over into what is called a " pad " and tied with a stem. It is in this fonn that they go to the cigarmaker. Every morning the stock is dis- tributed among the cigannakers. Each workman is given enough tobacco to make a certain number of cigars, and when his work is finished he must return either the full number of cigars or the equivalent in unused leaves. The tools of the cigarmaker consist merel}^ of a square piece of hardwood board, a knife and a pot of gum traga- canth. He sits at a table upon which rests the board, and at which there is also a gauge on which the different lengths are indicated. Fastened to the front of each table is a sack or pocket of burlap into which the cuttings that accumulate on the table are brushed. The operator deftly cuts his wrapper from the leaf, fashions the filler into proper form and size in the palm of his hand (this is known as the " bunch ") and rolls the tobacco into cigar form. In winding the wrapper around the " bunch " the operator begins at the " lighting end " of the cigar, called the " tuck," and finishes at the end that goes into the mouth, which is called the " head." A bit of gum tragacanth is used to fasten the leaf securely at the " head." The cigar is then held to the gauge and is trimmed smoothly off to the proper length by a stroke of the knife at the " tuck." The cigars are taken up in bundles of fifty each. They next pass into the hands of the selectors, who separate them into dif- ferent piles, according to the color of the wrappers, and who also reject any cigars that may be of faulty construc- tion. Broken wrappers, bad colors or any other defects are sufficient to cause the rejection of a cigar. The rejected cigars are known as resagos ("throwouts ") or secundos. From the selectors the cigars go to the packers, whose duty it is to place them in the boxes, and to see that the colors in each box are uniform, marking the temporary color classification on each box in lead pencil. After being SOME REMARKABLE FIGURES ABOUT TOBACCO 519 packed, the filled boxes are put into a press and so left for twelve hours or until the cigars conform somewhat to the shape of the box which con- tains them. On being removed from the press, if to be banded, the cigars are carefully removed in layers from the box, the bands afhxed, and the cigars replaced. The goods are then placed in an air-tight vault to await shipment. When the cigarmaker ties up his bundle of fifty cigars, he attaches to it a slip of paper upon which is marked his number. This enables the manu- facturer to keep an accurate account of the number of cigars made by each workman and also to place the respon- sibility for any defects in the workman- ship. Cigarmakers are paid by the piece, the scale of wages ranging from $i6 to $ioo per thousand. In nearly every factory there may be found advanced apprentices or old men work- ing at the rate of $14 per thousand and also there may be found skilled artisans making exceptionally large odd sizes at more than $100 per thou- sand, but these are not generally con- sidered in the regulation scale of prices. In averages, the workmen earn about $18 a week and make about 150 cigars a day. Just a Few Figures About Tobacco. The internal revenue from tobacco for one year woiild build fourteen battleships of the first-class; or it would pay the salary of the President of the United States for nearly a thou- sand years. It would pay the interest on the public debt for three years, and there would be enough left over to add a dollar to the account of every savings bank depositor in the United States. The money spent by smokers for cigars only, not counting cigarettes, smoking and chewing tobacco and snuff would more than pay for the building of the Panama Canal, besides taking care of the $50,000,000 paid to the new French Canal Co., and the Republic of Panama for i^roperty and franchises. And in addition to this it would cover the cost of fortifying the Canal. Or it woiild build a fleet of thirty- five trans-Atlantic liners, each exactly like the lost Titanic, coal them, pro- vision them and keep them running between New York and Liverpool with a full complement of passengers and crew, almost indefinitely. There are 21,718,448 cigars burned up in the United States every twenty- four hours; and 904,935 every hour; and 15,082 every minute; and 251 every second. The annual per capita consumption of cigars in the United States, count- ing men, women and children, is eighty-six cigars. If all the cigars smoked in the United States in one year were put together, end to end, they would girdle the earth, at its largest circumference, twenty-two times. As TO THE CIGARETTES, there are 23,736,190 of them consumed in the United States every day; and 989,007 every hour; and 16,482 every minute. With every tick of your watch, night and day, the year around, the butts of 2 7 5 smoked-up cigarettes are dropped into the ash tray. Cigarette smokers in the United States, not counting those who roll their own smokes from tobacco, spend $60,645,966.36 for the little paper- covered rolls. If all the cigarettes smoked in the United States in one year were placed end to end and stood up vertically they would make a slender shaft rising 512,766 miles into the heavens. // strung on a wire they would make a cable that would reach from the earth to the moon and back again, with enough left over to circle one-and-a-half times around the globe. If this quantity of tobacco could be placed on one side of a huge balancing scale it would take the combined weight of four vast annies, each army con- vSisting of 1,000,000 men, to pull down the other side of the scale. The weight of the tobacco consumed in the United States in a year is equal to the weight of the entire and com- bined ])Oimlation of Delaware, Mary- land, West Virginia, North Carolina, South Carolina, Georgia, Florida, Ten- nessee and Alabama. 520 HOW OUR FINGER PRINTS IDENTIFY US arch: ].\ THIS PATTERN' RIDGES RUN FROM ONE SIDE TO AXOTHF.R, MAKING NO BACK- WARD TURN. loop: some ridges i.\ this pattern >take a backward turn, but without twist. The Story in a Finger Print Our Fingers. One of the most interesting facts about our fingers is that every member of the human race, irrespective of age or sex, carries in person certain deli- cate markings by which identity can be readily established. If the inner surface of the hand be examined, a number of very fine ridges will be seen running in definite directions, and ar- ranged in patterns, there being four primary types — arches, loops, w^horls, and composites. It has been demon- strated that these patterns persist in all their details throughout the whole period of human life. The impres- sions of the finger^ of a new-born in- fant are distinctly traceable on the fingers of the same person in old age. The fact that these patterns on the bulbs of the fingers are characteristic of and differentiate one individual from another, makes it an ideal means of fixing identity. Even men who look so much alike that it is virtually im- possible to tell one from the other so far as facial characteristics are con- cerned, can be identified by their linger impressions. Innumerable illustrations can be given of how the perpetrators of crime have been identified and con- victed by their finger prints. Impres- sions left by criminals on such ar- ticles as plated goods, window panes, drinking glasses, painted wood, bot- tles, cash boxes, candles, etc., have often successfully supplied the clue which has led to the apprehension of the thief or thieves. One of our illus- trations is that of a champagne bottle which was found empty on the dining- room table of a house w^hich had been entered by a burglar in Birmingham, England. There was a distinct im- pression of a thumb mark on the bot- tle. An officer of the Birmingham City Police took the bottle to New Scotland Engravings and story by the courtesy of Scientific American. FINGER PRINTS OF DIFFERENT PEOPLE ARE DIFFERENT 521 WHORL : RIDGES HERE MAKE A TXIRN THROUGH AT LEAST ONE COMPLETE CIRCUIT. COMPOSITE : INCLUDES PATTERNS IN WHICH TWO OR MORE OF THE OTHER TYPES ARE COMBINED. Yard, London, and within a few min- utes a duplicate print was found in the records. The burglar was arrested the same evening. Alany similar instances could be given of how thieves have been caught by handling bottles and glasses. On one occasion a burglar entered a house in the West End of London, and be- fore leaving helped himself to a glass of wine. On the tumbler used he left two finger imprints, and these were subsequently found, upon search in the records at New Scotland Yard, to be identical with two impressions of a notorious criminal, who was in due course arrested and sentenced to four years' imprisonment. A somewhat gruesome relic is a cash-box which bears the blurred thumb mark of a man who was con- victed of murder. The box was found in the bedroom of a man and his wife who were murdered at Deptford, Lon- don, in 1905. The cash-box was taken to New Scotland Yard, and the imj)ression photographed and en- larged. Two brothers, suspected of the crime, were arrested, and the thumb print of one was found to be identical with that on the lid of the box. Our photograph of a gate re- calls a curious case that recently oc- cupied the attention of a London magistrate. In this instance a thief successfully climbed the gate, ^\dlich was ten feet high. In his attempt to reach the ground on the inner side he placed his feet on the center cross- bar, at the same time holding the spikes with his right hand. In this po- sition he fell, and the ring he wore on his little finger caught on the spike in- dicated by the arrowhead. This caused him to remain suspended in the air until his weight tore the finger from his hand. The ring with the finger was found on the spike, and in due course was received at New Scotland Yard. An impression was taken of the finger, and search among the rec- ords revealed a duplicate ])rint, which led to the man's arrest. If a criminal handles a piece of candle or removes a pane of glass and leaves these behind, it is a hundred to one he has left a valuable clue for the police. The candle shown on the follow- '■^^ *5n^n PALMARY IMPRESSIONS OF WHOLE HAND, SHOWING HOW IT IS COVERED WITH RIDGES AND PATTERNS. FINGER IMPRESSIONS OF AN ORANG-OUTANG (anthropoid ape) taken AT THE LONDON ZOO. THEY WERE MADE BY SCOTLAND YARD. ing page bears the imprint of a man's thumb, and was found in a house which a burglar had entered. By handling the candle, the thief virtually signed the warrant for his own arrest. The system was first used by the police in the Province of Bengal, India, at the instigation of Sir William Herschel. Its value was at once ap- parent. The work of the courts was considerably lightened, as the natives recognized that a system of identifica- tion had been discovered which was indisputable. Then from the police it was introduced into various branches of the public service, and here again its value was quickly demonstrated. When native pensioners died, for instance, friends and relatives personated them, and so continued to draw their allow- ances. By recording the identity of pensioners by finger prints, this evil was quickly stamped out. The wonderful lineations, in the form of ridges and patterns, which adorn the palmar surface of the hu- man hand, had, of course, been known for many years. Mr. Francis Galton, the famous traveler and scientist, was ])erhaps the first to give serious atten- tion to the subject of finger prints. He discovered many interesting facts about them. Then, in 1823, Prof. Purkinje, of Breslau, read a paper before the University of Breslau on the subject. Up to this date, however, no practical use could be made of the impressions for the want of a system of classifica- tion. Prof. Purkinje certainly sug- gested one, but little notice appears to have been taken of it. Naturally, to be of any value to the police or to any government depart- ment, it is absolutely essential to classify the prints in such a w-ay that they could be readily referred to and identity established without undue de- lay. It was virtually left to Sir Wil- HOW THIEVES HAVE BEEN CAUGHT THROUGH FINGER PRINTS 523 A CHAMPAGNE BOTTLE HAVING THUMB IM- PRINT, WHICH LED TO ARREST OF A BURGLAR. CANDLE BEARING THUMB MARK OF A BURGLAR. CASH-BOX IN BEDROOM OF MURDERED MAN AND WIFE. THE THUMB IMPRESSION (POINTED AT BY arrow) led TO ARREST OF THE MUR- DERER. liam Herschel, of the Indian Civil Service, to invent a really practical system of classification, so it may be claimed that the finger-print method of identification, as at present adojjted, is the discovery of an Kngh'shman. 1'hcn it is only fair to add that Sir I'xlward R. Henry, the Commissioner of the Metropolitan Police of T.ondr)n, has also devoted much time and study to the subject. His book, "Classifica- tion and Uses of Finger Prints," has passed through many editions, and has been translated into several foreign languages. Impressions are divided up into four distinct types or patterns. First, we have arches in which the ridges run from one side to the other, making no backward turn. In loops, however, some of the ridges do make a back- ward turn, but are devoid of twists. In whorls some of the ridges make a turn through at least one complete cir- cuit. Under composites are included patterns in which two or more of the former types are combined in the same imprint. Although similarity in type is of frequent occurrence, completely coincident ridge characteristics have never been found in any two impres- sions. It is not necessary here to enter into a detailed account as to how the classification of these wonderful linea- tions of the human hand is efifected. It is based on a number value, at- tained by an examination, by means of a magnifying glass, of the "deltas" and "cores," which break up a collec- tion into as many as 1024 separate primary groups, each of which can again, by a system of sub-classifica- tion, be further split up into quite a number of sub-groups. When the British police discover finger prints on articles at the scene of crime, the latter are at once conveyed to New Scotland Yard. If the impressions are very faint, a little powder, known to chem- ists as "grey powder" (mercury and chalk), is sprinkled over the marking and then gently brushed ofif with a camel-hair brush. This brings out the imprint much more clearly. If one places his dry thumb upon a piece of white paper no visible impression is left. If powder, however, is sprinkled over the spot and then brushed off, a distinct impression is seen. In the case of candles and articles of this nature, a drop of printer's ink is lightly smeared over ati im])rcssion, in or(k"r the more clearly to define the ridges and patterns. A SPIKE THAT CAUGHT A CRIMINAL ox THE SPIKE OF THE GATE (INDICATED BY AN arrow) a criminal LEFT HIS FINGER AND RING, WHICH LED TO HIS CONVICTION. At the headquarters of the British poHce at New Scotland Yard they possess special cameras and a dark room for photographing these thumb marks. The dark room is 21 feet long and 7 feet wide. When finger prints are required for production in court they are first enlarged five diameters with an enlarging camera. The nega- tives are afterward placed in an elec- tric light enlarging lantern, with which it is possible to obtain photographic enlargements of a thumb mark 36 inches square. The lantern is arranged on a specially made table 12 feet long, the lantern running between tram lines, so that when moved it is square with the easel. Criminals have naturally come to dread the value of their thumb marks as a means of identifying their movements. Some will try to obliterate the mark- ings by pricking their fingers, but so far this has not availed them. To suc- cessfully accomplish this it would be necessary to obliterate the whole of the palmary impressions on the tip of each finger of each hand. Then the system, too, is far in ad- vance of any other, both in reliability and simplicity of working. Compared to anthropometry, for instance, in- vented by M. Bertillon, in which meas- urements of certain portions of the body are relied upon as a medium of identification, the finger-print system is certainly preferable. In the first place, the instruments are costly and are liable to get out of order ; while the measurements can only be taken by a fairly educated person, and then only after a special course of instruction. In the finger-print system the acces- sories needed are a piece of paper and ink, while any person, whether edu- cated or not, after half an hour's prac- tice, can take legible finger prints. Then the classification of the latter is much simpler and readier of access than the former. At the time of writing there are some 164,000 finger-print records in the pigeon-holes at New Scotland Yard, and the number now being added to it is at the rate of about 250 weekly. The system, too, is not only in use in Great Britain, but in all the provinces of India, including Burma, and in most of the British colonies and dependencies. It is being rapidly ex- tended, not only throughout Europe, but also through North and South America. RECORDS OF FINGER PRINTS ARE KEPT AT HEADQUARTERS 525 SPECIMEN FORM. TU\< Fnrm i? not to Im? innn^^^^^ 0^h<^i:^i$ I, 1 i.—K. Riiif: Finycr -K. Little Fin-cr. mil m (Fold.) (Fold.) Impre.~=ic.ns tr> be so taken thit the fJesiire of the last joint shall bo imQiediately above th-; black lino mrirke^^l (Fold). If the ini])re--inn •<' any digit be defertivc a second print may be taken in the vacant space above it. When a finger is mis.«ing or so injured that the impression cannot be obtained, or is deformed and yields a b.ad print, the fact slmuld 1) • noted under 7?r/i:. //••'..-. LEFT HAND. il. — L. Thumb. 7. — L. Fore Finger, ;.^ -L. Middle FiD" -L. Rin- ['.n. Ji'.— L, i.irfle Finger. m »■: m.. Sm. i^ f ^m (Fold.) (Fold.) LEFT HAND. lidn impressions of the four fingers taken simultaneously. RIGHT HAND. Plain impressions of the ii.ur fin^'ers taken simultaneausly. f^k Jinjiiti'lont luhen I'j I'vUcc ) Farcf. S Claitijl^il III JI.C. lUiji^lrii hi) Teiifd al JI.C. lUglHrij bi/ kWJ3 6 ilfniiiii a r .jitiiMfa^ifcM^yfc^^iiiiiiiaiy, 526 WHERE HONEY COMES FROM COMBS OF HONEY AS WE RECEIVE SAME The Story in a Honey Bee- Of all the insect associations there are none that have more excited the ad- miration of men of every age or that have been more universally interesting than the colonies of the common honey- bee. The ancients held many absurd views concerning the generation and propagation of bees, believing that they arose from decaying animals, from the flowers of certain plants, and other views equally ridiculous from our present point of view. Where Does Honey Come From? Honey is a sticky fluid collected from flowers by several kinds of insects, particularly the honey bee; and the common honey bee from the earliest period has been kept by people in hives for the advantage and enjoyment which its honey and wax gives. It is fotmd vnld in North America in great numbers, storing its honey in hollow trees and other suitable locations, but not native to this country, having been introduced in North America by European colonists. The story of the honey bee is one of the most interesting of all stories of the living things found on the earth. The busy bee is the ideal example of hard and persistent work and has for a long time been the subject of interesting study for young and old. The bee is one of the busiest of all of the world's workers, and it is from the honey bee that we get our expression " as busy as a bee"; such other expressions as "to have a bee in one's bonnet"; also such others as " quilting bees " and " husk- ing bees " are founded on the known activities of the honey bee. The first expression means "to be flighty or full of whims or uneasy motions " which comes from the restless habits of bees, and " quilting bee " or " husking bee " Pictiires by Courtesy of E. R. Root Co. HOW A BEE MAKES HONEY 527 WORKER-BEE. QJEEN-BEE, MAGNIFIED. DRONE-BEE. originated from the knowledge that bees work together for the queen. In a quilting bee or husking bee a number of people get together and work to- gether for a time for the benefit of one individual. Honey Is Produced by Bees which Live in Colonies. A colony of bees consists of one female, capable of laying eggs, called the queen; some thousands of un- developed females that nonnally never lay eggs, the workers; and, at certain seasons of the year, many males, the drones, whose only duty is to mate with the young queens. These dif- ferent kinds of individuals can readily be recognized by the difference in size of various parts of the body, so that even the novice at bee-keeping can soon recognize each with ease. This colony makes its home in nature in a hollow tree or cave; but it thrives per- haps even better in the hives provided for it by man. In a modern hive, sheets Bbfc.3 LiVl.NO US CUMUS UUILT IN THE Ol'EN AlK. 528 WHAT THE QUEEN BEE DOES of comb arc placed in wooden frames which are hung in the hive-box in such a wav that they can be removed at the pleasure of the bee-keeper. A sheet of comb is made up of small cells in which honey is stored by the bees, and in which eggs are laid, and young bees develop. How Does a Bee Make Honey from Flower Nectar? In the s]mng of the year the colony consists of a queen and workers, there being no drones present at this time. CCCUMBER-BLOSSOM WITH A BEE ON IT; CAUGHT IN THE ACT. During the winter the bees remain quiet, and the queen lays no eggs, so that there are no developing bees in the hive. The supply of honey is also low, for they have eaten honey all winter, and none has been collected and placed in the cells. As soon as the days are wami enough the bees begin to fly from the hive in search of the earliest spring flowers. From these flowers they collect the nectar, which is transformed into honey, and pollen, which they carry to the hive on the pollen-baskets on the third pair of legs. The nectar is taken by the bee into its mouth, and then passes to an en- largement of the alimentary canal known as the honey-stomach, where it is acted upon by certain juices secreted by the bee. The true stomach lies just behind the honey-stomach; and if the bee needs food for its own imme- diate use it passes on through the oj^cn- ing between the two stomachs. On its arrival in the hive the bee places its head in one of the cells of the comb and deposits there the nectar which it has carried in. By this time the nectar has been partly transformed into honey, and the process is completed by the bees by fanning the cells to evaporate the excess of moisture which still re- mains. When a cell has been filled with the thick honey the workers cover it with a thin sheet of wax unless it is to be eaten at once. The pollen is also deposited in cells, but is rarely mixed with honey. The little pellets which the bees carry in are packed tightly into cells until the cell is nearly full. If a cell of pollen be dug out of the comb, one can often see the layers made by the different ■ pellets. This collecting of nectar and pollen con- tinues throughout the summer when- ever there are flowers in bloom, and ceases only with the death of the last flowers in the autumn. What Does the Queen Bee Do? Almost as soon as the honey and pol- len begin to come in, the queen of the colony begins to lay eggs in the cells of the center combs. The title of queen has been given to the female bee which normally lays all the eggs of the colony, under the supposition that she governs the colony and directs its activities. This we now know to be an error, but the name still remains. Pier one duty in life is that of egg-lay- ing. She is most carefully watched over by the workers, and is constantly surrounded by a circle of attendants who feed her and touch her with their antennae; but she in no way dictates what shall take place in the hive. The eggs are laid in the bottom of the hexa- gonal cells, being attached by one end to the center of the cell. The first eggs laid develop into workers, and are deposited in cells one-fifth of an inch across. As the colony increases in size by the hatching-out of these workers, and as the stores of honey and pollen increase, the queen begins to lay in larger cells measuring one- HOW THE EGG OF THE QUEEN BEE LOOKS 529 THE DEVELOPMENT OF COMB HONEY i fourth of an inch, and from the eggs laid in these cells drones (or males) develop. The eggs do not develop directly into adult bees, as might be inferred from what has just been said; but after three days there hatches from the egg a small white worm-like larva. For several days the larvae are fed by the workers, and the amount of food consumed is truly remarkable. The larva grows rapidly until it fills the entire cell in which it lives. The workers then cover the cell with a cap of wax, and at the same time the larva inside spins a delicate cocoon under the cap. fJSl THE QUEEN AND HER RETINUE. EGG OF QUEEN UM)I:K TIII: MICROSCOPE. 530 HOW HONEY DEVELOPS IN A COMB WHAT DRONES ARE GOOD FOR 531 What Are Drone Bees Good for? The worker brood can at once be distinguished from the drone brood by the fact that the workers place a flat cap over worker brood and a high arched cap over drone brood; and this is often a great help to the bee-keeper in enabling him to determine at once what kind of brood any hive contains. Twenty-one days from the time the egg is laid the young worker-bee emerges from its cell, having gone through some wonderful transformations during the time it was sealed up, this stage being known as the pupa stage. For drones the time is twenty-four days. About the time the drones begin to appear, the inmates of the hive begin to prepare for swarming, which, to any one watching the habits of bees, is one of the most interesting things which takes place in the colony. Several young worker larvee are chosen as the material for queen-rearing, generally located near the margin of the comb. The workers now begin to feed these MOW A bWAKM WILL SOMKTLMLb OCCLI'Y A b.MALL IKLL ANU IJLNU 11 U\ LU HV US WEIGHT. 532 HOW THE HONE\ COiWB IS MADE chosen larv?c an extra amount of food and at the same time the sides of the cells containing them are remodeled and enlarged by the destruction of surrounding cells. The queen (or royal) cell is nearly horizontal at the 3 4569 12 15 THE DAILY CROWTH OK LARV^. placed vertically on the comb, about as large as three ordinary cells. As the cell is being built, the queen larva continues to grow until the time comes for her to be sealed up and enter her pupa state. Although it takes the worker twenty-one days to complete its DRONE-COMB. WORKER-COMB. top, like the other cells of the comb, and projects beyond them; but then the workers construct another portion to the cell into which the queen larva moves. This is an acom-shaDcd cell development, the queen passes through all the stages and reaches a considerably larger size in but sixteen days. In the swarming season, at about the time the new queens are ready to ^^ £1 1^ lH mi m 9 1 iM i tS ii@9^S 4 1^' ■1 km H ^^1^ m k'^^^^HH mm Mi m Mi s KH^i^S! i ^^HV m ^ M SI ^SSB i n BS^? m s 9 s 2 Iiai i H A STUDY IN CELL-MAKING. Note that the cells are made independent of each other, and that it is the refuse wax, like drop- pings of mortar in brick-laying, that seems to tumble into the interstices to fill up. CLIPPING THE QUEEN BEE'S WINGS 533 HOW TO BUMP THE BEES OFF A COMB. MANNER OF USING GERMAN BEE-BRUSH M. G. Dcrvishian's method of catching queens, for caging or clipping their wings, by means of a jeweler's tweezers. THE PROOF OF THE PUDDING IS IN THE EATING." 534 WHAT AN APIARY LOOKS LIKE FS >-6 |S C !- 5-a rtrQ 1^-?^ .;£ c3 c r^ .^•o « S &.-o-^ ?^'o +^"" T ^ r- O (U c ^ . rt "? -CT3^ T-^-c o t b^-^ rt O +-> >'&i2 o OJ U} .S-o-- o S -O ^ >< as ns sur which mmer nty oj 1 ^ < vergree ory of In su ing pie <^'^ ■ > i^ "" ^ ^ O.X! . c3 a ^TJ T, who settled in Lynn in the year 1750. Dagyr was a celebrated shoemaker and was enabled, from his own means, to secure the best examples of work from abroad. He THE FIRST MACHINE FOR MAKING SHOES 545 possessed the peculiar quality of being able to teach the art to those who came under his charge. The fame of New England made shoes was due largely to the teachings of these men and the industry has continued to be one of the first in importance. In Massachusetts alone, according to the census of 19 lo, over 40 per cent of the entire value of shoes in the United States was produced. The young man of this period, who essayed to learn the shoemaking trade, was ordinarily apprenticed for a term of seven years under the most rigorous terms, as shown in some of the inden- tures of that period which are still in existence. He was instructed in every part of the trade and, upon comple- tion of his term of service, it was the custom for the newly fledged shoe- maker to start what was known as " whipping the cat " — which meant journeying from town to town, living with a family while making a year's supply of shoes for each member thereof, and then leaving to fill other engagements previously made. It was soon found that the master workman could largely increase his income by employing other men to do certain .portions of the work, while he directed their efforts, and this gradually lead to a division of the labor and was the beginning of a factory system — which, has been in process of development from that time. In the year 1795 it is recorded that there were in the city of Lynn, Mass., over two hundred master workmen, employing over six hundred journey- men, and that they manufactured shoes at the rate of about one pair per day per man. Factory buildings, as the words would Vjc known to-day, were prac- tically unknown at that time. The small Vjuildings, about ten feet .square, were in the back yards of many homes and in these little shops were employed from three to eight men. Strange as it may seem, jjrior to the year 1845 there had been little change in the tf)ols emjiloycd in making shoes. The workman of that period, seated at his low bench, used prac- tically the same implements that were employed by his prototype, the ancient sandal-maker of Egypt. The lap stone, the hammer, the crude needle and the knife being practically the only tools used. Not that there had been no effort to perfect machinery for this purpose; Napoleon I, in his endeavor to secure better shoes for his soldiers, had offered great rewards for the per- fecting of shoe machinery that would accomplish this purpose, but although great effort had been made there had been no successful machinery produced. In this year 1845 the first machine to be widely adopted by the industry was perfected. It was a simple form of rolling machine, which took the place of the lap stone and hammer used by the shoemakers for toughening the leather, and it is said that a man could, in half an hour, obtain the same results from this machine that would require a day's labor on the part of the hand workman employing the old method of pounding. This was followed in 1848 by the very important invention by Elias Howe of the sewing machine — which was not adapted for use in connection with sewing leather until several years later. It started, however, an era of great activity among inventors and in 1857 there was perfected a machine for driv- ing pegs, which came into successful operation. The First Machine for Making Shoes. This was shortly followed by a very important invention by L}TTian E. Blake, of Abington, Mass., of a machine for sewing the soles of shoes and this afterwards became famous as the " McKay Sewing Machine." This in- vention of Blake's was purchased by Gordon McKay, who spent large sums of money in perfecting it, and the first machine was established in Lynn in 1 86 1. The results obtained in the early stages of the machines were of an indifferent nature and it was only after large exj)enditurcs and the hiring of a numljcr (jf different inventors to work upon it that a successful machine was produced. 546 BOOTS OF THE CAVALIERS AND POSTILLIONS FRENCH POSTILLION BOOT OF THE FIFTEENTH CENTURY THE CAVALIER BOOT OF THE FIFTEENTH CENTURY MILITARY JACK BOOT OF CROMWELL's TIME MILITARY JACK BOOT OF SIXTEENTH CliNTLRY. HOW SHOE MACHINERY WAS DEVELOPED 547 While the quahty of work was pro- nounced by manufacturers to be a success, few had any faith in the possibility of manufacturing shoes by machinerj^ and McKay met with con- stant rebuffs in his endeavor to intro- duce his machine. It is recorded that in his desperation he finally . offered to sell all the patent rights in machines which he owned to a syndicate of Lynn manufacturers for the sum of $250,000.00 — the amount he had ex- pended — but the offer was refused. In his dilemma McKay at last offered to shoe manufacturers the use of his machines on a basis, which afterwards became famous and an inherent part of the shoe industry known as " royalty," whereby McKay placed his machines with manufacturers and participated to a small extent in the amount of money saved. Owing to the fact that shoemakers were leaving rapidly for the front and that there was a great scarcity of footwear, the manufacturers gladly accepted this proposition and the machines were very rapidly introduced. The success of his early machines accomplished, McKay set about the perfecting of others that would do different parts of the work and there was accordingly great activity on the part of inventors in their endeavor to perfect machines for the wide variety of uses made necessary in the prepara- tion of leather for shoemaking. There were soon machines on the market for a wide variety of purposes — including the lasting of the shoe, cutting the leather and for many other processes necessary in making a complete shoe. Contemporary with the early suc- cess of the McKay machines, a French inventor, August Dcstoncy, conceived the idea of making a machine which would sew turned shoes — then a iJOi)ular type of footwear for women. After several years of endeavor he finally secured the interest of John Hanan, a famous shoemaker of that time in New York City, and through him the interest of Charles (jood year— nephew of Goodyear of India-ruljber fame. No sooner had the machine h)ecome jjerfccted for the sewing of turned shoes, however, than he set to work to make changes which would fit it to sew welt shoes. (The welt shoe has always been considered the highest type of shoemaking, as, by a very ingenious process, a shoe is made which is perfectly smooth inside ; all the other types having a seam of thread or tacks inside which make them of considerable disadvantage. He was able to accomplish this a few years later, although the machines were not in extended use until about 1893, when auxiliary machines for perform- ing important parts of the work were perfected; and from that time head- way was made in the manufacture of this high grade type of footwear. The development of the industry — which has been very rapid with the introduction of machinery — suffered materially in the latter part of the last century through the bitter rivalry of machinery manufacturers, a common process being the enjoining of manu- facturers from the use of machines on which it was claimed the patents were infringed and this created a state of great uncertainty in the minds of many of those manufacturing shoes. This condition finally found its solu- tion in the formation of one large cor- poration, known in the shoe industry as the " United Shoe Machinery Com- pany," which purchased the patents for a sufficient number of machines to form a complete system for the " bottoming " — or fastening the soles and heels of shoes — and finishing them. These machines have been the sub- ject of constant improvement and others have been perfected to take care of operations which, prior to their intro- duction, were purely hand operations. Each machine has been standardized and so adapted to meet the require- ments of those used in connection with it that they collectively form the most remarkable and efficient system of machines used at the present time. Mention is made of this company owing to the important position it has taken in the organization and advancement of the industry, the American-made shoe being the one commodity of world-wide consumption whose supremacy is not contested. 548 MY LADY'S SLIPPERS OF EARLY TIMES EMBROIDERED RIDING BOOT EMBROIDERED RIDING BOOT WORN -BV NOBLES DURING FROM PERSIA OF ABOUT LAST DAYS OF POLISH 185O INDEPENDENCE FRENCH CALF BOOT MADE IN NEW YORK CITY, 1835 LADY S SHOE — PERIOD OF THE FRENCH REVOLUTION SHOE PERIOD OF LOUIS XVI. Has wooden heel. lady's ADELAID OR SIDE LACED SHOE — PERIOD 183O TO 1870 THE BEGINNING OF A SHOE How Shoes Are Made by Machinery At the present time the types of shoes ordinarily made are but five: the " peg " shoe, which is the cheapest type of shoe made; the " standard screw," which is used in the soles of the heaviest types of boots; the " McKay sewed," which is made after the fashion established by Gordon McKay; the " turn " shoe, a light type of shoe which was invented cen- turies ago and which is still worn at this time to a limited extent; and the " Goodyear welt," which has been universally adopted as the highest type of footwear. For this reason, this type of shoe has been selected to show the methods em- ployed in making shoes. The Goodyear Welt Shoe. — A Goodyear Welt shoe in its evolution from the embryonic state in which it is " mere leather and thread " to the completed product, passes through one hundred and six diflerent pairs of hands and is obliged to conform to the re- quirements of fifty-eight different ma- chines, each performing with unyielding acc-uracy the various operations for which they were designed. It might seem that in all this multi- plicity of ojjcrations confusion would occur, and that the many details and .spec-ifications regarding material and design of any given lot of shoes in ])roc- ess of manufacture would become hopelessly entangled with those of similar lots undergoing the same opera- tions. But such is not the case; for, when an order is received in any modem and well-organized factory, the factory management promptly take the pre- caution to see that all the details regarding the samples to which the finished product is to conform are set down in the order book. Each lot is given an order number and this number, together with the details affecting the preparation of the shoe upper, are written on tags — one for each two dozen shoes — which are sent to the foreman of the cutting room. Others containing details regarding the sole leather are sent to the sole leather room, while a third lot is made out for the guidance of the foreman of the making or bot- toming room, when the different parts which have received attention and been prepared according to specifica- tions in the cutting and sole leather rooms are ready to be assembled for the making or bottoming process. If the tags which were sent to the cut- ting room were followed, it would be found that on their reccii^t the fore- man of this dei)artment figured out the amount and kind of leather re- quired, the kind of linings, stays, etc., and tliat the leather, together with the 550 SHOEMAKINQ MACHINERY IS ALL BUT HUMAN tags which gave directions regarding the size, etc., was sent to one of the operators of the Ideal CHcking Machine. This machine has been pronounced one of the most important innovations that have been made in the shoe manu- facturing industry during recent years, as it pcrfonns an operation which has heretofore successfully withstood every attempt at mechanical aid. Prior to its introduction, the cutting of upper leather was accomplished by the use of patterns made with metal edges, which were laid upon the leather by cutter, who then ran a small sharp knife along the edges of the pattern, cutting the leather to conform to it. This was a slow and laborious process, and if great care was not taken, there was a tendency to cut away from the pattern; and in many cases, through some slip of the knife, the leather was cut beyond the required limits. This machine has a cutting board ver}^ similar to those which were used by the hand workman and over it is a beam which can be swomg either to the right or to the left, as desired, and over any portion of the board. Any kind of skin to be cut is placed on the board, and the operator places a die of unusual design on it. Grasping the handle, which is a part of the swing- ing beam, he swings the beam over the die, and on downward pressure of the handle a clutch is engaged which brings the beam downward, pressing the die through the leather. As soon as this is accomplished, the beam auto- matically returns to its full height and remains there until the handle is again pressed. The dies used are but three-quarters of an inch in height and are so light that they do not mar the most deli- cate leather when placed upon it. They enable the operator to see clearly the entire surface of the leather he is cutting out, and it is obvious that the pieces cut by the use of any given die must be identically the same. After the different parts required by the tag have been cut out by the opera- tor of the Clicking Machine, some of the edges which show in the finished shoe must be skived or thinned down to a beveled edge. This work is performed by the Amazccn Skiving Machine — a wonderful little machine in which the edge to be skived is fed to a sharp revolving disk that cuts it down to the desired bevel. The machine does the work in a very efficient maimer, conforming to all the curves and angles. This skiving is done in order that the edges may be folded, to give the ]jarticular edge on which it is perfonned a more finished appearance. The skived edges are then given a little coating of cement and aftJerwards folded on a machine which turns back the edge and incidentally pounds it down, so that it presents a very smooth and finished appearance. Aside from the work of skiving toe caps and folding them, there is generally a series of ornamental perforations cut along the edge of the cap. This is done very often by the Power Tip Press, by means of which the piece to be perforated is placed under a series of dies which cuts the perforations in the leather according to a predeter- mined design, doing the work all at one time. The number of designs used for this purpose are many and varied, combinations of different sized perforations being worked out in in- numerable designs. On one of the top linings of each shoe there has been stamped the order num- ber, together with the size of the shoe for which the lingings were intended. After all the lingings have been prepared in accordance with the instructions on the tag, they, in connec- tion with the various parts of the shoe, receive attention from the Stitchers, where all the different parts of the upper are united. The work is performed on a range of wonderful machines, which perform all the different opera- tions with great rapidity and accuracy. At the completion of these operations the shoe is ready to receive the eye- lets, which are placed with remarkable speed and accuracy by the Duplex Eyeletting Machine. This machine eyelets both sides of the shoe at one time with bewildering rapidity. The eyelets are securely placed and accu- rately spaced; and as both sides of THE DIFFERENT PARTS OF THE SHOE COME TOGETHER 551 the upper are eyeletted at one time, the eyelets are placed directly opposite each other, which greatly helps the fitting of the shoe, as thereby the wrinkling of the shoe upper is avoided. With the completion of this operation, the preparation of the shoe upper is finished, and the different lots with their tags are sent to the bottoming room to await the coming of the dif- ferent sole leather portions of the shoe. These have been undergoing prepara- tion in the sole leather room, where on receipt of tag the foreman has given directions for the preparation of out- soles, insoles, counters, toe boxes and heels, to conform with the require- ments of the order. The soles are roughly died out from sides of sole leather on large Dieing- out Machines, which press heavy dies down through the leather ; but to make them conform exactly to the required shape, they are generally rounded out on a machine known as the " Planet Rounding Machine," in which the roughly died-out piece of leather is held between clamps, one of which is the exact pattern of the sole. On starting the machine, a little knife darts around this pattern, cutting the sole exactly to conform with it. The outsole is now passed to a heavy Rolling Machine, where it is subjected to tons of pressure between heavy rolls. This takes the place of the hammering which the old-time shoemaker gave his leather and brings the fibres very closely together, greatly increasing its wear. This sole is next fed to a machine called the " Summit SpHtting Machine — Model M," which reduces it to an exactly even thickness. The insole — which is made of very much lighter leather — is j;rcpared in much the same manner, and in this way it will be noticed that both the insole and out- sole are reduced to an absolutely uni- form thickness. The insole also receives further preparation; it is channeled on the Goodyear Channeling Machine. This machine cuts a little slit along the edge of the insole, extending about one-half inch towards its center. It also cuts a small channel along the surface. The lip which has been formed by the Goodyear Channeling Mach ne is now turned up on the Goodyear Lip Turning Machine, so that it extends out at a right angle from the insole, forming a lip or shoulder against which the welt is sewed. The cut which has been made on the surface inside this lip serves as a guide for the operator of the Welt Sewing Machine, when the shoe reaches chat stage. The heels to be used on these shoes have also been formed from different lifts of leather which are cemented together. The heel is then placed under great pressure, giving it exact form and greatly increasing its wear. The counters are also prepared in this room, as well as the toe boxes or stiffening, which is placed between the toe cap and the vamp of the shoe. When these are all completed, they are sent to the making or bottoming room, where the completed shoe upper is awaiting them. Here a wonder- fully ingenious little machine called the " Ensign Lacing Machine," passes strong twine through the eyelets and in a twinkling ties it automatically. This is done so that all parts of the shoe will be held in their normal position while the shoe is being made. The knot tied by this machine is per- fect and is performed with mechanical exactness. On high-grade shoes this work was formerly performed by hand and it will be readily recognized how difficult it was to obtain uniformity. The spread of the upper at the throat can be regulated perfectly when this machine is used. The different parts of the shoe now commence to come together. The workman places the toe box, or stiffening, in the proper location as well as the counter at the heel, and draws the vipper over the last. To the bottom of this last has already been tacked by means of the U. S. M. Co. Insole Tacking Machine— which drives tacks automatcially — the insole, which, it \v\\l be noticed, conforms exactly to the shape of the bottom of the last. This last, made of wood, is of the utmost importance, for upon the last depends the shape of the shoe. 552 EACH SHOE MACHINE DOES SOMETHING DIFFERENT Operator locates back seam of upper on last. Machine drives two tacks wliich hold it in place. The shoe as completed up to this l)oint with the parts mentioned fastened together as shown, is now ready for assembHng. The workman, after placing the last inside the shoe upper, puts it on the spindle of the Rex Assembling Machine, where he takes care that the seam at the heel is properly located. He presses a foot lever and a small tack is driven part way in, to hold the upper in place. He then hands it over to the operator of the Rex Pulling-Over Machine. This machine is a very important one; for as the parts of the shoe upper have been cut to exactly conform to the shape of the last, it is necessary that they should be correctly placed on the last to secure the desired results. The pincers of this machine grasp the leather at different points on each side of the toe; and the operator, standing Draws shoe upper smoothly down to last- Operator adjusts it so that each seam occu- pies correct position on last. Machine auto- matically drives back to hold it in place. in a position from which he can see when the upper is exactly centered, presses a foot lever, the pincers close and draw the leather securely against the wood of the last. At this point the operation of the machine halts. By moving different levers, the work- man is able to adjust the shoe upper accurately, so that each part of it lies in the exact position it was intended when the shoe was designed. When this important operation has been completed, the operator again presses a foot lever, the pincers move toward each other, drawing the leather securely around the last, and at the same time there are driven automatically two tacks on each side and one at the toe, which hold the upper securely in posi- tion. These tacks are driven but part way in, so that they may be after- ward removed. HAND METHOD LASTING MACHINE Last sides of shoe. The shoe is now ready for lasting. This is one of the most difficult and imjjortant parts of the shoemaking process, for upon the success of this operation depends in a great measure the beauty and comfort of the shoe. The Consolidated Hand Method Welt Lasting Machine, which is used for this purj^ose, takes its name from the almost human way in which it per- forms this part of the work. It is wonderful to observe how evenly and tightly it draws the leather around the last. At each pull of the pincers a small tack driven automatically part way in holds the edge of the upper exactly in place, so that in the finished shoe every part of the upper has been stretched in all directions equally. The toe and heel of the shoe are con- sidered particularly difficult portions to last properly. This important part LASTING MACHINE Last toe and heel of shoe. of the work is now being very gener- ally performed on the U. S. M. Co. Lasting Machine — No. 5, a machine of what is known as the " bed type." It is provided with a series of wipers for toe and heel, which draw the leather simultaneously from all direc- tions. There can be no wrinkles at the toe or heel of shoe on which it is I)ropcrly used and the quality of work produced by it has been very generally recognized as a distinct advance in this important part of shoemaking. After the leather has been brought smoothly around the toe it is held there by a little tape fastened on each side of the toe and which is held securely in place by the surplus leather crim])led in at this ])oint. The suri)lus leather 554 A MACHINE THAT FORMS AND DRIVES TACKS crimpled in at the heel is forced smoothly down against the insole and held there by tacks driven by a very ingenious hand tool in which there is a constantly renewed sui)ply of tacks. UPPER STAPLING MACHINE Forms small sta- ples from wire. Holds shoe upper to lip of insole. In all of the lasting operations the tacks are driven but part way in, except at the heel portion of the shoe, where they are driven through the insole and clinched on the iron heel of the last. The tacks are driven only part way in, in order that they may be afterward withdrawn so as to leave the inside of the shoe perfectly smooth. In making shoes other than Goodyear Welts, with the exception of the Good- year Turn Shoe, it is necessary to drive the tacks through the insole and clinch them inside the shoe, so that the dif- ferent portions of the sole inside the shoe have clinched tacks. These are left even after the shoe is finished. This smooth interior of the shoe is one of the essential features of the Goodyear Welt Process. In the lasting operation there is naturally a surplus amount of leather left at the toe and sometimes around the sides of the shoe, and this is removed on the Rex Upper Trimming Machine in which a little knife cuts away the surplus portion of the leather very smoothly and evenly, and simultane- ously a small hammer ojicrating in connection with the knife pounds the leather smooth along the sides and the toe of the shoe. The shoe then passes to the Rex Pounding Machine, in which a hammer pounds the leather and counter around the heel so that the stiff portion of the shoe confonns exactly to the shape of the last. UPPER TRIMMING MACHINE. Trims off surplus part of shoe upper and lining. The shoe is now ready to receive the welt, which is a narrow strip of leather that is sewed along the edge of the shoe, beginning where the heel is placed and ending at the same spot on the opposite edge. This welt is sewed from the inside lip of the insole, so that the needle passes through the Hp, upper and welt, uniting all three securely and allowing the welt to protude evenly along the edge. The needle in making this stitch does not go inside the shoe, but passes through only a portion of the insole, leaving the inside perfectly smooth. This part of the work was formerly one of the most difficult and laborious tasks in shoe- making. As it was performed entirely by hand, the drawing of each stitch AN AUTOMATIC SEWING MACHINE WHICH NEVER TIRES 555 depended upon the strength and mood of the workman. It is of course obvious that with different operators stitches were oftentimes of different lengths and drawn at different ten- sions; for human nature is much the same ever}avhere, and it is impossible for a workman who has labored hard all day to draw a stitch with the same tension at night as might have been possible in the morning. evenly and tightly; for the machine never tires, and it draws the thread as strongly in the evening as in the morning. Every completed movement of the needle forms a stitch of great strength, which holds the welt, upper and insole securely together. As the lasting tacks as well as the tacks which hold the insole in place on the last were withdrawn just prior to this operation, it will be seen that WliLT AND TURNED SHOE SEWING MACHINE Upper portion shows operator at machine. The lower shows formation and location of stitch formed by this machine. It is surprising how quickly and easily the work is done on the Good- year Welt Sewing Machine. This fam- ous machine has been the leading factor in the great revolution that has taken place in shoe manufacturing. Its work should be carefully noted- - all stitches of equal length and meas- ured automatically, the strong linen thread thoroughly waxed and drawn the inside of the shoe is left perfectly smooth. After this process the sur- plus portions of the lip, upper and welt which protrude beyond the stitches made by the Goodyear Welt Machine are trimmed off by the Goodyear Inseam Trimming Machine — a most efficient machine, in which a revoK^ing cui>sha])ed knife comes in contact with the surjjlus ])ortions of the leather 556 PUTTING THE GROUND CORK AND RUBBER CEMENT IN SHOES Trims shoe upper lining and lip of in- sole smooth down to stitches. and trims them off very smoothly down to the stitches. At this stage the shoe is passed to the Universal Welt Beater, in which a little hammer \dbrating very rapidly beats the welt so that it stands out evenly from the side of the shoe. As the leather is bent around the toe, it is the natural tendency of the welt WELT BEATING AND SLASHING MACHINE Beats welt so that it stands out evenly round edge of shoe. to draw more tightly at that place, and this is taken care of by a little knife which the operator forces into operation, in the beating process, the toe is being taken care of, and it makes a series of little cuts diagonally along the edge of it. The insole and welt now receive a coating of rubber cement. This cement is contained in an air- tight tank and is applied by means of a revolving Inrush, which takes its supply of cement, as required, from a can. In this way, an even coating of any desired thickness is given to the insole PLACING SHANK AND FILLING BOT- TOM. Workman tacks shank in place and fills bottom with ground cork and rubber cement. and welt. This machine has many advantages; the cement being closely confined in the tank, there is almost no waste in its use. Formerly, when this was done by hand, the waste through evaporation or lack of care on the part of the workman was very material. The heavy outsole of the shoe also receives at this time proper attention. The flesh side of this sole, or the side next to the animal, receives a coating of rubber cement, and after it has dried slightly the operator of the Goodyear Improved Twin Sole Laying Machine MACHINES WHICH PUT THE SOLES ON SHOES 557 Presses outsole to bottom of shoe where it is held by rubber cement. takes the work in hand. In this machine there is a rubber pad, or mould, which has been made to con- form to the curve in the sole of the shoe. After placing the last on the spindle, which is suspended from the machine and hangs over the rubber mould, the outsole having been pre- viously pressed against the' bottom of the shoe, the operator by pre'ssing the foot lever causes this arm to descend, forcing the shoe down into the mould, so that every portion of the sole is pressed against the bottom of the shoe and welt. Here they are allowed to remain for a sufficient length of time for the cement to prop- erly set, the operation being repeated on a duplicate part of the machine, the operator leaving one shoe under pressure while he is preparing another. The next operation is that of trim- ming the sole and welt so that they Roughly rounds outsole and welt to conform to shape of last. Cuts small channel along edge for stitches. 558 SEWING THE SOLE TO THE SHOE will protrude a iinifonn distance from the edge of the shoe. This work is performed on the Goodyear Universal Rough Rounding Machine, which gauges the distance exactly from the edge of the last. It is often desired to have the edge extended further on the outside of the shoe than it does on the inside and also that the width of the * edge should be considerably re- duced in the shank of the shoe. This is taken care of with great accuracy by the use of this machine. The operator is able to change the width at will. By the use of this remarkable machine the operator is also enabled to make the sole of the shoe conform exactly to all others of similar size and design. Goodyear Outsolc Rapid Lockstitch Machine, which is very similar in operation to the Goodyear Welt Sewing Machine used in sewing the welt to the shoe. The stitch, however, is finer and extends from the channel which was cut for it to the upper side of the welt, where it shows after the shoe has been finished. The lock- stitch formed by this machine is a most durable one. Using a thoroughly waxed thread, it holds the outsolc securely in place, even after the connecting stitches have been worn off. This is one of the most important machines in the shoemaking process. It is able to sew even in the narrow shank, where a machine using a straight needle could not possibly place its stitch. The surplus portion of the leather is now trimmed off on the Heel-Seat Rounding Machine, and the channel cut by the knife on the Rough Round- ing Machine is tiimed up so that it leaves the channel open. This is done by the Goodyear LFniversal Channel Opening Machine, in which a little wheel, turning very rapidly, lays the lip smoothly back. The outsole is now sewed to the welt. This operation is performed on the CHANNEL CEMENT- ING MACHINE. Coats surface of channel so it may be laid to cover stitches. The " Star Channel Cementing Machine — Model A " is again called into operation for the purpose of coat- ing with cement the inside of the channel in which this stitch has been made. A special brush with guard is used for this purpose, and the operation is very quickly performed by the skilled operator. After this cement has been allowed to set a sufficient length of time, the channel lip, which has previously been MACHINES WHICH PUNCH THE SOLES OF SHOES 559 Rubs channel lip down to cover stitches. laid back against the sole, is again forced into its former position and held securely in place by rubber cement. This work is done by the Goodyear Channel Laying Machine, in which a rapidly revolving wheel provided with a peculiar arrangement of flanges forces back into place, securely hiding the stitches from observation on this por- tion of the shoe. The next operation is that of leveling, which is performed on the Automatic Sole Levelling Machine — one of the most interesting used in the shoe- making process. This is a double machine provided with two spindles, on one of which the operator places a shoe to be levelled. It is securely held by the spindle and a toe rest, and on the operator's pressing a foot lever, the shoe passes automatically beneath a vibrating roll under heavy pressure. This roll moves forward with a vibrating motion over the sole of the shoe down into the shank, passes back again to the toe, then cants to the right, and repeats the operation on that side of the shoe, returning to the toe and canting to the left, repeating the ojK'ration on that side; after which the shoe auto- matically drops forward and is relieved from pressure. This rolling motion removes every possibility of there being any unevenness in the bottom of LOOSE NAILING MACHINE Drives small nails which hold outsole in place at heel. the shoe, and while one shoe is under pressure the operator is preparing a second one for the operation. AUTOMATIC LEVEL- LING MACHINE. Rolls out any unevenness in soles. WHERE PAPER COMES FROM 561 A LUMP OF PULP. Paper such as found in this book is made from trunks and limbs of trees. The use of good fibers in book paper is a guarantee of quaHty and durabihty. The above illustration represents a lump of this pulp prepared for the beaters. How the Paper in this Book is Made Where Does Paper Come From? Egyptians were the first people to make what would today be called paper. They made it from a plant called papy- rus and that is where the name comes from. This plant is a species of reed. The Egyptians took stalks of reed cut into as thin slices as they could, laid them side by side ; then they arranged an- other layer on top with the slices the other way and put this in a press. When dried and rubbed until smooth, it made a kind of jiaper, which could be written uj)on. One of the first substances used for making the kind of jjaper we have to- day was cotton. I'apcr was made from cotton about 1100 A. D. Erom this thin cotton paper our present papers arc a development, i.e., paper today is largely made of vegetable fibers. Vegetable fibers consist mostly of cellulose sur- rounded by other things which hold the short vegetable libers together. The fibers best adapted for making paper are those of the cotton and flax plants, and while the tises of paper were few, no other material was needed when it was once learned that cotton and linen fibers would do for making paper. All we had to do was to save all the old rags and sell them to the paper man. In making paper from rags, the rags were allowed to rot to remove the sub- stances that incrust the cellulose, and tlien beaten into a pulp, to which a large fjuantity of water was added. This pulp was put into a sieve, until the greater part of the water had been drained off by shaking, and the fibers remaining formed a thin layer on the bottom of the sieve. This layer of fiber was put into a pile with other similar 562 HOW PAPER IS NOW MADE FROM WOOD layers, and the whole pile was placed under a press, where more of the water was removed. When they were dry, we had a very fair kind of paper which was, however, not much better than blotting paper and could not be written on with ink because it was loose in texture and very absorbent. To give it good writing surface it was necessary to fill the pores. This was done by sizing which gave the paper great firmness. Paper was sized by drawing the layers of paper through a solution of alum and glue, or some similar substances, and then drying them, then finally passed between highly polished rollers to iron it. This gave it the necessary smooth hard surface. In the modern method of making rag paper by machinery, the rags are boiled with caustic soda, which sepa- rates the cellulose fibers, and placed in a machine in which rollers set with knives tear the rags to pieces and mix them with water to form a pulp. This is called a breaker. The pulp is then bleached with chloride of lime, and is passed on to the sizing machine. This machine mixes the pulp with alum and with a kind of soap, made from suit- able resins which serves the purpose better than orlue. How Is the Water Mark Put Into Paper ? The pulp, which is now ready to be made into paper, is poured out upon an endless cloth made of fine brass wire. This cloth travels constantly m one direction, by means of rollers, and is given at the same time a sort of vibra- tory motion, to cause the paper fibers to become more closely felted together. On the wire cloth web are usually woven words, or designs, in wire, that rise above the rest of the surface. These are transferred to the paper, and are called water marks. The machine then winds the finished paper into rolls, so that it may be handled conveniently. During the past few years the uses for paper have increased so greatly that there have not been enough rags avail- able to meet the demand for material, and a successful effort was made to find other material from which paper could be made. Many fibers were tried before it was found that wood pulp could be used. Straw and esparto grass, a plant that grows wild in North America, were found to yield cellulose having the de- sired qualities and were used to some extent. But the problem was solved when it was learned that pulp made NOT A WOOD YARD BUT THE OUTSIDE OF A PAPER MILL. This shows the great piles of trunks and limbs of trees near a wnnd pulp paper mill used in making paper for newspapers, books, magazines, etc. GREAT FORESTS TURNED INTO PAPER 563 PAPER TREES. This picture shows the trees as they grow- in the woods. These trees are good for mak- ing paper. Your morning paper, may some morning be printed on what is left of one of these trees. from trunks and limbs of trees would, serve even then. At first the powder formed by grinding up logs was used, but the paper produced was not strong, and could be used for very few pur- poses. It was discovered finally that if wood shavings were boiled in strong solutions of caustic soda, in receptacles that would withstand very high pressure, the wood fibers were separated, and a very good quality of cellulose for paper manufacture produced, provided it was bleached before being made into paper, and most of our paper to-day is, there- fore, made of wood. Later on this process gave way to the sulphite process. In the sulphite process, a solution of sulphite of lime is used. Acid sulphite of lime results when the fumes from burning sulphur are passed through chimneys filled with lime. By this process the separation of the fibers and the bleaching are done GKIXniXG ROOM. In this picture we see how the trees are first cut into smaller chunks before being reduced to chips for making pulp. af the same time and an even whiter paper making material is obtained. The sulphite process is now used al- most exclusively in making paper from wood. The discovery of the process of mak- ing paper from wood has led to the use of paper for many purposes for which it could otherwise never have been used. The wood plup is also used in the form of papier-mache, a tough, plastic substance, which is made by mixing glue with it, or by pressing to- gether a number of layers of paper hav- ing glue between. Papier-mache can easily be molded into almost any form, and after drying forms a very tough substance and one that will stand rough usage. It has been employed for mak- ing dishes, water baskets and utensils of many other kinds, for making the ma- trices for and from electrotype plates, for car wheels, and many other pur- poses. 564 WHERE THE INGREDIENTS FOR MAKING PAPER ARE MIXED MIXING ROOM. The wood fiber must be mixed with other ingredients when paper is made from it. This shows a comer of the large electro-chemical department for the production of bleach and soda used in the preparation of rag and wood fibres. THE WATEK SUPPLY. A good deal of water is needed in making paper. From twelve to fifteen million gallons daily are drawn from the river and filtered through this plant in Maine; clean paper of bright color being dependent upon the use of pure water. BEATING THE INGREDIENTS FOR MAKING PAPER PULP 565 BEATER ROOM. The ingredients for making paper are first mixed thoroughly in machines called " beaters " before going to the paper making machines. The operation of beating is one of the most important in paper making. THE PAPER COMI.NCi ()!• 1' IN ROLLS. As the paper progresses through the machines, it passes over a long series of heated cylinders, drying and hardening the stock until it reaches the finished end. This illustration shows a web 135 inches wide being cut into two rolls. The air pressure in the machine room is slightly greater than the atmospheric pressure outside, preventing dust from entering. PAPER STOCK. A large amount of stock of paper mills. This paper is seasoned by holding it in stock and will be later given such surface as is caUed for. COATING MACHINES. Where the paper passes through a bath of coating mix- ture to a long drying gallery at the end of which it is rewound preparatory to being given the highly finished surface on the calendaring ma- chine. ' ' ' 1 ■■ •.':'-^--a''^i#— ^*"" rr' ■rL„.- -i ^14 ^■■■11^^?^ '-» . i^% f >■■■■ i ^^^^^^^^^^^H^i^^^^^^^^^^^^^'h •'^■\. -■ ^^^^W >-■ J:4X .^><»^^ V,:,. i A section of Fin- ishing Room de- partment where paper is passed through alternat- ing compressed fib- er and steel rolls giving it the surface required for dif- ferent classes of printing. The pap- er on which the Book of Wonders is printed has a liighly finished smooth surface so that the pictures will come out clear. 568 WHERE THE PAPER IS CUT IN SHEETS The finished rolls of stock pass through rotary cutters which produce the sliects of various required sizes. The paper in the Book of Wonders was cut in sheets 41x55 inches, thus making it possible to print 32 pages on each side of each sheet. Rotary Boiler for cooking rags or wood in making pulp for use in manufacture of paper. Illustrations showing manufacture of paper by courtesy of S. D. Warren & Co. HOW THE PRINTED TYPE OF THIS BOOK WAS SET 569 This picture shows the wonderful Linotype machine by which the type of this book was " set," as the printers say. The men who operate the machine are compositors. Originally the type matter of books was set by hand and the compositor composed in type what the author of the book had written. By pressing down on the keys which you see in tlie picture, the compositor sets the words in lines of metal. This machine is almost human. By toucliing the proper keys, the operator assembles a line of matrices the details of which are explained in another picture, and after this is done the machine automatically casts a slug from them, turns and delivers a slug into a galley ready for use and finally distributes the matrices back into their respective channels in the magazine, where they are ready to be called down again, by tlic toucli of the key button. The latest model linotype has four miig.'izincs and can be equipped with matrices which when assembled will cast lines in from six to twelve different sizes and styles of type. The assembling mechanism is the only part of the linotype where the iiuman niind is ajjplicd to the working of the machine. It is necessary for the eye to read what is to be printed, and the mind, through the medium of the fingers, to translate this into assembled lines of matrices; after that the machine acts automatically. 570 THE LINOTYPE— FOLR MACHINES IN ONE The keyboard is made up of 90 keys, which act directly on the matrices in their channels in the magazine. The slightest touch on the keybuttons releases the matrix, which drops to the assembler belt and is carried swiftly to the assembler. When a word is assembled, the spaceband key is tatched and a spaceband drops into the assembler. When the necessary matrices and spacebands to fill the line have been assembled, the operator raises the assembler by pressing a lever on the side of the keyboard. When the assembler reaches its highest point it automatically starts the machine and the matrices are transferred to the casting position. This illustration shows the manner in which matrices are constantly circulated in the Linotype. From the magazine they are carried to the assembler, then passed to the mold, where the line is cast, and from the mold after casting they are raised to the top of the machine and redistributed to their proper channels in the magazine. The Linotype is sometimes called a typesetting machine, but this is not correct: it does not set type. It is a substitute for typesetting. It is strictly speaking a composing machine, as it does composition but its product is not set type, but solid slugs in the form of lines of type with the printing face cast on the edge. It is in reality four machines so arranged that they work together in harmony — the magazine, the assembling mechanism, the casting mechanism and the distributing mechanism. The magazine is at the top of the machine sloping to the front at an angle of about 31 degrees, and consists of two brass plates placed together with a space of about five-eighths of an inch between. The two inner surfaces are cut i^nth 92 grooves or channels running the up and down way of the magazme, for carrying the matrices. The matrices slide down these channels on edge, with the face or punched edge down, and the V-end extending toward the upper part of the magazine. Each of these channels will hold twenty matrices. Linotype matrices are made of brass. In the edge of each matrix is either one or two letters or characters in intagho. The thickness of the individual matrices is dependent on the width of the character. By an ingenious arrangement either one- letter or two-letter matrices can be used in the same machine, and either character on a two-letter matrix can be used at will. The two-letter matrix bears two char- acters, one above the other, one of which may be a Roman face and the other an itali':, small capital, or black face. If a % ■ W^^''"^ ^^"^ '^ ^^ ^^ composed partly of the Roman ^ UPr face, which is in the upper position on the matrix, and partly of the other face, which is in the lower position, this is accomplished by means of a slide on the assembler operated by a small lever. When the lower characters on the ma- trices are required, the shde is shifted and the matnces are arrested at a higher level, so that the lower characters align with the upper characters of the other matrices in the assembler. When the slide is withdrawn the matrices are assembled at the lower level. By means of this simple contrivance, a line may be composed partly of one face, partly of the other face, or entirely of either face. ONE-LETTER AND TWO-LETTER MATRICES. THIS SHOWS HOW THE HEADINGS ARE MADE IN CAPITALS OF DIFFERENT TYPE. Linotypes are guaranteed to be capable of setting above 5000 ems of 6 point per hour, and this output is widely obtainerl in commercial printing offices with first class operators. When a compositor speaks of the amount of type he sets per hour or day he speaks of " ems." A column of type matter is so many " cms " wide. The term " em " means the square of the particular size of type that is being set. Thus if a column is said to be 13 ems wide it means that an em quad or square, could be set 13 times in the width of the column. Type is graded according to size by points. Machine type for book work runs from 5 points to 12 points. A point is one seventy-second of an inch, that is, there arc 72 points to an inch. This guarantee, however, by no means indicates the limit of speed at which the machine can be operated, as evidenced by recorrls of 10,000 to 11,000 cms per hour maintained for an entire day. The rapidity of the Linotype is limited only by the ability of the operator to manipulate the keys, and the extreme capacity of the machine has never yet been attained. 572 HOW THE LINOTVFM: MAKES SOLID TYPE SECTIONAL VIEW OF MAGAZINE SHOWING CHAN.NhL ILLL Ol- MATRICES. This picture shows the machine with part of the magazine top and side removed. We can thus see how the matrices are arranged in'their respective grooves in the magazine. When one of the keys of the keyboard is pressed down the first matrix in the corresponding grove in the magazine escapes and drops upon a conveyor belt and is carried in its proper order to an assembler, which answers much the same purpose as a printer's stick. The correct spacing or justification of the line of matrices is accomplished by means of spacebands, which are assembled automatically between the words in the line by the touch of a lever at the left of the kevb' :.r '. LINOTYPE SLUGS. Instead of producing single type characters, the Linotype machine casts metal bars, or slugs, of any length desired up to 36 ems, each complete in one piece and having on the upper edge, properly justified, the characters to print a line. These slugs are automatically assembled in proper order as they are delivered from the machine, when they are immediately available either for printing from direct or for making electrotype or stereotype plates. They answer the same purpose and are used in the same manner as composed type matter. CASTING THE SLUGS OF SOLID METAL 573 After the slug has been cast, the matrices are carried up to the second transfer position, where they are pushed to the right, and the teeth in the V at the top of the matrices engage the grooves in the distributor bar of the second eleva- tor, which descends from the dis- tributor box at the same time that the matrices rise to the se- cond transfer position. The sec- ond elevator then rises toward the distributor box, taking the mat- trices with it, but leaving the spacebands; these arethen pushed to the right and slide into the spaceband box, to be used again. As the second elevator rises toward the distributor box with its load of matrices, the distribu- tor shifter lever moves to the left until the elevator head has reached its place by the dis- tributor box. It then moves back to the right and pushes the matrices off the second elevator distributor bar into the distributor box, where they meet the " ma- trix lift " and are lifted, one at a time, to the distributor screws and distributor bar proper. The teeth in the matrix and the grooves in the bar are so arranged that when a matrix arrives at a point directly over the channel in which it belongs, it " lets go " and drops into its channel. If, however, there is a matrix in the line which was not designed to drop into one of the channels operated from the keyboard, it will be carried clear across the distributor bar and dropped into the last channel, and from there it will find its way to the sorts box. LINE OF MATRICES BEING LIFTED TO DISTRIBUTOR The casting mechanism consists of the metal pot, mold disk, mold, ejector, and trimming knives. The illustration shows a cross- section of the metal pot, mold disk, and mold, with a line of matrices in the casting position. When the line of matrices leaves the assembler, they pass to a position in front of the mold disk. The disk makes a one-quarter turn to the left, which brings the mold from the eject- ing position, where it stands while the machine is at rest, to the casting position. It then advances until the face of the mold comes in contact with the matrices. The metal pot advances until the pot mouthpiece comes in contact with the back of the mold; at this point the pump plunger descends and forces the metal into the mold and against the matrices. The pot then recedes, the mold disk withdraws from the matrices and makes three-fourths of a revolution to the left, stop- ping in the ejecting position, from which it started. The slug is ejected and assembled in the galley. During the last revolution of the disk the bottom of the slug is trimmed off, and in the process of ejection the sides of the slug are trimmed, so that when it drops in the galley the slug is a perfect line of type, ready for the form. SECTIONAL VIEW OK METAL I'OT WITH LINE OF MATKIfKS IN I'OSITION IiriOKK THE MOLD 574 HOW THE PRINTED PART OF A BOOK LOOKS AT FIRST SCIENTIFIC PRESS-OVE When Did K>n Firit Try to Fly t M\ ihr '^. oldtr than rctoriVd history \Vhcn a kite was rtown for »t»e first time the principle of aviation, or dynamic flight. wa& uncovered. For centuries nun has souf^t the mechanical e*iuivalents for «he things that keep a kite flxing stead- ily in the air.— the )>ovvcr that lies in the cord that keej^s a kite headed into (he wind; an equivalent for the wind's own power ; an equivalent for the tail which controls the kite's lateral and longitudinal balance. Eacli separate p.irt of the modern flying machine, or aero(>lane. was worked out long ago. with the excep- tion of the Ras engine lii;ht enouch and reliable enough to be u>ed for this work. The present pciicr.nion knows dynamic flight as a conimonpbce thing, not becau-e we are so much more clever than previous generation^ in^lesigniuc flying machines, but because of th '- velopment of the i\iodcrn ga-olir internal combustion engir Who IiTented Flying! No one invcnlfil llyinc. nnr did any one man invent .ill the stiarjie parts of the Hying macliinc. They are the re- sult of evolution, — of the combined work and thought of hundreds of men. many of whose names are unrecorded To attempt to find the true beginning of the modern flying machine would be as difficult as altemplins to ted today, and he went .so far as to foretell i!^e_ necessity of dcvcloi>ing the internal combustion engine before dynamic flight couW be a success Mr. F H. Wenham. in 180f>. also built a flying machine along convciuional lines and tried to fly It with a steam engine, which of course, proved too heavy. .\l A. Pcnaud. a Frenchman, in ex- penmcninig with mo•«" proven by otliers. Independently he covered the entire field of experirrent and after building hundreds of small models he succeeded, in ISOC^n making a machiiK weighing seset.Tl pounds c»»r^ght gasoline «igTne^^.a* flicmachine finally was^ CompTetcd, but was twice broken — through defective launching apparatus. Congress and Dr Langley were so ridi- culed by the public prc^i that the ma- ?^ ^ 'rtt^ A As the slugs of type, each of which represents a line, come from the linotype machine, they are arranged in order in a brass holder the width of the line of type, called a " galley.'' This holder is about twenty inches long. As soon as it is filled one of the men in the type- setting office takes it to a proof press where he makes a rough impression of it. He runs an ink covered roller over the top of the slugs, lays a piece of blank paper on it and then either runs another roller over it or puts it in a hand press and secures an impression of the type just as it is. This is called making a " galley proof." The galley proof is then sent to the proof- reader who reads it carefully and indicates such errors in setting as appear and must be changed. Before correcting the actual type, however, the composing room sends the galley proof to the one who is publishing the book. The publisher also reads the proof over carefully and, if he does not wish to change any of the wording, he sends it back to the composing room with his " O. K." attached in writing. If he wishes to change the wording, he does so and the galley proof is then returned to the composing room marked " O. K. after corrections and changes are made." The linotype operator then makes what- ever changes are desired or necessary by setting new lines where mistakes or changes occur. If there is only one wrong letter in a line, he must reset the whole line as the ma- chine, as you remember, only turns out solid lines of type. A revised proof is then sent to the pubhshing office and, if no further changes are to be made, he gives instructions to have the " galley " made up into pages. How the pages are made up is shown in the next picture. HOW THE PAGES OF A BOOK ARE MADE UP 575 5 immmmmtmHumm- u ■■■■■■■■■HHH v; ^^^^^^^^^^^^^^^^^^^^^^^^^^^H ^^^^^^^^^^^^^^^^^^H = . - i ? " - ' ' .. - -" "^ _ - ^ ":,. ~ ^-; X ' I; i^ ' 1/5 u z ^^■^■^^^1 1 - ; - i .,: T vtT J s " 'r t ■ -. " 'i "' ' 1 E ^ := ^ .ir ■— 5; •- ■- "C .3^ ' -^' ~ zz 'Z -". — - - ^ ~ ' ■■ ■' < ^^^^H^^^B^^^^^^H •f '' -. t. t^l-1 t ^2'^^ l^ ~ c ■■ " ■ . ■ -- "" ""- :.- S ^^Hk^^l^^HH ; f; j-^ ^if J ^"? s| S:5|^ : : ■:--; --"rt . z ^11 ^1 1 i-f H ^-i = i^^ii'fe ?-sl =^i - p i^^^^^^H ^BH ^^^^^^H 2 / - ■.S -T i- : ,^ = .- f"3 J— 5.sy|i--^-:_^,_^_ ^--^ _ •*" i^^^^^^^^^K jEPH ^^^^^^^^^1 ■j •^ ^^l^^^^^^l JM^vfi' ^^^^^^^^^1 -^ - -/-r: - ■ '.^ '.^ '^ - ^- —--■-■-•- -r '.-'' ■■ -. -^ / . ^^^P^U^H^I 1 S 5.~~ i5 * --3 ^^.^ |.E "^o j c-|s J'iS ^- = 1 ilJ^S-^jg. !- BwH T ^:^^^ijy^i|||4-j|j||i|.j |^|||| : _1 r : is ^.1 ,,J^-^-^ 1 ulii^.i^"-^ T^^'^^i < U ^^V -^B I^^^H V ^ -■- -5 - -= ~ -'i! 1 ~ -1 =' i "" ! '-: - ^ ■ ■ ' ^ ' ' ^^^^H^^^^^^^^^^^^^^H _ " - _ = = £ 2 s - 5 ~ _ .^- ;" _ 1: _; •- " -_- " ^-5 ^^^^^^^^^^^^^^^^^^^^H - ' 5-i "."S >, ~— =•^■7; £'' -5 = ,T ~ ■'.-.-" - " — 1 ^^^^^^^^H^^^^^^l 't •i--r1"S'i '^SE ? *--^-^^— r rj^?-"':'^^'^ - =- -i '^■".S O ss^sgi^ Ooi£g-5.*i-5sJ£-;s^-5^ S|So^ o -a be a a, 5.5 o-c (U~ bt >> -c n c " = a"! ^ ° au = -. = « .- D.*^ 11 ,- ^ 3 i2 n 5i o 1) ~ S ><- Ul r .i ra O ^- .Srt 3 bc-5 z a; < z - u -S - -0 i a i* ■': £-£€l-2i'=|=|-il fc i ill iiU4 1 ifjtllii PiltiiiJl £^ o.aij ^^ H ?-5 1 : : i=- 1 :; s Si d 1 i^ij:! M-sj g "•§:! iff 51 :^.^ gi^-i Z^Zlii &£t- \ =■? ^i §- ^.-^ =11 5 - v.-£5-s.g:.|'£^.5l''-s^ -crji •gSS.Ei's. 1 ■5 -11 ts s: c :■= *^ |5 'Of - - >s '; • •0 ; u E E n 3 •2. M be x; 4) 3 >, a •0 OJ c/l 1 ; CS J= 3 ^ r. iC , n u 4J . 0. bi _o j: bt a •^ " X XI 3 11 „ x: V. J3 rn c *^ ^ XI s ^ 0. in •a ,f-; , , c 3 G JZ •0 2 £^ « F M 3 a E be n a 0. T) 2-^ u x: b« a 6 £ J3 ■0 S T3 S_^'rt ,;; v •c-2 - M " •2 § > „,-«. ex 3 > w 576 HOW THIS BOOK IS PRINTED o „, a; -5 C o t/i ciJ.t! a. (u -tJ c £ ° w2 r § r- ?i & ,_ (D Oj '^ x: ^ O c ° y-o o CO cd d) tn CJ , 5 o rt ,C I- v- HOW THE BOOK OF WONDERS IS BOUND 577 When the printed sheets are received in the bindery they are fed into a folding machine which is shown here. A sheet of 64 pages is folded and cut and delivered in four sections of 16 pages each ready to be gathered. Here we see a machine which takes the folded sections of 16 pages each, which are called " signatures," and sorts them, dropping them into compartments in order, so that eachcorn- partment finally contains the printed matter for one book all arranged in the order which it will be bound. Courtesy of the J. F. Tapley Co. Now York. 578 SEWING THE PAGES OF THE BOOK OP WONDERS Here we see the girls at work operating the sewing machines which sew the sections together at the back side of the book. The men in this picture are making the backs of the books round and preparing them for the putting on of covers. Courtesy of the J. F. Tapley Co., New York. THE BOOK OF WONDERS IS READY TO READ 579 In this picture we see the " case makers " at work making the covers on which the actual book is bound. The book is now " bound " by having the rovers jnil (jii and is ready for distribution. Courtesy of the J- F. Tajjlcy Co., New York. 580 HOW THE PICTURES IN THIS BOOK ARE MADE How Is Photo Engraving Done? The first step is the making of the halftone negative which differs from an ordinary negative in being made up of different sized dots instead of shades of gray. This result is obtained by photographing the picture through a halftone screen consisting of two pieces of glass, ruled with black lines and cemented together so the lines cross at right angles and leave small squares of clear glass. This cut shows a section of a photo-engraving screen enlarged, illustrating the squares above-mentioned. In reality it would take from loo to 400 of these dots to make an inch, according to the fineness of screen. ts The efifect of making the negative in this way is to represent the differ- ent shades from black to white by large or small dots. Wet plate photog- raphy is usually used in this process because the film is thinner and more intensely black besides being cheaper than dry plates. This cut shows a portion of a halftone cut en- larged so that the dots can be seen very plainly. New Process Engraving Co. Having made the negative the next step is to make a printing plate from it. To do this, a piece of metal, copper if the work is fine, and zinc for coarser work, is coated with a solution which is sensative to light, fish glue is commonly used to which is added a small amount of ammonium bichromate. The metal being coated and dried, it is put in a very strong frame with the negative and squeezed together so that they are in perfect contact. A powerful light is now directed upon the negative with the metal behind it, the result being that wherever the light goes through the white spaces in the nega- tive, the coating on the metal is rendered insoluble. Where the dots on the negative are, the light is unable to get at the coating so that when the metal is removed from the frame and thor- oughly washed this part of the coating washes away, leaving the part which the light got at attached to the metal. This is now heated until the enamel, as the coating is called, turns dark brown and the picture can be easily seen. The picture is now on the metal but it must be made to stand out in relief before it can be used for printing from, so it is put in a bath of acid which eats away that part of the metal left uncovered by the washing away of the coating and this leaves the dots which make up the picture stand- ing up in relief. A roller covered with very thick paste-like ink is now rolled over the picture, or cut as it is now called, and when a piece of paper is pressed against the ink covered cut each little dot leaves a mark of ink on the paper the total making up the picture as we see it. There are many more wonderful things connected with the making of cuts such as the routing machine which has a tool that revolves so fast that it turns around 300 times while the clock ticks once, and other machines which cut hard metal as easily as you can cut a potato with a knife. Colored pictures are also made by the process outlined above. The pic- ture is photographed three times with a different colored piece of glass in front of the lens, the result being three negatives, one of which has all the blue, one all the red and the other all the yellow in the picture. By making cuts from each negative and printing them on top of one another in yellow, red, and blue, the original picture is reproduced in all its colors. This is how all our pretty magazine covers are made. ACKNOWLEDGMENT 581 ACKNOWLEDGMENT The Editors of the Book of Wonders make acknowledgment herewith to the following. All mentioned have been a great assistance in making the book not onl}^ possible but authentic: Spencerian Pen Co. Eastman Kodak Co. American Telephone & Telegraph Co. Remington Arms Co. Bethlehem Steel Co. American Portland Cement Alanufac- turers Assn. Brainerd & Armstrong Silk Co. Corticelli Silk Co. Curtiss Aeroplane Co. U. S. Beet Sugar Industry. Hartford Carpet Co. Haynes Automobile Co. Jacobs & Davis, Engineers. Pennsylvania Railroad Co. Endicott, Johnson & Co. United Shoe Machinery Co. Sherwin-Williams Co. Pittsburgh Plate Glass Co. The Colliery Engineer. Lake Torpedo Boat Co. Western Union Telegraph Co. New York Edison Co. Westinghouse Lamp Co. Consolidated Gas, Electric Light and Power Co. of Baltimore. Browning Engineering Co. The White Star Line. Marconi Wireless Co. Plymouth Cordage Co. American Woolen Co. The Vitagraph Co. The B. F. Goodrich Co. The Goodyear Rubber and Tire Co. The Lexington Chocolate Co. The Hecker-Jones Milling Co. The White Oak Mills. The H. C. White Company. A. L Root Company. Kohler & Campbell. Browne & Howell Co. P. & F. Corbin. Otis Elevator Co. ■ Scientific American. Joseph Dixon Crucible Co. Homer W. Laughlin Co. S. D. Warren & Co. C. B. Cottrell & Sons Co. Mergenthaler Linotype Co. J. F. Tapley & Co. New Process Engraving Co. Mutual Film Corporation. Tobacco Trade Journal Co. AlcClure's Magazine. James Arthur. Seth Thomas. American Locomotive Co. New York Central Railroad Co. Columbia Rope Co. Carl Werner. National Wool Growers Assn. INDEX 583 INDEX Acid, carbonic, what it is, 509 Aerial, on ship, (illus.), 455 Aeroplanes, English Channel crossing (illus.), 132 Curtis biplane (illus.), 131 first demonstrations of, 130 first flight in Europe, 129 first man-carrying (illus.), 128 first successful (illus.), 126 gas motors used in, 130 gliding, 137 greatest present value of, 136 records of, 131 red wing (illus.), 131 what two brothers accomplished for, 130 Wright Bros.' inventions, 130 Age, why do we, 196 Air, does it move with the earth? 400 does it weigh anything? 398 dust in, 38 extend, how far does, 243 Airlocks, description of in tunnel building, 213 Ammunition, first invention of, 40 fixed, 47 in prehistoric times, 40 Animals, can they think ? 194 is man an, 180 that leap greatest distance, 122 which foretell weather, 240 Anthracite seams (illus.), 260 Aqueduct (illus.), 505 Are matches poisonous, 294 Armor, in the Middle Ages, 44 Army, wireless in the, 448-451 Are there two sides to the rainbow? 254 Arrow, what causes it to fly? 408 At what point does water boil? 220 At what rate does thought travel? 242 Australian Ballot, where first used, 122 Automobile (illus.), axle, location of, 186 beginning of, 183 carburetor, location of, 184 carburetor, use of, 184 chassis, complete, 188 cog-wheels, use of, 183 cog-wheels, location of (illus.), 183 crankcase, location of (illus.), 183 cylinder, location of (illus.), 184 drive shaft, location of (illus.), 187 electric generator, use of, 185 exhaust, 184 fenders, location of, 188 fenders, use of, 188 finished car (illus.), 189 first American (illus.), 189 fly-wheel, location of (illus.), 183 fly-wheel, use of, 183 frame (illus.), 186 gasoline, what it does, 183 gasoline tank, location of, 187 gears, location of (illus.), 183 gears, use of, 183 heart of (illus.), 184 Automobile, how improved, 190 magneto, location of, 185 magneto, use of, 185 marvellous growth of twenty years, 189 modern power plant complete, 190 oil pan, use of, 184 oil pump, location of, 184 piston, location of (illus.), 183 piston, use of, 183 power plant, an (illus.), 185 radiator, location of (illus.), 188 radiator, use of, 188 ready for the wheels, 187 second stage of construction (illus.), 186 self-starter, location of, 185 self starter, use of, 185 Smithsonian exhibit of complete power plant, 190 springs, location of (illus.), 186 springs, use of, 186 steering gear, location of (illus.), 187 street scene 20 years ago, 189 transmission, location of, 1 86 tire pump,;use of, 185 tires, how made, 382 transmission, use of, 186 water pump, location of, 185 water pump, use of, 185 what the completed chassis looks like (illus.) 188 Bacon, Roger, discoverer of gunpowder, 44 Balance, effect of sunlight on, 37 Baldness, chief course of, 143 why some people are, 143 Ball, why it bounces, 63 bearings, what they are, 180 Balloon, what keeps it up, 199 why it goes up, 199 Ballot, when first used, 122 Australian, where first used, 122 Bearings, Ball, what they are, 180 Bee, how it lives, 336 why it has a sting, 336 Bell, Alexander Graham (illus.), 70 first telephone, 72 Bend, why things, 62 Biplanes, Curtiss (illus.), 131 in flight, Curtiss (illus.), 136 Birds, how do they find the old home? 408 how they learn to fly, 178 how they find their way, 407 reproduction of life in, 179 why do they sing? 408 Birds' Eggs, why different colors, 233 Blasting gelatin, definition of, 206 Bleriot, M., first European flights, 129 Blotter, capillary attraction of, 18 how it takes up ink, 18 Blush, why do we, 194 Boat, how it can sail under water, 269 hydroplane of submarine, 270 inside of a submarine (illus.), 272 Bodies, swiftest moving, 25 584 INDEX Boiling point of water, 220 what makes water, 220 Boring mill (illus.), 56 Bottles, gurgle in, 63 Bounce, why a ball will, 63 Bow, long (illus.), 42 Bow-and-Arrow, invention of, 43 Boxes, match, how made, 294 Brazil, Emperor of, receives first words over telephone, 74 Bread, how flour is made, 462 difference in Graham and whole wheat, 461 grinding wheat (illus.), 464 harvesting wheat, 460 loaves of world (illus.), 459 origin and meiming of, 460 purifying machine (illus.), 463 separating fibre germs (illus.), 463 wheiit conditioning (illus), 462 when wheat was first used in making, 461 where it comes from, 460 why so important, 460 Break, why things, 62 Breech, of a big gun, 53 Breech-loaders in Civil War, 48 in ride, 47 Brush, in writing, invention of, 13 in writing (illus.), 13 Bullets, cupro-nickel used in, 50 grading of, 51 weighing of (illus,). 49 Buildings, concrete, how made (illus.), 100 Buttons, on sleeves, 64 Building, tallest in the world (illus.), 395-508 what holds it up? 496 Building foimdations, construction of, 496 compressed air, use of (illus.), 500 cutting piles with a hot flame (illus.), 498 driving steel piles, 496 piles filled with concrete (illus.), 499 piles, length of, 497 piles, sinking of (illus.), 497 use of o.xyacetylene, 498 Cable, laying armoring machine (illus.), 437 arrived on other side, 433 bulge (illus.), 437. gear-paying-out (illus.), 431 Great Eastern, the, 434, 437 landing of (illus.) 433 machinery on cable ship (illus.), 431 paying-out machine (illus.), 431 shore end of (illus.), 429 storing of, aboard ship (illus.), 430 what they look like when cut in two (illus.), 428 Cable, ocean, Continental Morse Code, 438 how dropped (illus.), 432 how repaired (illus.), 435 inventor of, 434 laid, how, 429 man who made it possible, 434 pioneers of, 434 signals as received (illus.), 438 w^at is it made of, 429 Cable, repairing, grapnels (illus.), 435 how repaired, 435 on rocky shore, (illus), 438 powerful engines used (illus.), 436 splicing of (illus.), 436 Cable, service, map of Trans-Atlantic, 439 Cable, vault, <>f telephone (iUus.), 67 Cabriolet, 122 Cacao, beans, bags of (illus.), 388 how cured, 392 nibs, 392 Cacao, flaked, how made, 392 how gathered, 391 pods, how gathered, 391 free, discovery of, 388 and chocolate, difference between, 389 Cackling, why a hen, 233 Calibre of a gun, 53 Calico, name, where from, 123 Camera, 22 first moving picture, 375 Can a bee sting? 536 Can animals think? 194 Candles, did they come before lamps? 294 why it burns, 21 why it gives light, 21 why you can blow out, 21-36 when introduced, 296 Candy, why do children like? 409 why does eating candy make some peoj-lj fat? 409 Carbon, 352 Carbonate of Soda, used in developing, 23 Carburetor, in gas engine, 184 Carp<5ts, ciirding machine (illus.), 170 dyeing the yarn, (illus.), 170 examining and repairing (illus.), 173 how yam is dyed, 170 manufacture of (illus.), 169 modem, how made, 169 packing for shipment (illus.), 173 processes, 169-170-171, 173 stamping designs, 173 view of factory (illus.), 172 weaving, by machine (illus.), 171 wool, packing machine (illus.), 169 wool sorting, 170 Cartridges, invention of, 48 types of (illus.), 49 Cave, man who invented ammunition, 40 Cement, alumina in, 95 amount used in United States, 95 arch, 95 bagging (illus.), 99 bridges, 95 bucket (illus.), 97 burned (illus.), 98 calcined (illus.), 98 clay in, 95 crusher (illus.), 97 dams, 95 fireproof, 95 grinders (illus.), 98 industry, 95 in water, 95 kiln (illus.), 98 lime in, 95 machine (illus.), 97 marl in, 95 miU (illus.), 96-98 mixing (illus.), 99 mortar, 99 on farms, 95 origin, 95 plastic, 95 INDEX 585 Cement, Portland, 95 Cloth, Burr picker, 87 powder (illus.), 98 chloride of aluminum in making, 98 quarry (illus.), 96 EngHsh cap spinning (illus.), 89 reinforced, 95 finished, ready for market (illus.), 90 rock (illus.), 95-97 finish perching (illus.), 90 sewers, 95 fulling (illus.), 90 shale in, 95 how made from wool, 85 shovel (illus.), 96 how made perfect, 83 sidewalks, 95 how woolen is dyed, 87 sihca in, 95 mending perching (illus.), 88 strength of, 95 napping, 89 subways, 95 piece dyeing (illus.), 90 tunnels, 95 ring twisting (illus.), 89 walls, 95 sulphuric acid solution in making, 87 what is it, 95 teasel, 89 what made of, 95 weaving and scouring (illus.), 88 what used for, 95 web, 86 weighing (illus.), 99 woolen mule spinning (illus.), 89 where obtained (illus.), 97 worsted carding (illus.), 85 Chalk, where it comes from, 18 yam inspecting (illus.), 89 Chattering, why do my teeth, 218 Clothes, cost of wool in a suit of, 83 China-making, blungers, 404 of wool, 80 clay, in making dishes, 405 wool in one suit of, 83 decorating cups (illus.), 404-406 Coal, anthracite, 257, 258 dishes, how shaped, 405 anthracite seams (illus.), 260 glazing plates (illus.), 404 breaker (illus.), 257 grinders (illus.), 404 cars ready to go to surface, (illus.) 260 how the dishes are shaped, 405 dangers to the miners, 262 molding (illus.), 405 electric cap lamp (illus), 264 pressing water from clay (illus), 405 firedamp. 262 pulverizing materials, 404 gas illuminating from, 299 pulverizing mill (illus.), 404 gases, 262 saggers (illus.), 406 history of the safety lamp (illus.), 263 taking the dishes from kiln (illus.), 406 how the miners loosen the coal (illus.), 261 Chinese, probable discovers of gun powder 44 how the slate pickers work (illus), 259 Chocolate, broma, what it is, 390 lamp which saves many lives, 263 cacao beans (illus.), 388 man who invented the safety lamp, 264 cacao pods, (illus.), 391 mine workers that never see day light, 258 cacao tree, discovery of, 388 mules and their drivers (illus.), 258 cocoa butter, 390 peat, 262 cocoa mill (illus.), 390 safety lamp and firedamp, 262 cocoa roaster (illus.), 390 seams (illus.), 260 cocoa shells, 390 shaft gate (illus.), 260 cracking mill, 389 slate pickers (illus.), 259 cream mixing (illus.) 393 soft, 259 difference between and cacao, 394 spiral slate pickers (illus.), 259 dipping department, 394 stable underground (illus.), 258 finisher (illus.), 392 undercutting with compressed air ma- flaked cocoa, 392 chines (illus.), 261 heating machine (illus.), 393 undercutting with pick (illus.), 261 how are chocolate candies made? 394 Cocoa, see Cacao how made, 392 Cocoon, description of, 115 making, 393 completed (illus.), 116 milk, how made, 394 from which moths have emerged (illus), 117 mill (illus.), 392 how silk is reeled from, 118 mixer (illus.), 393 moths emerging from (illus.), 117 shell separator (illus.), 389 number required to one pound of silk, 117 what cocoa butter is, 390 silkworm beginning of (illus.), 116 wrapping individual, 394 silkworm, preparing for making of (illus.), Cigars, how they are made, 517 116 Clay, what is, 495 Coins, gold, 266 Circles, tendency to walk in, 91 in glass of water, 38 Clinking gla.sses, how it originated? 232 silver, 266 Clock, age of, 319 Cohesion, definition of, 219, 220 largest in the world (illus.), 321 Cold, wliy some things arc, 144 machinery which runs a hig'dlhis.), 322 Color, oxpf).sed to light rays, 36 in Independence Hall filhis.), 323 in i)aint, 229 in New York City Hall, 323 what it is, 123 Cloth, beaming (ilhis.), 89 Colors, difTercnt in birds' eggs, 233 Hurline (illus.), 88 in sunset, cause of, 253 586 INDEX Color, of rainbow, 253 red, why it makes a bvtll angry, 490 Columbus, lirought first sheep to America, 80 Comb honey, development of (illus.), 529 Compounds, compared with elements, 349 Compressed air, method in buiUling tunnels, 21 1 Concrete, buildings (illus.), 100 constniction (illus.). 100 decay, loi engineering, 102 forms (illus.), 100 houses (illus.), loi loads (illus.), 100 mold, 101 ornamental (illus.), 100 practical uses of (illus.), 100 rusting, lOO Silo (illus.), 102 stable (illus.), 102 sun dial (illus.), loi tensile strain, 104 tower (illus.), 102 walls (illus.), 100 water tower (illus.), 102 what it is, 95 wood, 102 Confucius, philosophy written with brush, 13 Cooking, when first used, 308 Copper, as a conductor of electricity, 267 wire, telegraph, 266 Com plant, how pollen fertilizes, 170 wliy it has silk, 176 Corn Silk, what.it is for, 176 baling presses (illus.), 476 Cotton, drawing frames (illus.), 472 slashers (illus), 475 spinning frames (iUus.), 473 warping machine (illus.), 474 what nation produces the most, 477 how much cloth will a pound of cotton make, 477 mill (illus.), 471 cloth, first steps in making, 472 putting fiber on bobbins (illus.), 473 cloth finished (illus.), 476 who discovered, 477 weave room, 475 w^here it comes from, 470 lapper machines, 471 card room (illus), 472 bobbins (illus.), 473 dye-house (illus.), 474 beaming frames (illus.), 475 inspecting tables (illus), 476 field a southern (illus), 470 breaker machines (illus.), 471 slubber machines (iUus.), 472 speeders (illus.), 473 spooling machine (illus.), 474 shipping (illus.), 476 w^hat used for, 477 cloths, what are the principle, 477 Counting, man, himself, 19 in tens, 19 in twelves, 20 Crying, what makes us, 195 when hurt, w^hy we, 93 Cross-bow, invention of, 44 Crude rubber, how treated, 378 Culverines, early type of, 45 Cylinder in gas engine (illus), 184 Darkness, cats can see in, 91 some animals can see in, 91 why wc cannot see in, 91 why we fear, 352 Deep sea diving, the telephone adjusting (illus.), 202 coming up (illus.), 204 cost of outfit, 203 helmet, putting on (illus.), 202 just before going down (ilhis.), 204 outfit, 202 shoes, putting on (illus.), 202 suit, putting on (illus.), 202 telephoning from bottom, 203 telephone, testing the (illus.), 203 testing, final (illus.), 203 water pressure at varjnng depths, 203 wealth recovered by diving, 204 weight of outfit, 203 Deer-stalking with the cross-bow (illus.), 42 Detonators, in firearms, 47 Developer, Pyro, in photography, 23 Diamonds, what made of, 351 Did candles come before lamps? 294 Die, why do we have to, 245 Difference in woolens and worsteds, 84 Dimples, what causes, 352 Discovery of gunpowder, 44 Discovery of stringed musical instruments, 479 telephone, 71 Diver's task made easy (illus.), 284 Diving, deep-sea, the telephone adjusting, (illus.), 202 cost of outfit, 203 hats of divers, 204 just before going down (illus.), 204 helmet, putting on (illus.), 202 shoes, putting on (illus.), 202 suit, putting on the (illus.), 202 suit, what consists of, 202 telephone from bottom, 203 telephoning, testing the (illus.), 203 testing final (illus), 203 water pressure at varying depths, 203 wealth recovered by diving, 204 weight of outfit, 203 Dixie, what name means, 124 W'hcre name originated, 123 Does air weigh anything, 398 Does the air surrounding the earth move with it? 400 Does thunder sour milk, 196 Does light weigh anything? 37 Does the sun revolve on its axis? 511 Do father and mother plants always live to- gether? 176 Do the ends of the rainbow rest on land? 254 Do the stars really shoot down? 255 Dog, why he turns round before lying down, 229 Dolls, why girls like, 368 Dom Pedro, Emperor of Brazil, who saved the telephone, 73 Do plants breathe? 241 Draft, created by chimney, 37 Dreams, cause of,'366 nightmare, 367 what makes us? 366 Drinking, origin of clinking glasses, 232 INDEX 587 Driving shield, airlock bulkhead (illus.), 210 Eyes, sparkle when merry, why, 92 erector (illus.), 210 why we can't sleep when open, 92 in tunnel building (illus.), 208 why we see stars when hit on, 268 inventor of, 209 Eye-wash, tears as an, 38 tunnels, front view (illus.), 209 Fabrics, worsted, 85 Ducks, why water runs off backs of, 233 Fahrenheit, what is meant by, 221 Dust, in air, 38 why so called, 221 what it is, 104 Fastest camera in the world, 25 Dyeing, silk, 121 Fathers and Mothers, do plants have, 175 Earache, what causes, 410 Federal Government, grazing fee paid to, 82 Earth, how big it is, 124 Fertilization, in birds, 179 light surrounding, 38 how corn plant fertilizes, 176 Echo, what makes an, 200 of fishes, 177 whispering gallery, 201 Fight, of Merrimac and Monitor, 32 Eggs, birds why different colors, 233 Film, before and after snapshot, 23 silkworm, how imported, iii sensitive, 23 Egyptians, how ancients wrote, 12 Finger prints, arch, (illus.), 520 Electric arc, temperature of, 35 composite (illus.), 521 Electric current, what it is, 334 of different people, 521 Electricity, conductors of, 331 enlargements of, 524 current, 334 how they identify us, 520 good conductors, 331 impressions of orang-outang (illus.), 522 how discovered, 333 loop (illus.), 520 non-conductors, 331 palmary impressions (illus.), 522 what is, 329 speciman form of, record (illus.), 525 Electric lighting, arc-hght, 307 spike that caught a criminal (illus.), 524 Edison's first lamp (illus.), 306 thieves caught through their, 523 incandescent carbon lamp (illus.), 306 thumb imprint on bottle (illus.), 523 Mazda lamp (illus), 306 thumb impression on cash box (illus.), tantalum lamp (illus.), 306 523 Tungsten metal lamps, 305 thumb mark on a candle (dlus.), 523 when introduced, 305 where first used, 522 Elements, carbon, 352 whorl (illus.), 521 compared with compounds, 349 Fingers, why they hurt when cut, 143 hydrogen, 349 why we have ten, 142 nitrogen, 350 Finger nails, why we have, 142 oxygen, 349 Fire, alarms when first used, 308 what an is, 349 first apparatus to fight, 308 Elevator, description of (illus.), 397 first fire department, 308 installation (illus.), 396 first real, fire engine, 308 principal parts of, 396 gases put out, 37 why does not the car fall? 397 how man discovered, 289 Emperor, saved the telephone, 73 how man learned to fight, 208 Emperor of Brazil, receives first message over how man learned to make a, 289 first telephone, 74 mark, of civilization, 290 Engine, gas (illus.), 181-182 why it goes out, 37 carburetor, 184 why is it hot? 401 cyHnder (illus.), 184 why put out by water, 222 horse-power, of, 256 Fire making, drilling (illus.), 289 Exchange, first telephone, 75 drilling with bow string (ilhis.), 290 Exhibition, of first telephone at Centennial, 74 drilling, two persons (illus.), 290 Experiments, with mirror resultant in photo- first matches (illus.), 292 graph, 22 flint and pyrites (illus.) 290 Exploding, a submarine mine, 34 flint, introduction of (illus.), 291 Explosions, how they break windows, 62 plowing (illus.), 290 in gas engines (illus.), 182 pyrites (illus), 290 of sulimarinc mines (illus.), 34 rubbing sticks together, 42 wliat happens in, 205 sawing (illus.), 289 Explosives, definition of, 205 steal and Hint (illus), 291 blasting gelatin, 206 tinder box (illus.), 291 gun-cotton, 206 tinder box, pistol (illus.), 291 nitroglycerine, 206 with matches, 292 ^ Eye, of a submarine (illus.), 274 Firedamp, 262 Eyes, closed, walking with, 91 ('xi)](ision in safety lamp, 262 hand quicker than, 376 Firearms, first cnjdc efforts of, 45 help brain in walking, 91 first, rc'.il (illus.), 45 in some pictures follow you, why, 36 fuse of, 45 ke(;i>ing body balanced, 91 in early Chinese history, 44 nature's way of protecting, 38 first trigger of, 45 jjrotccting with tears, 38 Firing, mortar, causes gas-rings, 27 588 INDEX First man-carrying aeroplane, 128 Gas, illuminating, Baltimore first city to use, real telegraph, 421 302 stringed musical instrument, 480 carbon in, 302 telephone (illus.), 72 discovered, when, 302 tel(.'i)hone line, 72 first American house to use, 302 telephone switchboard (illus.), 74 first practical demonstration of, 302 Fishes, how they are born, 177 generator house (illus.), 299 how they come to life, 177 holder (illus.), 298 motion in swimming, 233 how it gets into jet, 302 what the eggs are, 177 how it is purified, 303 Why they cannot hve in air, 232 how made, 303 Flag, made, how was American, 310 how the meter works, 304 made, when was American? 310 hydrogen in, 302 Flash pan, early type, 45 impurities removed from (illus.), 301 Flaxseed oil, what it is, 227 jet, the story in a, 303 Flight, i)f projectile, long, 30 made of, 302 Flint-lock, invented in seventeenth century, 46 meter, description, 304 invented by thieves, 46 purifying boxes (Illus.), 301 still in use in Orient, 46 removing tar from, 300 Floor, sounds through a, 79 shaving scrubl)crs (illus), 300 Flour, bolters (illus.), 465 GasoUne engine (illus.), 181, 182 how made, 462 Gases, generated at gun muzzle, 27 purifying machine (illus.), 463 how expelled in gun ingot, 55 sieves, 465 hydrogen, 349 Flowers, why they have smells, 176 nitrogen, 350 Flying, how birds learn, 178 oxygen, 349 boat, wonderful (illus.), 133 tendency to put out fire, 37 first Langley monoplane, 126 Gas-rings, in firing motor, 27 first successful aeroplane (illus.), 126 GatUng, inventor of guns, 310 machine, first models, 127 Gelatine, in photography, 23 some of the men who helped, 126 Gestures, talking by, 18 ten years of (illus.), 137 Ghosts, what are they? 367 Flying boat, fun in (illus.), 135 Glad, why do we laugh when, 92 gliding by, 137 Glass, why it cracks, 63 Flying boot, interior arrangement (illus.), 134 how long known, 247 monoplane type (illus.), 135 Glass, plate, casting (illus.), 249 six-passenger hull (illus.), 134 commercial, 246 speed of (Ulus.), 135 plate and window glass compared (illus.), the wonderful, 133 252 views of (illus.), 133 Glass, plate, making, annealing, oven, 249 Flying machines, 126 beveling, 247 Bleriol flew in Europe (illus.), 129 blanketing, 252 Curtis biplane in flight (illus.), 136 clay mixing (illus.), 248 Dr. Langley 's flying (illus.), 127 clay trampling (illus.), 248 early types of, 127 clay used, 247 first demonstrations, 130 grinding table, 250 first flight in Europe with, 129 materials used in, 247 first man-carrying aeroplane, 128 mercury, 253 first models, 127 nitrate of silver, 253 flying boat, 133 pots (illus.), 248 flying boat, exterior arrangement, 134 pots, drying of, 248 gliding experiments, 137 pots, length of usefulness, 248 Government interest in, 138 silvering, 247 hull of flying boat, 134 skimming the pot (illus.), 249 interesting governments in, 138 treading, 247 Wright Bros., first flights, 130 Glow-worm, why does it glow? 231 Focus, in eye, 22 Gold, why is it called precious? 266 Fog, T^hat it is, 105 Gong, why does it stop when it has been Food, how we learned to cook, 308 scunded, 78 Foreign monoplanes, some famous (illus.). Good luck, why a horseshoe brings? 311 132 Graphite in lead pencils, 468 Forsythe, LL.D. J., inventor of the primer 47 Gravitation, what is, 267 Freckles, w-hat makes them come, 125 Gravity, center of, in gun, 61 Fuse, for firearms in early history, 45 Gravity, force of, 61 Funditor, 42 Greek fre, in early history, 44 Gas, acetylene, 305 Growing, why do we stop, 195 definition, 348 Gun, action at muzzle, 27 first structure to be lighted by, 302 annealing a gun ingot, 57 in coal mines, 262 assembling of, 48-54 water, 305 arquebus of, 1537, 47 INDEX 589 Gun, barrels, erosin of, 35 Honey, finished product (illus.), 533 blow-holes, 56 frame (illus.), 535 bore searcher, 59 how to bump the bees off a comb (illus) , 533 breech of a, 53 bee-hat (illus.), 535 discharges, force of, 33 a study in cell-making (illus.), 532 calibre of a, 53 bee sting, can a 536, elastic Umit, 58 frame of bees (illus.), 535 elongation, 58 comb, how bees build, 536 forging a (illus.), 52 Honey-bee, poison-bag, 537 heat treatment, 58 egg of queen, under microscope (illus.) 529 hoops of a, 54 Dreparing for rearing, 531 improvements in, 45 iving on combs in open air, (illus.), 52 7 ingot, calibre of, 55 the daily growth of larvae (iUus.), 532 jacket of, 54 effect of a sting (illus.), 536 length of a, 53 worker-bee (illus.), 527 liner of, 54 what the queen-bee does?, 528 Ufe of, 35 drone-comb (illus.), 532 manufacture in America, 48 clipping queen bees wings (illus.), 533 measuring inside diameter (illus.), 59 cucumber blossom with bee on it (illus.) ,528 modern built-up (illus.), 54 queen-bee (illus.), 527 mold for ingot, 55 the queen and her retinue (illus.), 529 muzzle of, 53 queen-rearing, 531 pressure generated in a big gun, 54 queen-cells (illus.), 529 photography (illus.), 33 Honeymoon, why do they call it a? 311 J piping, 56 Horizon, how far away is the, 245 powder chamber of a, 53 what is it, 244 rifling (illus.), 60 where is it, 244 rifling of, 53 Horse-power, a, what it is, 256 shrinking pit, 59 Horseshoes, why it is said to bring good tensile strength of, 58 luck? 311 factory, testing materials, (iUus.) 50 Hot box, cause of, 368 tube of, 54 Houiller, French gunsmith, 48 tube, how it is tempered, 57 Houses, concrete (illus.), loi why called gatling, 310 How far does the air extend? 243 wire- wound, 54 is ammunition made (illus.)? 49 Gxin-barrels, imported from England, 49 does an arc light bum? 307 resisting pressure of, 34 are automobile tires made? 382 Gun-cotton, in smokeless powder, 35, 206 does a honey bee live? 336 Gunpowder, Chinese probable discovers of, 44 does a bee make honey? 527 discoverer of, 44 do bees build the honey comb? 536 experiments by Schwartz, 45 does the honey bee defend itself? 536 formula of Roger Bacon, 45 does honey develop in a comb (illus.)? 530 ingredients in, 205 do birds learn to fiy? 178 manufactured in monasteries, 44 do birds find their way? 407 what causes the smoke? 206 does the blotter take up the ink of a blot ? 18 smokeless, what made of, 206 this book is bound, 578 why some is fine and others large grained, this book is made, 561 _ 206 the paper in this book is made, 561 Gurgle, in bottles, 63 the pictures in this both are made, 581 Hail, what causes, 124 are bullets made? 51 Hair, what causes baldness, 143 is an ocean cable laid? 429 why it don't hurt when cut, 143 does a camera take a picture, 22? why it keeps growing, 144 is a cable dropped into the ocean (illus.) M32 Hand bombards, early types, 45 are modem carpets made? 169 Hands, shaking, why with the right, 231 is a carpet woven by machinery? 171 Hansom, why so called, 122 is china decorated? 406 Have plants fathers and mothers? 1 75 is china made? 404 Heart, why beats during sleep, 191 is chocolate made? 392 why beats faster when scared, 191 did the custom of clinking glasses in drinking | why beats faster when running, 191 originate? 232 Heat, light wave changed into, 36 are cigars made? 517 why a nail gets hot when hammered, 230 is cloth made from wool? 86 why some things are warm, 144 did the coal get into the coal mines? 257 how we obtain, 231 does a coal mine look inside? 260 Hemp, Manilla (illus.), 356 do the cocoa beans grow (illus.)? 391 Hobson's choice, how originated, 311 is the color put on the outside of the po ucil? Honey, apiary in summer (illus.), 534 469 , , how profluced, 527 is the honey comb made? 532 worker comb (illus.), 532 are concrete roads built (illus) ? 103 manner of using German bee-brush, 533 did man learn to cook his food? 308 590 INDEX How are concrete buildings made (illus.)? loo is woolen cloth dyed? 87 big is the earth? 124 much of the earth does the sun shine on at one time? 324 does an elevator go up and down (illus.) ? 396 was electricity discovered? 333 does the Hght get into the electric bulb? 305 is the eraser put on a pencil? 469 can an explosion break windows? 62 explosions may occur on submarines, 278 does the farmer use concrete (illus.)? 102 do our finger prints indentify us? 520 did man learn to fight fire? 308 did man learn to make a fire? 289 are fishes born? 177 was the flag made? 310 is flour made? 462 does a fly walk upside down? 454 did men learn to fly? 126 does the gas get into the gas jet? 302 is illuminating gas made? 303 is gas purified? 303 is plate glass made? 246 is plate glass ground? 250 a wire- wound gun is made? 54 was the first American gun made (illus.)? 47 is a gun ingot made? 55 do we find the length of a gun? 53 is a gun tube tempered? 57 do we obtain heat? 231 the heel of a shoe is put on (illus.), 560 did Hobson's choice originate? 311 far away is the horizon? 245 does a key turn a lock (illus.)? 491 does a spring lock work (illus.) ? 492 are lead pencils made? 467 do the miners loosen the coal? 261 is hght produced, 230 are magnets made? 335 are matches made? 293 are match boxes made? 294 did man learn to send messages? 412 does the meter measure the gas? 304 can microbes spread through the body? 410 are mirrors silvered? 522 big is a molecule? 348 did money originate? 455 are moving pictures made? 369 does the music get into the piano? 478-482 did the word news originate ? 312 did a nod come to mean yes? 19 did shaking the head come to come no? 19 are paints mixed? 228 is a photograph developed? 23 was the piano discovered? 479 do plants breathe? 241 do plants reproduce life? 175 does the shield cut through the ground in tunnel building? 212 are shooting shells photographed? 24 shoes are made by machinery, 549 shoe machinery was developed, 457 is crude rubber secured? 377 is rope turned and twisted? 358 are rubber tires made? 378 are modem rugs made? 169 to spUce a rope, 364 do men go down to the bottom of the sea? 202 How did the sand get on the seashore? 108 far back does the silkworm date? 109 was silk introduced into Europe? no are the silkworms cared for? 1 13 do we know a thing is solid, liquid or gas? 348 are sounds produced? 485 fast does sound travel? 486 can sound come through a thick wall? 79 is the volume of sound measured? 242 far does space reach? 256 do the slate pickers work? 259 does a captain steer his ship across the ocean? 407 can a ship sail under water, 269 is a submarine submerged? 270 do sponges grow? 286 do sponges eat? 287 are sponges caught? 287 are the stars counted? 241 big is the sun? 141 hot is the sun? 141 is a steel pen made (illus.), 17 did man learn to shoot, 40 do we get wool oflF the sheep? 82 is a stone thrown with a sling? 41 are metallic and paper shells filled with powder? 50 did man learn to talk? 18 did the telephone come to be? 70 fast does thought travel? 242 does a telegram get there? 414 did man learn to tell time? 313 did man begin to measure time? 314 did men tell time when the sun cast no shadows? 317 is the time calculated at sea? 315 is tobacco cultivated? 516 is tobacco cured? 516 was tobacco discovered? 512 is tobacco harvested? 515 is tobacco planted? 514 is a tunnel dug under water? 208 does water put fire out? 222 is white lead made? 225 are wires put under ground? 76 did writing first come about? il did the Chinese write? 13 did the Monks do their writing? 14 does a pen write? 18 does does the wool in a suit of clothes cost? much wool does America produce? 82 is wool taken from the sheep? 82 is the yarn for carpets dyed? 170 is oxide of zinc obtained? 226 does the water get into the faucet? 501 are the big water pipes laid? 504 did the name Uncle Sam originate? 458 Hvunan body, wonders of the, 311 Hunting, with the bow-and-arrow, 43 Hurt, why we cry Hydrogen, what it is, 349 Hypo, used in developing, 23 Impact, of projectile from guns, 28 Ink, how does a blotter take up? 18 Instruments, artillery, testing, 24 musical, 488 optical, based on refraction, 38 Incandescent lamp, development of, 306 Inside of a mine planting submarine (illus), 277 INDEX 591 Iron, cast, 265 Light, what makes match, 198 melts at, 35 in mirror, 22 the most valuable metal, 265 in negative, 23 wrought, 265 rays, 36, 495 Is a moth attracted by a light? 288 broken rays of, 38 man an animal? 180 , rays, heat from, 36 the hand quicker than the eye? 376 and refraction, 38 there a reason for everything? 200 speed of, 36, 140 there a man in the moon? 400 travels faster than anything in the world, 36 yawning infectious ?_ 192 surrounding earth, 38 Jacket, of a gun, 54 wave changed into heat, 36 Japan the natural home of the silk worm Lighting, arc, how does it burn, 307 (illus), 112 in America, first street (illus), 296 Kentucky rifles, 45 first oil lantern, 297 Key, how it works in a lock (illus.), 491 electric, when introduced, 305 Knots, different kinds of (illus.), 363 first steeet light in Paris,, 297 what makes, in boards, 223 gas tank, (illus.), 298 Lambs, Siberian, in South Dakota (illus.), 80 Lightning, why it follows thunder, 140 Lamps, first street light in America, 296 Lightning bugs, why they produce light, 231 the Clanny safety, 264 Lignite, found in coal mines, 262 did candles come before? 294 Liner, of a gun, 54 earliest forms of, 295 Linseed oil, extraction of, 228 Edison's first (illus.) , 306 what it is, 227 incandescent carbon (illus.), 306 where it comes from, 227 incandescent, development of, 306 Liquid, definition, 348 incandescent, electric, when invented, 305 Living, why do some people live longer, 199 French watch tower (illus.), 295 reproduction necessary why, 174 Mazda (illus.), 306 reproduction of, in birds, 179 from Nashagak hanging (illus.), 297 reproduction of, in fishes, 177 Pagan votive (illus), 296 Loading machines in powder factory, 50 Tantalum (illus.), 306 Lobsters, red, what makes them, 245 street, when first used, 295 Lock, cylinder (illus.), 492 chimney protects flame, 37 how a key turns a (illus.), 491 coal miners and safety, 262 how key changes are provided (illus.), 491 Lamp chimney, why it makes a better light, 37 how a spring lock works (illus.), 492 Langley, Dr. Samuel P., 19 14 flight of aero- master-keyed cylinder (illus.), 492 plane, 128 what happens when the key is turned? Languages, why so many, 197 (illus.), 491 Lantern, the first oil (illus.), 297 what happens when the knob is turned? the " Reverbere " (illus.), 297 (illus.), 491 Laugh, when glad, why we, 92 Locomotives, boiler of articulate type (illus.), nerves, 93 440 when tickled, why we, 93 boiler of (illus.), 442 Laughter, reflex action, 93 cab of (illus.), 442 Lead, as used in making paint, 267 cylinders description of, 441 in a pencil, 468 low pressure cylinders of (illus.), 441 why so heavy, 267 electric, newest (illus.), 443 as used in pipes for plumbing, 267 one of the largest (illus.), 440 ' Leather, how the hides are treated, 539 signal tower, latest (illus.), 444 treatment of hides, 538 stoker, automatic (illus.), 443 unhairing machine (illus.), 540 water tank (illus), 444 hide house (illus.), 538 Lodestone, what it is, 327 tanning process, 539 "Long Bow," in Sherwood Forest (illus.), 42 rolling room (illus.), 539 Loom, cloth making machine, 86 tanning sole leather, 539 Magnet, breaking iron (illus.), 330 how upper leather is tanned (illus.), 540 electro (illus.), 326, 328, 335 disposing of waste material, 540 electric lift (illus.), 326 wringers, 539 experiments with, 327 tan yard (illus.), 539 great lifting by (illus), 330 Legs, not same length, 91 how made, 335 .Lens, in the eye, 22 what makes it lift things? 326 Leyden jar, what it is, 332 wonders jjcrformcd by, 326 Life, bc;,'inning of, 174 work it can df) (illus.), 328 beginning of man's, 174 Man, writing, how man learned, 11 how plants reproduce, 175 covinting himsi'lf, 19 Light, attracting moths, 288 is he an animal? 180 glow-worms why they glow? 231 Matches, are they poisonous? 294 how produced, 230 first, 292 lightning bugs, made by, 231 how made, 293 where it goes when it goes out, 36 luc-ifcT (illus.), 292 592 INDEX Matches, making by machinery, 293 Mountains, what made them, 401 modern safety (illus.), 292 Moving pictures, Board of Censors, 373 oxymuriate (illus.), 292 developing room (illus.) 372 promethean (illus.), 292 drying room (illus.), 373 what we would do without, 292 continuous movement of film, 376 when first used (illus.), 292 exact size of film, 370 Match-lock, of early firearms, 45 first camera, 375 Melting of iron, 35 first exhibited at studio, 372 Men who made the telephone, 70 how made, 369 Mercury, fulminate of, 49 how freak pictures are made, 376 Merrimac and Monitor, fight of, 32 negative, stock, 370 Merry, why eyes sparkle when, 92 negative, perforated, 370 Messages, how men learned to send, 412 " Pigs is Pigs " (illus.), 374 Indian smoke signals, 412 rehearsing (illus.), 371 marathon runner by (illus), 413 scenario (illus.), 374 pony telegraph (illus.), 413 staging, 371 Messenger boy, how to call a (illus.). 414 taking a (illus.), 373 the first (illus.), 413 Mulberry trees, food for silk worms (illus), 112 Metal, what is a, 265 Mules and drivers (illus), 258 what is the most valuable? 265 Multiple switchboard of telephone, 69 why we use for coining, 456 Music, harp, 479 Meter, description of gas, 304 lyre, 479 how it measures gas, 304 note, what it is, 490 Milk, does thunder sour? 196 what pitch is, 489 Milky way, why is it called, 255 what is, 478 what is, 255 Musical talicing machines, 490 Mine cars (illus.), 260 Muzzle, of a big gun, 53 Mines, clearing channel of buoyant, 283 Muzzle-loaders, in Civil War, 47 exploding submarine, 34 Nails, wliy they get hot when hammered, 230 planting submarine, inside of (illus.), 277 Names, of people, 20 workers that never see daylight, 258 Nature, protecting eyes, ways of, 38 Mirror, collects rays of light, 22 Navigating on bottom of sea, 283 reflection in, 22 Negative in photography, 23 reflects rays of light, 22 Nerves, sensory, receive impression, 93 Mirrors, beveling (illus.), 251 transmitting impression, 22 how made, 251 News, how did the word originate? 312 how silvered, 252 Nightmare, cause of, 367 polishing, 251 Nitrogen, what it is, 350 roughing, 251 Ocean, why is it blue? 219 silvered with mercury, 253 what makes it green? 219 silvering mirror plates (illus.), 252 why don't water sink in? 219 Molectile, how big is a, 348 where did all the water in, come from? 218 what is a, 348 where is water at low tide, 219 Monasteries, where gunpowder was manufac- Of what use is my hair? 143 tured, 44 Of what use are pains and aches? 410 Money, how originated, 455 Oil baths, for gun (illus.), 57 metallic forms of, 456 Oil cake, from hnseed, 228 who made the first cent, 458 Oil, palm ohve, in soap, 411 who originated, 455 Omniscope, of submarine boat, 271 why do we need, 455 Onions, make tears, 38 why gold and silver are best for coining, 457 bad effect of on eyes, 38 Monitor and Merrimac, fight of, 32 Operatives, in powder factor>', girls as, 49 Monks, making gunpowder, 44 Optical instruments, based on refraction, 38 Monoplane, flying boat (illus.), 135 Organic matter, what it is, 174 German (illus.), 132 Origin of cement, 95 over Mediterranean (illus.), 132 of counting in tens, 19 Moon, why it travels with us, 399 names of people, 20 the man in the, 400 of nodding to indicate yes, 19 Morse, S. B., inventor of telegraph, 420 of shaking head to indicate no, 19 Mortars (illus.), 26 of turnpike, 104 Mothers and Fathers, do plants have, 175 Oxide of zinc smelter (illus.), 227 Moths, attracted by light, 288 how obtained, 226 emerging from cocoon (illus.) 117 Oxygen, what it is, 349 Motion bodies, swiftest 25 in air, 37 Motion, is train harder to stop than start? 223 Pain, of what use is, 410 of fight, 140 what it is, 244 of sound, 140 Paint, care of, story in, 224 perpetual, 61 how mixed, 228 perpetual, in mechanics, 240 uses of, 224 Motors, gas, used in aeroplanes, 130 what used for, 224 INDEX 593 Paint manxifactixring, colors, what makes dif- ferent, 229 buckles before corrosion (illus.), 225 buckles afterjcorrosion (illus.), 225 buckles placed in stacks (illus.), 225 buckles taken from stacks (illus.), 225 first step in making (illus.), 224 lead buckles making (illus.), 224 lead, white, how made, 224-225 lead white used in, 224 grinding lead in oil (illus.), 228 washing the lead (illus.), 226 mixing, 228 where paints are mixed (illus.), 228 linseed oil, where obtained, 227 pressing oil from flaxseed (illus.), 228 removing oil cake from press, 228 sulphur roasting furnace (illus.), 226 zinc smelter (illus.), 227 oxide of zinc, how made, 226 Paper, earliest forms of, 14 sensitive in photography, 23 shells, inspection of (illus), 49 papyrus, the first, 14 Papjrrus, invention of, 14 Patents, of original telephone, 73 Peat, as a fuel, 262 Pen, first metallic (illus.), 15 first steel (illus), 15 first metalHc pen, how made, 15 how it writes, 18 invention of the, 15 Pencils, " lead " where from, 466 eraser is put on, 469 making description of (illus.), 467 who made the first? 466 Periscope, description of, 275 how we look through a (illus.), 276 mirror of, 275 Perpetual motion, nearest approach to, 240 is it possible? 61 Persian rug, antique (illus.), 167 how made, 167 imitation (illus.), 167 Kurdestan (illus.), 167 where best are made, 167 Photographs, of projectiles, 25 Photography, resultant from experiments with mirror, 22 Piano, pitch, 489 finishing (illus.), 484 why not more than seven octaves, 480 Dulcimer (illus.), 479 spinet (illus.), 480-481 note what it is, 490 sounding board, 488 tuning, (illus.), 484 building case around (illus.), 483 how the music gets into the, 482 clavichord (illus.), 480 instruments, musical, 488 strings, fastening on (illus.), 482 psaltery, 480 sound fxjx, the first, 479 who made the first, 478 hammers (illus.), 483 action regulation (illus.), 484 virginal fillus.), 480-481 first (illus.), 478 tuning fork, 488 Piano, polishing (illus.), 484 sounding board, putting on the (illus.), 482 how discovered, 479 lyre, 479 octave, 480 harpsichord (illus.), 480-481 Pickers, boy, slate (ilJus.), 259 Pictures, with a fast camera, 39 moving, how made, 369 size of moving film, 370 never seen by the human eye, 31 taken in one five-thousandth of a second, 31 Pin money, why they call it? 231 how name originated, 231 Pistols, invented in Pistola, Italy, 46 Plants, com, why it has silk? 176 do father and mother plants live together, 1 76 how they eat, 511 how they reproduce, 175 why do flowers have smells? 176 why they produce leaves, 175 Plate glass, (illus.), 246 Portland Cement, why called, 95 Powder, filling shells, 50 gun-cotton in smokeless, 35 secret of smokeless powder, 35 smokeless, 35 in submarine mines, amoimt of, 34 Pressure, generated in bore of a big gun, 54 inside of a gun at discharge, 33 in gun-barrel, resistance of, 34 of Ught, on scales, 37 Primer, invented by, 47 Prof. Bell's vibrating reed (illus.), 71 Projectiles, photographs of, 25 arrival at target, 24 clear of smoke-zone (illus), 30 smoke- zone, emerging from (illus.), 29 height in air from mortar, 30 impact of, from guns, 28 leaving gun muzzle (illus.), 27 travel faster than sound, 32 velocity of, 33 viewed in transit, 33 weight of, 53 Proving grounds, for big guns, (illus.), 53 Pyro, used in developing, 23 Quarry, cement (illus.), 96 Quill the, in writing (illus.), 14 Quills, raising geese for, 14 Rails, steel making, blast furnace (illus.), 234 blooming mill (illus.), 237 crane, carrying ingot, (iUus.), 236 length of, 238 mixer (iUus.), 234 molten steel, pouring (illus.), 236 open hearth furnace (illus.), 235 pouring side of open hearth furnace, 235 shrinkage of, 238 soaking pit (illus.), 236 temperature in furnace, 235 Rain, where it goes, 222 why it freshens the air, 222 Rainbow, cause of, 253 colors in, what makes? 254 ends of, 254 Rays, change their course, 38 lieat from light, 36 of light, 36 Roentgen, 307 594 INDEX Rays-X, what are they? 307 Rubber, Para, 387 Reason, is there one for everything? 200 pneumatic tires, 383 Reed, the (ilhis.), 12 pure, why not used, 380 Reflection, in mirror, 22, 91 spreading, 381 Refraction, changing light rays called, 38 spreader room (illus.), 383 of liK'ht, 38 tapping (illus), 377 Reproduction, of life, in birds, 179 tire building machines (illus.), 385 in fishes, 177 tires, how made, 378-379-380 in plants, 175 tread laying room, 384 why we must have, 174 tubes, inner, how made, 385 Rifle,' Kentucky, 45 vulcanizing, 384 kick of, 47 washing, 378 modern automatic, 47 wild, what is, 387 over-loading, 47 why not used pure, 380 wheel-lock (illus.), 46 wrapping room, 386 Rifling, causes rotation of projectile, 32 Rugs, designs imitated by machinery, 168 a big gim (illus.), 60 Persian (Illus.), 167 of a gun, 53 Persian, how made, 167 invented in Avistria, 46 Persian, imitation, 167 Roads, concrete (illus.), 103 Persian Kurdistan (illus.), 167 Roentgen Rays, 307 Persian, wliere best are made, 167 Rope, breaker (illus.), 360 Tabriz, reproduction (illus), 168 compound laying machine (illus), 361 weaving by machine (illus.), 171 cross-section, 362 Rug manufacturing, carding machine (illus.), draw frame (illus.), 360 ^70 drying fiber, 354 examining and repairing (illus.), 173 Egyptian kitchen (illus.), 354 packing for shipment (illus.), 173 Egj-ptians making (illus.), 353 processes, 169-170 preparing the fiber in (illus.), 359 weaving by machinery (illus.), 171 four-strand (illus.), 362 wool .sorting, 170 hackling, 354 Sadness, cause of tears, 38 hemp (illus.), 356 Salt, beds, 493 hemp in warehouse (illus.), 356 chemical name of, 493 knots, 363 in water, 351 lengths, standard, 362 mines, 493 oiling in manufacture, 356 Salt Lake, 493 long made by hand, 354 soda, 493 machine (illus.), 358 supply for Umted States, 493 opening bales of fiber (illus.), 359 wells, 493 preparation room (illus ), 359 where it comes from, 493 scraping fiber (illus.), 354 Scales, pressure of light on, 37 sliver formation of (illus.), 360 School slates, where they come from, 495 spindles, 355 Score, origin of, 26 spinning after turn, 355 Scouring, wool (illus.), 85 Rope spinning, after turn, 355 Scouring and weaving, in making woolen foreturn, 355 cloth (illus.), 88 sphcing (illus.), 364 Screens, in shot tower, 51 spreader (illus.), 360 Sea, diver, 202 stakes, 355 how men go down to the bottom of, 202 Rope walk, modern (illus.), 357-358 navigating on bottom of, 283 old-fashioned (illus.), 355 time calculated on the, 315 Routine, of a telephone call (illus.), 68 what the bottom looks like, 202 Rubber, automobile tires, 382 what makes it roar, 401 biscuit, 377 Second, reckoning in millionths of a, 25 blisters, 379 pictures taken in one five-thousandth of a. blow holes, 379 31 breaker-strip, 384 Seeds, why plants produce, 175 calendering, 38 1 Seeing, why we cannot see in dark, 91 castilloa, 387 Sensation, of sight, 22 cement, 381 Sensitive, paper, 23 crude, 377-378 Service, military, U. S., 24 curing room, 382-383 Shadows, cause of, 495 dr>'er, 379 Shell, sounds in a, 79 fabric. 384 Shells, filling with powder, 50 furnishing pneumatic tires (illus.), 386 inspection of metalhc (illus.), 49 gathering (illus.), 377 putting metal heads on paper, 50 how secured, 377 wad-paper in making, 50 how are inner tubes made, 385 Sheep, coming out of forest (illus.), 82 marketing balls of, 377 first in America, 80 mixing, 379 fleece packing, 82 INDEX 595 Sheep, how much wool does a sheep produce? 83 how wool is taken from the, 82 how taken care of , 82 how we get wool off of, 82 industry in America, 80 industry in the colonies, 8 1 industry in the west, 81 number in the west, 81 shearing, 82 shearing machines, 82 wool-producing, 83 why sheep precede the plow in civilizing a country, 81 Shield driving, air lock bvilkhead (illus.), 210 caulking the joints (illus,), 214 description of airlocks, 213 erector at work (illus.), 214 erector (illus.), 210 at end of journey (illus.), 216 grommetting the bolts (illus.), 214 grouting (illus.), 214 how it cuts in tunnel building, 212 how thay meet exactly (illus.), 215 in tunnel building (illus.), 208 kej^ plate (illus.), 214 curves around (illus.), 216 models of Penna. RR. tunnel shields (illus.), 212 rear end in tunnel building (illus.), 210 tunnels, front view (illus.), 209 Ship, how does a captain steer his, 407 how can it sail under water? 269 Shoes, Amazeen skiving machine, 550 assembling machine (illus.), 552 automatic heel loading and attaching machine (illus.), 560 automatic leveling machine (illus.), 559 automatic sewing machine, 555 American made, 547 ancient and modem forms of sandals, (i.Uus.), 543 ancient sandal maker (illus.), 541 beginning of a shoe (illus.), 549 boot developed from the sandal, 544 boots (illus.), 546 channel cementing machine (illus.), 558 channel laying machine (illus.), 559 channel opening machine (illus.), 558 Crakron or peaked (illus.), 544 which church and law forbade (illus.), 544 description of ancient sandal (illus.), 542 dyeing out machine, 551 different parts come together, 551 duplex eyeletting machine, 550 edgei ri Imming machine (illus.), 560- Ensign lacing machine, 551 evolution of the sandal to the shoe (illus.), 542 first machine for making shoes, 545 hand method lasting machine (illus.), 553 heel breasting machine (illus), 560 heel'trimming machine (illus), 560 ideal clicking machine, 550 Inseam trimming machine (illus.), 556 insole tacking, 551 lasting machine (illus.), 553 loose nailing machine (illus.), 559 success of McKay machine, 547 machine that forms and drives tacks, 554 machines which punch the soles of, 559 Shoes, my lady's slippers (illus.), 548 placing shanic and filling bottom, 556 planet rounding machine, 551 power tip press, 550 pulling over machine (illus.), 552 putting the ground cork and rubber cement in, 556 rolling machine, 551 rounding and channelling machine (illus.), 557 sewing the sole on, 558 slugging machine (illus.), 560 sole laying machine (illus.), 557 Summit splitting machine, 551 upper stapling machine (illus.), 554 upper trimming machine (illus.), 554 welt and turned shoe machine (illus.), 555 welt beating and washing machine, 556 welt sewing machine, 551 what was the first foot covering like? 541 " whipping the cat," 545 who made the first shoe in America? 545 work performed by heeling machine (illus.), 560 Shooting tests (illus.), 48 Shotguns, assembling of, (illus.), 48 Shot pellets, 51 Shrinking, pit for big gun, 59 Shuttle, In weaving wool, 86 Siberian lambs, in South Dakato (illus.), 80 Signs, talking by, 18 SiUca, mine (illus.), 247 Silk, 109 called " bomby-kia," 1 10 caring for young worms, II3 culture, no drying skeins of, 119 dyeing, 121 first step in manufacture, 1 19 first used, 109 hatching eggs, 113 introduction of into Europe (illus.), no number of cocoons in poimd of, 117 manufacture of, 119 method of reeling, 113 moths depositing eggs (illus.), 112 preparing cocooning beds, 112 reeling silk from cocoon (illus.), 118 spinning (illus.), 120 thread made uniform (illus.), 120 threads ready for the weaver, 1 2 1 twisting (illus.), 120 use of, 109 water-stretcher (illus.), 12 1 winding (illus.), 119 Silk manufacture, doubling frames, 120 spinning, 120 twisting, 120 Silk moth, description of 114 Silkworm, age, 115 first breeder of, 109 chrysalis (illus.), 114 cocoon, 115 cocoon, beginning of (illus.), II6 cocooning bed (illus.), 112 description of, 114 domestication of. III eating (illus.), 1 15 female moth (ilhis.), 114 Ii'iw cared for, i 13 596 INDEX Silkworm, liow it eats, 1 1 5 Spinneret, of the silkworm, 115 home of, 112 Spinning wheel, in making cloth from wool, 81 eggs, how imported, 1 1 1 Sponge, capillary attraction of, 18 hatching the eggs (illus.), 113 Sponges, l)ree(ling time of, 286 how he does liis work, 114 how du tliey grow? 286 larvae of, (illus.), 114 how they eat, 287 motions of head in spinning, 115 how they are caught, 287 molting season, 115 where they come from? 286 moths emerging from cocoon (illus.), 117 Stable, underground (illus.), 158 male moth (illus.), 114 Stars, counted in photograph, 223 mulberry branches for (illus.), 112 do they shoot down? 255 one of the world's greatest wonders, 116 how counted, 241 preparing for making cocoon (illus.), 116 how many there arc, 223 rehired, how they (illus.), 115 photographed, 223 shedding old skin, 115 what makes them twinkle, 38 spinneret of the, 115 Steamship, beginning of (illus.), 337 spinning cocoon, 115 cross-section, 346 wild, 109 building of a (illus.), 337 Silver, definition of, 207 cradle of a, 338 use, history of, 207 double bottom, 339 why docs it tarnish, 266 end to end section, 346-347 Silver bromide, in photography, 23 funnel (illus.), 345 Skins, used for clothing, 80 gantry (illus.), 338 Sky, will it ever fall? 255 hull (illus.), 341 why is it blue? 253 hull before launching (illus.), 340 Soap, lye in, 411 inside of (illus.), 346-347 palm olive oil in, 411 launching of a (illus.), 340 what made of, 411 launching machinery (illus), 341 Soda, Leblanc process, 494 ready to launch (illus.), 340 ^ Solvay process, 494 plates (illus.), 339 where we get, 494 ribs (illus.), 338 Solids, definition, 348 skeleton (illus), 339 Some wonders of the human body . 311 turbine, weight of, 344 Sound, deadening of, 79 turbine (illus.), 344 first over a wire, 71 Steel pen, how made, 16 how measured, 242 Steel rail making, blast furnace (illus.), 234 how produced, 485 Blooming mill and engine (illus.), 237 speed of, 140-486 dump bugg>', 237 travels through air slowly, 31 crane, carrying ingot (illus.), 236 in a sea shell, 79 ingot, 237 what is, 78-485 ingot becomes a rail (illus.), 238 waves, 79 mixer (illus.), 234 waves, length of, 487 molten steel being poured into ladle (illus.), where comes from, 78 236 Slate pencil, why cannot write o'^ paper with, open-hearth furnace (illus.), 235 18 furnace, pouring sides of an open hearth Sleep, where are we when, 365 (illus.), 235_ with eyes open, why we cannot. 92 iron, purification of, 235 ghosts, 367 soaking pit (illus.), 236 why heart beats during, igi furnace, temperature in, 235 why we go to, 365 Stick, why it bends in water ,538 restless, 92 making a fire with, 42 Sling, man in action (illus.), 41 Stockings, where it goes when the hole comee, how first made, 41 64 Slings, and their drawbacks, 42 Stone-throwing, 41 Slow match, of early firearms, 45 Stones, where they come from, 494 Smells, why do flowers have, 176 Story in an automobile, 181 Smoke-cone, in gun-firing (illus.). 28 in a loaf of bread, 460 Smokeless powder, 35 in a book, 561 Smoke-rings, hard as steel, 27 in a building foundation, 496 Smoke signals, of Indians, 412 in a cablegram, 428 Smoke-zone, in gun firing, 1 1 1 in a barrel of cement, 95 Sneezing, what makes us, 194 in a stick of chocolate, 388 why do we, 194 in a suit of clothes, 80 Snowflakes, what makes them wh ite? 409 in a lump of coal, 257 Space, extends, how far, 256 in a bale of cotton, 470 Sparkle, when merry, why eyes, 92 of a'cup and saucer, 404 Spear, as a weapon, 42 of the deep sea diver, 203 Specific gravity, meaning of, 268 in an electric light, 305 Speed, of lij^dit, 36 in an elevator, 395 INDEX 597 Story in a finger print, 520 in a flying machine, 126 in a gas jet, 303 in a gun, 40 in a honey bee, 526 in a magnet (illus.), 326 in a lead pencil, 466 in lighting a fire, 289 in a lock, 491 in a can of paint, 224 in a pen, 1 1 in a piano, 478 in a photograph, 22 in " Pigs is Pigs " (illus.), 374 in a pipe and cigar, 512 in a railroad engine, 440 in a coil of rope, 353 in a ball of rubber (illus.), 378 in a rug, 167 in a pair of shoes, 541 in a steel rail (illus.), 234 in a submarine boat (illus.), 269 in a lump of sugar, 145 in a telegram, 412 in the telephone, 65 in a time piece, 313 in a tunnel, 208 in a drink of water, 501 in a window pane, 246 in the wireless, 455 in a yard of silk, 109 in a piece of leather, 538 Stringed instruments, the first, 480 discovery of, 479 Stretching, why do we, 192 what happens when we, 193 Stylus, iron, 13 the in writing (illus.), 11 Submarine, accidents and their causes, 278 air and how it may become poisonous, 278 buoyancy of, 270 " Bushnell's Turtle," 280 cargo, recovering of, 285 clearing a channel of buoyant mines (illus.), 283 development of, 280-281 divers' compartment, 270 equilibrium, 270 explosions, 278 first practical (illus.), 271 gas, explosion of, 278 " G-i " (illus.), 272 Holland, 282 how we look through a periscope (illus.), 276 hydroplanes on, 270 hydroplane, 282 ice, unfler (illus.), 279 inside of a (illus.), 272 lens, of periscope (illus.), 276 living quarters (illus.), 285 mice on, 278 mine planting inside of (illus.), 277 omniscope, 271 one of the first practical, 271 " Proctor," first practical, 271 " Proctor" suhmc-rgcfl (illus.), 271 jjcriscopc top t){ (ilhis.), 276 rudflcr, horizontal, 270 sailin^( dose to surface Cilltis.), 273 Submarine, seeing in all directions at once, 276 Simon Lake, American inventor of, 282 steadiness of (illus.), 273 under the ice (illus.), 279 submergence, 270 water pressure on, 270 who made the first, 280 Submarine boat, " Argonaut the First " (illus.), 269-282 " Argonaut Junior " (illus.), 269-282 who made the first, 280 Submarine mines, amount of powder used, 34 Sugar, carbonatation station (illus.), 150 chemical laboratory in factory (illus.), 149 cucular diffusion battery in factory (illus.) 149 filter presses (illus.), 150 how taken from beets, 150 sulphur station (illus.), 150 washing the beets, 149 Sugar factory, carbonatation station (illus.), chemical laboratory in (illus.), 149 circular diffusion battery (illus.), 149 filter presses (illus.), 150 sulphur station (illus.), 150 Suit, cost of wool in a, 83 Sulphite of soda, used in developing, 23 Sun, distance from earth, 141 revolving on its axis, 511 Sim-dial (illus.), 315 in determining noon (illus.), 316 concrete (illus.), loi Sunlight, effect on balance, 37 Svmset, cause of colors in, 253 Swallowing, what happens when we, 195 Swimming, why man must learn, 125 Switchboard, telephone, 69 back of a, telephone (illus.), 69 telephone, the first (illus.), 74 Talking, how man learned talking, 18 signs and gestures, 18 Talking machines, 490 Target, floating, 31 Never seen by men firing mortar, 29 projectile, arrival at, 24 Tears, caused by onions, 38 as an eye-wash, 38 run along channel, 38 where they come from, 94 where they go, 94 Teeth, why they are called wisdom, 125 why they chatter, 218 Telegram, how it gets there, 414 story in a, 412 Telegraph, cables (illus.), 424 code, 419 calling a messenger, 414 waiting calls (illus.), 414 arrival at destination (illus.), 417 duplex, 417 electric, 420 electric, first suggestion of, 420 inventor oi, 420 two men inventors (jf , 42 1 instruments, 425 instrumens, first sending (illus.), 426 instrument, sending, 41H key, modern (illus.), 427 key, .'I l;it{ projectiles, 53 What does the air weigh? 398 animal can leap the greatest distance? 122 causes an arrow to fly? 408 makes some peojjle b;ild? 143 What keeps a balloon up? 199 makes a ball stop bouncing, 63 are ball bearings? 180 happens when a bee stings? 537 makes the hills look blue sometimes? 255 makes me blush? 194 was the origin and meaning of bread? 460 is the hottest spot on earth? 239 holds a building up? 496 makes a bubble explode, 108 is carbonic acid? 509 is a cable made of? 429 is the eye of the camera? 22 do ocean cables look like when cut in two? (illus.), 428 do we mean by i8-carat fine? 266 is clay? 495 is color? 123 produces the colors we see? 123 makes the colors in the rainbow? 254 makes the colors of the sunset? 253 are cocoa shells? 390 is cement? 95 is cement used for? 95 a cement miU looks like (illus.), 96 is cement made of? 95 is cement used for, 95 is concrete? 95 makes some things in the same room colder than others? 144 does woolen cloth come from? 80 was the cross-bow? 44 are diamonds made of? 351 causes dimples? 352 makes us dream? 366 were man's first divisions of time? 314 makes things whirl around when I am dizzy? 402 is dust? 104 becomes of the dust? 104 are drone bees good for? 531 is meant by deadening a floor or a wall? 79 causes earache? 410 makes an echo? 200 are the principal parts of an elevator? 396 causes the explosion in a gas engine? (illus.) 182 happens when .anything explodes? 205 is an element? 349 makes the hollow place in a boiled egg? 179 is electricity? 329 is an electric current? 334 makes an electric magnet lift things? 326 do we mean by Fahrenheit? 22 1 makes a fish move in swimming? 233 is fog? 105 makes the water from a fountain shoot into the air? 198 makes freckles come? 125 makes a gasoline engine go? 181 is gravitation? 267 does sj)ecific gravity mean? 268 makes a cold glass crack if we put hot water in it? 63 are ghosts? 367 causes the gurgle when I pour water from a bottle? 63 causes hail? 124 is the horizon? 244 causes a hot box? 368 What good are the lines on the palms of our hands? 402 does horse-power mean? 256 is hydrogen gas? 349 makes us feel hungry? 243 makes knots in boards? 223 were the eiirliest lamps? 295 were tlie lamps of the wise and foolish maidens? 295 happens when we laugh? 93 makes us laugh when glad? 92 is a leyden jar? 332 is a lodestone? 327 makes lobsters turn red? 245 makes the lump come in my throat when I cry? 195 makes a match light when we strike it? 198 would we do witJiout matches? 292 is a metal? 265 is the most valuable metal? 265 is the milky way? 255 is a molecule? 348 is money? 455 is motion? 61 made the mountains? 401 is music? 478 does a note in music consist of? 490 is organic matter? 174 is oxygen? 349 is nitrogen? 350 makes nitroglycerin explode so readily? 206 causes nightmare? 367 is pain and whj- does it hurt? 244 makes the different colors in paint? 229 is pitch in music? 489 is the principle of the wireless? 455 makes some pencils hard and others soft? 467 makes rays of light? 230 makes us red in the face, 192 makes the rings in the water when I throw a stone into it? 197 is rubber? 386 is wild rubber? 387 should I do if stung by a bee? 537 is the cause of shadows? 495 makes the sea roar? 401 does the bottom of the sea look like? 220 becomes of the smoke? 106 and w'hy is smoke? 105 causes the smoke when a gun goes ofT? 206 is smokeless powder made of? 206 makes snowflakes white? 409 depth of snow is equivalent to an inch of rain? 241 is soap made of? 411 makes a soap bubble? 108 shot tower looks like? 51 makes us sneeze? 194 is silver? 207 happens when we stretch? 193 makes me want to stretch? 192 happens when I swallow? 195 is sound? 485 are the properties of sound? 486 are the sounds we hear in a sea shell? 79 makes the sounds like waves in a sea shell? 79 does a sounding board do? 488 is meant by the length of sound waves? 487 makes us thirsty? 243 makes me tired? 403 What a great steamship looks like inside (illusj, 346 did the first telephone look like? (illus.) 72 occurs when we think? 194 are the big tanks near the gas works for? 298 makes the stars twinkle? 38 a ship's turbine looks like (illus.), 344 is the largest tree in the world? 242 happens when we telephone? 65 makes water boil? 220 is the boiling-point of water? 220 causes a whispering gallery? 201 makes a wireless message go? 455 makes the works of a watch go? 368 makes the white caps on the waves white? 410 is worry? 207 causes the wind's whistle? 139 makes the kettle whistle? 198 causes wrinkles? 196 are X-rays? 307 is yeast? 288 When did man first try to fly? 126 did man begin to live? 174 were candles introduced? 296 was illuminating gas discovered? 302 was wheat first used in making bread? 461 I throw a ball into the air, while walking why does it follow me? 401 was silk culture introduced in America? in were street lamps first used? 295 Where does bread come from?, 460 does water in the ocean go at low tide? 219 does silk come from? 109 are we when asleep? 365 did the name calico come from? 123 cement is obt^iined (illus.), 97 does chalk come from? 18 does chocolate come from? 388 our coal comes from? 257 does cotton come from, 470 does the day begin? 324 does the day change? 325 did the term Dixie originate? 123 does honey come from? 526 is the horizon? 244 does the hour change? 325 the gas is taken from the coal (illus.), 299 did all the names of people come from, 20 did the expression " kick the bucket " originate? 321 does leather come from? 538 do living things come from? 174 did life begin on earth? 174 do we get ivory? 239 do lead pencils come from? 466 does the wooden part of a lead pencil come from? 469 does a light go when it goes out? 36 does linseed oil come from? 227 does paint come from? 224 does the rain go? 222 are the best Persian rugs made? 167 does rope come from? 353 does salt come from? 493 do we get soda? 494 do all the little round stones come from? 494 does the part of a stocking go that was where the hole comes? 64 does sound come from? 78 do school slates come from? 495 INDEX 601 Where do shoes come from? 541 do sponges come from? 286 do tears come from? 94 do the tears go? 94 did the name tobacco originate? 512 is Havana tobacco grown? 513 does tobacco come from? 512 does'tobacco grow? 512 did all the water in the ocean come from? 218 does our drinking water come from? 501 does most of our wool come from? 81 does the wind begin? 139 jp the wind when it is not blowing? 139 does wool come from? 80 did the term Yankee originate? 243 Wheat, bread loaves of the world, 459 grinding (illus.), 464 harvesting (illus.), 460 scouring of, 463 tempering^of, 463 when first used in making bread, 461 will it grow wild? 461 Wheel-lock rifle (illus.), 46 Whispering gallery, accidental, 201 cause of, 201 what it is, 201 Whistle, what makes the kettle, 198 White Lead, making (illus.), 225 buckles, before corrosion (illus.), 225 buckles after corrosion (illus.), 225 buckles, making, 225 Who started to make clothing from wool in America? 81 discovered electricity? 333 invented electric telegraph? 420 who make the first felt hat? 239 made the first cent? 458 made the first submarine boat? 280 first discovered the silkworm? 109 first discovered the power of gunpowder? 44 invented flying? 126 made the first piano? 478 brought the first sheep to America? 80 first wove silk thread into cloth? 109 make the first shoes? 541 made the first umbrella? 312 Why don't the air ever get used up? 140 can't we see air? 140 do we grow aged? 196 does an apple turn brown when cut? 106 do coats have buttons on the sleeves? 64 has a long coat buttons on the back? 64 cannot babies walk as soon as born? 180 are some people bald? 144 don't the birds stay South? 408 drx;s a ball bounce? 63 does a balloon go up? 199 do we call voting balloting? 122 does a barber pole have stripes? 310 do some things bend and others break? 62 do the birds come back in the Spring? 407 do l)irds sing? 408 do birds go .South in the Winter? 407 are birds' eggs of flifTerent colors? 233 has a bee a sting? 336 can you blow out a candle? 21, 36 are bubbles round? 108 ' docs red make a bull angry? 490 do we get a bump instead of a dc-nt when wc knock our heads? 201 Why can't, we bum stones? 105 has a long coat buttons? 64 is bread so important? 460 do I get out of breath when running? 191 do we call a cab a hansom? 122 does a hen cackle after laying an egg? 233 do children like candy? 409 is cement called Portland cement? 95 do I get cold in a warm room? 125 is it cold in winter? 141 does cold make our hands blue? 192 does an ear of corn have silk? 170 do we count in tens? 10 we cannot see in the dark, 91 does the dark cause fear? 352 do we have to die? 245 does a dog turn round and round before he Hes down, 229 do we know we have dreamed when we wake up? 367 does eating candy make some people fat? 409 don't an elevator fall? 397 do our eyes sparkle when we are merry? 92 do the eyes of some pictures follow us? 35 is it difficult to walk straight with my eyes closed? 91 do I get red in the face? 192 are some faculties stronger than others? 403 is a fire hot? 401 does a fire go out, 37 we fear the dark? 352 cannot fishes live in air? 232 do we have finger nails? 142 are our fingers of different lengths? 142 have we five fingers on each hand and five toes on each foot? 142 do we have finger nails? 142 does a gasoline engine go? 181 do girls like dolls? 368 is gold called precious? 266 are gold and silver best for coining? 457 is some gun-powder fine and others coarse grained? 206 are some guns called gatling guns? 310 does a glow-worm glow? 231 do we stop growing? 195 do we have hair? 143 does the hair grow after the body stops growmg? 144 don't my hair hurt when it is being cut? 143 does my hair stand on end when I am frightened? 143 is the right hand stronger than the left? 309 does my heart beat faster when I am scared ? does the heart beat when the bram is asleep? 191 do our hearts beat faster when we arc running? 191 do they call it a honeymoon? 31 is a horseshoe said to bring good luck? 311 does it hurt when I cut my finger? 143 we cry when hurt, 93 does iron turn red when red hot? 107 does iron sink in water? 106 doesn't an iron .ship sink? 106 do we have twelve men on a jury? 239 does a lamp give a better light with the chimney on? 37 are there many languages? 197 602 INDEX Why do we laugh when glad? 92 is lead so heavy? 267 do they call them lead pencils? 466 must life be reproduced? 174 are some people light and others dark, 402 did people of long ago live longer than we do now? 199 do we use metal for coining? 456 do thay call it the milky way? 255 do we need money? 455 does the moon travel with us when we walk or ride? 399 should we not sleep with the moon shining on us? 366 do my muscles get sore when I play ball in the spring? 310 does a nail get hot when hammered? 230 do we have only seven octaves on a piano? 480 does ocean look blue at times? 219 does oiling the axle make the wheel turn more easily? 400 does an onion make the tears come? 38 can't I write on paper with a slate pencil? 18 does a pencil write? 18 are some races white and others black, yellow and brown? 537 do they call it pin money? 231 do we call them pistols? 46 do plants produce seeds? 175 does a poker get hot at both ends if left in the fire? 107 does rain make the air fresh? 222 are most people right-handed? 403 don't we make roads perfectly level? 104 don't we use pure rubber? 380 does salt make us thirsty? 351 don't the scenery appear to move when I am in a street car? 399 does the scenery appear to move when we are riding in a train? 399 can cats and some other animals see in the dark? 91 can we see farther when we are up high? 245 do I turn white when scared? 193 docs silver tarnish? 266 does the sheep precede the plow in civiliz- ing a country? 81 is the sky blue? 253 do I sneeze? 194 do we see stars when hit on eye? 268 many stars are there? 223 does a stick in water bend? 38 does a sound stop when we touch a gong that has been sounded, 78 can we make sounds with our throats? 78 do people shake with the right hand? 231 do we go to sleep? 365 does it seem when we have slept all night that we have been asleep only a minute? 366 can't we sleep with our eye open? 92 we can hear through speaking tubes, 487 does a human being have to learn to swim? 125 are cooking utensils made of tin? 267 do we use copper telegraph wires? 266 do my teeth chatter? 218 are some things transparent and others are are not? 350 Why do I laugh when tickled? 93 can \ve think of only one thing at a time? 193 does thunder always come after the light- ning? 140 do we call them wisdom teeth? 125 are some roads called turnpikes? 104 is the sea water salt? 351 will water run of? a duck's back? 233 do we worry? 207 don't the water in the ocean sink in? 219 is it warm in summer? 141 does water run? 219 do we say water is soft or hard? 221 does a piece of wood float in water? 106 do we wake up in the morning? 365 do I yawn? 173 does yeast make bread rise? 288 Will people all be bald sometime? 144 the sky ever fall down? 255 Windows, how an explosion breaks them, 62 "^Vireless, accidents, prevention of, 449 aerial on R. R. stations (illus), 451 aerial on ship (illus.), 455 antenna;, 447 antenna; on trains (illus.), 450 battery, 447 coil, 447 compass, 454 development of, 454 direction finder, 454 distance of sending, 448 equipment, 446 first Marconi station, 452 how it reaches ships at sea, 446 icebergs (illus.), 449 ' in the army (illus.), 447-448 inventor of, 452 key, 447 masts, height of, 44.8 G. Marconi, portrait, 452 on trains (illus.), 450 prevents accidents, 449 principles of, 455 receiving station in U. S. Army (illus), 451 spark gap, 447 stations, shore (illus.), 446 stations on trains (illus.), 450 transmission automatic (illus.), 453 transmission of messages (illus.), 453 what kind of signs are used in? 446 why don't the message go to the wrong stations, 455 world-wide use, 454 Wires, copper telegraph, 266 how put underground (Ulus.), 76 wire-wound gun, 54 Wonders performed by electric lift magnet (illus.), 326 Wool beaming (illus.), 89 bobbin in weaving machine, 86 Burling (illus.), 88 burr picker, 87 carding, 85 carding, finisher in cloth making (illus.), 89 chloride of aluminum in making cloth, 87 cleaning, 85 made clothing from, 81 combing (illus.), 86 cost of in a suit of clothes, 83 crop of the United .States, 82 INDEX 603 Wool dyeing, 85-87 fabrics, 85 fiber description, 83 finishing, box (illus.), 87 finish, perching (ilkis.), 90 fulling cloth (illus.), 90 gilling after carding (illus.), 86 gilling and maldng top after combing (illus.), 86 gilling (illus.), 87 greasy matter in, 84 how we get it off the sheep, 82 how much does a sheep produce. 83 how much does America produce, 82 how made into cloth, 85 how woolen cloth is made perfect, 88 how shipped, 82 loom, 86 mending, perching (illus.), 88 mending room (illus.), 88 woolen mule spinning (illus.), 89 napping, 89 next to food as a vital necessity, 81 piece dyeing (illus.), 90 quahty of a hundred years ago, 83 raised to sell to manufacturers, 81 reducer machine in v/ool making (illus.), 87 ring twisting (illus.), 89 shipped to manufacturers, 82 shuttle in weaving, 86 scouring (illus.), 85 sorting (illus.), 84 spinning process, 86 spinning, 89 English cap spinning, 89 in one suit of clothes, 83 sulphuric acid solution in making cloth, 87 teasel, 89 tramper, 82 in United States, bulk of, 82 warp thread, 86 web, 86 weaving (illus.), 88 where does most of our wool come from? 81 woof of, 86 made into yam, 86 Wool yarn inspecting (illus.), 89 yolk of, 84 Woolen cloth, ready for market (illus.), 90 Woolens and worsteds, difference between, 84 Woolworth building (illus.), 395 Words, formation of, 19 the first over a telephone, 74 World's bread loaves (illus.), 459 Worry, definition of, 207 what it is, 207 Why we, 207 Worsted carding (illus.), 85 fabrics, 85 Worsteds and woolens, difference of, 84 Wright Brothers, first successful flights, 130 Wrinkles, what causes, 196 Writing, brush, the (illus.), 13 earhest ways of, 12 first done upon rocks, 1 1 first imitation of, 12 first metallic pen introduced, 15 fluids for developing, 13 how man learned to, 1 1 how the monks did their, 14 how a pen writes, 18 modern way of, 16 paper for, earliest, 14 pen invention of, 00 pen, first steel (illus.), 15 quill, the (illus.), 14 Reed, the, in (illus.), 12I steel tube pen in (illus.), 15 • steel pen, modern (illus.), 16 Stylus, the (illus.), 11 with chalk, 18 why a pencil writes, 18 X-rays, what are they? 307 Yankee, where word originated, 243 Yarn, made from wool, 86 Yawning, why do, 173 is it infectious, 192 Yeast, what it is, 288 why it makes bread rise, 288 Yes, meaning of nod, 19 ZoUner, Casper, inventor of rifling, 46 University of California 4nl2V^"5?^ REGIONAL LIBRARY FACILITY 405 Hilgard Avenue, Los Angeles, CA 90024-1388 Return this material to the library ^rom which it was borrowed. « * ^ I ^