x^ mm M MHM St/4 ■ y S;;r, •■/'.. ' ZZfrU' University of California • Berkeley Purchased from CHABOT AND DIECKMANN MEMORIAL LIBRARY FUND #& ■? ^cZ^^—' Digitized by the Internet Archive in 2007 with funding from Microsoft Corporation http://www.archive.org/details/cyclopediaofusefOOantirich TEE HOME CYCLOPEDIA CYCLOPEDIA OF THE USEFUL ARTS; INCLUDING AGRICULTURE, ARCHITECTURE, DOMESTIC ECONOMY, ENGIN BERING, MACHINERY, MANUFACTURES, MINING, PHOTOGENIC AND TELEGRAPHIC ART: AN EXPOSITION OF THEIR PRINCIPLES AND PRACTICE AND A COMPEND OF AMERICAN AND EUROPEAN INVENTION. BY T. ANTISELL, M. D, NEW YORK: A. S. BARNES & CO., 51 JOHN-STREET CINCINNATI :— H. W. DERBY & CO. 1855. Entered according to Act of Congress in the year 1854, By A. S. BARNES & CO., In the Clerk's Office of the District Court of the United States for the Southern District of New Yorjs. PREFACE. The aim and scope of this volume is perhaps sufficiently indicated in the title-page. It is intended to comprise, in a clear and com- prehensive form for popular reference, a dictionary of all terms used in the application of science to the useful arts. It is believed that a manual of this kind — sufficiently full in its details for ordinary purposes, and accurately posted up to the present time, yet in a comparatively moderate compass — will meet a very important want in this country, which is yet unfilled by the larger and more expen- sive works already before the public. The number of new inventions of various sorts constantly brought forward in the United States is so enormous, and the propor- tion of those which prove really valuable is so small, that it would be needless in a volume like this to attempt any thing more than a reference to the most important and established improvements. The number of applications for patents in the year 1849 was 1955, — of which 1066 were granted. The editor of this volume has endea- vored to condense in its pages as much practical information as the limits of the work would admit, from various recent sources, such as the reports of the Patent Office, and the scientific periodicals, as well as from the standard works of Brande and Ure. He has, in short, combined the best foreign information at present accessible 11 PREFACE. with the latest details of the progress of the Useful Arts in the United States. In some fewjnstances, this work contains topics which are also treated of in the other volumes of the series : but in this volume practical details are given, while the others are intended to give merely the scientific definitions It is not to be supposed that infallibility is claimed for a com- pilation of this kind. Every care has been used to secure accuracy, but the publisher will still be glad to avail himself, in future edi- tions, of all useful suggestions and corrections with which he may be favored. CYCLOPEDIA THE USEFUL ARTS ACETATE. A saline compound formed by the union of an alkali, or an earth with Acetic Acid. ACETIC ACID. The sour principle of vinegar. This acid occurs in the vege- table kingdom in the elder and some varieties of rhus. It exists in the gas- tric juice and other animal secretions. When vegetable matter is distilled in close vessels, this acid is always one of the products. Alcoholic liquids are ca- pable of producing acetic acid, and it is the last stage in the fermentation of many vegetable bodies containing starch or su- gar — as paste, &c. Pyroligneous acid is acetic acid derived from wood — for the manufacture of which see under that head. The purest acetic acid is that made by the oxydation of alcohol. The oxydation is produced by the action of the atmosphere. In Germany, where this process was first adopted, "the alco- hol was exposed in very large surface to the action by being made to trickle along the shavings of wood. These were placed in a deep barrel, perforated at the sides with a number of holes so that free access of air to the inside of the vessel was effected ; on the upper part of the barrel was a raised rim capable of hold- ing a certain head of alcohol, and the up- per end of the barrel was perforated with a few fine apertures so that the alcohol might slowly stream down on the shav- ings; it was thus exposed to a large quantity of air constantly renewed, and by the time it reached the bottom of the vessel it was converted into vinegar, or dilute acetic acid. It was drawn off by a cork from the lower part of the barrel, placed in a still and distilled with a gen- tle heat ; the portions which come over first, contain the acetic acid. A great improvement on this process has been the substitution of spongy pla- tinum (see Platinum) for the wood shav- ings. The principle in both is the same, being the oxydation of alcohol by the air. Into a large case of wood with glass sides or windows for observing the process, and fitted with shelves within a few inches of each other, is placed a number of saucers filled with the alco- hol, and over each saucer is suspended a small portion of the black platinum powder. The quantity of alcohol in the saucers varies with the dimensions of the case ; 100 cubic inches of air being capable of oxydizing 11 grains of abso- lute alcohol, and converting it into 12*2 of absolute acetic acid and 6s grains of water. The case must now be warm- ed up to 80° Fahr. by solar or arti- ficial heat and the alcohol induced to evaporate off the saucers by some lead- ing points, as strings or folds of paper set endways in the liquid : in a short time the temperature inside the box rises ; vapors form, condense on the in- side, and roll down to the bottom. This process continues so long as there is any oxygen of the air in the vessel uncon- sumed : now and then fresh supplies of air are needed — 8 oz. of the platinum powder will in a day's work convert one pound of alcohol into acetic acid. The change arises from the absorption of oxy- gen from the air, and its union with the elements of alcohol, which results in the formation of acetic acid and water. By the chemist the change is expressed by the formula : alcohol C* H« 0« -f- 0< from air = C* H3 O 3 acetic acid -j- 3 H wa- ter. Hence 100 parts of alcohol absorb nearly 69 parts of oxygen, and there are produced nearly 111 parts of acetic acid and 58 parts of water. Strong acetic acid is also made by distilling crystalled bin- CYCLOPEDIA OF THE USEFUL ARTS. [adz acetate copper (verdigris) in close ves- sels at a high heat. It can also be made by distilling acetate of potass and acetate of lead (sugar of lead) with oil of vitriol. In its purest state it is united with an atom of water, and has a specific gravity of 1 '063. It is caustic on the tongue and to the skin : it is used as a scent, and when essential oils are added, constitutes the aromatic vinegar. It dissolves cam- phor, gluten, resins, gum resins, fibrine, and albumen. ACETONE. A term for pyro-acetic spirit. ACIDS. A class of chemical substances remarkable for their sour taste and their readiness to unite with alkalies and earths to form salts : there are many hundred acids, distributed in the three kingdoms of nature. With one exception they red- den vegetable blue colors, as blue cabbage and litmus. Some exist naturally in the mineral, animal, and vegetable world, and some are the result of chemical pro- cesses : a few are solid bodies and some gaseous, but the greater number are in the liquid form. ACTINOLITE. A hornblend mineral of a green tint, and crystallized in slender needle prisms! ADIPOC1RE. The change which flesh undergoes after death when placed in circumstances where putrefaction does not proceed in the ordinary way. In Paris, when in the latter quarter of the last century the dead bodies were re- moved from the Innocents to the Cata- combs, those which lay in a pit — to the number of 1500, in coffins packed close together — had their flesh converted into a white fatty soap : it resembled sperma- citi, and was named adipocire by Four- croy. Chevreul found it to be made up of fatty acids. Moisture appears to be necessary to produce this substance, as it is not produced in dry earth : and it is very doubtful if it be formed from the muscle of man, but rather some altera- tion of the fat actually existing in the body at the time of death. ADULAEIA. A variety of felspar. AFFINITY. A term denoting the force of chemical attraction by which dissimi- lar bodies are brought into union and retained so. It is distinguished from cohesion, which is exerted between bodies of a similar nature. Cohesion is a force antagonistic to affinity, and for two dis- similar substances to" unite it is neces- sary that one of them should be fluid : if both be fluid, affinity comes into play more readily, as in the case of alloys : dissolving the substances in some special liquid, or heating them until melted, are the modes of bringing the particles of matter sufficiently close to form chem- cal union. Every process of chemical manufactures implies the union and de- composition of bodies, which are effected by calling into play their affinities. Many bodies, although dissimilar, have no ten- dency to unite — as oil and. water, mer- cury and water, mercury and oil. This is explained by saying that these bodies have no affinity for one another: while alcohol and water, sulphuric acid and potass, oxalic acid and lime, unite readily because their mutual affinities are strong. ADHESION. That property possessed by bodies of dissimilar natures of resist- ing a force applied to separate them ; and it differs from cohesion and affinity. Adhesion cannot occur between two solid bodies, for then the force which binds them together is either some modifica- tion of the attractive force, or it is due to atmospheric pressure : for perfect adhe- sion, one of the bodies ought to be fluid or semifluid ; it may afterwards return to the solid condition without destroying the adhesion, unless it crystallize. It is desirable also that they should not con- tract unequally in cooling, for then the adhesion would be destroyed : for the union of two surfaces into one it is there- fore necessary that both should contract equally : and cement for uniting different surfaces depends for its fitness upon this property: to cement metals with other solids, solders are needful, and particular solders for various metals. Such bodies as pitch, which even at reduced tempera- tures will expand, are those which ad- here most firmly. The adhesion between solid bodies is sufficiently strong to over- come the cohesive force of one of them — as when two pieces of wood are glued together and then separated forcibly, a layer of glue remains on each piece. The adhesion of the wafer on the envelope is greater than the cohesion between the particles of the paper, and a layer comes off on the surface of the wafer when the latter is separated. When a solid dips in a liquid, its adhesion is sometimes greater than the cohesion for the parti- cles of the liquid, as when wood or metal is dipped into water : the water adhering is said to wet it. Wood or the finger, dipped into quicksilver, is not wetted. Oils have no adhesion for water. (For other instances of adhesion, see Cement.) ADZE — Addice. A cutting chisel with an arched blade and the edge at right '] CYCLOPEDIA OF THE USEFUL ARTS. 3 angles to the handle : it differs from | the chisel in application, the force "being impact and arising from a blow and not that of mere pressure. The adze cuts the wood, if its edge be fine ; but if not, the wood is split and the tool acts then more like the axe as a wedge than the chisel. In coarse preparatory work, the adze is carried through the space be- tween the workman two feet, and the quantity of wood removed is very great ; in fine work, the foot is placed upon the wood and the adze is carried two or three inches under the sole, and the smooth- ness and delicacy of the work accom- plished is surprising. AER ATEDW ATERS. Artificial drinks impregnated with carbonic acid — as soda water, ginger beer, carrara water, &c. AGARIC. A species of fungus or puff- ball ; occasionally used as a tinder and as a black dye in combination with per-salts of iron. AGATE. A name given to many com- binations of chalcedony, carnelian, quartz, amethyst and flint. It is one of the varied forms of silicious minerals, and contains 98 per cent, of silica ; it is opaque, and has a resinous fracture with deep tints, produced by traces of iron. when a section is made it displays a series of dark lines or bands, sometimes irregular, some- times rounded, which are the edges of successive deposits made by the mineral during its formation. Agates take a high polish", and are much valued as ornamen- tal stones in the manufacture of cups, rings, seals, knife-handles, snuff-boxes, &c. ; hurnishers are made of agate for the use of bookbinders and silversmiths. These gems occur naturally in amygdaloid trap rocks, lying in nodules, surrounded by chloritic clay, also in beds of streams and rivers, where they have been washed down. They are made darker in tint by being boiled" in oil, and then dipped in oil of vitriol. The carnelian is an agate of a flesh red or yellow tint : it is com- mon in the sandy plains f Africa, India, and Asia Minor. AIR. The gaseous envelope of the earth. Our planet has two coverings: one the water which is distributed as lakes and seas, filling up the deep cavities of the solid surface, tending to produce a more level superficies ; the second covering is the air or atmosphere which rests upon the top of the water and the dry land, enveloping the highest mountains, and rising upwards to an altitude somewhat above 45 miles ; it is a true aeriform ocean surrounding our earth, and has upon its upper surface waves and tides ; and throughout its mass, currents flowing in constant and variable directions, precisely as those of the ocean comport themselves ; it is held down to the surface of the earth by attraction, and rotates with the planet ; its density varies with its actual height at the place of observation, of whicn the barometric pressure is the evidence. This pressure diminishes as the elevation above the sea increases, owing to the up- per portions of the atmosphere pressing upon and condensing the lower strata so much so, that one-half the actual weight of the atmosphere is comprised within the space of the lower 5 miles of its total height, the remaining 40 miles in height containing the other half. The air is highly compressible and clastic, and its volume diminished inversely as the pressure increases. This accounts for the facility of setting it in motion and its ve- locity. Like fluids, it presses equally in every direction, and when it comes in contact with a more expanded, and there- fore lighter portion of air, it pushes it up and occupies its place, producing currents of air and winds when it flows in streams, and sound when it is thrown into vibra- tions or undulations. The air is warmed solely by the earth, and not by the trans- mitted rays of the sun, — hence warm air exists within the tropics, and diminishes toward the poles, and sensibly decreases every 350 feet of elevation. Air was ono of the simple substances of the ancient Shilosophers ; but it has been shown by cheele and Cavendish to be a compound body made up of oxygen gas and nitro- gen. The proportions in which they are found to exist, are 21 of oxygen and 79 of nitrogen by volume in 100 parts. These substances are not chemically united, they are merely mixed together. There is also contained in the atmosphere a small quantity of carbonic acid, amount- ing to one twenty-five hundredth part, winch, no matter at what elevation the air may be drawn, is still found. Saussure detected it at Mont Blanc, and Boussin- gault on the Andes, so that it is a regular constituent. Liebig has shown that am- monia can also be detected in the atmos- phere, to which may be added a variable quantity of watery vapor, odors of plants, and other volatile substances ; it no doubt also contains floating particles (miasmata), during periods of epidemic disease. The chemical properties and the beneficial effects of the air are due to the pressure of oxygen, the removal of which, or any alteration of its amount CYCLOPEDIA OF THE USEFUL ARTS. [ALA and condition, renders the air injurious to life. (See Ventilation.) Although air is invisible, and much lighter than solid or fluid bodies, yet it is still subject to all the physical laws which govern gases ; in a large quantity, as when the sky is clear, it gives us a blue tint to the eye, which may be due to the vapor of Avater in the atmosphere refracting the light. It occu- pies a given space, and is impenetrable, and no other substance can occupy where it is except it be by displacement. It is ca- pable of communicating weight : and 100 cubic inches of it are found to weigh 31-0117 grains at the temperature of 60°, and the barometric column standing at 30°. This weight is equal, on the whole atmosphere of 45 miles height, to a pres- sure of 15 lbs. on every square inch. This pressure varies in different places and at different times. {See Barometer.) This pressure is exerted upon every sub- stance at the level of the sea. Air may be compressed into a smaller volume, in proportion to the pressure exerted upon. Doubling the pressure condenses the air into one-half its bulk; when released from pressure it expands to its original bulk : this is due to its elasticity, which, like all gases, is very great. A 1 R-P U M P — Exhausting Syringe. Instruments founded upon the elastic property of the air. The syringe consists of a brass cylinder with an air-tight piston ; a valve at the top opens upwards into the body, and one at the lower part opens outward (at the side) into the external air. This apparatus is screwed on to any vessel which requires to have the air re- moved. On raising the piston the air from the vessel below follows it upward, filling the cylinder ; if the lower stopcock be now closed, and the cylinder pressed down, the air will escape by the valve at the side, and the cylinder can be emptied in this way. By constant repetitions of raising the piston, and then expelling the contained air of the cylinder, the greater part of the air of the attached vessel is drawn up and removed. The whole air cannot be discharged in this way : for after it has been worked some time, and the greater quantity of air discharged, the elastic force of the remainder is so slight as not to be able to raise the valve. The air-pump is a doubly exhausting syringe, which has its valves in the pis- ton or plug. There are two moving in the cylinder or barrels, with a reciprocat- ing motion communicated by a toothed wheel and racked piston rods. The bar- rels communicate by means of a tube with a table of metal, upon which is fixed a bell-glass or receiver, made stoutly, and with a strong rim at the bottom ground finely, so as to fit smooth on the table ; a a little tallow or fat is used to smear the table to make the fitting more tight. The receiver is thus a transparent air-tight chamber in which any object may be placed from which it is needful to remove air. A stopcock is fitted to the connect- ing tube, to shut off or let on external air when desired. To good air-pumps a mercurial gauge is attached. AIR-BEDS. Another application of the elasticity of the air to supply the padding or stuffing material of pillows, cushions, and beds, by the use of air, in- stead of solid substances : a bag of cloth is rendered air-proof by means of a var- nish of India-rubber or gutta percha, a tube and stopcock are affixed to one cor- ner, through which the air is blown in to inflate the bag. When moderately dis- tended with air these beds and cushions are tolerably soft. The objection to these is that they warm too soon — the heat of the body accumulates in the pillow, the air of Which is a non-conductor. AIR-GUNS are syringes used for con- densing air, acting somewhat similarly to the exhausting syringe. In the air-gun the vessel for" holding the air is a small metal ball, having a small hole and valve turned inwards. The ball is screwed on to a barrel fitted with a bullet, when upon turning a cock, communicating between the condensed air and the bullet, the lat- ter is driven out with great velocity. To condense the air requires the syringe to act in the reverse manner to that used for exhaustion. ALABASTER. A term sometimes ap- plied to stalactitic carbonate of lime. By the ancients was understood small white stone vessels of a peculiar form, made at Alabastron in Egypt ; it is now generally applied to that variety of sulphate of lime, known as granular gypsum, used for carving small statues, groups of figures and animals, and boxes and vases, which are turned in a lathe. For these purposes it is well adapted by its white- ness, translucency and softness. The best is quarried near Volterrain Tuscany. In this duchy are the hot springs of San Filippo, where the water, almost boiling, contains in solution a large quantity of carbonate of lime, held dissolved by sul- phureted hydrogen, which escapes as soon as the water is exposed to tlie air. Advantage is taken of this property to make bas-reliefs of much hardness, by alk] CYCLOPEDIA OF THE USEFUL ARTS. placing moulds of sulphur obliquely in wooden tubs, open at the bottom. The water of the spring, after depositing its turbid matter, is conveyed above those tubs, which have affixed to their top wooden cross-pieces, the water is allowed to fall upon them, and is then poured in fine streams over the moulds hanging be- low. From two to four months are re- quired for obtaining castings. ALCARAZZAS. A species of porous earthenware used in Spain for cooling liquors. ALBUMEN. The white portion of the egg is in great part albumen. It is also a constituent of the fluid portion of the blood, and of the sap of some plants, as potato, parsnip, carrot, in the seeds ol the cereals, and in most nuts. The cha- racteristic property of albumen, under any circumstance, is its coagulating at a temperature about 160° Fahr. When pure, vegetable and animal albumen are the same substance. That from the egg soon putrefies in the air ; but if it be spread out in thin films, it dries readily, and may then be preserved unaltered for any length of time. Once coagulated, albumen will not dissolve again in wa- ter, but is soluble in caustic alkalies. The solidification of albumen is believed to be due to the loss of alkali, dissolved out by the boiling water. From having this property, albumen is used to clarify syrups, coffee, &c. It is also coagulated by alcohol, the majority of acids, except the acetic, which dissolves it, and by a few metallic salts, such as corrosive sublimate, for which it is an antidote. Lime, baryta, and strontia, form com- pounds with albumen, which harden in drying, and become good lutes or cements for china or glass, or spread on paper for chemical apparatus. ALCOHOL. The liquor procured by distillation of vegetable infusions of a saccharine nature, and juices which have passed through the vinous fermentation. Ordinary alcohol is not pure, containing usually half its weight of water, from which it may be freed by redistillation at a gentle steam or water-bath heat, until its specific gravity is -880. To free it per- fectly, it is necessary to add into the still, or retort, caustic lime, calcined pearl- ashes, or fused chloride calcium ; it is then perfectly free from water, and has a specific gravity of -793 ; it then boils at 169° Fahr. Alcohol may also be concen- trated by exposing it in ox bladders, ow- ing to the property which the latter possess, of allowing water to pass through the pores and evaporate out, but giv- ing little or no facility for the vapor of alcohol to escape. Both surfaces of the bladder should be soaked in wa- ter, and freed from fat and minute ves- sels adhering on both the outer and inner surfaces ; it then should get a couple of coats of a solution of isin- glass on the outer, and double the number on the inside surface ; the spirit is then Eoured in, but the bladder not quite filled y it, a portion of air occupying the top : it is then tied tightly at the mouth, and hung in a warm place near a stove or oven. In this way alcohol may be concentrated in twelve hours, and this kind is well adapted for varnishes. Alcohol has a great attraction for water, and if left ex- posed, rapidly attracts moisture from the air: it should therefore be kept in well closed vessels. From this property it is well adapted for preserving anatomical specimens. It has the property of dis- solving many substances, as soap, cam- phor, resins, essential oils, castor oil, forming varnishes, essences, perfumes, and extracts. If these solutions be mixed with water, milkiness or opacity is pro- duced, owing to the alcohol separating these substances, by preferring to unite with the water. The strength of alcohol is determined by instruments which read off* its specific gravity, calculated tables for which may be found in more techni- cal works. The instruments are termed alcoholmeters, hydrometers. Gay-Lus- sac's instrument, the " alcoometre," is probably the instrument yielding the most correct results : absolute alcohol consists chemically of 4 atoms of carbon, 6 of hydrogen, and 2 of oxygen. ALE. Infusion of barley and infusion of hops, fermented together. ALEMBIC. A vessel used in distilla- tion, for receiving the liquid to be dis- tilled. ALEMBROTH SAL. An old term for white precipitate of mercury, or the dou- ble chloride of mercury and ammonia. ALIZARINE. One of the principles of the madder plant : from which it may be obtained by charring the powder root with oil of vitriol, washing the black mass well with water, drying and heat- ing, when alizarine is obta'ined in crystals of an orange-red color. ALKALI. A name first applied by the Arabians to the carbonates of soda and potash derived from the ashes of plants, but now extended to those substances which dissolve in water, generally form soaps with oils, and neutralize acids form- 6 CYCLOPEDIA OF THE USEFUL ARTS. [alr ing crystalline salts. The chief alkalies of importance in the arts are potash, soda, ammonia, and qninia. They have a com- mon effect upon some colors — such as turning the red colors of roses, cabbages, and radishes to green, the red of litmus to purple, and the yellow of turmeric and a few other vegetable dyes to brown. Even when these three first named alkalies are united with carbonic acid, they exert the same reaction, by which they are readily distinguished from lime and magnesia. When pure they have an acrid and urin- ous taste, dissolve animal matter readily, and unite with oils : they also unite with water in airy proportion. A strong solu- tion in water is termed a lye or ley. ALKALIMETER. An instrument used for testing the strength of the alkalies of commerce. The operation is termed al- kalimetry, the general principle of which consists in ascertaining the quantity of real alkali in a given weight of the sub- stance examined, by finding how much of the latter is required to neutralize a known quantity of an acid — as sulphuric acid. The first step is to prepare a stock of dilute sulphuric acid ot a known strength, containing for example, 100 grains of real acid in every 1000 grain measures of liquid. A large quantity — as a gallon or more — may be prepared at once : thus, the oil of vitriol, if it be good and of the specific gravity of 1-85, con- tains in every 49 grains 40 grains of ab- solute acid. For the proportion required above — every gallon or 70,000 grains of dilute acid — 7000 grains of real or abso- lute acid is demanded ; this, at the com- position of the acid given, is equal to 8571 grains of common oil of vitriol. All that is required, is then to weigh out 8571 grains of vitriol and dilute it with water until when cool the mixture shall measure exactly one gallon. The " Alkalimeter" is next to be con- structed out of a piece of even cylindri- cal glass tube, fifteen inches long and six-tenths of an inch wide internally, closed at one end and moulded into a spout or lip at the other ; a strip of paper is pasted on the tube and suffered to dry, after which it is graduated by counter- poising it in a nearly upright position in the pan of a delicate balance, and weigh- ing into it successively one, two, and three hundred grains of distilled water at 60° until the whole quantity of 1000 grains be reached, the level of the tube after each addition being carefully marked with a pen upon the strip of paper while the tube is neld quite upright and the mark made between the top and bottom of the curve formed by the surface of the water. The smaller divisions of each hundred parts may then be made with the compass into tenth parts. The gra- duation oeing accurate and complete, the operator may transfer the marking to the glass by means of a file, and the paper may be removed with hot water. The numbers can be scratched with the hard end of the file. When this instrument is used with the dilute acid above, every division of the glass will correspond to one grain of real acid. The alkali is examined thus : 50 grains of the sample are weighed, dissolved in warm water, and if needful, filtered : the alkalimeter is then filled to the top of the scale with the dilute acid, and the latter poured from it into the alkaline solution, which is tried from time to time with red litmus paper. When the solution, after being heated a few minutes, no longer affects either blue or red litmus, the measure of liquid employed is read off, and the quantity of soda or potass present in the state of carbonate or hy- drate in the 50 grains of salt, is found by the rule of proportion. Suppose soda was the alkali, and that 33 measures of acid had been used ; then by taking their atomic proportions in which the acid and soda unite, it would stand thus : as Sulph. acid 40 : soda 31-9 : : 33 : 25-6 in 50 grains. The sample therefore con- tains 51-2 per cent, of available alkali. The quantity of alkali in a carbonated form may be known bv weighing the body before and after the expulsion of carbonic acid ; from the loss may be cal- culated the per centage of alkali. By the use of Fresenius's apparatus for this pur- pose, the precision attained leaves no- thing to be desired. ALKALOID. Alkalies found existing in vegetables united with peculiar acids. They are produced by the plant during growth. They dissolve readily in boil- ing alcohol, and sparingly in water: they crystallize out of the alcohol by cooling the latter, from which they can be separated in a crystalline form ; they restore the blue color to red litmus, and. render vellow turmeric brown. The chief alkaloids are quinine and cinchonine from Peruvian bark, nicotine from tobacco: morphia, codeine, narcotine, thebaine, from the papaveraceaj ; and in other fami- lies, strychnine, atropine, brucine, vera- trine, emetine, berberine, and cafeine. They all contain nitrogen not existing in the form of ammonia. ALU] CYCLOPEDIA OF THE USEFUL ARTS. ALKANET. A root used for dyeing i red. The plant, anchusa Uvxtoria, belongs | to the family Boraginese, and is a species of bugloss, cultivated largely in the south of France : the roots yield a deep red to alcohol and oils, and a dull red to water, j It is used extensively to color ointments, i oils, cheese, and perfumery in general. ! White marble is stained a deep tint by the alcoholic solution. ALLOY. A compound formed of two or more metals fused together. Thus bronze is an alloy of copper and tin ; brass an alloy of copper and zinc : they all have lustre, are sonorous, elastic, duc- tile, and malleable, like simple metals. Metals do not alloy indifferently with each other, but are governed by peculiar affinities. Silver unites readily with lead, copper, and gold, but will scarcely alloy with iron. When a metal is united with mercury, it generally receives the title of an amalgam. When metals are united in an alloy the specific gravity of the new compound is not the mean of its constituents, but occasionally is greater — in other instances, less : its melting point also is not the mean of the melting points of the two Inetals, but it is gene- rally somewhat lower in temperature — the fusibility of an allov is increased. Although the number of metals is very great (43), yet only a few are extensively found or of much use — perhaps the num- ber frequently employed is not more than twelve : where purity of a metal is not required, but some property which a single metal does not possess, an alloy is found to supply the want. Even the property of an alloy itself may be varied by uniting with a portion of a third metal. Thus in the case of the alloy brass ; when it is required to have brass fit for turning, a small quantity of lead is added. This improves it for that pur- pose, but renders it unfit for hammering. The number of useful metals can be thus multiplied, as it were, by the formation of alloys. Alloys can only be properly formed by fusion, as by melting the two metals to- gether in a crucible. They require to be stirred well while melting,' lest the metals separate from each other, the heavier taking the bottom of the vessel. The strength or cohesion of alloys is greater than that of its constituents. The most refractory metals, which can scarcely be fused in a crucible at the greatest heat of the furnace, melt down with ease when surrounded by the more fusible metals. The surfaces of the superior metal are melted down or washed away, layer by layer, until the whole becomes liquified. Nickel is nearly as difficult to melt as iron; but it is usefully employed with copper in German silver, to which it gives whiteness and hardness, and renders the alloy less fusible. Platinum cannot be melted at the highest heat of a furnace, but it combines so readily with zinc, tin, and arsenic that it is dangerous to heat one of these substances m a platinum spoon, for an alloy would be formed and the spoon destroyed. An alloy, remarkable for its easy fusi- bility, is made by melting together eight parts of bismuth, five of lead, and three of tin. This melts in boiling water, even in water of the temperature 198° Eahr. It is on this account called fusible metal. The proportions may be varied to make a more or less fusible compound. Safety plugs for valves of steam-boilers, are made of this material : a hole made in the boiler is stopped with one of these plugs, so that when from any derange- ment of the valve steam above the usual pressure and temperature be formed, it would melt the plug and force its way out through the aperture rather than burst the boiler. When quicksilver is added to this alloy, it becomes more fusible ; and is used by dentists for stuffing de- cayed teeth. Solders are alloys, and generally con- tain a portion of the metal they are used to connect. (See Solder.) ALMOND OIL. A bland, fixed oil, obtained from the seeds or kernels of bitter almonds, either by subjecting them to pressure in a hydraulic press m the cold, or by the aid of hot iron plates. ALUM. One of the most useful salts manufactured ; it is extensively employed in dyeing and calico-printing, to which it supplies the mordant. In candle-mak- ing, it is used to harden and whiten tal- low ; in bread-making, it is often used for a similar effect ; it is added to paste to prevent its decomposition ; it is em- ployed in preparing and preserving skins, and also m pharmacy. Our alum was unknown to the ancients, who under that name used a different substance, as sul- phate iron, or the latter mixed with alum earth. Alum is composed of sulphuric acid, alumina, or the earth of clay and pot- ash. It is a double sulphate of alumina and potash. Crystals of alum are sometimes found ready formed in the earth, as along the chain of the Andes — as aluininitc in Germany, New-York, and other parts of the United States. The materials for alum 8 CYCLOPEDIA OF THE USEFUL ARTS. [ALU are, however, found in a state of combi- nation almost fit for manufacture into alum in various parts of the world. In Italy, Hungary, Sweden, Scotland, and North of England, there are rocks and earths termed alum stone— alum slate, A. clay, slate clay, and bituminous shale. These furnish the main material, and when treated in various ways yield the greater part of the alum of commerce. These clays and rocks are abundant in this continent. The Genesee black slate of the New-York system of rocks is highly impregnated with bitumen and withlron pyrites (sulphuret of iron) ; these by re- acting on each other produce a decompo- sition of the rock, and an approach to the formation of the salt ; and from these is prepared in various ways the alum of commerce. In the slaty stratum there are, among other elements, sulphur, alumina, and iron ; and these, by the long-continued action of air and mois- ture, lead to the formation of sulphate of alumina and sulphate of iron. Heat aids this transformation, and hence there are two modes of treatment — one for the efflorescent, or powdery ore, and one for the stony ore. Alum slate, or alum shale, is a very abundant source of alum. It occurs in Tennessee, and in New-York in the small lake district. It occurs in the lower se- condary rocks, and in the latter district is exposed by the ravines, which have cut their way over and through the strata in the passage to the Lakes : the Falls of Lodi, in Seneca Co., N. Y., is over alum slate, and the rough mineral crystallizes out on the surface of the cas- cade. Alum shale is a grayish or blu- ish colored rock, splitting readily, and friable on exposure to the air : it dries or effloresces on the surface, and acquires an astringent taste. The first step m the process is the roasting of the ore. Some- times the shale contains so much bitu- minous matter that after being fired it keeps up its own combustion : in most cases it is necessary to add additional fuel, either brushwood or coal : a thin layer of wood is generally spread on the ground, and then above it a layer of slate. This is set fire to, and while'burn- ing an additional layer of brushwood and of slate are added, and alternate layers are supplied as those below become roast- ed: by this process the iron pyrites in the ore is decomposed, the sulphur and the iron are both oxydized — the sulphur being converted into sulphuric acid, and the iron into oxide of iron — then unite to form sulphate of iron, or copperas, and any additional sulphuric acid unites with the alumina to form sulphate of alumina. These salts are then removed from the ore by washing it. The ore is put into large flat pans of wood, or masonry, called "steeps," and the water is left upon it for twelve or sixteen hours when it is fresh ore : this process is repeated three times on each batch of ore, dimin- ishing the time of maceration as the pro- cess is repeated. The water, which has lain upon a weak slate, is transferred to one containing more saline matters. From these steeps the liquor is pumped into a series of long-arched boilers, so formed as to apply heat. By this means the water is evaporated, and the highly con- centrated liquor is then transferred to large coolers, where it remains for a fort- night undisturbed. During this interval crystallization goes on : the liquor con- tains sulphate of iron and sulphate of alumina, and the former of these separ- ates from the latter by gradually crystal- lizing out. Sticks are immersed in the liquid in the coolers, and around these sticks large bundles of beautiful green crystals collect, forming the well-known green vitriol or copperas of the shops. When the crystals of copperas have been removed, the remaining liquor is drawn off into an evaporating boiler in order that the sulphate of alumina may go through the same process as the cop- peras ; and after being boiled down to a certain strength, the liquor is drawn off into a cooler. Sulphate of alumina will not crystallize without potash or some other alkali be added, and this substance is therefore added to the cooler, in which, after some days standing, crystals of alum are produced : it is thus a double salt, a sulpnate of alumina and a sulphate of potash. This is crude alum, and it is further purified by other processes of boiling, evaporating, and crystallizing. When the hard or stony ore is used, a preparatory process is necessary. This ore is in appearance midway between slate and stone coal, contains sulphur, iron, and alumina, like the decomposed ore ; but these three elements have not yet been combined into the sulphates of iron and alumina: the aid of heat is ne- cessary for this transformation. The ore after being broken into small pieces is built up into long ridges with fuel be- neath, and air-holes in different parts, and it is then fired ; after which the ore undergoes the same treatment as before described. The copperas is thus always 4 CYCLOPEDIA OF THE USEFUL ARTS. 9 an extra product in the manufacture of alum. It is impure, and is usually roasted at a strong heat ; and when washed yields more alum. The red residue after roasting is ground to a fine powder, and when dried is used as a Venetian red pig- ment : by altering the temperature at which it is dried, a yellow ochre is ob- tained instead of a red. In France alum is made from clay, which is first finely ground, and mixed with half its weight of crude sulphate of potash : these are formed into balls five inches in diameter, and calcined in the furnace ; they are then transferred to the bottom of the chamber in which sulphuric acid is made, where they swell up, and open on all sides, owing to the acid vapor entering them. They are then lixiviated with water, and crystals of alum are obtained by evaporating the liquid. Dr. Turner, of England, took out a pa- tent in 1842 for obtaining alum by the decomposition of felspar. It is occasionally made from the pure materials themselves. The finest pottery clay is calcined in an oven to drive off the water, and the vegetable matter combined with it ; it is then placed in a tank sunk in the ground, and to this is added sul- phuric acid : the reaction is so powerful that both together soon form a boiling mixture, although no heat bo applied. Water is then added, and the whole al- lowed to settle ; the clear liquid (solution of sulphate of alumina) is then pumped up into leaden vessels, where it receives the addition of some sulphate of potash as a means of giving the third ingredient necessary to form crystallized alum. It is, however, not yet pure, or fine in quality, and has to undergo the process of roaming : this is meant to imply the production of an alum similar to rock alum, which derives its name from Koc- cha in Syria, where it was first made. In roaching, steam is brought to act upon the alum so as to dissolve it, and form a strong solution. This is done in a leaden vessel, from which the solution is trans- ferred to large cylindrical crystallizing I vessels, where it attains the final state in | which it is sent into market. There is a peculiarity about alum which has led to an entirely new branch of i manufacture. Alum is not necessarily a sulphate of alumina and potash ; in some ! instances soda, and in others ammonia, I has been used, instead of potash, forming soda alum and ammonia alum! These bodies merely aid by facilitating the crys- tallization of the sulphate of alumina, 1* but they are of no practical service in the chief purpose to which alum is ap- plied in the arts : the sulphate of alu- mina is the real working agent, and if this could be obtained m a pure and solid state the alkali would in most cases be unnecessary. It happens that the iron contained in small quantity in the clay, and which would injure the alum if allowed to remain, is with difficulty re- moved except by crystallization ; re- cently, however, a new process for form- ing a " patent alum" has been adopted. In making this alum sulphuric acid and porcelain clay are used as before, but the clay is used in greater proportion, so as to form a mortar, which is placed in a heated trough, where it is converted into a dry earth : thence it is removed to tanks, where water dissolves it* and while here the composition is actea upon by an agent intended to remove the iron. This is yellow prussiate of potash, which by uniting with the iron forms Prussian blue ; this latter is allowed to subside, the clear liquor decanted off and boiled down to a solid residue, which is formed into cakes two inches thick, and it is sent into the market. It is now an opaque earthy solid, differing from com- mon alum by containing no potash. The Prussian blue is collected, and is so treated as to be restored to the form which it had previous to use, and is thus ready for a fresh quantity of crude sul- phate of alumina. Crystallized alum is composed of 1 atom of sulphate of alumina, 1 atom of sulphate of potash, 24 atoms of water Or by weight — Alumina 10*32 Potash 9-94 Sulphuric acid 33-77 Water 45-47 100-00 The ammonia alum contains more water. ALUMINA. An earth of very com- mon occurrence in primitive and secon- dary rocks : in the minerals felspar and mica it is associated with silica, iron, and potash ; from the decomposition of these clay is formed. It is the oxide of a metal named aluminum, and it consists of 2 equivalents of that metal united to 3 equivalents of oxygen. It can be ob- tained pure by adding ammonia to a so- lution of potash alum, washing the pre- cipitate with warm water, and drying it : 10 CYCLOPEDIA OF THE USEFUL ARTS. [amb it is then hydrated, or united with water, from which it may be freed by exposure to a red heat in a crucible ; it is then a clear white powder, soft to the touch, adhesive to the tongue, and insoluble in acids. Its density varies from 2 to 4, acquiring the latter gravity after being burned ; when mixed with a small quan- tity of water, it becomes doughy and plastic : if dried in this state in the air, and then heated, it cracks and shrinks from loss of water. This property is communicated to common clays, which cracks in great droughts, and to model- ling clays : Wedgewood made use of it as a measure of neat in his pyrometer, which is now obsolete. Alumina has a great affinity for coloring principles and organic compounds, and its use in dye- ing and calico-printing depends on its affinity for these substances and for woody fibre : from its double affinity it seizes upon the coloring matter and upon the tissue of the stuff, and brings them both into contact, and holds them to- gether. It is on this account the basis of mordants. When ligneous fibre is not present, and alumina be added to a coloring matter of vegetable or animal origin, it unites with the latter, and car- ries it down to the bottom of the vessel, leaving the liquor colorless. Colors so prepared are called a lake. Alumina freshly made is soluble in acids, and acts as a base to them ; with potash, and a few other bases, it unites, and acts as an acid. When moistened with nitrate of cobalt, and exposed to a red heat, it affords a fine blue color, by which it may be readily detected in small quantity. Alumina occurs native and pure in the sapphire, oriental ruby, topaz, and chry- solite. Gibbsite and diaspore contain water united with the alumina : corun- drum and emery are less pure varieties, where the alumina is mixed with a little silica and oxide of iron. AMADOU. A fungus (boletus igni- arius), which grows on the cherry, ash, and other trees, prepared by the Ger- mans into tinder for striking lights with. It is gathered in Autumn, and is cut and beaten until it can be readily torn by the finger. In this state it is valuable as a styptic: by steeping with nitre it forms the tinder. Puff-balls are frequently used as a substitute for amadou. AMALGAM. The union of mercury or quicksilver with other metals. Many of fhet-e crystallize definitely, and may be separated from the excess of mercury with which they are surrounded. They are mostly brittle and soft. Tin and mercury unite by mere rubbing ; it has a high reflecting surface, and is used as the back of looking-glasses. Amalgam for the electrical machine is made of mercury 4 parts, zinc 2 parts, and 1 part tin. These when melted and rubbed up with a little lard are fit for use. AMALGAMATION. The mode by which silver ores may be reduced, mer- cury being used in the process. The separation of gold from sand and im- purities by mercury is an amalgamation. AMBEK. A fossil, vegetable, solid, resin, of various tints of yellow : it is hard and transparent, when polished, a little heavier than water, has a resinous taste, and an odor resembling turpen- tine : it burns readily, giving off a white, pungent, aromatic smelling vapor. By friction it becomes highly charged with negative electricity, and from this pro- perty being first observed in this mineral, called by the ancients electron, it received the name electricity. According to Gop- pert and others, amber is the indurated resin of various fossil trees of the family coniferse. It is found in the same con- dition in all latitudes, lying in nodules or masses, disseminated in the sand or fragments of lignite (brown coal) of the plastic clay at the junction of the lower tertiary with the upper secondary bed (chalk) : the size varies from that of a nut to masses weighing several poimds. It is sometimes found containing insects — a proof of its once being in a soft or semi-fluid condition. Pictet has num- bered 800 fossil species of insects- occur- ring in it. The feather of a bird and a little of the hair of the bat have been found imbedded, with one or two molluscous shells. These species are those which could only have inhabited tropical cli- mates. Copal resembles amber, and common copal inclosing insects has been often fraudulently sold for amber. It occurs in Pomerania, and on the other shores of the Baltic, thrown up on the sand after storms. It is also found in the beds of streams. Pits are occasion- ally sunk above 100 feet down in the sand, and the amber sought for by a true mining operation. It is found in Sicily associated with bitumen in beds of clay and marl ; also in Poland, Saxony, Siberia, and Greenland. The finer kinds are used for ornament, as ear-rings, bracelets, necklaces, &c. ; and the coarse kind in medicine and the arts. Amber dissolved in drying linseed-oil makes a good durable varnish. With resin, as- ANC] CYCLOPEDIA OF THE USEFUL ARTS. 11 phaltum. and drying oil, it forms the coachmaker's varnish. Amber furnishes an oil used in perfumery and also suc- cinic acid used in chemistry. (See Var- nish.) AMBERGRIS. A substance used in perfumery. It is found swimming on the sea, off the coast of Coromandel, Japan, Moluccas, and Madagascar. It is the pro- duct of a diseased condition of the liver of the spermaceti whale ; its color is gray, white or marbled yellow, and black. AMIANTHUS. A hornblend mineral. (See Asbestus.) AMMONIA. Volatile alkali, first ob- tained by Priestly in a gaseous form, from sal-ammoniac, whence its name. It is a volatile gas, composed of one equivalent of nitrogen and three equivalents of hy- drogen. It is found in tlie vegetable and animal kingdom. Urine decomposing always contains it: hence the use of that substance in making alum, scouring wool, n ; for the pressure on s q acts in the direction perpendicular to * q or O n ; the pressure on C H is perpendicu- lar to D O, and wDis perpendicular to the direction of gravity. The pressure on s q is, therefore, to the pressure on C II as n D to D O. In like manner, the voussoir p r q s being so shaped that r p, when produced, meets OH in the point O ; the pressure on the joint r p is to that on C H, as m D to D O. Hence, the pressure on sqis, to the pres- sure on r p as 1) » to D m. We are thus led to infer that the voussoirs ought to increase in length, from the key-stone 18 CYCLOPEDIA OF THE USEFUL ARTS. L' to the piers, proportionally to the lines i)»,Dffl, &c. ; for in this case, the sur- faces of the joints heing increased in proportion to the pressure they sustain, the pressure on every point of the arch will De equal. It will also be observed that the angle n O D is equal to the angle made "by a tangent to the curve at m of the second; hence the" pressures on the suc- cessive joints are proportional to the dif- ferences of the tangents of the arches reckoned from the crown. From this property, when the intrados is a circle given in position, and the depth of the key-stone is given, the curve of the ex- trados may be found. When the weights of the voussoirs are all equal, the arch of equilibration is a catenarian curve, or a curve having the form which a flexible chain of uniform thickness would as- sume if hanging freely, the extremities being suspended from "fixed points. Such is the form which theory shows to be the best adapted to give strength to an arch, on the supposition that there is no superincumbent pressure. But it seldom if ever happens that this is the case, and therefore it is entirely unneces- sary, in the actual construction of an arch, to adhere closely to the form deter- mined on the above supposition. In- deed, on account of the friction of the materials and the adhesion of the cement, the form of the fu*ch, within certain lim- its, is quite immaterial, for the deviation from the form of equilibration must be very considerable before any danger can arise from the slipping of the arch-stones. The Roman arches are almost semi-cir- cles, yet they have lasted many centuries. The arch is not found in an Egyptian building nor in the earlier Greek.* The Romans understood the advantage of the arch from an early period. The cloaca maxima is of the age of the Tarquins. The Etruscans originated the arched dome, and the Romans first applied the arch to bridges and aqueducts. The Sointed arch was introduced in the mid- le ages by the associated architects, who have left extant the noblest piles of architecture, and in which the arch is multiplied and combined in all possible ways. (See Beidgk.) ARCHIL. OrghU. Cudbear. A violet dye obtained from many species of li- chen, chiefly the BocelXa tinctoria, fuci- formis, which grow in large quantities in the Canary Islands. Archil is chiefly used to improve the dye of other colors, and to give richness and brilliancy to them. The lichens grow on rocks near the sea ; they are collected and fermented with ammoniacal liquor, which brinsrs out the color ; the mass is then pressed out, and made into a paste with chalk and plaster of Paris. It is then archil. The coloring matter is due to the chemical principle orcine. In silk-dyeing archil produces the lilac color; it economises the use of indigo on woollen cloth. It also stains marble violet. AREOMETER. An instrument for measuring the density or specific gravity of liquids. ARGAND. {See Lamps.) ARGIL. Argillaceous earth. A name applied to the earth of clay, termed alu- mina, from its being found so pure in alum. ARGOL. The tartar of wine. ARICINA. An alkaloid discovered by Pelletier in a species of cinchona. ARRACK. A spirituous liquor ob- tained by distilling termented rice or the juice of the cocoa-nut. ARROW ROOT. The commercial name of the starch obtained by washing the grated root of the maranta arundi- nacea, which it yields to the amount of twenty -five to thirty per cent. It is sometimes adulterated with potato starch, and the fraud is not easily detected ; it, however, gives a disagreeable flavor and smell, like that of tlie raw potato, and forms a less firm jelly with hot water that when the arrow root is genuine. The roots when one year old are dug and washed; they are grated, and the Eulpy matter agitated with water. The bres are collected by hand and removed, and the milky liquor strained through a sieve and left to settle. The white pasty mass is the arrow root, which is perhaps again washed, then dried, and packed for exportation. The arrow root of Ber- muda is considered the finest. Tous le mois, or starch, is obtained from the roots of canna coccinea ; Otaheite arrow root from the tacca pinnatifida. The East In- dian from a curcuma, and the Portland arrow root from arum maculatum are oc- casionally used as substitutes. The grains of arrow root are in the form of small globes or spheres when viewed by the microscope. ARSENICT. A very soft, brittle, and eminently poisonous metal, of a steel ARS] CYCLOPEDIA OF THE USEFUL ARTS. 19 gray color : its sp. gr. 5*7. It volatilizes, exhaling a strong odor of garlic, before it fuses, at a temperature ot 365° F., and is easily inflammable. It combines with oxygen in two proportions ; and as both compounds are sour, and form salts with bases, they have been termed arsenious and arsenic acids: the former is com- posed of 38 arsenic and 12 oxygen, and the hitter of 38 arsenic and 20 oxygen. Ar- senious acid is more commonly known under the name of white arsenic^ and is the usual state in which this poison oc- curs in commerce ; it is obtained during the extraction of several of the metals from their ores, and is a white, brittle, semi-transparent substance, having little taste, but is virulently poisonous. Its sp. gr. is 3 - 7. It forms a dull white powder, and it is in this form that it is usually sold. When heated in the flame of a candle, it rises in the form of a white poisonous vapor, and exhales, in consequence of its partial reduction, a strong garlicky smell : 1000 parts of cold water dissolve about 2i of white arse- nic ; but when the water is boiled with the arsenic, 1000 parts take up between 77 and 78 ; and this solution, after stand- ing a few days, deposits rather more than half of the white arsenic, in the form of small crystals, retaining about 30 grains in permanent solution. White arsenic dissolves in the alkalies, and com- bines with the metallic oxides, forming a class of salts called arsenites : they are all poisonous. Of these the arsenite of potash is used in medicine, under the name of Fowler's mineral solution : it is employed in very small doses in the cure of agues, and is an effective remedy, but requires much care in its administration. When white arsenic is taken as a poi- son, — that is, in large doses, it produces violent spasmodic pains of the stomach and bowels, attended by a sense of heat, and constriction in the mouth and throat ; an increased flow of saliva, tightness about the head, itching of the face and neck, and nausea. These symptoms are succeeded by vomiting and purging and excruciating pains ; the pulse at "first full, hard, and frequent, sinks and becomes irregularly feeble, and clamminess of the skin, cold sweats, purple spots, and con- vulsions, precede death ; or if the pa- tient escape this catastrophe, it often happens that hectic fever, paralysis, and mental and bodily debility, attend him for the remainder of his days. It is often said that the bodies of persons poisoned by arsenic are very prone to putrefaction; but this does not appear to be always the case. After death the stomach and bowels are usually found inflamed, but often only slightly so ; and it appears from Sir B. Brodie's observa- tions, that this poison kills by some pe- culiar action upon the heart and nervous system. The treatment of persons thus poisoned consists in promoting the vo- moting by an emetic, composed of a so- lution of 20 grains of sulphate of zinc in two ounces of water, aided by copious draughts of warm barley-water or gruel ; but the most effective means of getting rid of the arsenic, is by the use of the stomach-pump, which, wlien immediately resorted to, has often saved the patient. The after-treatment requires much cir- cumspection. The only ready means of ascertaining the presence of white arsenic is by heat- ing the suspected substance upon a red- hot coal, or in the flame of a candle or spirit lamp, when it will exhale the pe- culiar arsenical odor resembling that of garlic ; but the treatment of persons poi- soned by arsenic, and its detection in doubtful cases, must be left to the medi- cal man and the chemist. It is impossi- ble too strongly to represent the evil which results from the unfettered sale of arsenic, and from the unwarrantable use of it as a poison for rats, and as a veteri- nary remedy, for it is thus that it finds its way into culinary vessels, gets acci- dentally mixed with articles of iood, and that bottles which have contained it are used for beer, wine, vinegar, or medi- cine : its sale should be rigidly prohibited. This metal occurs native in the state of white oxide (arsenious acid) ; also with sulphur, known as yellow and red ar- senic. It is associated with a great many metallic ores, but chiefly with cobalt in Silesia, in Europe. It is separated from that metal by roasting, and the arsenic is obtained as white oxide. Arsenic enters into the composition of flint glass, the body of which it whitens and purifies : it is apt, however, to make the glass milky. It is used in candle-making, to remove the crystalline tendency of stea- rine. It is also used to destroy rats and vermin. It has a remarkable tendency to preserve the parts of the animal body it is brought into contact with, and hence it has been used in the stuffing of birds and the preservation of other objects of natural history. To make an appropriate preparation Dumas gives the lollowing recipe : White soap and arsenious acid, of each 20 CYCLOPEDIA OF THE USEFUL ARTS. [AM 100 parts ; carbonate of potash, 30 parts ; camphor, 15 parts ; quicklime, 12 parts. The potash, soap, and lime, are melted together;^ then the arsenic is added. The camphor is dissolved in alcohol, and added in when the mass is cold. Some of this soap mixed with water is laid on with a brusn. Arsenic alloyed with me- tals makes them more brittle and fusi- ble : with copper it forms white tombac. Arsenic acid is more soluble and sour, but equally poisonous with the arsenious acid. Its salts are called arseniates, and the arseniate of potash obtained by de- flagrating a mixture of white arsenic and nitrate of potash is occasionally used in medicine : it is the active ingredient in the tasteless ague drop. It is also used in calico-printing as a resist paste laid on by blocks to prevent the mordant acting on the cloth in those places. ARTESIAN FOUNTAINS, or AR- TESIAN WELLS. (Fr. Puits Artesiens.) Vertical perforations of the exterior crust of the earth, of small diameter, and fre- quently of great depth, through which subterraneous water arises to the sur- face, often forming abundant and ele- vated jets. The name Artesian is derived from Artois, a province of France, where especial attention has been given to this means of obtaining water ; but it ap- pears, from sufficient historical evidence, that wells of this kind were perfectly well known to the ancients. Niebuhr cites a passage from Olympiadorus, who flourished at Alexandria about the mid- dle of the sixth century, in which it is stated that when wells" are dug in the Oasis to the depth of two hundred, three hundred, or sometimes five hundred yards, rivers of water gush out from their orifices, of which the agriculturists take advantage to irrigate their fields. The oldest Artesian well known to exist in France is in the ancient convent of the Chartreux, at Lillers in Artois. It is said to have been made in 1126. Others exist at Stuttgart, of great antiquity, though their dates cannot be fixed with pre- cision. The inhabitants of the great de- sert of Sahara appear also to have been long acquainted with this mode of ob- taining water, and the Chinese are said (but the truth of the statement is ques- tionable) to have practised it for thou- sands of years. Various conjectures have been made as to the source of the water which comes from the Artesian wells. It was long believed that the water of the sea must necessarily penetrate by way of infiltra- tion into the interior of the continents, and at length form large bodies of sub- terraneous waters, which, excepting for capillary influences, would not rise above the general level of the ocean. Another opinion, maintained by Aristotle, Seneca, Cardan, and even Descartes, was, that the subterraneous water, from which the sources of rivers and springs are sup- plied, is the product of the condensation of aqueous vapors ascending from the interior parts ot the earth in consequence of the central heat. But these hypo- theses are founded on mere conjecture, unsupported by the slightest evidence, and consequently merit no attention. The simplest and most natural explana- tion is, that the water of ordinary wells, of Artesian fountains and rivers, is sup- plied by the rain which falls on the sur- face at a higher elevation, and which penetrates through the pores and fissures of the ground till it meets with some im- permeable stratum, or is collected in subterranean reservoirs. It has been objected that springs are sometimes situ- ated on or near the summits of moun- tains, which could not be supplied in this way ; but on an attentive examina- tion of all the circumstances — that is to say, on measuring accurately the extent of surface at a greater elevation than the spring, and comparing it with the quan- tity of rain that falls annually in the same climate, it has been found, in every instance, that the aqueous deposition from the atmosphere greatly exceeds the supply from the spring. It is computed that not more than a third part of the rain which falls in the valley of the Seino is conveyed to the sea by the river ; the remaining two-thirds support vegetation, supply fountains and springs, or are re- turned to the atmosphere by evapora- tion. The immense bodies of water which some continental rivers roll towards the ocean are but a small part of the rain which falls in the surrounding countries. The average fall of rain in these lati- tudes is about 40 inches of rain, or about 3,500 tons of water deposited in the course of the year on every acre. In sandy districts this rain-water penetrates like as through a sieve. In mines sunk in limestone rocks the water increases in the galleries very remarkably after a fall of rain. Assuming, then, that the subterra- neous water is supplied from atmospher- ical deposition, it remains to be explained how it arrives at the situation it occupies in the interior of the earth, and by what art] CYCLOPEDIA OF THE USEFUL ARTS. 21 forces it is raised from great depths to the surface. All persons who have paid the slight- est attention to geology are aware that in stratified countries (and it is in such only that Artesian wells exist) different beds of rocks are superposed on one another, and ranged in a certain constant order. The strata sometimes follow a horizontal direction for a considerable extent of country ; at other places they are inclined, and even placed perpen- dicularly to the horizon, naving the ap- pearance of having been bent and burst through by the action of a powerful force from beneath. In those cases the edges of the strata arc often exposed, especially on the summits and flanks of hills, to the action of the atmosphere. The following diagram illustrates this : it represents a basin composed of perme- able strata {a a a) separated by imper- meable layers (b o h). The water which falls on the edges of a on the side x will sink down and fill the beds until the water rises on the other side, and has a tendency to run out at A. If tubes be sunk in the middle, as at c d h it acts ; therefore for a given weight P, the sensibility of the balance, all other circumstances being equal, is proportional to the length of the beam. Let us next consider the force which tends to restore the beam when the equi- librium is disturbed. This is made up of two parts ; the first of which is pro- portional to W X C G, that is to say, proportional to the weight of the beam (which may be regarded as concentrated at the centre of gravity) multiplied into the length of the lever on which it acts ; and the second proportional to L X C D, that is, to the load also multiplied into its length of lever. The whole restoring force is therefore proportional to W X CG + LXCD. Now this force is pre- cisely that which the preponderating weight P has to overcome in turning the scale ; consequently any circumstance which tends to increase it, increases the stability and diminishes the sensibility of the balance ; and any thing which tends to diminish it, diminishes the stability and increases the sensibility. By bend- ing the arms of the balance, or altering the points of suspension of the scales, the points G and I) may acquire different positions relatively to C. Supposing G to be above C in the vertical line joining those points ; the term W X C G would become negative, and the restoring force proportional to L X C D — W X C G. In this case, if the load L, or the distance C D, were diminished till L X C D be- came less than "W X C G, the balance would be useless ; because if moved ever so little from the position of rest, it would have no tendency whatever to return. The best construction is to make CD = I O, that is, to place the three points of ! action A, C, B, in the same straight line, i and to construct the beam so that G, the j centre of gravity, shall fall a little below I the line A B. The sensibility is then in- ■ dependent of the load, and is simply in i the inverse portion of W X C G ; so that i by diminishing the weight of the beam. i or the distance C G, it may be increased j to any required degree. It is supposed that the two arms are precisely of the I same length, or that C is placed exactly ! in the middle between A and B, and I also that they are perfectly inflexible. The conditions now determined from | theory must be the guide of the artist in the construction of a good balance. It is of importance that the beam be as light ! as possible, consistent with inflexibility ; i for not only the inertia, but also the fric- j tion, is increased in proportion to the I weight, and the sensibility consequently | diminished. In order to give lightness 1 and strength at the same time, the beam ! should be formed of two hollow cones of | brass, joined together at the broad ends. bal] CYCLOPEDIA OF THE USEFUL ARTS. 27 A cylinder of steel, passing through the middle of the beam at right angles, forms the axis • and its extremities, ground into sharp edges on the lower side, serve as the points of support. The two edges must be accurately in the same straight line, and turn on smooth planes of agate or polished steel carefully levelled. The scales should likewise be suspended from the extremities of the beam on knife edges, crossing each other at right an- gles: those in the beam being sharp up- wards, and those to which the scales are attached sharp downwards. A needle, or tongue, is usually attached to the beam, pointing directly upwards or down- wards when the beam is horizontal, for the purpose of indicating the deviations of the beam from the horizontal position on a graduated scale. It is better, how- ever, to bring the arms to terminate in sharp points, and to place a scale behind each ; in this way the slightest flexure of the beam will be rendered evident, if the zeros of the scales are placed exactly in the same level. The scale is indis- pensably necessary, because the balance, if very sensible, would require a long time to come to rest ; but it is known to be poised, when the excursions of the needle on both sides of the zero of the scale are equal. In order to preserve the knife edges, the beam, when not in use, is supported on rests. Props should also be placed under the scales while loading or unloading the balance. The whole apparatus must be placed under a glass case, to protect it from the disturbing in- fluence of currents of air. The sensibility of a balance constructed with due care, according to the princi- ples now explained, may be carried to an almost inconceivable extent. There is one in the possession of the Royal So- ciety, made by Kamsden, which weighs ten pounds, and is said to turn with the ten millionth part of that load, or the thousandth part of a grain. Neverthe- less, whatever skill mav be employed in the construction, it is plain that the con- ditions necessary to mathematical accu- racy can never be entirely fulfilled. It is impossible to make the two arms of the beam exactly similar, or exactly equal in length. Absolute precision is unattain- able in practice. This difficulty, how- ever, may be overcome by the following simple method, imagined by Borda, by which accurate results are obtained in- dependently of extreme precision in the construction of the balance: it is only necessary that it be very sensible. Let P, the substance to be weighed, be placed in the 6cale A ; instead of placing known weights in the scale B, put into it some other substance, for instance bits of iron, chips of wire, or sand, added in minute quantities till the substance P is exactly counterpoised, or the beam becomes ex- actly horizontal. This being done, let the substance P be gently removed out of the scale A, and let known weights, as grains, be put into it till the substance in the scale B is again exactly counter- poised. It is now of no consequence whether the balance was accurate or not, or whether the body P was exactly equal in weight to the substance against which it was weighed in B. The weight of P must be precisely equal to that of the grain weights ; because, under exactly the same circumstances, they both form- ed a counterpoise to the substance placed inB. Odnese Balance. This is formed of a slender tapering rod of wood or ivory, about a foot in length. A silk thread passed through a hole perforated nearer one of its extremities than the other, serves as the point of suspension. The balance has thus two unequal arms. From the extremity of the shorter a small scale is suspended to hold the sub- stance to be weighed. A sliding weight passes along the other arm, on which divisions are marked ; and when the counterpoise is made, the distance of the standard weight from the fulcrum indi- cates the weight of the substance. In order to procure a greater range, the rod has generally four holes or points of sup- port, at different distances from the ex- tremity, and a corresponding set of divi- sions is marked on each of its four sides. The principle of this machine is exactly the same as that of the common steel- yard. The Danish Balance, much used in the north of Europe for weighing coarse com- modities, is usually formed of an iron bar or a batten of hard wood, having a lump of lead at one of its extremities. The goods are fixed on a hook in the other end ; and the whole is suspended through a loop of cord, which is passed backwards and forwards under the rod till equilibrium is obtained. The weight of the goods is then to the weight of the lead reciprocally as their respective dis- tances from the loop. Roman Balance or Steelyard. {See Steelyard.) BALCONY. In architecture a projec- tion from the external wall of a nouse, 28 CYCLOPEDIA OF THE USEFUL ARTS. [bal borne by columns or consoles ; usually placed before the windows or openings. BALLAST. Is a mass of weighty ma- terial placed in the bottom of a ship or vessel to give her stiffness ; that is, to in- crease her tendency to return to the up- right position when inclined or heeled over by the force of the wind or other cause. Ballast consists of shingle (the coarse gravel of the sea-beach), stones, &c. This tends to give excess of stabi- lity, which renders the vessel uneasy from the suddenness of the motion : this defect is remedied by winging up the ballast, whereby its centre of gravity is raised. For the like reason in stowing the ballast it is tapered to a point at the fore and after extremities. Iron ballast, from the greater cleanliness, is more healthy for the crew than that of other materials. When a ship has no other loading, she is said to be in ballast. The quantity of ballast and the mode of its stowage differ greatly in different vessels ; and the connection between the motions of a ship and her stowage has not yet been analyzed sufficiently to lead to the discovery of direct rules on these important points. BALL-COCK. A hollow sphere or ball of metal attached to the end of a lever, which turns the stop-cock of a cistern pipe, and regulates the supply of water. As the surface of the water rises in the cistern, the ball is raised by its buoyancy ; and as the water descends, it falls by its own weight. The cock is thus closed when the water rises to a certain height, and the supply stopped; but when a part of the water is drawn off from the cistern, the cock is again open- ed, and the water admitted through the BALLISTIC PENDULUM. An in- strument, invented by Benjamin Eobins, for measuring the force or velocity of cannon and musket balls. To one ex- tremity of an iron bar is fixed a heavy cubical block of wood, lined at the back with iron. A transverse bar of iron at the other extremity of the first bar serves as an axis of suspension, in which the pendulum swings freely backwards and forwards. The instrument being thus fitted, if the weight of the pendulum be known, and likewise the respective dis- tances of its centres of gravity and oscilla- tion from the axis of suspension, it is easy to determine the quantity of motion that will be communicated to the pendu- lum by the percussion of a body of a given weight moving with a given velo- city and striking it at a given point. Con- versely, if the pendulum, when at rest, is struck by a body of a known weight, and the vibration which the pendulum makes after the blow is known, the velo- city of the striking body may thence be determined. In order to measure the extent of the vibration, a riband is at- tached to the lower end of the pendu- lum, passing loosely through an orifice in a horizontal bar in the frame-work : when the pendulum is raised it draws the riband along with it, and the quan- tity which thus passes through the ori- fice measures the chord of the are of vibration. BALLOON. (Fr. ballon, a little ball.) The name of a machine, which, consist- ing of an envelope containing a gas speci- fically lighter than common air, rises into the atmosphere with a greater or less de- gree of ascensional force. A car, sup- ported by a net-work which extends over the balloon, supports the aeronaut : and a valve, usually placed at the top, to which a string is attached reaching to the car, gives him the power of allowing the gas to escape, and of descending at pleasure. During the dark ages, and for some time after the revival of science, numer- ous projects were entertained for navigat- ing the air ; but it is only in very recent times, since 1783, that any of them have been realized. The first idea was to em- ploy some mechanical contrivance resem- bling the wings of birds ; but Borelli de- monstrated that all attempts on the part of man to fly must necessarily fail, from the utter disproportion of his muscular power to the force that would be neces- sary to give impulsion to wings of such enormous magnitude as would be required to sustain his weight in the air. The principle by which a balloon rises in the atmosphere is exactly the same as that which causes the ascent of a cork from the bottom of a vessel filled with water. The weight of the volume of air which it displaces must exceed the weight of the balloon and all that it carries with it. That bodies must rise and remain suspended in a fluid denser than them- selves was proved by Archimedes ; but the weight of the air is a modern discov- ery • and it was only in the latter half of the last century that chemistry detected the nature and differences of specific gra- vities of aeriform fluids. Mr. Cavendish, in 1766, by some ingenious experiments, recorded in the I'hilosophical Transactions, vol. lvi., found hydrogen gas to be from about seven to eleven times lighter than bal] CYCLOPEDIA OF THE USEFUL ARTS. 29 common air, according to the mode of its preparation. In its pure state it is found to be nearly sixteen times lighter than common air. This substance, therefore, if prevented from diffusing itself, and al- lowed to obey the force "by which it is impelled upwards, will continue to mount till it arrives at a stratum of the atmos- phere sixteen times more attenuated than at the surface of the earth. Accordingly, no sooner had Cavendish announced his discovery, than it occurred to Dr. Black that a very thin bag rilled with hydrogen gas would mount to" the ceiling of a room. Through some imperfection, the experi- ment when he attempted to execute it failed : and it was several years later be- fore an envelope was thought of suffici- ently light, and at the same time imper- meable to the gas. Cavallo made a series of experiments on this subject in 1782, but did not succeed in raising any thing heavier than a soap-bubble. The expense attending the preparation of the gas Pro- bably prevented the experiment from being made on a great scale. Knowing the specific gravities of atmos- f)heric air, of the gas with which the bal- oon is to be filled, and the weight of the envelope in which it is confined, it is not difficult to compute the size the balloon must have in order to rise from the ground, or carry a given weight to a given eight in the atmosphere. A globe of air, one foot in diameter, at the level of the sea and under the ordinary pressure, weighs about l-25th of a pound avoirdu- pois. An equal globe of hydrogen gas, obtained in the usual way by dissolving iron filings in dilute sulphuric acid, may be assumed (making every allowance for imperfect preparation) to be about six times lighter than atmospheric air ; con- sequently 5-6ths of its whole buoyant force will act in impelling it upwards : that is to say, the force with which a sphere of such gas, one foot in diameter, will tend to rise in the atmosphere, will be J-XfT—^V °f a pound avoirdupois. The ascensional forces of different spheres will be proportional to their magnitudes, that is to the cubes of their diameters : therefore a sphere 12 feet in diameter would rise with a force of 57 pounds, and one of 24 feet in diameter with a force of 8X57=456 pounds. But these determina- ations must be diminished by the weight of the envelope. The best material for the purpose at present known is thin silk varnished with elastic gum, or Indian rubber. The quantity of this material required to cover a globe one foot in di- ameter, weighs about l-20th if a pound. Now for a globe of a greater size, the quantity required will increase with the square of the diameter ; hence the cover- ing of a balloon 12 feet in diameter must weigh about 7 pounds, and of one 24 feet in diameter 28 pounds. It follows, there- fore, that a balloon of 12 feet diameter will only raise from the ground a weight of 50 pounds, and one of 24 feet 428 pounds. Computing in the same man- ner, it is found that a balloon 60 feet in diameter would raise a weight equal to about 6,950 pounds ; and that one of a foot and a half would barely float, the weight of the bag being just equal to that of the imprisoned gas. The height to which a balloon will rise is determined from the law according to which the density of the atmospheric strata diminishes as the distance from the earth is increased. The buoyant force diminishes with the density ; and when it is reduced to a quantity only equal to the weight of the balloon and its appen- dages, no further ascension can take place. Another circumstance also con- fines the possible elevation within moder- ate limits. As the pressure of the exter- nal air is diminished, the expansive force of the confined gas becomes greater, and would ultimately overcome the resistance of any material of which a balloon can be made. A balloon quite filled at the sur- face of the earth would inevitably be torn to shreds at the height of a few miles in the atmosphere, unless a portion of the gas were allowed to escape. For this pur- pose the balloon is iurnished with a safety valve, which can be opened and shut at pleasure ; but to prevent unneces- sary waste of gas, it ought to be made of such a size that it requires only to be partly filled. A balloon half filled at the surface of the earth would become fully distended at the height of 3£ miles. We have hitherto spoken only of bal- loons filled with hydrogen gas ; but it is evident that any other substance specific- ally lighter than air would answer the purpose; in fact, the first balloons by which any one was raised into the atmos- phere were not filled with hydrogen, but simply with rarefied air, the rarefaction being produced by kindling a Are under them; and as they thus became filled with smoke, they were called smoke-bal- loons. The ascensional force, however, which can be gained in this way is not great ; besides the aeronaut must carry a portion of fuel with him for the purpose of maintaining the fire, which adds scnsi- 30 CYCLOPEDIA OF THE USEFUL ARTS. [bal bly to the weight to he raised. The keep- ing up of the fire is also attended with inconvenience, and even danger. Two brothers, Stephen and Joseph Montgolfier, proprietors of a paper manu- factory at Annonay in France, have the honour of first preparing and sending up a balloon into the air. After one or two previous trials, they announced a public ascent on the 5th of June, 1783. The balloon was prepared of linen cloth ; a fire was kindled under it, and fed with bundles of chopped straw. This sub- stance was used with a view to produce a large quantity of smoke. It would seem that they attributed the elevation of the balloon to the ascending power of the smoke, instead of its true cause, the rare- faction of the heated air. In the space of five minutes it was completely dis- tended ; and on being let slip, ascended rapidly. It reached an elevation of about a mile, remained suspended ten minutes, and fell at the distance of a mile and a half from the place of its ascension. When the news of this experiment was carried to Paris, the surprise was general, and the virtuosi began immediately to consider how it could be repeated. It was determined to apply hydrogen gas on this occasion ; and Charles, a celebrated lecturer on natural philosophy, undertook the superintendence of the process. On the 26th of August, 1783, the preparations were complete, and the balloon was trans- Sorted with much ceremony to the Champ- e-Mars. On the following day, at five o'clock in the afternoon, the report of a cannon announced to the assembled mul- titude that every thing was ready. " The globe, liberated from its stays/ shot up- wards, to the great surprise "of the spec- tators, with such rapidity that in two minutes it reached the height of 3000 feet. It traversed successively several clouds, by which it was repeatedly ob- scured. The violent rain which began to fall at the moment of its ascent did not retard its rapid progress, and the experi- ment was attended with complete success. The satisfaction was so great that even elegantly dressed ladies remained with their eyes intently fixed on the balloon, regardless of the rain, which fell on them in torrents." (Libes. Dktionnaire de Physique.) This balloon remained in the atmosphere only three quarters of an hour ; it fell at a distance of about fifteen miles, when it was discovered that a rent was made in the upper part, through which the gas had escaped. The first adventurers who had courage to undertake an aerial ascent in a balloon, were Pilatre de Kosier, a young naturalist, and the Marquis d'Arlandes. On the 21st of November, 1783, they took their seats in the basket of a smoke balloon ; and after rising to am elevation of upwards of 3000 feet, descended safely to the earth. The next ascent was made by MM. Charles and Kobert in a balloon filled with hydrogen gas, on the 1st of January, 1784. After a flight of a hour and a half they alighted on the meadow of Nesle, about twenty-five miles from Paris, with- out the slightest accident. As the bal- loon still retained a considerable buoyant force, M. Charles resolved on another ascent alone. It rose to the height of near two miles in about ten minutes ; and the aeronaut had the satisfaction of see- ing the sun, which had set when he left the earth, again rise above the horizon. After remaining about thirty-five minutes in the air, he descended safely at a dis- tance of about nine miles from the spot from which he had risen. So many aerial voyages executed with safety encouraged other attempts : and no accident occurred till the accomplished Pilatre de Eosier, with his companion Eomain, were killed in an attempt to cross the channel from France to England. On the 13th of June, 1785, they ascended from Boulogne. Under the principal bal- loon, which was of hydrogen gas, they had suspended, for the purpose of in- creasing or diminishing the ascensional power at pleasure, a smoke balloon, which occasioned the disastrous issue. Scarcely a quarter of an hour had elapsed when the whole apparatus, at the height of 3000 feet, was perceived to be on fire, and the unfortunate voyagers were precipitated to the ground. This calamitous occur- rence, however, did not damp the cour- age of aeronauts. It was obvious that it had been occasioned by the want of pro- per precautions ; accordingly ascents con- tinued to be multiplied, and have since become so common as to be an ordinary spectacle in the principal cities of Europe. When balloons first began to be con- structed, it was expected that they would be found applicable to many important purposes. These expectations have been disappointed, chiefly because it has been found impossible to guide or control their course. The only power the aero- naut possesses over hisballoon is to regu- late its elevation within certain limits. In one or two instances they have been successfully used for military reconnois- sance. The victory which Jourdan ol>- bar] CYCLOPEDIA OF THE USEFUL ARTS. 31 tained over the Austrians at Fleurus, in 1794, was ascribed to the knowledge ob- tained of the enemy's movements by means of a balloon. A very interesting ascent was made by Biot ancf Gay Lussac, in August 1804, and by Gay Lussac alone in September of the 'same year, with a view to make meteorological observations in the upper strata of the atmosphere. In the first voyage, the two philosophers, at an elevation of between 9,500 and 13,000 English feet, found the oscillations of the magnetic needle to be perfonned in the same time as at the surface of the earth. At 12,800 feet the thermometer, which stood at 63i° at the observatory, had sunk to 51° of Fahrenheit, being^ only a decrease of 1° for every thousand feet. The hygroscope indicated increased dryness in proportion to the elevation. In the second ascent, performed by Gay Lussac alone, the variation of the com- pass at the height of 12,680 was found to remain unaltered. At 14,480 feet, a key held in the magnetic direction attracted with one end and repelled with the other the north pole of the magnetic needle. The same was the case at 20,150. At 18,000 feet the thermometer fell to the freezing point, and at 22,912 feet to 14-9° of Fahr. Two flasks, which had been previously emptied of air, were opened and filled at an elevation exceeding 21,400 feet; and the air brought down from this region was found, on being analyzed, to contain exactly the same proportions of the constituent elements as at the surface. The utmost elevation which he reached was 23,040 feet, or four miles and a quar- ter above the level of the sea, consider- ably higher than the loftiest peak of the Andes. Excepting in these two remarkable as- cents of Gay Lussac, nothing has been gained to science by the use of balloons. The numerous other ascents undertaken, both before and since, have as yet served no other purpose than to gratify idle curi- osity ; and from the totalfailure of every scheme that has been proposed for direct- ing their course through the air, there is little rvason to anticipate any great advan- tages from them to society. Neverthe- less, the comparative cheapness and fa- cility with which they can be filled by coaf gas, now so generally used for the purposes of illumination, have been the cause of directing public attention to the subject. Mr. Green crossed the channel from Vauxhall to Nassau, in Germany, in 1836, after a journey of eighteen hours, carrying two companions and a ton of ballast. This feat (crossing the English Channel), has been repeated since more than once, — the last voyage being in the spring of 1851 from London, and landing within a few miles of Boulogne. BALSAMS. Exudations from and juices of certain plants which are liquid, or soft-solid, and consist of a substance resembling resin either combined with Benzoic acid or an essential oil, or both. The principal balsams are those of Peru, Tolu, Benzoin storax, and liquidambar. Those contain Benzoic Acid, while Co- J)aiva balsam, Mecca balsam, and Japan- ac do not. BALUSTRADE. A parapet or pro- tecting fence formed with balusters. BANDANA. (See Calico Printing.) BARBERRY. (See Berberry.) BARILLA. The name given to the impure carbonate of soda imported from Spain and the Levant. It is the ash of the salsola soda and other plants, which are grown on the shore for the purpose of supplying the ash. It seldom contains more than 20 per cent, of real alkali, be- sides sulphates and chlorides of soda, lime, and alumina, with some sulphur. It was much used in soap manufacture ; it is now almost entirely superseded by the carbonate of soda obtained from common salt. BARIUM. The metallic base of bary- ta. It is a white metal, of the color and lustre of silver, malleable, fusing below a red heat, oxidizing in the air, and de- composing water. The oxide of barium or baryta is abundant in nature, as car- bonate and sulphate of baryta, forming the vein-stone in many lead mines. Pure baryta is a white earth, resembling lime in its affinity for water and carbonic acid. Nearly all the baryta compounds are poi- sonous, except the sulphate. The best antidote is a solution of sulphate of soda. Baryta, of all substances, has the greatest affinity for sulphuric acid. The sulphate of baryta is used as a pigment "perma- nent white," and as an adulteration in white lead ; it is also used in the manu- facture of jasper and other earthen ware. BARK. The outer covering of the trunk of the tree. It is the depository of many of the secretions of the plant, and generally contains a large quantity of tannic and gallic acids. The most important barks are those of the oak and cinchona trees : for which see Tanning and Peruvian Bark. BARLEY. A valuable grain for malt- ing, but a poor one for bread : the seeds of the Hordeum distichon. It grows 32 CYCLOPEDIA OF THE USEFUL ARTS. [bar well on light lands, and is used in fattening black cattle, hogs, and poultry. 30 bush- els is a good crop of 63 lb. each, and the weight of the straw is about 1-Gth more. 1000 parts of barley contain, according to Einhof, starch, 720 ; mucilage, 50 ; sugar, 56 ; gluten, 36*6 ; vegetable albu- men, 12-3 ; water, 100 ; phosphate of lime, 2-5 ; ligneous matter, 68. Pot bar- ley is barley deprived of its outer skin ; pearl barley lias also a portion of the grain removed, leaving merely a small round kernel. Both kinds are made in the same mill, but the pearl barley re- ceives more grinding. BARM. Another name for yeast. (See Beer.) BAROMETER. A well-known instru- ment for measuring the weight or pres- sure of the atmosphere. The invention of the barometer was in some degree owing to an accident. Some workmen employed by the Duke of Florence to prepare a sucking-pump for a deep well, found to their surprise that notwith- standing the "utmost care in forming and fitting the valves and piston, the water would not rise higher than 18 palms, or about 32 English feet. For an explanation of this unexpected difficulty they applied to the illustrious Galileo, then passing the evening of his life at his villa near Arcetri ; but the philosopher was not yet prepared with the true answer. In that age the doctrine of a plenum was an axiom in philosophy ; and the ascent of water in the barrel of the pump was uni- versally ascribed to nature's horror of a vacuum. Galileo, either fearing to en- counter further persecutions by pro- pounding opinions at variance with the prejudices of the times, or pre-occupied by the prevailing metaphorical modes of expression, evaded the difficulty by say- ing that the power of nature to overcome a vacuum was limited, and did not ex- ceed the pressure of a column of water 82 feet in height. That he was himself little satisfied with this explanation, is evident from the circumstance that pre- viously to his death, which happened soon after, in 1642, he earnestly recom- mended to his pupil Torricelli to under- take the investigation of the subject, which the infirmities of advanced age no longer permitted him to prosecute. Tor- ricelli, suspecting the true cause of the suspension of the water, namclv, the weight of the atmosphere, happily con- ceived the idea of trying the experiment with mercury. He perceived that if the weight of the atmosphere forms a coun- terpoise to a column of water of 32 feet, it must also counterpoise a column of mercury of about 28 inches in height, the weight of mercury being about 14 times greater than that of water. Hav- ing accordingly procured a glass tube of about 3 feet in length and a quarter of an inch in diameter, hermetically sealed at one end, he filled it with mercury ; and covering the open end with the fin- ger, he immerged it in an open vessel containing mercury. On bringing the tube to the vertical position, and remov- ing the finger, the mercury instantly sank, leaving a vacuum at the top of the tube, and, after making several oscilla- tions, stood in the tube at the height of about 28 inches above the surface of that in the vessel. On covering the mercury in the vessel with a portion of water, and rais- ing the tube till the lower end came into contact with the water, the mercury all ran out, and the water rushed up to the top of the tube. This experiment, called after its author the Torricellian experiment, de- monstrated that the mercury was sustain- ed in the tube, and the water in the barrel of the pump, by exactly the same counterpoise, whatever the nature of it might be. Torricelli died shortly after, in the flower of his age, without com- pleting his great discovery ; but the fame of his experiment was soon carried into other countries, and the subject engaged the attention of the most eminent phi- losophers; among others the celebrated Pascal. After a variety of ingenious ex- periments on the subject, all of which tended to establish the pressure of the atmosphere, it at length occurred to Pas- cal that if the mercurial column was really supported by atmospheric pres- sure, it must be affected by the weight of the superincumbent mass of air, and consequently be diminished at considera- ble elevations. In order to verify this conjecture, he requested his brother-in- law, Perier, to try the experiment on the Puy de Dome, a lofty conical mountain in the province of Auvergne, which rises to the height of 500 toises. At the foot of the mountain Perier filled two tubes, and observed the mercury in each to stand at precisely the same height, nearly 28 English inches. Leaving oiie of them under the care of a person to watch its rise and fall, he carried the other to the top of the mountain ; and on repeating the experiment there, the mercury stood at the height of only 24*7 English inches. At two intermediate stations in his de- scent, the mercury was observed succes- bar] CYCLOPEDIA OF THE USEFUL ARTS. 33 sively to rise, and at the foot of the moun- tain it stood at exactly the same height in the tube as at first. This experiment was decisive ; the result of it was com- municated to Pascal at Paris, who, after confirming it by similar observations made successively on the ground, and at the top of a glass-house and the belfry of a church, proposed the barometer as an instrument for measuring the height of mountains, or the relative altitudes of places above the surface of the earth. The barometer had been but a short time invented before it was observed that the height of the mercurial column is subject to variations connected in some way with the changes of weather. But the variations are confined within a limit- ed range, scarcely exceeding 3 inches in all, and often, for many days together, do not exceed a few hundredths of an inch. It therefore was considered de- sirable to render these minute oscilla- tions more apparent by increasing their range ; and accordingly, of the numerous forms^ which the barometer has received, or which have been suggested, the greater part have been proposed with a view to this purpose. The most remarkable or useful constructions are the following, the descriptions of which will be readily understood with the assistance of the diagrams : — Fig. 1, is the Cistern Barometer, and is merely the inverted tube of Torricelli alroady described. The tube must be about 34 inches long. When placed in the cistern, the mercury sinks till the column between the two surfaces m and n just counterbalances the pressure of the air. The space above the mercury, a m, is or ought to be a perfect vacuum, or only filled with the vapor of mercury. In this barometer, as the diameter of the cistern is generally very much greater 2* i than that of the tube, almost the whole effect of the rise or fall is perceived in the variation of the upper surface at m. For supposing the section of the cistern 20 times greater than that of the tube, and that the height of the column m n sutlers a diminution of one inch ; it is evident that, as all the mercury which goes out of the tube passes into the cis- tern, when it falls at m it must rise at n, but less in proportion as the section of the cistern exceeds that of the tube. In the case supposed, therefore, the altera- tion of the level at m will be 20 times greater than at n; that is to say, there will be a fall of § T of an inch at m, and a rise of 2V of an inch at n. Fig. 2, is the Siplion Barometer, which was also proposed by Torricelli, as being more convenient than the former. It is merely a tube hermetically sealed at the upper end, having the lower or open end bent upwards in the form of a siphon. The variations in this are only half as great as in the cistern barometer ; for the tube being of the same width through- out, a diminution of the column m n amounting to one inch will be marked by a fall of half an inch at m and a rise of half an inch at n. This inconvenience may, however, be remedied by having the lower branch blown into a wide bulb ; but as it is very difficult to procure the bulb to be blown into a perfectly regular shape, this enlargement ot the bulb is found to give rise to. inaccuracies. Fig. 3, is the Wheel Barometer, pro- posed by Hooke. A small weight floats on the surface of the mercury in a siphon barometer, which is very nearly counter- poised by another weight, w, connected with the former by a string passing over a pulley, p. When the mercury rises at n, the weight w descends, and turns the pulley. An index attached to the axle of the pulley shows on a dial the quantity of revolution. This barometer, though very commonly met with, is a mere toy ; and indicates neither the absolute height of the mercurial column, nor its varia- tions, with sufficient accuracy to be of the slightest use for any philosophical purpose whatever. Even as a weather- glass, it is the worst of all the common forms of the barometer. Sir Samuel Moreland proposed to en- large the scale, by inclining the upper part of the tube so as to form a consider- able angle with the perpendicular. By this contrivance the scale is increased in the proportion of radius to the cosine of the angle of inclination ; but the friction 34 CYCLOPEDIA OF THE USEFUL ARTS. [bar on the sides of the tube is greatly in- creased, and it is very difficult to deter- mine the exact plane of the top of the column which requires to be read off on a vertical scale. This construction is easily conceived without a diagram. We shall notice two other forms of the barometer, proposed with a different view from that of enlarging the scale. Fig. 4, is a modification of the siphon barometer proposed by Gay Lussac. It differs from the common form in this respect, that, after the tube has been filled, the short branch is hermetically closed at the top, and the communication with the atmos- phere takes place through a small capil- lary hole drilled laterally through the tube at o, so fine that though it admits the air to pass freely, it prevents the passage of the mercury. The barometer is thus rendered very convenient for car- riage ; but notwithstanding the promising appearance of this barometer, it has been found, particularly in travelling, that a portion of air wiil frequently insinuate itself through the mercury. In order to prevent the possibility of the accident, an ingenious modification lias been made by M. Bunten, a Parisian artist. It con- sists in causing the part of the tube a b to terminate in a very fine point, and to penetrate to some depth into the other part c o, to which it is joined at c, in the manner represented in Fig. 5. Now if an air bubble from the end f lime. BASALT. A common species of trap. Essentially composed of felspar and au- gite, of a compact texture, and dark-green gray or black color : often found crystal- lized in pentagonal or six-sided figures, as those in the Giants' Causeway and tho Island of Staffa are magnificent exam- ples. The Palisades on the Hudson rive* are of basalt. CYCIOPEDIA OF THE USEFUL ARTS. 37 BASE. In chemistry the substance with which an acid is combined: thus in the sulphate of iron, iron is the base united with sulphuric acid. Almost all oxides of metals are bases. BASSORINE. A modification of gum, originally found by Vauquelin in gum bassora. It is semi-transparent, and forms a thick mucilage with water with- out dissolving : an addition of a little nitric or muriatic acid aids its solubility very much. BATTEN. Wooden scantling from two to six inches broad, and from one to two inches thick, used in walls to secure the laths over which the plaster is laid. BAY SALT. A large grained salt ob- tained by the spontaneous evaporation of sea water in large shallow pits exposed to the full action of sun and air. BDELLIUM. An African gum resin of a dark brown color : common in sam- ples of myrrh. BEAM. A horizontal piece of timber used for resisting the strain of a weight ; as a tie-beam, which acts like a string or chain by its tension; a straining-piece where it acts by compression ; or a bres- summer where it bears a resisting weight. BEEK. Wine made from grain, chiefly by fermenting an infusion of barley, malt, and of hops, and bears different names according to the color and the strength. Wheat and maize are suscepti- ble of undergoing a like change with barley. Oats and rice also are capable of producing beer ; and many other vegeta- ble bitters arc substituted for the hop. The objects in view in this manufacture are to form sugar, and consequently the alcoholic portion of the liquor, the other to communicate a particular flavor, and assist in its preservation. The first stage is to convert the barley into malt, by making the grain germinate up to a cer- tain point, when a peculiar azotized sub- stance called diastase is formed, which possesses the remarkable property of converting the starch into a fermentible BUgar, resembling grape-sugar. This change does not take place at once, for the starch is first changed into a gummy mucilaginous substance called dextrin. This substance does not ferment on the addition of yeast; but by the action of diastase it is readily converted into starch- sugar, which is 'fermentible. This is generally a distinct operation from that of brewing, and consists of four pro- cesses, namely, steeping, couching, floor- ing, and kiln-drying. In steeping, the malt is placed in sunk cisterns, sprinkled with water so as barely to cover it, and let lie for about 40 hours. The barley im- bibes moisture and increases in bulk ; it gives out carbonic acid, which dissolves in the water ; some of the husk colors the water also. The grain becomes whiter and so soft that the two ends of a grain can be squeezed between the finger and thumb ; the water is then drained off; it is then heaped or couched. When it warms and begins to germinate, the grain absorbs oxygen and gives out car- bonic acid, and the temperature rises to 90°. The germination of the malt is now stopped by drying on a kiln, which con- sists of a chamber, floored with an iron plate, full of holes, and furnished with a vent in the roof for the escape of fumes. Below this floor is a furnace containing charcoal or coke, the heat of which as- cends through the malt. Pale amber and brown malt can be pro- duced from the same kind of malt, by varying the temperature of the drying. Pale malt is dried at the proper temper- ature, and produces the best beer ; the other varieties are scorched and charred. The brown malt gives a bitter taste, and being less alcoholic, became a more fa- vorite drink with the laboring classes of London : and hence its name " porter." The malt is then ground or crushed into coarse powder, and then passed into a mash tun containing water heated up to 170°. Here it digests on the malt till all the sugar is extracted, when the liquor, now called worts, is drawn off. The grain receives three waters, which, when drawn off, are mixed together. The first wort is sometimes set aside for superior ales, and the second and third for inferior beers. The malster regulates the strength of his worts by an instrument called the saccharometer, a variety of hydrometer. The worts are next concentrated by boiling, and cleared of the vegetable al- bumen which coagulates. The hops are added in this vessel, and are kept stirred, so as not to lie on the bottom. The quantity of hops added depends on the quality of the beer, the season, and cli- mate to which it may be exported. In warm weather a larger portion is added. In strong English beer 4£ lbs. of hops is allowed for a quarter of malt : for ale and porter 1 lb. of hops to a bushel of malt. The boiling being completed, the liquid is now cooled suddenly. It is then passed into the fermenting tun, and yeast added. One gallon of yeast generally sets 100 gallons of wort in active fermentation; 38 CYCLOPEDIA OF THE USEFUL ARTS. |B*JR by this latter action the sugar is changed into alcohol. Before this is fully com- pleted the worts are racked off into large hogsheads, with the bungholes open, where fermentation is allowed to complete itself. By this means no vinegar is pro- duced, which would be the case were the process to be completed in open vessels. The fermentation over, the beer is pumped up into store-vats of great size, where it is kept until required to be drawn off for consumption. The casks are bunged down tightly. The beer cleanses itself j in these vats, throwing down a scum of flocculent matter. Isinglass, or finings, is sometimes added for this purpose, to ex- pedite the clarification. BEET. The sweet succulent root of Beta vulgaris, a Chenopodiaceous plant of biennial duration. It is used in the win- ter as a salad, for which purpose the red and yellow beets of Castelnaudari are the best ; for the food of cattle, under the name of mangel-wurzel ; and for the ex- traction of sugar : for the last object a white-rooted variety with a purple crown is the most esteemed. Sea beet, Beta maritima, is a well known and excellent substitute for spinach. To Napoleon is due the merit of having established the extraction of sugar from beet as a branch of manufacture, which is now in so nourishing a condition in France as to gradually exclude the Colo- nial sugar in the French market. Its ma- nufacture was twice attempted in Ireland with such success, that the West India planters had their jealousy aroused : and their influence was such, that a heavy prohibitory duty was laid on beet sugar, which crushed the trade ; it is now, however, removed, and the manufacture of sugar from beet, will, in a few years, in temperate latitudes, exclude that of the cane and the maple. (For a descrip- tion of the process, see Sugar.) BELL METAL. An alloy of 80 parts of copper and 20 of tin. The Indian gong metal is a similar alloy. An English Dell metal analyzed by Dr. Thomson was found to consist of 800 copper, 101 tin, 56 zinc, and 43 leajf. Small shrill bells generally contain zinc. BELLOWS. A machine contrived to propel air through a tube or orifice. It is used for blowing fires, supplying the pipes of organs, and other purposes, and is constructed according to various forms ; but the principle is the same in all of them. The dimensions of a space in which air is confined are contracted ; the air being permitted to escape only at a small opening, rushes out with a velocity proportional to the pressure and to the smallness of the opening. (For improved bellows and blowing machines, see Metal- lurgy.) BEN NUTS. The seeds of an Arabian plant called moringa aptera • they yield an oil called oil of ben, and have been employed in syphilitic diseases. BEN, OIL OF. The expressed oil of the nut of the marimba aptera. This oil is remarkable for not becoming rancid by age ; and as it is perfectly insipid and in- odorous, it is used for extracting the fra- grancy of certain flowers, such as jessa- min, orange, &c. The same tree fur- nishes the lignum nephriticum, supposed to be useful in certain affections of the kidneys. BENGAL STKIPES. Ginghams, a cotton fabric woven with colored stripes. BENZOIC ACID. A constituent of many balsams, generally obtained by heating benzoin upon a shallow iron pan, surmounted by a frame capped with car- tridge paper, upon which the acid sub- limes at a gentle heat. It may also be obtained by boiling benzoin with slaked lime, and decomposing the newly-formed benzoate of lime by nydrochloric acid ; it is in either case obtained in white crystalline plates. Its chemical composi- tion is C 14 H 5 O 3 , and is classed as the oxide of a supposed radical benzule. Benzoic acid melts at 212°, dissolves in 200 parts of cold and 25 parts of boiling water, in twice its weight of alcohol, and freely in ether, fats, and volatile oils. It is an ingredient of fumigating powders and pastiles. It enters into the composition of Friar's balsam, a veteri- narv medicine, and of the cosmetic vir- gin's milk, made of two drachms of the al- coholic solution of benzoin with one pint of rose water. BENZOIN. The resinous exudation of the styrax benzoin, a tree which is a na- tive of Sumatra. Benzoin is a combina- tion of resin and benzoic acid. It has a mottled or amygdaloid texture, and is composed of a mixture of brown and white parts. It has a fragrant odor, and is much used in perfumery and varnishes. BERBEREN. A yellow bitter princi- ple, contained in the alcoholic extract of the root of the barberry tree. BERBERRY. (Lat, bcrberis.) A spiny shrubby plant, bearing yellow flowers, and succulent one-celled fruit growing in racemes. It is one of a genus in which the fruit is universally fleshy and acid, although often less so than m the com- bis] CYCLOPEDIA OF THE USEFUL ARTS. 39 mon kind (berberis vulgaris.) Some of the species nave pinnated leaves, many are evergreens, and several have a black fruit ; even the common sort has a variety of this description, as well as others with pale yellow and stoneless fruit. There is an idea among people in the country, that a berberry bush brings blight to a wheat field: but the parasitical fungus which attacks the berberry is altogether differ- ent from that which produces the mildew of wheat, which cannot possibly be com- municated by the one to the other. It gives a yellow dye to leather. BERGAMOT, ESSENCE OF. The es- sential oil of the rind of a small pear- shaped fruit, the produce of the citrus limetta bergamium. It is much used as a perfume, and apt to be adulterated with the oils of orange and lemon peel, and with alcohol. BEVEL. In architecture, an instru- ment for taking angles. One side of a solid body is said to be bevelled with re- spect to another when the angle con- tained between their two sides is greater or less than a right angle. BEVEL ANGLE. A term used among artificers to denote an angle which is neither a right angle nor half a right angle. BEVEL GEEE. In mechanics, a spe- cies of wheelwork, in which the axles of two wheels working into each other are neither parallel nor perpendicular, but inclined to one another in a certain angle. "Wheels of this kind are also called coni- cal wheels, because their teeth may be regarded as cut in the frustrum of a cone. BILE. A fluid secreted in the liver, of a yellow color, and a nauseous taste, compounded of sweet and bitter; it sinks in water, and mixes with it in all pro- portions ; it is slightly alkaline, and feels soapy. It contains a peculiar bitter prin- ciple, which lias been called picromel, and a little free soda and saline matters. According to Berzelius, the solid con- stituents of bile amount to about one- tenth of its weight. Modern chemistry regards bile as a soda soap, and on this account ox, gall or bile is used by water-color painters and scourers of cloth, but it requires to be freed from its green color : this is accom- plished by letting it settle, and then eva- porating it in a water bath to thickness, and letting it dry into thin cakes. A little alum added to a solution of gall, removes the color after lying together for three months.. Prepared gall gives solidity to colors and paints, either by being mixed with them, or passed over them on pa- paper. Mixed with gum it thickens the colors, prevents the gum cracking and the colors from running into each other. It heightens the tint of carmine, ultra- marine, green, and the most delicate co- lors, and spreads them smoothly on ivory and paper. Coated over black lead or crayon drawing, it keeps them from being rubbed off; removes grease spots from ivory, paper ; and cloth ; and a small portion added to ink, renders it fluid. BINNACLE. The case or stand in which the steering compass is placed ; it is fixed near the tiller or wheel. At night the compass is illuminated by a lamp placed over it. BINOCLE, or BINOCULAR TELE- SCOPE. A telescope to which both eyes may be applied at once, and in which, consequently, an object may be observed with both eyes at the same time. BIRDLIME. A glutinous substance extracted by boiling the bark of the holly tree : a similar substance may be obtain- ed from misletoe, from the young shoots of elder, and some other plants. It is much used in India for destroying in- sects. It contains resin, mucilage, free acid, and coloring matter. BISCUIT. In sculpture, a species of porcelain, of which groups and figures in miniature are formed, which are twice passed through the furnace or oven. It is executed without glaze upon it. In pottery, this term is applied to earthen- ware and porcelain, after it has been hardened in the fire, and before it re- ceives the glaze : in this state it is per- meable to water. On which account it is now largely used as porous cells for elec- trotype purposes. Biscuit. An unfermented bread, which, when well prepared, may be kept for a long time ; and hence valuable as a common form of bread at sea. In Eng- land, the sea biscuit manufacture by hand for government-contract has been sus- ? ended by the machinery invented by '. T. Grant, Esq., of the Royal Clarence yard, which is this : the meal or flour is conveyed into a hollow cylinder four or five feet long and about three feet in dia- meter, and the water, the quantity of which is regulated by a gauge, is ad- mitted to it; a shaft, armed with long knives, works rapidly round in the cylin- der with such astonishing effect, that in the short space of three minutes, 340 lbs. of dough are produced, infinitely better made than that mixed by the naked arms 40 CYCLOPEDIA OF THE USEFUL ARTS. b of a man. The dough is removed from the cylinder and placed under the break- ing-rollers ; these latter, which perform the office of kneading, are two m num- ber, and weigh 15 cwt. each ; they are rolled to and fro over the surface of the dough by means of machinery, and in five minutes the dough is perfectly knead- ed. The sheet of dough, which is about two inches thick, is then cut into pieces half a yard square, which pass under a second set of rollers, by which each piece is extended to the size of six feet by three, and reduced to the proper thickness for biscuits. The sheet of dough is now to be cut up into biscuits, and no part of the operation is more beautiful than the mode by which it is accomplished. The dough is brought under a stamping or cutting-out press, similar in effect, but not in detail, to that by which circular pieces for coins are cut out of a sheet of metal. A series of sharp knives are so arranged that, by one movement, they cut out of a piece* of dough a yard square about sixty hexagonal biscuits. The rea- son for a hexagonal (six-sided) shape is, that not a particle of waste is thereby- occasioned, as the sides of the hexagonals accurately fit into those of the adjoining biscuits ; whereas circular pieces cut out of a large surface always leave vacant spaces between. That a flat sheet can be divided into hexagonal pieces without any waste of material is obvious. Each biscuit is stamped with the queen's mark, as well as punctured with holes, by the same movement which cuts it out of the piece of dough. The hexa- gonal cutters do not sever the biscuits completely asunder- so that a whole sheet of them can be put into the oven at once on a large peel or shovel adapted for the purpose. About fifteen minutes are sufficient to bake them ; they are then withdrawn and broken asunder by the hand. The corn for the biscuits is purchased at the markets, and cleaned, ground, and dressed at the government mills. In quality it is a mixture of fine flour and middlings, the bran and pollard being removed, The ovens for baking are formed of fire-brick and tile, with an area of about 160 feet. About 112 lbs. weight of biscuits are put into the ovens at once. This is called a suit, and is reduced to about 110 lbs. by the baking. From twelve to sixteen suits can be baked in each oven every day, or after the rate of 224 lbs. per hour. The men engaged are dressed in clean check shirts and white linen trowsers, apron, and cap; and every endeavor is made to observe the most scrupulous cleanliness : 450 lbs. of dough may be mixed by the machine in four minutes, and kneaded in five or six mhmtes ; we need hardly say how much quicker this is than men's hands could effect it. The biscuits are cut out and stamped sixty at a time, instead of singly : besides the time thus saved, the biscuits become more equally baked, by the oven being more speedily filled. The nine ovens at Gosport used to employ 45 men to produce about 1,500 lbs. of bis- cuit per hour ; 16 men and boys will now produce, by the same number of ovens, 2,240 lbs. of biscuit (one ton) per hour. The comparative expense is thus stat- ed: Under the old system, wages, and wear and tear of utensils, cost about 1*. €>d. per cwt. of biscuit : under the new sys- tem, the cost is 5d. British money. BISMUTH. A brittle, yellowish-white metal, of crystalline texture. Its specific gravity is 10 ; it fuses at 476°, and at a red heat it sublimes in close vessels. II conducts heat less perfectly than most ol the other metals. When strongly heat- ed it burns with a bluish white flame, and is rapidly oxidized. Its equivalent upon the hydrogen scale is 71 ; and it forms only one salifiable oxide, the equi- valent of which is 79. "When nitrate of bismuth is dropped into water, a white powder is thrown down, formerly called magistery of bismuth or pearl white : it is a subnitrate. This is used as a cosmetic. A brown peroxide of bismuth is obtained by fusing the protoxide with caustic potash. Some of the alloys of bismuth are remarkable for their fusibility : a compound of 8 parts of bismuth, 5 ot lead, and 3 of tin, melts in boiling water, and is commonly called fusible mttal. The ores of bismuth are not common ; but it occurs native, and combined with oxygen, sulphur, and arsenic. The Ger- mans call it wismuth. Bismuth, alloyed with lead and tin, has been used as the patent safety plug in steam boilers to guard against explosion. It was supposed that at a high tempera- ture, the alloy would melt and allow the steam to blow itself out. This has not been found the case, for this alloy, when exposed a long time to the action oi steam, undergoes a process of change by which the more fusible alloy is melted out, and what remains is so hard as not to fuse : after the explosion of boilers, these plugs have been found unmelted. ble] CYCLOPEDIA OF THE USEFUL ARTS. 41 Fusible metal has been used for casts for anatomical preparations, casts from medals, and even the surfaces of wood and paper. Cake moulds for toilet soap manufacture, are made of this metal. BITTERN. The mother liquor or un- crystallized residuum of salt works, so called on account of its bitter taste. Chlo- ride of magnesium and sulphate of mag- nesia, are its chief ingredients. BLACK LEAD. (See Plumbago.) BLACK PIGMENT. A fine lamp- black, obtained in England by burning a thick jet of coal gas with a small quantity of air, by which its carbon is deposited very fine. In this country it is made by the combustion of oil and of rosin, car- ried on incompletely. This fine and light black is used in the manufacture of the better quality of printing ink. BLACKING. An article prepared in various ways for polishing shoes and boots. Each manufacturer has his own recipe, in which ivory black or some other black color, oil, and vinegar, with molasses, are the principal ingredients. The following is the mode of making the waterproof or India-rubber blacking : 18 ounces of caoutchouc are to be dis- solved in about 9 pounds of hot rape oil. To this solution 60 pounds of fine ivory black and 45 pounds of molasses are to be added, along with 1 pound of finely- ground gum arabic, previously dissolved an 20 gallons of vinegar, of strength No. 24. These mixed ingredients are to be finely triturated in a paint-mill till the mixture becomes perfectly smooth. To this varnish 12 pounds of sulphuric acid are to be now added in small successive quantities, with powerful stirring for half an hour. The blacking thus compounded is allowed to stand for fourteen days, it being stirred half an hour daily ; at the end of which time, 3 pounds of finely ground gum arabic are added, after which the stirring is repeated half an hour every day for fourteen days longer, when the liquid blacking is ready for use. In making the paste blacking, the above quantity of India-rubber, oil, ivory black, molasses, and gum arabic, may be used, the latter being dissolved in only 12 pounds of vinegar. These ingredients are to be well mixed, and then ground together in a mill till they form a perfectly smooth paste. To this paste 12 pounds of sulphuric acid are to be added in small quantities at a time, with powerful stirring, which is to be continued for half an hour after the last portion of the acid has been introduced. This paste will be found fit for use in about seven days. BLANKET. (See Woollens.) BLAST FURNACE. (See Ikon.) BLEACHING. The art of depriving stuffs and goods of the coloring matters contained within their texture, whether natural or artificial. When calico, muslin, or other cotton fabrics have been spun and woven, they generally pass into one or other of these establishments before being brought to market. If they are to bo sold in the white state, they require bleaching • if in a colored state, they require dyeing ; if in a decorated or ornamented state, they re- quire printing ; and hence it arises that there are in one establishment or congre- gated together, oleach-worlcs, dye-works, and print-works. As, however, a well- printed piece of cotton requires to be bleached and dyed as well as printed, the print-works "have, in most cases, the means for carrying on the bleaching and dyeing as well as the printing processes ; and there are thus facilities for witness- ing all three operations in one establish- ment. Most of these works are situated in the valleys (when not worked by steam-power), in order to have a supply of water from the streams which flow through them. Bleaching is now a very different pro- cess from what it was in the last century. At that time it required a period of several months to bleach a piece of cloth, and this, too, only in the summer time. In some cases the cloth was sent in the spring of the year to Holland, to be bleached on the level grassy plains of that country, and returned in the au- tumn ; while in other cases, when bleach- ed in the English fields, there was so much depredation as to lead to an unhap- py system of severe laws and general distrust. Chemists were thence led to inquire whether means might not be adopted more expeditious than that of exposure to the open air of a bleach- ground. Home, Scheele, Berthollet, and Henry, made successive steps in this direction, and paved the way for the in- troduction of the use of bleaehing-poxvder, by Mr. Tennant, about the year 1800. From that date the present most efficient system of bleaching has been followed in the great works of the north, modified occasionally in the minor details. Most large bleach-works exhibit a con- siderable range of buildings, comprising a croft or bleach-house, a dye-house, re- servoirs and water-filters, and subsidiary 42 CYCLOPEDIA OF THE USEFUL ARTS. [blk buildings. The supply of water required in bleaehing and dyeing is enormous, and extensive arrangements are necessary for the filtering of the water before using, since the success of the process very much depends on the purtiy of the water. Matters are then ready for the bleach- ing process. The croft (so named proba- bly because it renders the same service as the croft or bleaching-ground under the old system), is generally a large stone- floored building, filled with coppers and vessels of various kinds, abundantly sup- plied with water, and not often free from clouds of steam. Here successive wash- ings, boilings, and steepings bring the cotton to a white state. In the first place the singed cloth, which has ac- quired a kind of nankeen colour, is fur- ther sewn up, until five hundred pieces are connected together, end to end ; that is, there are 500 X 28 = 14,000 yards, or eight miles of cloth in one continuous piece. This enormous piece passes into a wasking-en Ivoky Black.) In the calcination bones lose half their weight, and the resulting charcoal is more valuable when the bones have been steamed pre- viously, so as to remove fat and mem- brane. It is after being calcined, ground in a mill, and sifted. In the calcina- tion volatile inflammable gases and oils are given off, — the latter are used to fon lamp black ; at the close of the process muriate of ammonia and sulphate of soda, — the latter is washed out, and the for- mer, which is a valuable salt, is sublimed. Bone black has a remarkable attraction for organic coloring matter; this varies with the heat at which it was made : if too high, it becomes glazed ; if too low a heat was employed, the albumen of the bone is not destroyed. After this char- coal has been used, it may be renovated by heating it to redness in a furnace. BOOKBINDING. There are several and distinct branches of this business, — plain and ornamental binding, — law bind- ing, — blank book and ledger binding ; the latter is a department in itself, and usually conducted by stationers. The various sizes of a book are desig- nated by the number of leaves in which the sheet is folded : thus folio is 2 leaves ; quarto, 4 leaves ; octavo, 8 leaves ; duo- decimo, 12 to a sheet; and so on to the smallest sizes of 24mo and 32mo. After the sheets of a book have been folded, they are collated by the wumeral or letter placed at the foot of the first page in the first sheet, in order to ascertain that the work is perfect. The next process is that of pressing: this is done in a hydraulic press. The back of the sheets is then sawed by machine, after which the sewing process com- mences. This last is a quick operation, as a girl can sew three thousand sheets a day. The middle of the sheets are stitched with thread to the upright cords fastened on the press; as soon as one sheet is fastened to all the strings, ano- ther is laid down on it, and fastened in a similar manner. India-rubber binding supersedes the necessity of sewing, bind- ing every leaf as securely, and giving greater flexibility. When the sewing is finished the strings are cut, leaving an inch or so hanging, which are used to fasten the book to its case. The backs of the sheets are now all glued to increase the connection. By hammering on wooden blocks, or better still, by passing the sheets be- tween rollers, the back is rounded and the front hollowed out, and a grooved hollow made, into which the millboard is fitted, the covers being fastened by the strings through the boards. The book is next placed between boards and screwed up in a press, with one of its ends pro- jecting. The ends of the leaves are now cut off fair'by a plough, the cutting edge of which, in its action, is midway between a knife and a plane-iron. When books 46 CYCLOPEDIA OF THE USEFUL ARTS. are bound in leather, the sides of the covers are previously stamped with a de- vice, or embossed as it is termed. The embossing machine sometimes exerts a pressure of 50 tons. The devices on the back, edges, and margin, are placed on by hand \vith a revolving wheel, which has on its edge the device cut out, and which leaves its impression when the wheel is rolled along. Gutta percha has lately been introduced into binding, to imitate the antique old oak binding. When books are to be gilt, the edges are scraped and burnished with the agate burnisher, then colored over with red bole or chalk, ground in soap, rubbed in fine paper, and aerain well burnished; this brightens up the gilding. The gold leaf is then cut into slips, and laid on. Gilding on marbled edges has a very beautiful effect, as the marbling is per- ceived through the gold. Several of the book binderies in New- York, Philadelphia, and Boston, employ from fifty to one hundred persous, in- cluding females who stitch and fold. BORACIC ACID. (See Boron.) BORAX. This salt is found native in some of the lakes of Thibet and Persia, and is imported from India under the name of tlncal, which, after purification, forms the refined borax of commerce. Of late years borax has been obtained by combining native boracic acid with soda. Borax forms hexahedral prisms, slightly efflorescent, and requiring 20 of cold and 6 of boiling water for solution. When heated, water of crystallization is driven off, and the residuary salt fuses into what is called glass of borax. Crystallized borax consists of 68 boracic acid + 32 soda + 90 water. It has upon some tests an alkaline reaction, and lias hence been called svb-borate of soda. Bor- ax is chiefly used by workers in metals as a flux : it is also employed in medicine. Dry borax acts on metallic oxides at a high temperature, melting and vitrifying them into beautiful colored glasses", on which account it is a most useful reagent with the blow-pipe. It tinges oxide of chrome, emerald green ; oxide of cobalt, intense blue ; oxide of copper, pale green ; oxide of tin, opal ; oxide of iron, bottle- green ; oxide manganese, violet. In the fusion of metals it protects the surface from oxidizement, and dissolves any ox- ides off the surface : hence it is an excel- lent flux in the hands of the goldsmith, in soldering precious metals, and to the brazier, in soldering copper and iron. When mixed with shell-lac, in the ratio of 1 to 5, it renders the lac soluble in wa- ter, and forms with it a species of varnish. BORON. The base of boracic acid, discovered by Davy in 1807. It may be procured by heating dry boracic acid with potassium. It is a dark olive-colored substance, a nonconductor of electricity, insoluble in water, infusable, and of a specific gravity = 2, Heated to redness it burns into boracic acid, which consists of 20 boron + 48 oxygen. Boracic acid is found in the hot springs, and amongst the volcanic products of the Lipari islands, and in the waters of Sasso in the Florentine territory ; it also occurs in some minerals. It may be obtained by adding excess of sulphuric acid to a strong solution of borax. Its specific gra- vity is 1*48. In its usual state of scaly crystals it is a hydrate, composed of 68 dry acid + 27 water. In this state it re- quires about 30 parts of cold and 3 of boiling water for its solution. It dis- solves in alcohol, and the solution burns with a characteristic green flame. It reddens litmus ; but renders turmeric brown, like an alkali. When its water is driven off by fusing it at a high heat, the anhydrous acid concretes into a glassy substance of the specific gravity of 1*8. It is a useful flux, and was formerly used in medicine under the name of Homberg's sedative salt. The boracic^ acid lagoons of Tuscany are an interesting instance of the conver- sion of a natural phenomenon, which seemed only a subject of wonder, into a productive manufacture. These lagoons are depressions or mud holes in the soil, from which issue hot vapors highly im- pregnated with boracic acid, which were formerly regarded with terror by the inhabitants of their vicinity, and they sought by public prayers a deliverance from this scourge. In 1818, Mr. Lan- derel conceived the idea of rendering these vapors a source of profit. The la- goons being situated upon the declivity of a mountain, they were surrounded by a basin of mason work, and water from the mountain stream conducted into them, so as to form a series of artificial lakes at different levels. The water is let into the upper basin, where it remains some twenty or thirty hours and becomes impregnated by the acid vapors ; at the end of this time the water is drawn off into the second basin, when it receives a further pregnation ; and so on successive- ly through six or eight, until it reaches the evaporating reservoirs. These are bra] CYCLOPEDIA OF THE USEFUL ARTS 41 of lead, and the heat for carrying on the evaporation is obtained from the vapors themselves, which are brought in pipes below the boilers. All the means of ma- nufacture are furnished by the locality itself. The annual product of these la- goons is two and a half millions of pounds. The boracic acid is converted into borax bv combining with soda. 'BOTTLE. (See Glass). BK AN. The husk of wheat which im- mediately covers the grain, and which remains in the bolting machine. It is gently laxative ; an infusion of it, under the name of bran tea, is frequently used as a domestic remedy for coughs and hoarseness. Calico prmters employ bran and warm water with great success to re- move coloring matter from those parts of their goods which are not mordanted. This appears to be due to the quantity of earthy phosphates which the bran con- tains. BRANDY. A spirituous product ob- tained by distilling wine : the quality va- ries with the wine employed. When pure it is perfectly colorless, and only ac- Suires a pale-brown or yellow tint from le cask. The deep color of common brandy, intended to imitate that which it acquires from great age in the cask, is generally given by the addition of burn- ed sugar. The average proportion of al- cohol in brandy varies from 48 to 54 per cent. The best brandy is made in France, the preference being generally given to that shipped from Cognac. (See Distil- lation). BRASS. An alloy of copper and zinc : to make brass, the English method is by melting together copper in round masses, or in bars, with calamine, which is a na- tive oxyde or ore of zinc, and a native carburet of zinc combined with oxyde of iron, which make it of reddish color, and it usually contains more or less lead. The calamine is powdered and separated by washing, then heated on the hearth of a reverberatory furnace, which expels nie volatile matter, usually water and carbonic acid. The remainder is oxyde of zinc, and a small portion of carbon, which the heat cannot wholly remove, and some earthy substances, 'the proportions are nearly equal weights of copper and cala- mine and one-tenth of their weight of pulverized charcoal, which are together put into a crucible capable of containing 100 pounds of brass when completed, but when charged holding: 663, calamine 93, and charcoal 13, which is covered with clay, sand, &c, to keep it free from the air. The fire is continued from twelve to twenty hours, when the refuse is poured oif, the metal cast into ingots, then usually remelted and cast, to render it better and finer, when it is rolled, drawn, or made into castings for use. Brass is often made by melting toge- ther small pieces of cast copper and zinc, which is made into ingots, then rolled into sheets slitted and drawn into wire. For knife scales, sheet brass is used which is not annealed, but stiff and hard. Corinthian brass, famous in antiquity, was an alloy of gold, silver, and copper. Lucius Numminus, 146 years before Christ, captured and burned the city of Corinth ; and the violence of the confla- gration formed, from the abundance of metals in its course, a solid sea of this alloy in the streets and low places. Ger- man chemists make copper of a gold co- lor, by exposing it to the fumes of zinc. The comparative stiffness of this alloy permits it to be cut by saws and files, turned and worked much easier than iron. The metal anciently called brass, is the copper of modern times ; and the Colos- sus at Rhodes, and other so-called brazen fabrics, were formed entirely of the last named metal. Brass-making was introduced into Eng- land in 1694, where it proved a failure to its first manufacturers, but it is now a great business in that country. Brass must be annealed after it is cast into moulds, or it will be so brittle that it cannot be drawn. Brass is lighter than pure copper, but it is harder. It is only malleable while cold. If brass is heatea beyond a cherry red, the zinc separates from the copper in the form of gas. There are a great variety of brass alloys. Four parts of copper and two of zinc, makes a beautiful brass. The copper must be first melted then the zinc is introduced, and as soon as it is melted it must be stirred then run into the mould. The reason for doing this is, that zinc is volatilized at the heat of fluid copper, therefore, if the zinc and copper were in- troduced together, before the copper was all melted a great portion of the zinc would have departed in the state of vapor. The usual proportion of metals in yel- low brass, is 30 of zinc and 70 of copper. Tomback or red brass, is an alloy of copper and zinc containing not more than 20 per cent, of the latter. Pinchbeck, is made of 2 parts copper and 1 of yellow brass. Prince's Metal, 3 parts copper and 1 of zinc. 48 CYCLOPEDIA OF THE USEFUL ARTS. I' Mannheim gold, 28 copper, 12 yellow brass, and 3 tin. Cast white metal-buttons, are made of an alloy of 32 parts brass (yellow), 4 parts of zinc, and 2 of tin. The French state that brass containing two per cent, of lead works more freely in the turning-lathe, but does not ham- mer so well as the ordinary brass. BRASS FOIL. Dutch-leaf: it is made from very thin sheet brass, beat out under a hammer worked by water power which gives 3 or 400 strokes per minute : from 40 to 80 leaves being laid over each other. By this treatment it acquires its characteristic solidity and lustre. BRAZIL WOOD. A valuable wood, imported from South America and the West Indies, where it is produced by certain species of Ccesalpima, especially G. echinata and Braziliensis / large trees with repeatedly pinnated leaves, showy yellow flowers, and long richly colored, stamens. It is used for the preparation of a red dye, but the consumption of it in this country is inconsiderable. The coloring matter is easily affected by acids, producing an orange or yellow color which is durable : with alkalies, a violet and purple color is produced — these are fleeting. The color given to silks, known as false crimson, is by means of Brazil wood. The silk is boiled with 20 parts of soap, rinsed and passed through a bath charged with this wood. Stronger colors are gained by giving a ground of annotto to the silk, or by adding log- wood to the bath. Nicaragua and peach wood, are varie- ties of the Cfflsalpkna, and produce dyes. The coloring .substances belonging to Brazil, are called by chemists braziUne and brazileine ; the first being the color- ing matter of the wood, and the second a colorless substance which appears to pass into the proper coloring matter by oxidation. BREAD. (Ger. brod.) This impor- tant article of food is made of the flour of different grains ; but it is only those which contain gluten that admit of con- version into a light or porous and spongy bread, of which wheaten bread furnishes the best example. When flour is made into a tough paste or dough by the ad- dition of a little water, rolled out into thin cakes, and more or less baked, it forms biscuit. For the formation of bread a certain degree of fermentation, not unlike vinous fermentation, is requi- site, care being taken to avoid acetous fermentation, which renders the bread sour, and to most persons disagreeable. If dough be left to itself in a moderately warm place (between 80° and 120°), a degree of fermentation comes on, which, however, is sluggish, or, if rapid, ace- tous / so that to effect that kind of fer- mentation requisite for the production of the best bread, & ferment is added, which is either leaven or dough which is already in a fermenting state, and which tends to accelerate the process in the mass to which it is added ; or yeast, the peculiar matter which collects in the torm of scum upon beer in the act of fermenta- tion. Of these ferments leaven is slow and uncertain in its effect, and gives a sour and often slightly putrid flavor. Yeast is more effective ; and when clean and good, it rapidly induces panary fer- mentation ; but it is often bitter, and sometimes has a peculiarly disagreeable smell and taste. All, then, that is essential to make a loaf of bread is dough to which a certain quantity of yeast has been added. This mixture is put into any convenient mould or form, or merely shaped into one mass ; and after having been kept for a short time in rather a warm place, so that fermentation may have begun, it is subjected to the process of baking in a proper oven. Carbonic acid is generated ; and the viscidity or texture of the dough preventing the immediate escape of that gas, the whole mass is puffed up by it, and a light porous bread is the result. Along with the carbonic acid traces of alcohol are at the same time produced, but so insignificant and impure as not to be worth notice ; hence the attempts which have been made to collect it upon the large scale have entirely failed in an economical point of view. Other flour besides that of wheat will, under similar circumstances, undergo panary fermen- tation ; but the result is a heavy, un- palatable, and often indigestible bread ; so that the addition of a certain quantity of wheat flour is almost always had re- course to. It is the gluten in wheat which thus peculiarly fits it for the man- ufacture of bread, chiefly in consequence of the tough and elastic viscidity which it confers upon the dough. It is well Known that home-made bread and baker's bread are two very different things : the former is usually sweeter, lighter, and more retentive of moisture ; the latter, if eaten soon after it has cooled, is pleasant and spongy ; but if kept for more than two or three days, it becomes harsh and unpalatable. The •] CYCLOPEDIA OF THE USEFUL ARTS. 49 cause of this difference may perhaps be obvious from the following details of the operations of the wholesale baker. In making his dough he takes the water, or part of it, which he intends to use, and having slightly warmed it, dis- solves in it a certain portion of salt ; then he adds the yeast, and then a certain quantity of flour. This mixture is set aside in a warm place, where it soon be- gins to ferment. This process is called setting the sponge ; and according to the relation which the water in it bears to the whole quantity to be used in the dough, it is called whole, half, or quar- tern sponge. The evolution of carbonic acid causes the sponge to heave and swell ; and when the surface bursts it subsides, and then swells again, and so on ; but the baker is careful to use it before this fermentation has communi- cated sourness to the mass. He then adds to the sponge the remaining quan- tity of flour, water, and salt, which may be required to form dough of proper quality and consistence, and incorporates the whole by long and laborious knead- ings till the entire mass acquires unifor- mity, and is so tough and elastic as to bear the pressure of the hand without adhering to it. It is then left for a few hours, during which fermentation goes on ; and the inflated mass is again kneaded, so as to break down any lumps or portions which had accidentally escap- ed diffusion in the first operation, and to confer perfect uniformity on the whole. The dough is then weighed out into loaves, which are shaped, and put aside in a warm place for an hour or two, during which they swell up to about double their original size ; they are then put into the oven and baked : "during which ope- ration they again enlarge considerably in bulk, in consequence of the dilatation of the previously generated carbonic acid pent up in the dough ; for, as soon as the mass is exposed to the heat of the oven, the fermentation is put an end to. II' we compare the baked loaf with the flour of which it is composed, we shall find that panary fermentation has pro- duced a considerable change in the latter. The gluten and the starch, which (exclu- sive of a trace of sugar) were the compo- nents of the flour, have mutually acted upon and altered each other ; the tough- ness and viscidity of the gluten is gone, and the starch no longer forms a gelati- nous mixture with hot water ; a little sugar is generally formed, as well as al- cohol; but the principal cause of the 3 change in the characters of the flour is the evolution of carbon and of oxygen in the form of carbonic acid, the production [ of which is independent of the presence of external oxygen (or of air). Small quantities of alum are also, it is said, invariably used with the view of whiten- ing or bleaching the bread ; for it may be observed, that whatever may be the quality of flour which is used, home- made bread is always of a comparatively dingy hue. According to Mr. Accum, the requisite quantity of alum for this purpose depends upon the quality of the flour. The mealman, he says, makes different sorts of flour from the same kind of grain. The best flour is chiefly used for biscuits and pastry, and the in- ferior kinds for bread. The smallest quantity of alum used is from three to four ounces to the sack of flour of 240 pounds. Another article occasionally employed in bread-making is carbonate of ammo- nia. As it is wholly dissipated by the heat of the oven, none remains in the baked loaf. It renders the bread light, and perhaps neutralizes any acid that may have been formed (exclusive of car- bonic acid) ; but it is too dear to be much employed. To some kinds of biscuit it gives a peculiar shortness, and a few of the most celebrated manufacturers use it largely. The French chemists have ac- cused the bakers of employing sulphate of copper or blue vitriol, for the purpose of improving the color of the bread ; but so dangerous and easily detected an addi- tion can scarcely be supposed to be com- mon. According to Mr. E. Davy, bread, especially that of indifferent flour, is materially improved by the addition of a little carbonate of magnesia, in the pro- portion of twenty to thirty grains to the pound of flour; it requires to be very intimately mixed with the dough. The most nefarious adulteration of bread con- sists, however, in the addition of certain insipid and colorless earthy substances, with a view of increasing its weight; such as pipe-clay, porcelain clay, chalk, and plaster of Paris. These, however, are probably very rarely resorted to; though in one instance the writer of this article had occasion to examine a quantity of biscuits, which were adulterated with gypsum to the amount of 10 per cent. For the manufacture of domestic bread the following, perhaps, may not be un- acceptable. White Bread. — Take an earthen vessel, larger at the top than the bottom, and 50 CYCLOPEDIA OF THE USEFUL ARTS. [bre in it put a pint of milk- warm water, II lbs. of flour and i pint of good malt yeast ; mix these well together and set it away (in winter it should be in a warm place) until it rises and falls again, which will be in from three to five hours. It may be set at night if wanted in the morning. Then put two large table- spoons full of salt into two quarts of wa- ter, and mix it well with the above ris- ing. Then put in nine pounds of flour, and work your dough well ; then set it by until it becomes light. Then make it out in loaves, of which it will make four. As some flour is " dry," and other " run- ny," the above quantity will be a guide. The person making bread will observe that runny, or new flour, will require one-fourth more salt than old or dry flour. The water also should be tem- pered according to the weather. In spring and fall it should only be milk- warm. In hot weather cold, and in win- ter warm. Brown Bread. — Take one part of rye meal and two parts of Indian meal, mix it well, add a little salt, and thoroughly wet the whole with boiling milk. Stir it frequently, until cold, and add cold milk till it is thin enough to pour into pans. Bake it in a brick oven five or six hours. Take six quarts of water, one teacup full of salt, one pint of lard or other clean grease, one pint of yeast, the whole to be quite warm ; then stir in meal enough to make a stiff batter, let it stand till it rises, then mix up and put in pans to bake. The quanties can of course be reduced proportionately as desired. Unfermented Bread. — Five pounds of flour, i oz. sesqui carbonate soda, i dram sesqui carbonate of ammonia, 4 teaspoon- fuls of common salt. Mix well together, and then add 2£ pints (50 oz.) cold wa- ter, and 5 drams of hydrocloric acid. It requires li hours to bake. The theory of panification (bread-bak- ing) is easy of comprehension. The flour owes this valuable quality to the gluten, which it contains in greater abundance than any other of the^cerealia (kinds of corn). This substance does not consti- tute, as had heretofore been imagined, the membranes of the tissue of the peris- perm of the wheat ; but is inclosed in cells of that tissue under the epidermic coats, even to the centre of the grain. In this respect the gluten lies in a situa- tion analogous to that of the starch, and of most of the immediate principles of vegetables. The other immediate prin- ciples which play a part in panification are particularly the starch and the sugar ; and they all operate as follows : — The diffusion of the flour through the water, hydrates the starch and dissolves the sugar, the albumen, and some other soluble matters. The kneading of the dough, by completing these reactions through a more intimate union, favors al- so the fermentation of the sugar, by bringing its particles into close contact with those ot the leaven or yeast; and the drawing out and malaxating the dough softens and stratifies it, introducing at the same time oxygen to aid the ferment- ation. The dough, when distributed and formed into loaves, is kept some time in a gentle warmth, in the folds of the cloth, pans, &c, a circumstance propitious to ^lume by mentation. The dimensions of all the the development of their volume by fer- lumps of dough now gradually enlarge, from the disengagement of carbonic acid in the decomposition of the sugar ; which gas i*: imprisoned by the glutinous paste. Were these phenomena to continue too long, the dough would become too vesic- ular ; they must, therefore, be stopped at the proper point of sponginess, by plac- ing the loaf lumps in the oven. Though this causes a sudden expansion of the enclosed gaseous globules, it puts an end to the fermentation, and to their growth, as also evaporates a portion of their wa- ter. The richness or nutritive powers of sound flour and also of bread are propor- tional to the quantity of gluten they con- tain. It is of great importance to deter- mine this point, for both of these objects are of enormous value and consumption ; and it may be accomplished most easily and exactly by digesting in a water-bath, at a temperature of 167° F., 1000 grains of bread (or flour) with 100Q grains of bruised barley-malt, in 5,000 grains or in a little more than half a pint, of water. When this mixture ceases to take a blue color from iodine <^that is, when all the starch is converted into so- luble dextrine) the gluten left unchanged may be collected on a filter cloth, washed, dried at a heat of 212°, and weighed. The color, texture, and taste of the glu- ten, ought also to be examined, in form- ing a judgment of good flour, or bread (See Flour.) BKICK. (Dutch, bricke.) In archi- tecture, a mass of clay earth, sometimes mixed with coal ashes, chalk, and other substances, formed in a mould, and burned in a kiln or clamp. The earth used for this purpose is of two sorts. BRl] CYCLOPEDIA OF THE USEFUL ARTS. 51 The one a stiff clay, with little or no ex- traneous mixture, which produces a hard red brick ; the other a yellowish-colored fat earth, called loam, which produces a gray-colored brick. The clay is usually tempered in a clay mill. For the sea coal ashes that are mixed with it in cities, they substitute in the country a light sandy earth. In making the paste as lit- tle water should be introduced as possi- ble. In moulding them, which is done in a wooden mould, a clever workman will mould about five thousand in fifteen hours. The kiln in which they are burnt is a large building, about 13 feet long, 10 feet 6 inches wide, and 12 feet high,"" fur- nished with a proper furnace. When otherwise burnt, the clamp, as it is called, is formed of the bricks themselves, gene- rally oblong on the plan, and the founda- tions made with place bricks. Each course of bricks is laid on a layer of breeze or cinders : and flues are formed, filled with coals, breeze, and wood. The burning continues from twenty to thirty days. The size of bricks, when burnt, is 'required in England to be 84 inches long, 2i inches thick, and 4 inches wide. The different varieties of bricks are, malms, which are of a yellowish uniform color and texture ; seconds, not quite so uniform in color and texture as malms ; red and qrey stocks, the former being burnt in kilns, both of a quality rather inferior to seconds ; place bricks or peck- iii'js, sometimes called sandel or samel bricks, which are those furthest from tho fire, and rarely well burnt,' — these should never be used in a building where dura- bility is required ; burrs or clinkers, which are masses of several bricks run together in the clamp or kiln from the violent action of the fire ; fire bricks, of a red color, about 9 inches lon^r, 4i inches broad, and an inch and a half thick, — they are made for use in furnaces to re- sist the action of the fire, and from having been formerly manufactured in the neigh- borhood of Windsor, they are sometimes called Windsor bricks ; paving bricks, made for the purpose their name implies ; compass bricks, are circular on the plan, chiefly used in walling wells and the like ; Dutch clinkers or Flemish bricks, chiefly used in stables ; the Dutch clinkers 6 inches long, 8 inches broad, and 1 inch thi^k. The moulding of bricks in tins country is altogether performed by machinery; one of the latest improvements in which is the invention of J. Z. A. Wagner, of Philadelphia, of which the annexed is an illustration. This machine consists of a large re- volving metal wheel, which has a num- ber of boxes in its periphery, of the form of the brick to be moulded, and which constitute the moulds. In the inside of these moulds are plungers, which recede to allow the clay to come in for mould- ing, but when they come to an endless apron below, a earn acts upon the said plungers, and they push out the bricks, 52 CYCLOPEDIA OF THE USEFUL ARTS. [lIRI delivering them on the endless apron to be carried away. This is an outline of its main working features. A is the me- tal base of the machine ; B is the frame ; is a pully on the shaft of the mould wheel, E. 'The rims of the mould wheel are made of toothed gearing, and gear into wheels, F (one on each side), of a pressure metal roller, which works close up against the face of the mould wheel, excepting that part opposite the moulds, which is a little recessed all around, leav- ing a space between the two ; D is a pul- ley to drive the drum (fig. 2), of the endless apron, J. G is the hopper to re- ceive the prepared clay. This hopper is supported by screw rods or posts, M (one on each side). The hopper has a rim which fits snugly into recesses in the mould wheel, and the pressure roller, F, to keep the clay from getting between the teeth of the wheels. In case, how- ever, that the moulded brick might stick to the end of the plunger, Mr. Wagner has attached a lever on each side, secured to the inside of the frame, B, under the mould wheel and above the apron, and the end of these levers are touched by cams on each side of the mould wheel (one cam for each mould) when the lever immediately pushes the moulded brick from contact with the mould wheel, and it drops on the carrying' apron. The first roller, F, acts like a feeoTroller to pack the moulds with the clay, but leaving a little clay projecting out, and then the second pressure roller, by being placed closer to the face of the moulds, presses the clay solidly into the moulds, and smooths the face of the brick. This is a rotary brick moulding machine. Mr. H. Roberts, of Hyde Park, London, has lately taken out a patent for a new kind of bricks, which are so made that there will be no vertical joints in the wall which may be built of them, as are now made by the headers, where the English and Flemish bonds are used. The bricks are made hollow to be lighter. They are made so that one side of the brick is inclined to the top or the bottom, or the one part projecting beyond the other, so that one brick being' laid the other is to be reversed, so that the pro- jecting sides of the bricks will fit into one another, to bond the work, using only stretchers to avoid vertical joints. Mr. Legros has taken out a patent in London for machines to mould bricks, tiles, and other articles, by which supe- rior produce is obtained at less cost. In one of his inventions Mr. L. lias adapted the principle of motion on a small rail- way to the performance of the several steps of the manufacture. For this pur- pose rails are laid down so as to traverse on the same level all the buildings in which the various parts of the machin- ery are erected. One machine will turn out 66 bricks in a minute, or 40,000 in a day, at an economy of one dollar per thousand. BRIDGE. (Sax. brigge.) In Archi- tecture, a structure for the purpose of connecting the opposite banks of a river, gorge, valley, &c. &c, by means of cer- tain materials, forming a roadway from one side to the other. It may be of stone, brick, iron, timber, suspended chains or ropes ; or the roadway may be formed by means of boats. Long previ- ous to the introduction of bridges con- structed upon geometrical principles, the modes of crossing rivers by throwing the trunks of trees across them, or by sus- pension of ropes, or twisting together the branches of trees from bank to'bank, were so obvious that they must have been resorted to at an early period. The former method, however, could only have been practised over narrow streams, whilst the latter might have been carried to almost any required extent. Mungo Park found this mode employed in Afri- ca ; and in South America rope bridges of bujuco, or thongs made from the hides of oxen, are in use at the present day. Don Antonio de Ulloa tells us, that over some of the rivers of Peru the bujuco bridges are of such dimensions that loaded mules in droves pass over them, and especially on the river Apurimac, forming the liigh road for the trade car- ried on between Lima, Cuzco, and other places to the southward. Though such bridges are the contrivance of man in a less civilized state, they are the only means by which many streams whose currents are deep and rapid can be crossed ; and the stupendous suspension bridges of the present day are but im- provements on the simple scheme of the untutored architect of a savage period and people. The use of the arch in bridging ap- pears to have been first practically ap- plied by the Romans. The Chinese, though using the arch, did not make it strong enough to bear wheel carriages. In Egypt and India it was unknown, or was not applied. There is no trace of the arch in the ancient works of Plienicia and Persia, and even the Greeks have a doubtful claim to it. Over the Tiber the '] CYCLOPEDIA OF THE USEFUL ARTS. 53 ancient Romans built -wooden bridges ; J such was that which joined the Janicu- lum to the Mons Aventinus, and was called the Pons Sublicius, from the word j suhlLcce (stakes) of which it was formed. Without enumerating the bridges of | Koine, some of which are still standing to attest the science of their architects, wc must mention the Pons Narniensis, on the Flaminian way, near Narni, and about sixty miles from Rome. It was built by Augustus, and vestiges of it re- main to the present day, one arch above 150 feet span and 100 feet high being still entire. But of works of art, perhaps the most wonderful ever raised was the bridge built by Trajan over the Danube. It consisted of twenty piers, whose height from their foundation was 150 feet, and 170 feet apart ; its breadth being sixty feet. This stupendous work was demo- lished by Hadrian, the successor of Tra- jan, under the pretence that it might serve as a passage for the barbarians, if they became masters of it ; but some writers have said it was through envy of the fame that attached to its founder. Over the Tagus, in Spain, an ancient Roman bridge, near Alcantara, is still partly standing. It consisted of six arches of eighty feet span, extending al- together 600 feet in length, and some of the arches 200 feet high above the water. Of the temporary bridges of the Romans, the most famous was that of timber thrown by Caesar over the Rhine. From the fall of the Roman Empire to the revival of the arts, the history of bridge architecture is, with the exception of the Moorish works in Spain, of no in- terest. It appears from Gautier, who uses the authority of Mag. Agricola of Aix, that when the arts beganto revive in Europe, an order was founded by St. Benezet, under the title of Brethren of the Bridge ; and that under them was begun, in 1176, the bridge at Avignon, consisting of eighteen arches and about 3000 feet in length. During the conten- tions of the popes, in 1385, some of its arches were destroyed, and in 1602 three others fell. In 1670 the ice destroyed all but the third pier, which, with the Cha- pel of St. Nicholas upon it, still remains. In 1354 a bridge of three arches was con- structed at Verona, the roadway sloping from the city ; the largest of its arclies, which are segmental, is 160 feet span ; but a still larger arch was built at Vielle- Brioude in France, over the Allier, in 1454, of nearly 184 feet span, which is the largest stone arch upon record. Among the most celebrated bridges of Italy, is that of the Rialto at Venice, whose span is 98i feet. It was begun in 1588, and finished in 1591, from the designs of Antonio dal Ponte, though by most au- thors absurdly attributecf to M. A. Buo- narroti. In this city alone there are no less than 339 bridges; but they are mostly of small spans. We must not omit in this place the bridge of Delia Santissima Trinita, at Florence, by Am- manati, which, as Milizia truly observes, has not been surpassed since the revival of architecture. It is of three arches, the middle one of 96 and the two side ones 86 feet span, the width of the piers being 26 feet 9 inches ; the breadth of the car- riage and footways between the parapets is 33 feet. It has been usual for writers to call the form of the arches of this bridge cycloidal ; but from our own mea- surements and most particular investiga- tion, we can assert that they are not of that form. They are very slightly pointed, after the fashion of what is called the Tu- dor arch of this country ; the point at the summit, which is extremely obtuse, being hidden by the ram's head sculp- tured on the key-straes. During the two last centuries, the French have ad- vanced their bridge architecture to very great perfection ; but more particularly in the latter part of the last century, in which appeared Perronet, the father of the modern system of the art, whose elegant designs have not since been im- proved upon, either in France or in any other country. His is the beautiful bridge of Neuilly over the Seine. It con- sists of five arches, each about 128 feet span and 32 feet rise : it was finished in 1774, and remains a splendid monument of the powers of its architect. Some of the more modern specimens of their bridges do great honor to the French school, in which beauty of form is united with sound engineering. In England, the progress of bridge ar- chitecture has kept pace with that of the Continent; and if her bridges cannot boast the elegance in design of her lively neighbors, they are fully equal to them in boldness of conception and exe- cution of the work. Indeed, if the de- signs of the late Messrs. Telford and Rennie had been equal to their engin- eering skill, no country in the world would have been able to compete with what she would have been able to exhibit. And here must not be forgotten the bridge over the river Taaf, near Llan- trissart, in Glamorganshire, celebrated 54 CYCLOPEDIA OF THE USEFUL ARTS. b for its great span ; the work of William ; Edwards, a country mason, in 1765. The chord line is 140 feet, and the versed sine 35 feet. Of timber bridges the boldest and most ingeniously constructed was that at SchafFhausen, in Switzerland, destroyed by the French in 1799. It was designed and executed by Grubenman, a common carpenter, in 1758. The total length of the bridge was 364 feet, but it was re- lieved by a pier in the middle of the river. This country has some of the grandest specimens of timber bridges in the world. The Colossal bridge over the Schuylkill, at Philadelphia (since burnt) was 340 feet span, with a rise of only 20 feet, and the thickness of the timber at the vertex only 7 feet. That at Piscataqua, over the river of same name, has a span of 250 feet, and a rise of 27, built in 1794 by Palmer. The bridge of the Kennebec and Port- land Railroad, over the Androscoggin River at Topsham, is one of the largest and most substantial structures of the kind in the United States. It is a deck bridge, the upright posts and rods being about 18 feet from the lower to the upper deck. One of them reaching from centre to cen- tre of the piers, is one hundred and eighty feet. The piers are of granite laid in the most durable manner. The whole length of the bridge is over seven hundred feet. The track of the road along the upper deck will be about fifty feet above tide water. The large lower and upright timbers, and the iron work, together with the X work between decks, give the bridge an appearance of strength and solidity sufficient for any weight. Suspension bridges derive their chief value from the fact of their independence of the bed of the river. Hence they may be used where it is impossible from the force of the current or the altitude of the banks to erect centreing for a stone bridge. They are built with ease and expedition, and are economical. The celebrated suspension bridsre over the Menai Strait, by the late Mr. Telford, is almost the giant of its species, and renders unnecessary any enumeration of others. It consists of one opening of 560 feet between the points of suspen- sion, the height between high water and the under side of the roadway being 100 feet. The platform is 30 feet in breadth. The whole is suspended from four lines of strong iron cables by perpendicular rods 5 feet apart. On the tops of the pil- lars the cables pass over iron rollers, and are fixed under ground to iron frames, which are retained in their places by ma- sonry. The weight of the whole bridge between the points of suspension is 489 tons. In suspension bridges it has been found that the most trying circumstances under which they can be placed, as af- fecting the stability of their equilibrium, is the heavy and measured tread of a long line of infantry, whose feet drop at the same instant of time. The wire suspension bridge at Wheel- ing, Va., over the Ohio, has been com- pleted by Charles Ellett, Jr., Architect. The flooring is supported by 12 cables of iron, each cable 4 inches in diameter, composed of 550 strands of No. 10 wire, and is 1,380 feet long ; and from centre to centre of the abutments, the flooring is 1,010 feet long, 24 feet wide, with two foot-ways, each 3£ feet, and an interme- diate carriage-way 17 feet wide. The cables rest on iron rollers, placed on the summits of the towers, the movements of which will relieve the towers of the strain, and are anchored into the heavy masonry of the wing walls at each end of the bridge. The length of the wood- work which rests on the cables is 960 feet ; its weight 546 lbs. per lineal foot, or 524,160 pounds of 262 tons in the whole. The weight of each lineal foot of the 12 cables, composed of 6,600 strands, is 330 pounds, making, with the weight of timber, bolts, castings, sus- penders, &c, 920 lbs. per lineal foot, or 441 tons as the permanent weight of the bridge itself. Above its own weight the bridge is constructed to support the greatest transitory weight that is ever likely to be, or we may say, can possibly be brought upon it, such as two columns of teams, and the sides loaded with men, so as to weigh, jointly, 297 tons, or the average weight of 4,000 men, and the strength of the bridge is calculated to support three times t'Ae amount of ten- sion that ever can be brought to bear upon it. This bridge will no doubt last long as a monument of American skill and enterprise. The wire suspension bridge erected across the Cumberland River at Nash- ville has the following measurements. The length of the bridge is 656 feet, and the whole lencrth of the bridge and em- bankment 1,956 feet. Width of super- structure, 28 feet ; carriage way, 20 ; two footways, each 4 feet. The bridge will span the Cumberland opposite the south- east corner of the public square of tho BRl] CYCLOPEDIA OF THE USEFUL ARTS. 55 city, at an elevation of 110 feet above low water, over the main steamboat channel. Base of pier, 60 by 20 feet, solid mason work ; anchorage, 60 by 56 on the north side ; solid limestone clitf on the south side. There- are to be 16 cables, each cable composed of 200 strands of No. 10 wire, each wire tested to bear 1500 lbs. The whole work is calculated to bear a weight of 4,800,000 lbs., or 2400 tons. The cost of this mag- nificent structure is estimated at but $100,000, though the Wheeling Bridge, 1010 feet long, "cost $225,000. The wire suspension bridge over the Niagara River is the largest of its kind in the world. It is built over the river H miles below the Falls, and directly over the rapids, which commence at this point. It is nearly 800 feet long, and 260 feet above the river. Towers 80 feet high are erected on the bank each side, and at a point 100 feet in their rear the immense wire cables which sustain the . bridge are firmly secured. These strands pass from their fastenings immediately over the top of the tower upon either clitf ; they pass thence across the chasm, and then over the top of the tower on the opposite cliff, in the rear of which the ends are fastened in the rock. It is 10 feet wide, and a temporary path of wire and slats of wood has been constructed on each side. The flooring is composed of light planks resting upon their scant- lings, to which the wires are fastened. Mr. Ellett is the architect. Mr. Dredge, of Bath, England, builds his suspension bridge on a very improved plan, hi which bars connected the road- way to the catenary chain, are not verti- cal, as in other suspension bridges, but are made by him to pass obliquely from the tower toward the centre, as shown >^^N^^^^ in the cut, where C represents the cen- tre, B the tower, and E the platform ; g shows the point to which dependence on the tower extends : this tends to strength- en the bridge considerably. The chains in his bridge are made of great thick- ness at the points of suspension, and taper off to the middle of the bridge, where the strain is least. Mr. Dredge has erected in England, Ireland, and Scotland, many bridges on this plan, which are models of "cheapness, beauty, and durability. This represents a portion of the bridge at Ballock Ferry, Loch Lomond, Scotland, erected on that principle. Mr. Eemington has planned a bridge which appears to be the simplest as yet designed, and is remarkably cheap in construction, according to the length of span. Models of his' bridge have been exhibited in New- York and the other cities of the Union, as well as in London. That exhibited in New-York was 160 feet in the clear, composed of four stringers of a little over two inches square at the abutments, and tapering to about an inch square at the centre. It is of the form of an inverted arch. The stringers are made 56 CYCLOPEDIA OF THE USEFUL ARTS. [bri of several pieces of white pine joined to- gether by a scarfe joint ; their ends, when they are'joined, being bevelled at a very slight angle, and the bevelled parts lapped over each other, and attached with glue, so that when united, each Btringer ap- pears to be a continuous and single piece. These jointings are so arranged as that only one of them ever occurs in the same cross section of the bridge, and they are neither bolted nor clamped, but depend entirely upon the glue for their adhesion. Each of these stringers have about nine feet bearing on the abutments or suspen- sion piers, to which they are firmly at- tached by iron bolts. At New Orleans, Mr. E. exhibited a model, extending " across a space of nine- ty-six feet, and eievated some ten feet from the floor. Its appearance is so fragile, that few men, judging from this alone, would willingly trust themselves upon it, yet plenty walk over it and stand on it. It has four longitudinal supporters, each less than one inch square at the centre, but increasing gradually in size, until at the ends or points fastening, they are 2i inches square. The bridge has one caten- ary and two parabolic curves, by which strength and beauty are both secured. The flooring is attached diagonally, and is made to sustain a portion of the strain. The deflexion of the supporters is 22* inches. It is capable of bearing the pres- sure of 7 tons ; while each of the support- ers, occupying their place in the bridge, will sustain a weight greater than the ab- solute strength of the timber and the di- rect cohesion of its fibres." Upon this pin n, Mr. Remington has erected one in Montgomery, Alabama, that was opened for travel last year. The span is 436 feet, and the track is 10 feet wide. It is without hand-rails, and is described as appearing at a dis- tance like a slight ribbon, or shaving of wood, flung across a ravine — apparently too frail to bear the pressure ot a bird, but proved to be capable of bearing al- most any amount of weight that can be placed upon it. Hundreds of people crossed it on the day it was opened, who were completely convinced of its strength. Its strength is due to the fact that the fibres of the stringers are not subject to any transverse strain, the only action upon them being exerted in the direction ot the length of the fibre. Each end of one of its stringers is firmly bolted down to an abutment, and any weight being laid upon them between the abutments, causes just the same tension of the fibres as in the case of an attempt to break a walking-stick by drawing it apart, while holding the ends. Wiebiking states that a rise of 1 in 24 is a convenient ascent for a bridge. In timber bridges the settlement is 1 in 72 : that is, if a timber bridge of 144 feet span rise one foot in the middle when first framed, it will settle so as to be horizon- tal ; so that when it is intended for the bridge to have an ascent of 1 in 24 when finished, it must be framed so as to have a rise of 1 in 18 : for -^ = 2V + ^. The Britannia Tubular Bridge is one of the most remarkable structures in the world, the design of the celebrated Ar- chitect, Sir E. Stephenson. This bridge is on the line of the Chester and Holyhead Railway, crossing the Menai Straits, within sight of Telford's Chain Suspen- sion Bridge. It is made of cast iron of a tubular form, in the tube of which the railway passes. Four of these span the Strait, and are supported by piles of ma- sonry; that on the Anglesey side is 143 feet 6 inches high, and from the front to the end of the wing walls is 173 feet. These wing walls terminate in pedestals, on which repose colossal lions of Egyptian character. The Anglesey pier is 196 feet high, 55 feet wide, and 32 feet long. In the middle of the Strait is the Britannia Eock, from which the bridge derives its name ; on this the Britannia pier is raised. It is equally distant from the Anglesey and Caernar- von piers, being 460 feet in the clear from each, and sustains the four ends_ of the four long tubes, which span the distance from shore to shore. There are two pair of short and two *" of long tubes, the lengths of these pairs being 250 feet and 470 respectively. Tho Egyptian lions are 25 feet 6 inches long, 12 feet BRO] CYCLOPEDIA OF THE USEFUL ARTS. 57 6 inches high, 8 feet wide, and weigh 80 tons. Two thousand cubic feet of stone were required for each lion. The total quantity of stone in the bridge is 1,400,000 cubic feet. The weight of malleable iron in the tubes is 10,000 tons, of cast iron, 1,400 tons. The whole length of the en- tire bridge, measuring from the extreme front of the wing walis, is 1,833 feet, and its greatest elevation at Britannia pier, 240 feet above low-water mark. The total cost of the structure is £601,865. The following observations refer to the arrangement of parts in ordinary bridg- ing : In the building of bridges, where piers are required in the stream for the support of the arches, it is important to place them as nearly as possible at right angles to the stream or current ; and the piers should be made convex towards the stream, for their better resistance to floods. The position of a bridge, more- over, should not be in a narrow part, nor one liable to swell with tides or floods, inasmuch as the contraction of the water- way increases the depth and velocity of the current, and may thus endanger the navigation as well as the bridge itself. It is usual to construct bridges with an odd number of arches, and this on several ac- counts : among which arc, that the stream being usually most powerful in the mid- dle, an egress through that part is best provided for by having a central arch ; and again, if the bridge be not perfectly horizontal, symmetry is gained by rising from the sides to the centre, and the whole roadway may be made one con- tinued curve. When a bridge is equally high throughout, much saving of cen- tring is made, because the arches being all equal, two sets of centres will be sufficient. If, however, the bridge be higher in the middle than at the extremities, the arches on each side the centre one must dimin- ish similarly, so as to be respectively symmetrical; and by this arrangement beauty is gained, and the centring for one side equally suits the other. It is de- sirable to construct a bridge with as few arches as circumstances will allow, that there may be a free passage for the water, aa well as for the vessels tha. have to pass up and down, not to mention the saving ot materials and labor where there are fewer piers and centres. When a single arch can be compassed, no more should be permitted. The piers should be of sufficient solidity to resist the thrust or push of the arch, independent of other arches, so that the centring of an arch 3* may be struck without danger of over- turning the pier left naked ; and the piers should' also be spread as much as possible on the bases, and diminish gradually up- wards from their foundations. The me- thod of laying the foundations in a river is now usually by means of coffer-dams, which are large inclosures, made by pil- ing round the space to be occupied by the pier, so as to render it water-tight, and then pumping out the water, and keeping the space dry till the pier is built up to the ordinary level of the water ; but if the ground about be loose, this method can- not be well practised, and recourse is had to caissons, which are a species of flat- bottomed boat, in which the pier is built up to a certain height, and then sunk over the place where it is intended to re- main, the bed of the river being dredged out to receive it, or piles driven on which it may lodge when the sides of the chest or caisson are knocked away. In con- structing the centres, great care must bo taken to make them incapable of bending or swerving while the arch is being turned, otherwise the form of the arch will be crippled. BRIMSTONE. (See Sulphur.) BRINE. (See Salt.) BRITISH GUM. When starch is ex- posed to a temperature of about 600°, it Becomes of a brownish color, and so far altered in its chemical character as no longer to form a blue color with iodine : it is also soluble in cold water. In this state it is used, under the above name, by calico printers. BROMINE. (Gr. /fyw/jos, a strong odor.) An undecompounded substance, discovered in 1826 by M. Balard of Mont- pelier. In its general chemical habitudes it much resembles chlorine and iodine, and is generally associated with them. It exists, but in very minute quantities, in sea-water, and in the ashes of marine plants. It is usually extracted from bit- tern by the agency of chlorine. At com- mon temperatures it is a very dark red- dish liquid, of a powerful and suffocating odor, and emitting red vapor. Its spe- cific gravity is about 3. It boils at 116°, and congeals at 4°. The density of its vapor is 5*5 ; 100 cubic inches at mean temperature and pressure weighing 167*25 grains. It is an electro-negative ; it lias bleaching powers, and it is very poison- ous. Its equivalent number is about 78 ; it combines with hydrogen to form hydro- bromw acid gas, 100 cubic inches of which weigh 84*7 grains. With oxygen it forms the bramic acid. Its combinations are 58 CYCLOPEDIA OF THE USEFUL ARTS. termed bromides ; they have not hitherto heen applied to any use, hut some of them are probably possessed of powerful medical qualities. In this country bromine is obtained from the mother waters of the Salt Springs in the Valley of the Mississippi. Its chief use is in daguerreotyping, as an accelerator, to coat the silver plate, and aid the iodine in producing the image in a shorter period. BRONZE. A material used for casting statues, groups, &c, in a mould similar in principle to that wherefrom all plaster casts are produced. From the extraordi- nary dimensions which involve the chief differences between the operations of cast- ing in brass and plaster, much intelligence and care on the part of the sculptor is necessary to produce the fac-simile of the work on which his labor has been expen- ded. The material employed for the pur- pose is a compound chiefly consisting of copper^ tin, and other metals. The pro- cess ot procuring the cast depends on circumstances requiring much nice ar- rangement. Bronze is a compound metal, consisting of copper and tin, to which sometimes a little zinc and lead are added. The alloy is much harder than copper, and was cm- ployed by the ancients to make swords, hatchets, &c, before the method of ma- king iron was understood. The art of casting bronze statues may be traced to the most remote antiquity: but it was first brought to a certain degree of re- finement by Theodorus and Roocus of Samoa about 700 years before the Chris- tian era, to whom the invention of model- ling is ascribed by Pliny. The ancients were well aware, that by combining cop- per with tin a more fusible metal was obtained, that the process of easting was therefore rendered easier, and that the statue was harder and more durable; and yet they frequently made them of cop- per nearly pure, because they possessed no means of determining the proportions of their alloy, and because by their mode of managing the fire, the copper became refined in the course of melting, as has happened to many founders in our own days. It Avas during the reign of Alex- ander that bronze statuary received its greatest extension, when the celebrated artists Lysippus succeeded by new pro- cesses of moulding and melting to multi- ply groups of statues to such a degree that Pliny called them the mob of Alex- ander. Soon afterwards enormous bronze colossuses were made to the height of towers, of which the isle of Rhodes pos- sessed no less than one hundred. The Roman consul Mutianus found 3,000 bronze statues at Athens, 3,000 at Rhodes, as many at Olympia and at Del- phi, although a great number had been previously carried off from the last town. In forming such statues the alloy should be capable of flowing readily into all the parts of the mould, however minute ; it should be hard, in order to resist acci- dental blows, be proof against the influ- ence of the weather, and be of such a na- ture as to acquire that greenish oxidized coat upon the surface which is so much admired in the antique bronze. The chemical composition of the bronze alloy is a matter therefore of the first moment. The brothers Keller, celebrated founders in the time of Louis the Fourteenth, whose chefs cPceuvre are well known, di- rected their attention towards this point, to which too little importance is attached at the present day. The statue of Desaix, in the Place Vendome in Paris, is a noted specimen of most defective workman- ship from mismanagement of the alloy3 of which it is composed. On analyzing separately specimens ta- ken from the bas-reliefs of the pedestal of this column, from the shaft, and from the capital, it was found that the first contained only 6 per cent, of the alloy, and 94 of copper, the second much less, and the third only 0-21. It was there- fore obvious that the founder, unskilful in the melting of bronze, had gone on progressively refining his alloy by the oxidizement of the tin, till he had ex- hausted the copper, and that he had then worked up the scoria in the upper part of the column. The moulding ot the seve- ral bas-reliefs was so ill-executed that the chisellers employed to repair the faults, removed no less than 70 tons of bronze, which was given them, besides 300,000 francs for their work. The alloy most proper for bronze med- als, which are to be afterwards struck, is composed of from 8 to 12 parts of tin, and from 92 to 88 of copper; to which if 2 or 3 parts in the hundred of zinc be added, they •will make it assume a finer bronze tint. The medal should be sub- jected to three or four successive stamps of the press, and be softened between each blow by being heated and plunged in cold water. Bell-Metal. The bronze of bells, or bell metal, is composed in 100 parts of 78 cop- per and22 tin. This alloy has a fine com- pact grain ; is very fusible and sonorous. BRO] CYCLOPEDIA OF THE USEFUL ARTS. 59 The other metals sometimes added are ra- ther prejudicial, and merely increase the profit of the founders. Some of the Eng- lish bells consist of 80 copper, 10-1 tin, 5-6 zinc, and 4-3 lead; the latter metal, when in such large quantity, is apt to cause in- sulated drops, hurtful to the uniformity of the alloy. A little phosphorus is some- times added with advantage. The Chinese gongs are composed of 78 parts copper, and 22 parts tin. This alloy when newly cast is as brittle as glass, but by being plunged at a cherry-red heat into cold water, and confined between two discs of iron to keep it in shape, it becomes tough and malleable. The Chi- nese cymbals consist of 80 parts copper and 20 parts tin. Common Metal consists of about 90 or 91 copper, and 9 or 10 of tin. Never less than 8 or more than 11 parts of tin in the 100 should be employed. Speculum Metal. One part of tin and two parts (or more exactly 100 parts tin and 215 parts copper) form the ordinary speculum metal of reflecting telescopes, which is of all the alloys the whitest, the most brilliant, the hardest, and the most brittle. The alloy of 1 part tin and 10 of copper, is the strongest of the whole series. The bronze founder ought to melt his metals rapidly, in order to prevent the loss of tin, zinc, and lead, by their oxi- dizement. Keverberatory furnaces have been long used for this operation, the best being of an elliptical form. The fur- naces with dome tops are employed by bell founders, because their alloy being more fusible, they do not require so in- tense a heat ; but they also would find an advantage in using a more rapid mode of fusion. The surface of the melting met- als should be covered with- small charcoal or coke, and when the zinc is added it should be dexterously thrust to the bot- tom of the melted copper. Immediate! y after stirring the melted mass so as to in- corporate the ingredients, it should be poured out into the moulds. In general the metals most easily altered by the fire, as the tin, should be put in last. The coating should be as quick as possible in the moulds to prevent the metals separa- ting from each other in the order of their destiny, as they are very apt to do so. The addition of a little iron in the form of tin-plate, to bronze is reckoned to be ad- vantageous. Bronzing (of Objects in Imitation, of Metallic Bronze), blaster of Paris, paper, wood, and pasteboard, may be made to resemble pretty closely the appearance of articles of real bronze, modern or an- tique. The simplest way of giving a brilliant aspect ot this kind is with a var- nish made of the waste gold leaf of the beater, ground up on a porphyry slab with honey or gum-water. A coat of drying linseed-oil should be first ap- plied, and then the metallic powder put on with a linen dossil. Mosaic gold ? ground up with six parts of bone-ashes ms been used in the same way. When it is to be put on paper, it should be ground up alone with white of eggs or spirit varnish, applied with a brusn, and burnished when dry. When a plate of iron is plunged into a hot solution of sul- phate of copper, it throws down fine scales of copper, which being repeatedly washed with water, and ground along with six times its weight of bone-ashes, forms a tolerable bronze. Powdered and sifted tin may be mixed with a clear solution of isinglass, applied with a brush, and burnished or not, ac- cording as a bright or dead surface is de- sired. ' Gypsum casts are commonly bron- zed by rubbing brilliant black-lead, gra- phite, upon them with a cloth or brush. Keal bronze long exposed to the air gets covered with a thin film of carbonate of copper, called by virtuosi antique cerugo (patine antique, Fr). This maybe imita- ted in a certain degree by several appli- cations skilfully made. The new bronze being turned or filed into a bright surface, and rubbed over with dilute acquafortis by a linen rag or brush, will become at first grayish, and afterwards take a green- ish blue" tint; or we may pass repeatedly over the surface a liquor composed of 1 part sal ammoniac, three parts of carbo- nate of potash, and 6 or sea salt, dis- solved in 12 parts of boiling water, to which 8 parts of nitrate of copper are to be added; the tint thereby produced is at first unequal and crude, but it becomes more uniform and softer by time. A fine green-blue bronze may be obtained with very strong water of ammonia alone, rub- bing it at intervals several times upon the metal. The base of most of the secret compo- sitions for giving the antique appearance is vinegar with sal ammoniac. Skilful workmen use a solution of 2 ounces of that salt in an English quart of French vinegar. Another compound which gives good results is made with an ounce of sal ammoniac, and a quarter of an ounce I of salt of sorrel (binoxalate of potash), dis- | solved in vinegar. One eminent Parisian I sculptor makes use of a mixture of half an 60 CYCLOPEDIA OF THE USEFUL ARTS. [but ounce of sal ammoniac, half an ounce of salt, an ounce of spirits of hartshorn, and an English quart of vinegar. A good re- Bult will also be obtained by adding half an ounce of sal ammoniac, instead of the spirits of hartshorn. The piece of metal being well cleaned, is to be rubbed with one of these solutions, and then dried by friction with a fresh brush. If the hue be found too pale at the end of two or three days, the operation may be repeated. It is found to be more advantageous to operate in the sunshine than in the shade. In bronzing plaster figures a cement may be used or not ; if used, the bronz- ing will be more durable, the powders are mixed with strong gum water or isin- glass, and laid on with a pencil. The sub- ject may be covered with gold-size dilu- ted with turpentine, and when nearly dry rubbed with a piece of soft leather. Coins of copper and medals may be bronzed thus : — Dissolve in vinegar 2 parts of verdigris and 1 part sal ammoniac. Boil, shim, and dilute the solution with water until it ceases to let fall a white precipitate. The solution is then boiled and poured upon the objects to be bron- zed, previously made perfectly clean and free from grease, the articles are then washed and dried. A deposit of brass or bronze may be thrown on objects by the electrotype pro- cess, by employing a solution of 500 parts carbonate of potash, 20 parts chloride of copper, 40 parts sulphate zinc, 250 parts nitrate of ammonia. For bronzing, a salt of tin is substitu- ted for the zinc salt. By this solution, iron, cast iron steel, lead, zinc, tin or their alloys are easily, coated with brass or bronze, by placing the article in contact with the negative pole of a Bunsen bat- tery, and a plate of bronze or brass used as a positive pole. BRUNSWICK GREEN. A pigment obtained by exposing metallic copper to the action of muriate of ammonia. It is a compound of chloride and oxide of cop- per. It is also generated by the action of sea water upon copper, as 'in the green matter which incrusts the copper sheath- ing of ships. BUDE LIGHT. (See Gas). BURETTE. An instrument occasion- ally used in the chemical laboratory, and in the assay office, for the purpose of dividing a given portion of any liquid into 100 or 1000 equal parts. BUOYS. Vessels formed of wood, cork, or some light substance, moored or anchored so as to float over a certain spot, in order to indicate the situation of a shoal or sand-bank, and mark out the course a ship is to follow. When used for this purpose, buoys are usually close vessels in the form of a cone, of large dimensions, in order that they may be seen from a distance ; and generally painted of some particular color, in order that they may be more readily distin- guished from one another. Private buoys are used for the purpose of indicating the situation of ships' anchors (to which they are fastened by a rope), in order that the ship may be prevented from running foid of the anchor, and that the anchor and cable may be recovered when the latter happens to be broken, or has been cut. BUTTER. The oil or fat of milk. The light matters suspended in milk separate in the form of cream, and this cream by churning becomes separated into butter and buttermilk. During this process the temperature of the cream is slightly raised, a little oxygen absorbed, and the acid produced : this change is not, how- ever, essential to the separation of the butter which takes place when air is ex- cluded and depends upon tho rupture of the oil globules. It is naturally of a yel- low color, and is deepened when cows are fed in rich pastures ; and carrot juice and arnotto are often added to heighten the tint. The Tartars and French pre- serve butter by melting it in a water bath at a temperature of 176°, whereby the al- buminous and curdy matters, which are putrescible, are coagulated. If it be de- canted while liquid, strained and lightly salted, it may be kept fresh for years. In November, 1849, a patent was grant- ed to Mr. Elias H. Merryman, of Spring- field, Illinois, for improvements in But- ter-working Machines. His claim is the use of two or more rollers, with adjusta- ble scrapers, held in contact with the rollers by^ springs, or other devices, operating in a vat of running water, to wash butter and separate the broken capsules, cheesy matter, buttermilk, and other impurities, by dissolving thost that are soluble in water, and washing away those that are not soluble, sub stantially as described — the water bcina let into the vat from a cistern placed above the level of the vat, and escaping at the spout, on a level with the journals of the rollers. According to the census return of 1845, the quantity of butter mode in the State of New-York, was 79,501,770 pounds; which at twelve and a half cents a pound, but] CYCLOPEDIA OF THE USEFUL ARTS. 61 would amount to $9,937,716. American butter, if well prepared, would find a leady sale in the English market. The following, taken from the Patent- Office Reports of 1847, is the plan, in substance, pursued by Philip Physick of Germantown, who has taken the pre- mium of the Philadelphia Agricultural Society for two or three years succes- sively. In the first place, great atten- tion is paid to cleanliness : the tin pans are put into a boiler and boiled for an hour, then scoured with white silver- sand and pure hard soap and rinsed in pure water, and then put away for use. The udders of the cows are washed for three days, and wiped with a clean towel. The milk is also drawn in tin pails, which have been cleansed in the same manner as the pans ; it is strained through a per- fectly clean muslin strainer, and put into the spring-house till four milkings are collected ; then *he whole milk and cream are thrown into a common barrel-churn, which has been rinsed with boiling wa- ter with a quarter of a peck of hickory ashes and live coals stirred about in it by turning the crank, and then thrown out and the churn rinsed several times with boiling water ; the cows' udders are then washed and milked, and this milk strained and poured warm into the churn — the churning is done slowly, as the tenacity and hardness of the butter depends on this; it should take three hours. When the butter has come it is collected by a clean wooden ladle and laid on a clean linen cloth as flat as possible, not more than two inches thick. Next take a clean coarse cotton bag, which will hold a half peck or more, and fill it with ice, and with a mallet mash it down flat about four inches thick ; place the cloth on it till it is hard ; then on a clean white marble slab add finely pulverized salt to suit the taste, and work out the butter- milk with a wooden spoon and ladle; spread the butter flat again, and again sopping up the buttermilk with the linen cloth, which must however, be done very slowly. When it is free from all the but- termilk, make it up into pounds or half pounds. BUTTONS. .The materials of which buttons are made are very various, and this variety gives rise to a subdivision somewhat akin to that which marks many other departments of manufac- tures. Besides the well known gilt but- tons, plain and figured, there are plated, silk, florentine, and other covered but- tons—pearl, horn, shell, bone, wood, glass, and porcelain buttons, and proba- bly many others. The two latter-named varieties are made at the works where cither glass or porcelain articles are ma- nufactured ; but the rest are produced chiefly at Birmingham, the different ma- nufacturers producing their respective varieties. The number of females to which the manufacture gives employment is very large, and the nimbleness with which most of the processes are carried on by them is truly remarkable. We may first select a common gilt button, and follow it through its pro- cesses of manufacture. The'material of which these are made is sheet copper, or a mixed metal of which copper is a compo- nent part. From these sheets, "blanks" or circular pieces are cut out, a trifling degree larger than the intended size of the button. This is done by means of small presses, of which there is a large number in every factory, devoted to one or other of the different kinds of button. The press for cutting the "blanks" ha3 a circular ' cutter or punch, worked by a lever or handle ; and a female holding a sheet of metal in one hand and the lever of the press in the other, cuts the blanks with surprising rapidity, shifting the copper after each cut in order to expose a new part of the surface, and causing the punch to descend after each adjust- ment. Whatever be the form or nature of the button, this preliminary punching of the blank is almost always observed; but beyond this, many varieties occur. The common flat gilt buttons for coats are flat on both sides, and consist of but one thickness of metal, which is punched out in the form of a blank. But there are many kinds of livery buttons, small glo- bular buttons for boys' dresses, and other kinds, which are convex on the outer surface ; and this convexity has to be given to them after the blawk is cut. Again, of those which are convex, some are of one thickness only, presenting at the back the concave side of the same piece of metal which is convex in front ; while others (called "shell" buttons) are hollow, and made of two pieces of metal — one for the front and the other for the back. In this latter case, there are two blanks or circular pieces punched out separately ; one called the " shell," and the other the " bottom." The shell, as well as convex buttons generally, is pressed to a convex shape by a machine similar in principle to the punching 62 CYCLOPEDIA OF THE USEFUL ARTS. [but press, but having a curved polished sur- face to act upon the metal, instead of a punch. One female will stamp twelve gross in an hour, or nearly thirty per minute. The rawness of the edge is removed by turning each button slightly in a lathe, to give regularity of surface. To bring both parts of the shell button together, they are pressed in a die and punch, so peculiarly adjusted that the edge of the shell becomes bent over and lapped down upon the bottom, securing the two together in a way at once firm and neat without the employment of any solder, rivet, or other mode of fastening. The device, or letters on buttons, is given by steel dies, and a stamping press simi- lar in construction with the wood-cut. The shank of a button is in some re- spects more remarkable even than the blank, partly on account of its manufac- turing arrangements — strange as they will appear to most persons. It might well be supposed that in large factories where five or six hundred persons are employed in making buttons, the pro- duction of the bit of twisted wire which forms the shank, would at least form one of the departments. Yet this is not the case : the button-makers are not shank- makers ; the latter branch being carried on by a \> holly distinct class of manufac- turers, of whom there are three or four in Birmingham. The reason seems to be, that the machinery employed is so costly and intricate, and the value of each shank when made so extrcmelv minute, that nothing less than making for a great many button-makers could pay for the maintenance of a regular establishment ; so that the button-makers, as a body, can buy the shanks cheaper than make them, Thus does the commerce of manufac- tures adjust and regulate itself, when left to seek its natural channels. The shanks are made of brass wire, and vary from eight to forty gross per pound weight. In the beautiful machine now employed for their manufacture, a coil of wire is so placed that one end gradually advances towards a point where a pair of shears cut off a short piece ; a stud then presses against the middle of the piece, and forces it between the two jaws of a kind of vice in a staple-like form ; the jaws then compress it so as to form the eye of the shank ; a little hammer next strikes the end to make it level ; and lastly, an- other movement enables the shank to drop into a box quite ready for use. Some English firms manufacture two hundred million shanks per year. The blanks or body of the buttons be- ing ready to receive the shank, they are handed over to workwomen who 'con- nect them. The button is laid flat, bot- tom upwards ; the woman places the shank in the proper position with a piece of bent iron, like a spring clasp ; she presses the shank tightly to the bottom, touching then the foot of the shank where it joins the bottom, with a little solder. When some hundreds are so adjusted, the whole are placed on an iron plate and ex- posed on an oven to a heat sufficient to melt the solder and unite the shank firmly to the button. To cleanse the buttons, they arc dipped twice in nitric acid, and let drain. To be silvered they are put in an earthen pan, containing a nearly dry mixture of silver, common salt, cream tartar, and some other ingredients, and well stirred up for a minute or two. This gives them a sil- ver white color. The gilding is a more elaborate process, in some cases the gilding is only applied to the face, 01 top gilding ; in others, to the whole sur- face, called all-over gilding. For the lat- ter purpose the buttons are first pickled in dilute sulphuric acid, and then im- mersed in a solution of nitrate of mer- cury, which leaves a thin mercurial de- posit over the whole surface. For top- gilding, the tops are laid on a board, and washed over with a brush. Five grains ot gold will cover 144 one-inch buttons, and sometimes even half of that quantity is made to serve. A few grains of gold leaf dissolved in ten times its weight of mer- cury, is the amalgam used in gilding. This is gently heated in an iron ladle, cab] CYCLOPEDIA OF THE USEFUL ARTS. 63 and stirred with an iron rod; then poured in cold water, and finally strained through wash leather, to remove the su- Serfluous mercury. This mass is then issolved in dilute nitric acid, and the buttons either dipped in or washed with it. The next process is to drive off the mercury by heat. This is done by plac- ing the buttons in a wire cage, within a furnace, framed to carry up and condense the mercurial vapors, and passing them into a vessel of water, to polish them. They are now removed to the lathe, and carefully burnished with bloodstone. The ilorentine and silk buttons have now nearly superseded the gilt button manufacture. These contain each two circular bits of iron, a piece of thick pasteboard, another of canvas, and the outer silk or florentine covering. All these are cut out by stamping presses. The sheet of iron, of paper, of canvas, or of Ilorentine, is shifted gradually till it is nearly all cut up into little discs'. The mode in which all the pieces are fixed together is very remarkable. There is no glue or cement, no riveting, no sew- ing, plaiting, twisting, or other modes of fastening ; 'all being adjusted and fixed simply by stamping or pressure. With- in tne outer cloth cover is an iron casing called the ' shell,' within this is a disc of Eaper, then a disc of cloth, and at the ack of all a disc of iron having a hole in the centre, through which some of the canvas is forced as a means for sewing the button on the coat or garment. All these are placed, in their proper order, in a kind of die or cell, and a descending punch, worked by a press, first fixes the cover to the shell, and then these two to the other three bits, curling up the edges of the two discs of iron in such a peculiar way as to enable them to clasp all the five bits firmly, and to hide all raggedness and imperfections of edge. The internal mechanism of the presses, to effect this, is beautiful and ingenious. Some of the silk buttons have the iron ' shell ' blacked with japan before being used ; some are convex, while others are flat ; some have a woven device in the centre of each, obtained by having the silk or other material woven expressly for the purpose, and by having each lit- tle disc marked out carefully by a separate apparatus to insure accurate punching ; some have braided edges, produced by an additional number of pieces, and an addi- tional complication of the stamping pro- cess ; and, indeed, there are numerous mo- difications of the covered button which it would be difficult to particularize here ; but the punching out of separate little discs, and the fixing of these by stamping or pressure, are the prevailing features of the manufacture among all. White linen buttons, of a remarkably neat appearance, are among the novelties of recent times. They consist of a tin or white metal ring, over which a disc of linen is stretched like the parchment of a tamborine ; and the beautiful manner in which the two are fixed together by a singular action of the press is very strik- ing. The buttons made of bone, of horn, of wood, of mother-of-pearl, and of other materials, are generally the produce of other manufacturers, who work out their results by the aid of the circular saw, the lathe, the press, and a few other pieces of apparatus. CABLE. The rope or chain by which the anchor of a ship is held. Cables, un- til within a recent period, were usually made of hemp, but of late years iron chains have come much into use. A hempen cable of 12 inches girth, and length 120 fathoms, weighs 3075 lbs. Since the weights of two cables of equal lengths will be as their sections, or squares of their girths, it is easy to de- duce the following rule for the weight of any hempen cable : — Multiply the square of the girth in inches by 21-3"(or 21 near- ly enough), the product is the weight in lbs. Since also as the breaking strain, or resistance against the force to part the cable, will be as the section, it will be as the weight, and will be found nearly by dividing the weight in lbs. by 100: the quotient i~ the breaking strain in tons. This rule is of course liable to 64 CYCLOPEDIA OF THE USEFUL ARTS. [CAL great uncertainty from the quality or wear of the cable. Chain cables possess great advantages over hempen cables ; they are not liable to be destroyed by chafing on rocky grounds, nor to become rotten and insecure from alternate expo- sure to the air and water ; and by reason of their greater weight the strain is ex- erted on the cable rather than on the ship. In order that the ship may be en- abled to let slip her cable in case of neces- sity, chain cables are furnished with bolts at distances from each other of a fathom or two, which can be readily with- drawn. A chain of which the section is 1 inch in diameter breaks with 16 tons ; such a chain is equivalent to a 10 inch hemp cable nearly. And the dimensions of the chain cable corresponding to any hemp cable are therefore easily found by merely dividing the circumference of the hemp cable by 10. The strength of every part of the chain is proved before it leaves the manufactory. CADMIUM. A white metal, much like tin. It fuses and volatilizes at a temperature a little below that at which tin melts. Specific gravity about 9. Its ores are associated with those of zinc. It was discovered in 1818 by Professor Stromeyer of Gottingen. Its equivalent number is 56. It forms a yellow sali- fiable oxide eomposed of 56 cadmium+8 oxygen=64 oxide of cadmium. Its scarci- ty prevents its employment in the arts, but the oxide has been used as a pig- ment, and the metal has been used in stopping teeth. CAFFEINE. A bitter crystalline sub- stance contained in coffee. It is volatile, and part of it is lost in roasting the berry. It is also found in tea, and in the ilex guaranensis of Brazil. It has not been applied in the arts to any useful purpose. CAISSON. In architecture, a sunken panel in a flat or vaulted ceiling, or in the soffit of a cornice. In ceilings they are of various geometrical forms, and often enriched with rosettes or other orna- ments. Caisson, in bridge building, is a large chest or vessel in which the piers of a bridge are bnilt. This sinking as the work advances, its bottom at last comes in contact with the bed of the ri- ver, when the sides are disengaged, its construction being such as to admit of their being thus detached without injury to the floor or bottom. CALAMINE. Native carbonate of zinc. CALCINATION. The reduction of substances to cinder or ash. The term is derived from the Latin word calx, quick- lime, which, as is well known, is pre- pared by the action of heat upon lime- stone; and hence the old chemists em- ploy the word calcination to express any supposed analogous change, metallic sub- stances being apparently converted into earthy matter by calcination. CALCIUM. The metallic base of lime, discovered in 1808 by Davy. This sub- stance has hitherto been obtained in such small quantities, that its properties have not been accurately investigated. It is probably a brilliant white metal, highly inflammable, and more than twice as heavy as water. Combined with oxygen it forms lime, which consists of 20 cal- cium+8 oxygen=28 lime. (See Lime.) CALENDERING. The subjection of cloth and other articles to a machine, which, when so prepared, are calendered, literally meaning 7iot-pressed ; by passing between cylinders or rollers it acquires a level or uniform surface. After goods are bleached and washed, they are twisted and tangled, so that they would not pass smoothly between the cylinders. Ihcy are previously passed over the surface of a water-cistern, and reaching the rollers in a damp state, they unfold themselves readily. The first pair of rollers over which the cloth is passed, does not dry or quite smooth it. The rollers in the calender are fixed in a vertical series in an upright frame, the rollers being pressed forcibly together by lever power. The lower rollers are generally grooved to remove creases ; the" upper rollers are smooth, and of wood and brass. In pass- ing between these the cloth is smoothed and stretched, when it is wound upon a roller, ready to be starched. The starch is made from flour, fer- mented and strained to separate the bran ; a little indigo is added to give a blue tint, and the liquor thickened with por- celain clay, or calcined gypsum, to give apparent strength and thickness to the cloth, and make it more attractive to the purchaser. The starch is laid on by a stiff- ening mangle ; the cloth first passing un- der a roller into a trough containing the starch-liquor, becomes filled with starch, and then carried upwards, passes be- tween rollers of brass and wood, tightly fitting against each other, by which the superfluous starch is pressed out, and falls down into the trough below. The cloth is then dried by being passed over tin or copper cylinders, heated by steam. Muslins arc merelv stretched on long frames to dry. T^ic finish for cotton cal] CYCLOPEDIA OF THE USEFUL ARTS. 65 goods is generally by glazing^ which gives a bright gloss to the material. In this case the cloth must first be damped, which is done by passing it over a cylin- der, while a brush is at the same time scattering fine spray of water on the stuff. It is then passed between the rollers of the colors, and gets a silky lustre. Copper-embossed rollers are occasion- ally used for producing figures and pat- terns on velvet goods. After the cloth has received its final gloss, it is smoothly folded on a clean board, and taken to be measured preparatory for sale. There are upwards of one hundred ways for making up goods. Muslin is made up in book-folds, in pieces of 24 yards ; usually two half pieces are made up in one book. Cambrics and linens are in pieces 34 inches wide, and 8s yards long, fold- ed up small, and tightly pressed. Hand- kerchiefs are sometimes folded in dozens. CALICO PKINTING. The art of pro- ducing figured patterns upon cotton by colored substances. Silk and woollen fa- brics have been made of late years, sub- ject to a similar style of dyeing. The fab- ric takes its name from Calicut, a district where it has been practised for many hundred years. The art of Topical dye- ing was also known to the ancient Egyp- tians. Before cloth can receive good colored impressions, it must be freed from fibrous down by singing, and be rendered smooth by the calender. They are next bleached, except those intended for Turkey-red; after being bleached, dried, singed, and calendered, they are lapped in lengths of several pieces, stitched together. Four different modes are in -jse for printing figures upon calico : the oldest is by wooden blocks, on the face of which the design is cut, which are worked by hand. The wood-blocks measure about twelve inches by seven. They have a smooth surface of sycamore on a substra- tum of some commoner kind of wood : and the design, after being sketched on the block, is cut as in common wood-en- graving, the parts being left pi'ominent which are to constitute and print the pat- tern. In some patterns, where there are fine lines, the wood would soon be worn away, or brought to a defective state by use ; and to obviate this, little slips of copper are inserted into delicate grooves cut for them, the copper slips all stand- ing at an equal height, and forming the printing surface. Small pieces of felt are in some places introduced to fill up the instertices between the coppers, so as to imprint a broader patch of color. One block can only print one color : and, therefore, if five or six colors form the design, and all be printed by blocks, there must be five or six blocks, all equal in size, but the raised parts in each block corresponding with depressed parts in all the other blocks. The principle involved is precisely the same as that displayed in floor-cloth printing. Another method, quite of modern in- troduction, is somewhat analogous to stereotype printing. In the first place a model is formed from the design, com- prising so much of it as may be included within a space of five inches long bv an inch and a half wide. This model is formed of bits of metal inserted into a ground or block, and a mould is produced by stamping from the model. From the mould fixed in a block, and adjusted in a convenient way, stereo- type pieces or copies are pro- duced, in a mixed metal of tin, lead, and bismuth. When a number of these pieces are prepared, their surfaces are brought to a perfect level by means of a file, and they are then firmly fixed down upon a stout and carefully prepared piece of wood. The block - printing room generally exhibits a number of machines similar to that in the cut. The cloth wound off rol- lers, passes on the surface of the table to be printed, 66 CYCLOPEDIA OF THE USEFUL ARTS. fcAL and, after printing, passes on to another roller, the printer regulating this move- ment. Each machine is besides attended by a boy and a girl : one of these dips a brush into the color-vessel, and spreads a layer on the elastic trough. The prin- ter takes his engraved block by the nan- die on its back, and presses it on the trough, the elasticity of which allows every part of the raised device on the block to take up a layer of color, and then prints a portion of the cloth equal to the size of the block. There are small pais or guide-marks on the corner of the block, by which the printer is enabled to adjust each successive impress from the block. When the whole piece has been worked over with one block, the printer goes over the same piece with a second, perhaps with a third, and so on according to the number of colors in the design, a new block being used for every color. Another mode of printing is that by which all the colors may be laid on at once by stereotype plates. A flat piece of wood is provided two or three feet square, on which are fixed all the stereo- type pieces ; those for one color are ranged in one row or stripe, five inches wide : those for another color form a se- cond stripe, contiguous to and parallel with the first, and so on for the 3d, 4th, or 5th. The length of each stripe is equal to the breadth of the cloth, the whole forming a compound printing-block, di- vided in five compartments. These block* are used in a printing-machine similar to type-printing: the block is fixed, face downwards, to the bottom of a descend- ing frame, capable of receiving a vertical motion, and the cloth being laid on a ta- ble beneath, the block is brought down at intervals upon it, by means of a lever managed by the pressman. The color is laid on the block thus : The boy has five troughs of color (or more) ranged before him; with a long piece of wood so formed as to dip in all these, and take up a small portion from each, he dabs it on a flat felt cushion ; then with a brush he spreads these five colors in an equal number of patches over the surface of the felt, without combining or smearing one over the other. He next slides the cushion along a kind of railway till it comes underneath the block, which is made to descend upon it, and to imbibe a layer of color all over its surface, each one of the five rows of device falling upon one particular color on the cushion, without touching the others. The boy then draws out the cushion, and the man guides the block in its descent upon the cloth, which it imprints upon five differ- ent places in five different colors. All this is repeated a second time ; but be- fore the wetted block actually descends, the cloth has been made to shift about five inches length- wise, or equal to the width of one row of the block. By this means each color falls upon a part which had been printed with a different color in the former de- scent. At each de- scent the cloth is shifted, so that each portion of the cloth is brought into con- tact -with each of the five divisions of the block, and thus re- ceives five different colors. The illustration serves to convey an idea of this which is termed press print- ing. cal] CYCLOPEDIA OP THE USEFUL ARTS. 67 The cylinder printing machine con- sists of an engraved copper cylinder, so mounted as to revolve against another cylinder lapped in woollen cloth, and imbued with a colored paste, from which it derives the means of giving colored impressions to pieces of cotton passed over it. The cylinder as it rotates dips in a long trough of color, and every part of it becomes coated. The excess of color has to be removed from the sur- face of the cylinder with a knife : this is called doctoring. The cloth then passes in a continuous strip between the cylin- der and a large roller or drum above, by which it is pressed close so as to imbibe the color from the sunken device on its surface. As the cylinder is continually revolving while the cloth passes, the printing goes on uninterruptedly with- out stoppage or break. When a ma- chine prints several colors, there are as many cylinders as colors required, each having a trough and doctor of its own, and the cloth passes in contact with each in turn. Each cylinder machine prints a piece (23 yards) of cloth in a minute and a quarter, or three quarters of a mile per hour. In the subjoined illustration the cloth may be seen traversing the cylinder. The economy of cylinder printing is very great. One machine with a man, and a boy to tend the color trough, being capable of printing as many pieces as 200 men and boys could do with blocks. A modification of cylinder printing is with wooden rollers cut in relief ; it is called surface printing, the thick color being first laid on a tense woollen surface, and then transferred to the cylinder. When copper and wooden cylinders are com- bined in one appara- tus, it has gotten the name of union print- ing. Having alluded to the mechanical operations, those which are chemical require now to be noticed. If one hundred patterns of cotton re- quire to be printed, nearly one hundred different modes of proceeding are ne- cessary in the print- ing; for not only must the coloi-s be different, but each color may perhaps require a peculiar groundwork to make it adhere to the cloth. Herein lie the delicacy and com- plexity of the calico- printer's operations ; and hence arises a different chemical formula for almost every different pat- tern. Sometimes a piece of cloth is par- tially printed, then dyed, and then printed again ; at 68 CYCLOPEDIA OF THE USEFUL ARTS. [CAl other times the printing is effected at once 5 and at others a portion of the printing is to lay on color which is to be afterwards visible, while the other por- tion is merely to imprint the cloth with a chemical agent which shall exert some peculiar effect on the colors. This may perhaps be rendered intelligible by al- luding to four different kinds of liquids or mixtures which are printed on the cloth by means of the cylinder, the press, or the block. These four are colors, mordants, dischargers, and resists. The name colors speaks for itself; it relates to the pigments or pastes which impart color to the cloth, and includes a very wide range of vegetable and mineral substances. A mordant is a liquid mix- ture which enables the coloring sub- stance to combine permanently with the textile fibre ; and this is used when the mordant has a combining affinity with the cloth as well as with the color, al- though the two latter, used singly, have no affinity for each other. Thus, if a red color were imparted to cloth by mad- der, it would wash out, or not be a " fast Ofjlor;" but if the cloth were previously wetted with an aluminous salt, the mad- der color would be permanent. In most cases the mordant is a body of liquid, into which the cloth is immersed ; but sometimes it is used in the same way as a paint or ink by the cylinder-machine. Dischargers, instead of being intended to fix the 'color to the cloth, are used to drive off or discharge the color after the latter is applied. This kind of chemical agent is used in combination with mor- dants, thus : the cloth is wholly satu- rated with the mordant, but certain parts are also printed with a discharger formed cf lemon-juice or some other substance ; the result of which is, that when the dye-color is afterwards applied, it com- bines with the cloth at the parts where the mordant has been unaffected, but becomes a "loose" color at the parts printed with the discharger, so as to be easily washed out from those parts. Re- sists are mixtures which enable the printer to produce white portions of pat- tern by a process rather different from the discharge-method. The mordant is printed, not dipped, in those parts which are to be colored in the pattern ; while those which are to be kept white are previously printed with a mixture called a resist or resist-paste. The cloth is then wholly immersed in a dye-vat, but those portions which had been printed with the resist refuse to receive the dye, and hence remain white. It will be seen, therefore, that in " discharge work," as it is called, the white portions are re- tained by driving out the mordant, which would otherwise fix the color ; while in " resist- work" the white portions are re- tained by shielding the cloth at those parts from the action of the color. In calico printing it is necessary to bring the mordant or the color into that state of consistence that it will not spread in the cloth beyond the limit of the design. The usual mordants are alum or sulphate of alumina, acetate of alumina, peroxide of iron, protoxide of tin, and oxide of chrome : their solu- tions are made of the proper density by thickeners, such as wheat, starch, ancl flour ; other thickeners are used, as gum arabic, British gum, gum Senegal, traga- canth, jalap, pipe clay, dextrine, potato and rice starch, sulphate of lead, with gum, sugar, molasses, and glue. These with either the colon, or mordants are prepared in vessels furnished with steam jackets. The manner of applying a pattern on cloth is called a style : of these there are six. 1. The madder style. 2. Printing by steam. 3. The padding style. 4. The resist style. 5. The discharge style. 6. The china blue style. The madder style is not confined to that color, but the process is applied to many others. In it the cotton is first printed with a mordant over those parts where it is desired to have a color pro- duced. When the mordant has been laid on by the cylinder the cloth is hung up in a room for a few days, when the mordant has suffered an alteration where- by it becomes insoluble, and fastened into the fibre of the cloth. Any portion of the mordant which remains soluble has now to be removed, or the color when applied would pass beyond the pattern. It is removed by passing the dry calico through a warm mixture of cowdung and water. This operation is called dunging. It is then washed in water in a urine pit, and again in a dash wheel. By this process the thick paste is removed which accompanied the mor- dant. The difficulty of procuring cow- dunof in sufficient quantity has led to the employment of other substances, which are easily procured, and which are found on analysis to be the active agents in the dung : thus solutions of phosphate of cal] CYCLOPEDIA OF THE USEFUL ARTS. 69 soda and phosphate of lime, thickened with glue, are used under the name of substitute for this purpose. After wash- ing in cold water, the cloth mordanted^ is rinsed through a weak solution of substitute and size, when it is ready for the color : this is laid on by drawing the cloth for two or three hours through a colored solution {see Dyeing) ; the color attaches itself permanently to those por- tions of the cloth to which the mordant has been applied, and form a chemical compound with it. On the portions not mordanted the color is so fee ibly attached as to be removed by washing in soap and water, or in bran and water, or in a dilute solution of chloride of lime. This is called clearing. The processes for finishing a piece of cloth, even with one color, are very nu- merous : thus if a red stripe be required on a white ground, no less than nineteen processes have to be passed through, viz.: 1. Printing on mordant of red liquor (acetate of alumina) thickened with flour, and dyeing. 2. Exposure of cloth till mordant is altered. 3. Dunging. 4. Wincing in cold water. 5. Washing at the dash-wheel. 6. Wincing in dung sub- stitute and size. 7. Wincing in cold water. 8. Dyeing in madder. 9. Wincing in cold water. 10. Washing with dash wheel. 11. Wincing in soap water with a salt of tin. 12. Dash-wheel washing. 13. Win- cing in soap water. 14. Wincing in a so- lution of bleaching powder. 15. Washing at the dash- wheel. 16. Drying by the water extractor. 17. Folding. 18. Starch- ing. 19. Drying by steam. From this it "may be seen how impor- tant the washing and rinsings are t> In steam printing the mordant is first laid on and the cloth then dipped in the color vat : union does not however take place between the mordant and the color until steam is brought into contact with the cloth, when immediately the two unite. In some instances the cloth is hung in a room into which steam is ad- mitted. In other, the goods are put in a box made almost steam tight and the steam admitted through a pipe perforated with a multitude of "small holes; most commonly the cloth is wrapped round a cylinder perforated with holes into which the steam is admitted by a pipe. The temperature is kept at 212° to pre- vent condensation, which would make the colors run ; a higher temperature is injurious. The steaming is carried on for half an hour or less according to the nature of the color. This gives a great brilliancy and delicacy of finish to the cloth. A variety of cheap goods are Srintedin fugitive colors ; these, not being xed by steaming or by a mordant, are called spirit or fancy colors : they wash off. The padding style is only applied to mineral colors. The cloth is uniformly imbued with a color and then dried. This color is sometimes obtained by once dip- ping in the trough ; at others it is neces- sary to dip the cloth first in one mineral solution and then in a second, when an insoluble color becomes fixed in the tissue ; after each dipping the cloth is dried, or the cloth may be padded in one solution and afterwards winced in the other. To produce a design on a white or colored ground, the cloth is printed with one of the solutions and then padded or winced in the other. In the resist style the cloth is first printed with a resist paste to prevent the cloth from taking up the color when it passes through the, dye bath. Some resists act mechanically, such as fat resists, these are used for silk ; others act chemically, such as acetates of copper andlead, chlorides of zinc, and mer- cury, and arseniate of potash, thickened with gum, pipe clay, and til. The dis- charge style, is that when a white or col- ored pattern is to be produced upon a colored ground. Here the mordanted cloth is printed with a substance called the discharger, which acts either on the coloring matter, or on the mordant, by converting them into colorless or soluble matters, which may be removed to allow the parts thus discharged to be died of another color. Vegetable and animal coloring matters are discharged by chlo- rine and chromic acid, and a mordant is usually discharged by an acid solution, such as lemon or lime juice, cream tartar, oxalic, citric, and weak sulphuric acids, thickened with gum or starch. In this way are produced the imitations of Ban- dana handkerchiefs, in which white fig- ures are formed on a ground of Turkey red by means of a solution of chlorine, which is made to flow through the red cloth on certain points defined by the pressure of hollow lead types, inserted in plates of lead contained in a hydraulic press. This is furnished with' pattern plates, one fixed on the upper block and the other on the lower, or movable plate. Fourteen pieces, previously dyed with Turkey red, are laid flat and smooth one on another, the whole is wound on a roller at the back of the press. The first 70 CYCLOPEDIA OF THE USEFUL ARTS. [CAL yard is then unwound and laid flat on the slab of the machine. Then the workman turning a handle brings the pressure to act from a hydraulic machine, and the bed plate rises slowly till the cloth comes in contact with the upper horizontal plate ; such is the power of the machine that the cloth is pressed between the two plates with a force of 300 tons. The chlo- rine liquor is then poured into the trough on the upper plate, and after remaining a short time is drawn off by a small cock, the pressure is removed and the bed Slate sinks down ; the cloth is now with- rawn and comes out diversified with white spots, which are as clearly defined on the lowest of the fourteen as on the top one. The red dye has here been im- mediately removed from the stuff by the chlorine ; fifteen minutes is found to be a sufficiently long exposure. These white spaces are occasionally dyed of another color subsequently. The China Um style is only practised with indigo. The bleached cotton is printed of the desired pattern with a mix- ture of indigo, orpiment, sulphate of iron, gum and water. It is then exposed to the air for two days and then stretched on a frame. This is immersed in three cis- terns containing different liquids ; 1st, in milk of lime ; 2d, in a solution of sul- phate of iron ; 3d, in a solution of caus- tic soda. The frames are dipped several times alternately in 1 and 2. The dip- ping in No. 3 is less often, but follows immediately that into 2. The insoluble indigo which had been applied to the surface becomes converted into solu- ble indigo or indigotin, which is dissolved and transferred to the interior of the fibre when it is gradually precipitated in the insoluble form. CALIPER COMPASSES, or simply Calipers, are compasses with curved legs, for measuring the caliber or di- ameter of cylinders, "balls, or other round bodies. Calipers of the best sort are made with a scale having different sets of numbers engraved on it, like a sliding rule, for the purpose of exhibiting at once various relations depending on the magnitude of the diameter of the body measured. Thus, as the weights of balls of the same metal are in a constant ratio to the cubes of their diameters, the scale may be so graduated and numbered that the observer may read oil' either the di- ameter in inches,*or the weight in pounds. Other numbers having a less immediate application arc also frequently attached; for example, the degrees of a circle, the proportions of troy and avoirdupois weight, tables of the specific gravities and weights of bodies, &c. It is obvious that these may be varied infinitely, ac- cording to the purposes proposed to be accomplished. CALOMEL. Protochloride of mercu- ry, composed of mercury 10, chlorine 35. It may be made by rubbing mercury with corrosive sublimate, and applying heat to sublime the mixture; the white powder which rises is calomel : this is called sub- limed calomel. Precipitated calomel is made by adding proto-nitrate of mercury in solution to a solution of common salt. Dr. A. T. Thompson has patented a mode of making calomel, by combining chlorine in the gaseous state with the vapor of mercury. Mr. Jewel prepares a finely divided calomel by passing its vapor into a room into which steam was admit- ted. It is one of the most useful of medicines. CALOKIMETEE. ^ An instrument for measuring the quantity of heat given out by bodies passing from one temperature to another. CALORIMOTOK. This terrn has oc- casionaly been appllied to a peculiar form of the voltaic apparatus composed of one pair of plates or great extent of surface, the electricity of which, when transmit- ted through good conductors, produces intense heat. To Dr. Hare of Philadel- phia, the philosophical world is indebted tor the most powerful apparatus of this kind. CALOTYPE is the name given by Mr. II. Pox Talbot to his improved Photo- graphic method. The method of obtain- ing Caloty pe pictures is as follows : — Take a sheet of the best writing paper. Dis- solve 100 grains of crystallized nitrate of silver in 6 ounces of distilled water. Wash the paper with this solution, with a soft brush, on one side, and put a mark on that side, whereby to know it again. Dry the paper cautiously by a distant fire, or else let it dry spontaneously in a dark room. When dry, or nearly so, dip it into a solution of iodine of potassium, of 500 grains to a pint of distilled water, and let it stay two or three minutes in this solution." Then dip it into a vessel of water, dry it lightly with blotting pa- per, and finish drying it at a fire, or spon- taneously. All this is best done by candlelight. The paper so prepared the author calls iodized paper. It is scarcely sensitive to light; nevertheless it ought to be kept protected from the 'light. Shortly before this paper is wanted for cal] CYCLOPEDIA OF THE USEFUL ARTS. 71 use, wash a sheet of it with this liquid: Dissolve 100 grs. of crystallized nitrate of silver in 2 oz. of distilled water ; add one sixth of its volume of strong acetic acid : let this mixture be called A. Make a saturated solution of crystallized gallic acid in cold distilled water ; the quanti- ty dissolved is very small ; call this so- lution B. When a sheet of paper is wanted for use, mix together the liquids A and B in equal volumes, hut only mix a small quantity of them at a time, he- cause the mixture will not keep long without spoiling ; call this mixture the gallo-nitrate of silver. With it wash the iodized paper on the marked side, by candlelight. Let the paper rest half a minute, and then dip it into water, Then dry it lightly with blotting paper, and at a distance from the fire. The author has named the paper thus prepared Calotype paper, on account of its great utility in obtaining the pictures of objects with the camera obscura. If this paper be kept in a press, it will often retain its quali- ties in perfection for three months or more, being ready for use at any mo- ment ; but this is not uniformly the case. It is best used a few hours after it has been prepared. The Calotype paper is sensitive to light in an extraordinary degree, which transcends a hundred times or more that of any kind of photo- genic paper ; it will take an impression From simple moonlight not concentrated by a lens. Use of the Paper. — Take a piece of this paper, and having covered half of it, expose the other half to daylight for the space of one second in dark cloudy weather in winter, when there will be a strong impression upon the paper, but latent and invisible, and its existence not to be suspected by any one. To make it visible wash the paper once more with the gallo-nitrate of silver, and then warm it gently before 'the fire. In a few se- conds, the part of the paper upon which the light has acted begins to darken, and finally grows entirely black, while the other part of the paper retains its whiter nass. This paper is well suited to re- ceive images in the camera obscura. When the aperture of the lens amounts to one third of the focal length, and the object is very white, as a plaster bust, &c., one second is sufficient to obtain a pretty good image of it, made visible bv washing and warming. < T7ie Fixing Process.— First wash the picture with water, then lightly dry it with blotting-paper, and next wash it with a solution of hromide of potassium, containing 100 grains of that salt dis- solved in eight or ten ounces of distilled water. After a minute or two it should be again dipped in water, and then finally dried. The picture is in this manner very strongly fixed ; and with this great advantage, that it remains transparent, and that, therefore, there is no difficulty in obtaining a copy of it. The Calotype picture is a negative one, in which the lights of nature are represented by shades ; but the copies are positive, hav- ing the lights conformable to nature. A negative calotype may serve to furnish several positive ones, but after a while it grows faint ; but it may be restored by washing by candlelight with gallo-nitrate of silver, and warming. A second series may now be taken. CALP. Argillaceous limestone, con- taining sulphuret of iron and vegetable matter. CAMBRIC. Very fine white linen, first made at Cambray, in Flanders, whence its name. CAMEL. A machine invented by the Dutch for carrying vessels into harbors, where there is not a sufficient depth of water. It consists of two large boxes, or half ships, built in such a manner that they could be applied on each side of the hull of a large vessel. On the deck of each part of the camel a number of hori- zontal windlasses were placed, from which ropes proceeded on one side, and being carried under the keel of the vessel, were attached to the windlasses on the deck of the other part. When about to be used, as much water as necessary was suffered to run into them ; all the ropes were then cast loose, and large beams were then placed horizontally" through the port-holes of the vessel, the ends resting on the camels alongside. When the ropes were made fast, and the vessel properly secured, the water was pumped out, on which the camels rose and bore up the vessel. A ship drawing 15 feet can be made by one of these "to draw only 11 feet. The length of one of these camels was 127 feet, and the greatest breadth 22 feet. CAMLET, or CAMBLET. A light stuff, of several varieties. Some are made of goat's hair ; in some the warp is hair, and the woof hair or silk: others en- tirely of wool, or a warp of wool and a woof of thread. Camlets may be striped, watered, and figured. CAMPIIENE. One of the hydrocar- 72 CYCLOPEDIA OF THE USEFUL ARTS. [CAN bons, composed of 10 atom3 of carbon and 8 atoms of hydrogen. It is identi- cal with oil of turpentine. Camphor may be looked on as its protoxide — a term applied to one of the numerous fluids used for illumination : it is made of one part of oil of turpentine, mixed with about twelve parts of alcohol, and then distilled. CAMPHOR.. The produce of the cam- phor laurel of Japan and China. The roots and wood chopped small are boiled with water in an iron vessel, to which an earthen cap, filled with straw, is fitted. The camphor sublimes, and is condensed up- on the straw. There are two kinds of camphor; 1, the Dutch or Japan cam- phor; and 2, the crude or China cain- Shor. The first is the finest quality, rude camphor resembles moist sugar before it is refined. This process is car- ried on in thin glass globes, which are filled with crude camphor, with a little bone-black and quick-lime. The globe is then placed on a water bath, and boiled. The camphor rises and sublimes upon the upper part of the vessel. When the sublimation is completed, the vessel is cracked by pouring cold water on it while hot, and the cake of camphor is removed. Camphor (C 10 H 8 O) is a white and semi- transparent solid of a crystalline fracture, and warm pungent taste. It is soft and tough, and not easily powdered, until mixed with spirit of wine. It evaporates in the air, and in phials at ordinary tem- Eeratures, and attaches itself to the sur- ice most exposed to the light. Camphor floats on water, and ro- tates rapidly if the water be clean ; if the surface be greasv, the phenomenon will cease. It fuses at 347°, and boils at 400°, is sparingly soluble in water (about 5 grains in a pint) but readily in alcohol, ether, sulphuret of carbon, a few volatile oils, and other substances. It is used as a stimulant, both externally and internally, but it is a powerful poison. It is also used in some varnishes. CAMPHORIC ACID. Obtained by boiling camphor in nitric acid ; its com- position is C'» H? 03XH 0. CAMWOOD. A red dye-wood, ob- tained from Sierra Leone. Its coloring matter differs but little from Nicaragua wood. CANAL. An artificial channel filled with water, formed for the purpose of draining, irrigation, supplying towns with water, or of inland navigation. The Cay- uga Canal, which drains the marshes at the head of the lake, and empties into the Ontario Lake, is an illustration of the first. Those of Ancient Egypt are the best instances of the second. The supplying stream from the Croton river to the re- ceiving basins in New York, illustrates the third. It is to the fourth kind, that for inland navigation, that the term is now almost wholly restricted. There is no country in the world where the advantages of canals are more appre- ciated than in China. From time imme- morial the rivers that intersect that vast empire have been united by innumerable canals ; and the Grand Canal is said to be the most stupendous work of the kind that has ever been executed. Russia, too, exhibits a remarkable degree of en- terprise in the construction of canals for the purpose of inland navigation ; and though innumerable difficulties peculiar to that country for a long period impeded the progress of works of this description, that empire is now traversed by an un- broken line of water communication from St. Petersburg to the Caspian Sea. The section of a canal is usually a tra- pezium, of which two sides are parallel and horizontal, and the other two equally inclined to the horizon. The inclination depends on the nature of the soil. It is least in tenacious earth, and greatest in loose soil ; but no soil will maintain itself unless the base of the slope exceeds its height at least in the ratio of four to three. In loose soils the base requires to be twice as great as the height. A canal is usually confined between a bank on one side, and a towing path on the other, the breadth of whose upper surface must be sufficient for a road on which the animals employed in draught may easily pass. This requires the breadth of the upper surface to be at least 9 feet. The usual mode for the other bank is to make the breadth at top equal to the height, measured from the bottom of the canal: but in this case there should be a berm of a foot, or a foot and a half, at the level of the water, which increases the thickness of the bank at bottom, and prevents the wash of the banks from tailing into the canal. To prevent the entrance of rain-water, a counter-ditcTi is formed on the outside of each of the banks. The form of a wcll- constructed canal will therefore present the following figure :— The dimensions of navigable canals must depend on the size of the vessels in- tended to navigate them. In order that can] CYCLOPEDIA OF THE USEFUL ARTS. ■78 they may enable two vessels to pass each other with freedom, the breadth at bot- tom is usually made twice as great as the breadth of the beam of the vessels ; the depth requires to be at least one foot more than the vessel's draught of water. The bed of a canal must be absolutely level, or have no more slope than is ne- cessary to convey water to replace that which has been wasted. Hence, when a canal intersects a sloping country in a se- ries of channels at different levels, means must be provided to enable vessels to pass from one level to another. This is commonly effected by means of a lock. The invention of locks as a means of carrying a canal through an undulating country has given an entirely new fea- ture to the inland navigation of Europe. Various nations have claimed the honor of this invention ; but it would appear that the controversy which has arisen on the subject is not yet settled. A lock is a chamber, formed of masonry, occu- pying the whole bed of the canal where the difference of level is to be overcome. This chamber is so contrived that the level of the water which it contains may be made to coincide with either the upper or lower level of the canal. This is effected by two pairs of gates, one of which pairs is placed at each end of the chamber of the lock. By this means, while the gates at the lower end of the chamber are opened, and those at the upper end are closed, the wa- ter in the chamber will stand at the lower level of the canal; and on the con- trary, when the lower gates are closed, and the upper ones are opened, the level of the water in the lock will coincide with the level of the water in the upper part of the canal. In the first case, a boat may be floated into the lock from the lower part of the canal; and if then the gates be closed, and water is admitted into the lock from the upper level unite the surface of the lock is in a line with the water above, the boat will be floated up, and on the opening of the upper gates may be passed onward. By revers- ing the course of procedure, boats may be as readily conveyed from the upper to the lower level. (See Lock.) The supply of water required for main- taining a canal depends on the lockage or quantity wasted in passing a vessel through the locks, on the evaporation from the surface, and on the leakage. It has been found by experiment that the annual quantity of evaporation from the canal of Languedoc is 32 inches ; that is to say, the body of water required to supply this waste is equal to a parallelo- piped whose base is the whole surface of water in the canal, and whose altitude is 32 inches : in most calculations it has been customary to take this altitude at 36 inches. With respect to the leakage, when the soil is porous the inner surface of the banks may be lined with an earth retentive of water, or a portion of the middle of each bank may be built up with earth of this character. The opera- tion of lining a bank with clay, or earth retentive of moisture, is called puddling. The advantages derived from canals are now so generally known and acknow- ledged, as to render it almost superfluous to allude to the question. The beneficial effects of canals are felt in a greater or less degree by all classes of society: by their means the manufacturer is enabled to collect his materials and his fuel with less labor and expense ; the farmer ob- tains a supply of manure at a cheap rate, and a ready conveyance of his produce to the most profitable market; and the merchant is enabled to extend his com- merce by exporting greater quantities and varieties of goods from places remote from the sea, and by more easily supply- ing a wider extent of inland country -with articles of foreign produce. In short, general arguments in favor of ca- nals are superseded by the rapidly im- proving and thriving state of all the ci- ties, towns, and villages in their neigh- borhood ; while the great works of every kind to which they have been conducted, and to which a large portion of them owe their rise, are their best recommenda- tion. Experience has shown that the formation of railroads does not yet su- persede the necessity for canals, as where cheapness, and not expedition, is re- quired, the canal will be preferred. The general introduction of steam propulsion on our canals would be of great service. It has been tried on the Erie, and Chesa/- peake, and Ohio Canals. CANDLE. Candles can be made from any fatty substance which, at ordinary temperatures, is in a solid state ; wax, spermaceti, and tallow being the usual substances employed. That very essen- tial part of a candle, the wick, performs an office which involves a scrap of philo- sophy not always well understood. The wick is composed of a dozen or more fibres of soft cotton, ranged side by side, and having just sufficient twist given them to make them cling together. The threads are not so close together but that 14: CYCLOPEDIA OF THE USEFUL ARTS. [can oil, or tallow in a melted state, will as- cend between them, by virtue of that ca- pillary attraction which will cause a piece of loaf-sugar to become wet throughout, if placed on a wet spot. When a candle is lighted, the heat melts the upper part of the tallow, which then ascends between the fibres of the wick, and furnishes minute streams of combustible matter as fast as the oxygen of the air will consume it in the form of flame. The current of air constantly supplying oxygen, keeps the outer surface ot the tallow cool, and causes the formation of the cup which contains the melted tallow that other- wise would run down and disfigure the candle : the tallow is the combustible matter, and the wick is the series of tubes through which it ascends to the flame. Wax candles are made by pouring melted wax over the wicks, which for the convenience of turning and placing them successively over the caldron, are usually attached to the circumference of a hoop ; when of a proper thickness, they are rolled smooth upon a table, and the ends are cut and trimmed. It is in con- w.quence of this method of manufacture, that when we cut a wax candle we ob- serve it composed of successive layers or coats. Attempts have been made to cast wax candles in moulds, but those which are thus made never burn so well as those which are poured. Spermaceti can- dles, are mixtures of wax and spermaceti. This material forms a very good and cleanly candle ; but in consequence of its ready fusibility and hardness when con- crete, it does not admit of being carried about without spilling the melted mate- rial. The fused portions also, which run down the candle^ are apt to curl and fall upon the table. Composition candles. This term was originally conferred by a manufacturer who had a large stock of spermaceti candles on hand which were of a dirty hue, and which therefore were ansalable ; he advertised them under the above name, and they were soon dis- posed of, under the notion of their being composed of some new combination of materials. The term has since been ap- plied to various mixtures ; but what are now sold under the name of composition candles are chiefly mixtures of sperma- ceti, tallow, and a little resin, and occa- sionally wax. Tallow candles, which are either cast upon the wick in pewter moulds, or made by dipping the wicks, attached in rows to proper frames, into melted tallow. Stearine candles. Under this term we may include cocoa-nut oil candles, and a few others made of the stearine, or what may be compared to the spermaceti of the vegetable oils. The stearine, or rather the stearic acid of tal- low, is also now extensively employed for making candles. Mould candles are made in two ways. 1. From ten to six- teen cylindrical pewter moulds are placed together in a wooden frame, so that their upper ends terminate in a kind of trough common to the whole. The wicks are inserted and kept firmly in their proper places in the centre of each cylinder by strong wires. The frame being then placed with the trough uppermost, the moulds are filled with melted tallow, and are placed in the air to cool, after which the wires by which the wicks have been fixed are withdrawn, the superfluous tal- low is removed from the trough, and the candles are pulled out of the moulds. In the following illustration of a mould candle machine, a represents the candle, b the mould through which the candles are pushed by the rod c. Messrs. Mattewson, candle manufac- turers of Baltimore, have introduced a new English patent machine for making candles, which is both ingenious and possesses uncommon merit in an econo- mical point of view. It consists of a number of moulds, holding 18 each, which are furnished with a bobbin to each mould, holding wick for over 100 candles on each bobbin. At the commencement, the first mould is threaded by hand. It is then placed on a railroad and brought under a cistern from which it is filled with tallow ; it is then shoved along to a carriage, which, when it has received its load, is convey- ed by rail outside to an open shed in the yard, where it is allowed to cool. "When that operation is completed it still con- tinues its circuit on the railroad, until it arrives at the machine, upon which it is placed, and a stroke of a lever ejects the whole 18 candles, at the same time threading the moulds for a fresh charge ; a revolving saw-knife cuts oft 7 the wicks as quick as the hand can move it across the machine ; the ends of the wicks are seized by pincers, which grip each of them as a person would with the finger and thumb; it is again placed on the rail and continues its course to undergo the same operation. On their way over the rail they are interrupted by a person who removes the pincers and trims the butt-ends of the candles. Mr. A. L. Brown of New Haven, Conn., took out a patent in October, 1849, for an can] CYCLOPEDIA OP THE USEFUL ARTS. 76 improved moulding apparatus. The im- provement in this apparatus consists in constructing the mould with a screw- on the upper part, about two inches from the end, for ad- justing and secur- ing it in the frame, and a shoulder near the upper end, to support the tallow table, and a hole to admit the wire which supports the wick : also in attaching all the wires which sup- port the wicks to a slide worked by a jointed wire han- dle, and governed by a guard, so that _ be evened by one motion of the hand, and then be all centred by another motion ; also in using a smooth tallow table, level with the tops of the moulds, to allow the tallow to be easily scraped off and the whole kept clean. Fig. 1, is a side-view of one of the moulds, showing the screw by which FIG.l. fig. 2. the wicks may it is to be adjusted and secured in the frame; the shoulder on which the tal- low table rests, and the hole through which the wire passes. Fig. 2, is a sec- tional view of one of the moulds, show- ing the wick when in the mould, as supported by the wire. Great care is requisite in selecting the cotton for the wicks of candles, which should be of such a nature as to leave no ash, or scarcely any, when burned. The wick is occasionally impregnated with different substances, and sometimes so platted as to curl out of the flame. The following table contains the results of some experiments made by Dr. Ure, with a view of ascertaining the relative inten- sities of light and the duration of dif- ferent candles : a . fl il il P il P || S s . U 3 § o o M £ w 2 ° 10 Mould 5 h. 9 m. 682 132 12.25 68-0 5-70 10 dipped 4 36 672 150 13.00 65-5 5 25 8 Mould 6 31 856 132 10.50 59 5 6 60 6 Ditto 7 2* 9 36 1160 163 14.66 660 5-00 4 Ditto 1787 186 20.25 80-9 3 50 Argand oil flame 512 69.40 100*0 In reference to the above table, it ap- pearsfrom Dr. Ure's experiments that one-eighth of a gallon of good oil, weigh- idg 6,010 grains, or 13 and l-10th ounces avoirdupois, lasts in a bright argand lamp 11 hours 44 minutes. The weight of oil it consumes per hour is equal to four times the weight of tallow in candles eight to the pound, and 3 and l-7th times the weight of tallow in candles six to the pound ; but, its light being equal to that of five of the latter candles, it appears from the above table, that two lbs. weight of oil, value one shilling (sterling), in an argand lamp, are equivalent in illuminat- ing power to 3 lbs. of tallow candles, which cost about three shillings, sterling. The larger the flame in the above candles, the greater the economy of light. In re- ference to the comparative cost of coal gas, oil, tallow, and wax, it appears that the cost of a lamp fed by gas, and giving the light of about seven candles, will be 76 CYCLOPEDIA OF THE USEFUL ARTS. [CAO cannon are about one penny sterling per hour ; of an argand lamp, "fed with spermaceti oil about threepence, of mould candles about threepence-halfpenny, and of wax candles about one shilling. Ninety cubic feet of good coal gas, value about one shilling sterling, will produce the light of about ten wax candles for one hour. CANE MILL. {See Sugar, Manufac- ture of.) CANNELL COAL. (Perhaps candle coal, from the flame with which it burns.'* A species of coal found in most of the English collieries ; especially at Wigan in Lancashire. It is difficultly frangible, does not soil the Angers ; when burn- ing it splits and crackles, but does not cake, and leaves 3 or 4 per cent, of ash. It is sometimes worked into ornamental utensils, like jet. CANNON. A military engine for pro- jecting balls, shells, &c, by the force of gunpowder. The principal parts of a 1. The breech, which is the solid metal from the bottom of the bore, or concave cy- linder, to the extremity of the cascabel, a. 2. The trun- nions, b b, which project on each side, and serve to sup- port the cannon in equili- brio, their axis being in the vertical plane passing through the centre of gra- vity, but intersecting it be- low that point. 3. The bore or cylindrical cavity. This in several sorts of cannon is made of smaller diameter towards the breech, thus assuming the shape of two cylinders, united by a portion' of a spherical surface. The smaller part of the bore is of such a length as to receive the maximum service charge of gunpowder, and is called the chamber. The entrance of the bore, c, is called the mouth or muzzle. Cannon are made either of cast iron or brass, the latter being an alloy of copper and tin, in the proportion of about 10 parts of copper to 1 of tin, and called gun-metal. This has a greater tenacity than iron, but is objectionable on account of its greater density and higher price, besides being liable "in rapid service to soften and droop at the muzzle, whereby it is rendered unserviceable. Since the advantage of using smaller charges of gunpowder was discovered, cast iron, though possessing less tenacity than gun- metal, has been substituted for ship, gar- rison, and battering guns. But the small- er species of cannon (field-pieces) con- tinue to be made generally of brass : for by reason of the rapid cooling of the iron in small masses its strength is considera- bly impaired, so that it is difficult to be procured of the requisite quality. Cannon were formerly cast with a cave or hollow, but they are now always cast solid; experience having shown that when cast solid they are stronger, and less liable to burst, that the metal is freer from honeycombs, and that the bore, can be rendered more perfect, and its axis made to coincide more accurately with that of the piece. In boring cannon, the gun itself is made to revolve about the bit or borer, the size of which is succes- sively increased. CANNON-METAL. Bronze; a cop- per alloy. CANVAS. A very clear unbleached cloth of hemp or flax, woven regularly in little squares, chiefly used to make sails for shipping. Besides serving for various domestic purposes, such as for the ground of tapestry work, canvas forms the cloth on which painters usually draw their pic- tures. A kind of canvas made solely from hemp, and called huckaback, is used for coarse towels and table-cloths. CAOUTCHOUC. This curious sub- stance is the inspissated juice or sap of several plants ; the principal supplies are from South America and Java, and are derived from the Shphonia elastica (Hevea caoutchouc), and probably from other Eu- phorbiaceous plants. It is often termed gum elastic and India-rubber. Its gen- eral properties and uses arc well known. Among its more recent applications are those of elastic wove fabrics, formed of caoutchouc stretched into threads and covered with cotton ; and various water- proof clothing, which is made by inter- posing a layer of caoutchouc between two folds of the cloth, and then forcibly unit- ing them by pressure. For this purpose the caoutchouc is dissolved by coal naph- tha, and in that state brushed over the surfaces which are to be united. Caoutchouc is a compound of carbon and hydrogen ; when heated it fuses, and afterwards remains viscid. When sub- jected to destructive distillation at a high temperature, it yields 4-5ths of its weight of a highly inflammable and very light volatile oily liquid (hydrocarbon), which has been called caouUhovcine, and which is a good solvent of the unaltered caout- chouc. Washed sulphuric ether dissolves CAPJ CYCLOPEDIA OF THE USEFUL ARTS. 11 caoutchouc, and it is also soluble in sev- eral essential oils ; but of these latter so- lutions the greater number leave it in a sticky state on evaporation. The trees have incisions made into them through the bark ; the milky juice exudes, is collected on clay moulds, dried in the sun, or with the smoke of a lire, which blackens it. The juice itself is a pale yellow, creamy liquid, which is mis- cible in water ; it dries off into caoutchouc, and loses 55 per cent. Caoutchouc is in- soluble in alcohol, but is soluble (besides ether), in naphtha from coal, oils of sassa- fras and lavender, and linseed oil. It melts at 248°, and burns with a bright flame and much smoke. It is not acted on by caustic potass, cold sulphuric acid, nor nitric acid, unless very concentrated. From its great elasticity it has been used in articles of dress and machinery. (See Elastic Bands.) The India-rubber manufacture is one of the most important branches of art, rivalling that of some of the older textile fabrics. In this country it has made pro- digious strides within a few years. The India-rubber shoes are made by women on the Amazon, by dipping the lasts, sent there from this country, into the juice of the tree, and then holding the last over a palm Are to dry it off quickly ; the last is then dipped again in the milk, and again dried, and "so repeated till it ac- quires the due thickness ; this is com- pleted in five minutes. Two gallons of milk suffice for ten pair of shoes. The shoes are then sun-dried, and next day stamped with pointed sticks, or the spines of the palm. The shoe is then cut from the last, and is ready for packing. From its softness and impermeability it is made into bougies, catheters, gas- tubes, and bottles. Its use as a varnish is almost endless, dissolved in any of the solvents previously mentioned, or in bi- sulphuret of carbon, without the use of heat. This constitutes Parker's patent solvent. Chloroform is an excellent sol- vent, but it is too costly. By digesting the rubber in solution of carbonate of soda, or water of ammonia, previously, it dissolves more readily. India-rubber is now rarely used alone in manufacture, but is previously mixed with other matters, which do not to any great extent affect its elasticity, or its waterproof properties. By mixing in sulphur when the rubber is in a semi- fluid condition it is said to be vulcanized, but as this gives an unpleasant odor to Uie fabric, various improvements have been made to obviate it. Patents have been taken out to use the hyposulphites, either alone or combined with sulphites and sulphurets. The sulphuret ot anti- mony has been used with advantage. In another patent the rubber after being steamed and dried is thionized, which consists in submitting the mass to the action of the fumes of sulphur or sul- phurous acid, by which the sulphur be- comes incorporated. For manufactur* the rubber is now never prepared by so lution in turpentine or other menstruum but it is reduced into a pasty mass bj heavy grinding, and then passed througl a succession of rollers until it is brought into sheets of uniform texture. CAOUTCHOUCINE. A volatile hy drocarbon obtained by distilling India rubber in an iron vessel at 600° Fahr. it is purified by rectification, when it ia colorless, and has a sp. gr. of 680. Thi"' liquid is a solvent for caoutchouc, copal and very many resinous and oleaginous bodies when combined with alcohol. Ir the liquid state it is the lightest liquid known, but its vapor is so heavy that it may be transferred from one vessel to another by simple pouring. The liquid is very volatile, mixes readily with oils, and renders viscid oil paint liquid. Its constitution is C 8 II 7 . CAPERS. The buds or unexpanded flowers of the Capparis spinosa, in com- mon use as a pickle. • CAPSICUM. The berry or seed-ves- sel of different species of capsicum. The larger pods of the Capsicum annunm ) and the smaller ones of the C. baccatum or bird pepper, when powdered, form the Kyan pepper of commerce, so well known as a powerful condiment, and often use- ful as a stimulating medicine. Kyan pepper is often grossly adulterated with common salt, and occasionally red lead and earthy powders are said to be added to it : it often has a disagreeable rancid odor, owing to its being sprinkled with oil to prevent its dust affecting those who powder and sift it. CAPSTAN, sometimes called CAP- STERN. A strong massive piece of timber, in the form of a cylinder or trun- cated cone, round which a rope is coiled ; and being turned by means of bars or levers, it affords an advantageous mode of applying power to overcome an ob- stacle. The capstan is chiefly employed in ships, where it is used for weighing anchors, hoisting sails, &c. It is gene- rally placed vertically, the lower end be- ing' let down through the deck of the 18 CYCLOPEDIA OF THE USEFUL ARTS. [car ship, and the levers inserted in holes in the head or top; so that the force of the men can be exerted con- tinuously, and that there may be no ne- cessity for removing the levers from one hole to another, as is the case when it is placed horizontally. The power of the capstan may be greatly increased by adapting an arrangement of wheel work to it — an improvement which has been adopted for several years past in the navy. Improved forms of capstan have been patented in this country within the last few years. CARAT. A weight used by gold- smiths and jewellers. Originally the Kuara bean was used for this purpose — hence the name. A carat is a weight of 4 grains, used in weighing diamonds. The term carat is also used in reference to the fineness of gold, in expressing which the mass spoken of is supposed to weigh 24 carats, of 12 grains each ; and the pure gold is called fine. Thus, if gold be said to be 22 carats fine (or standard), it is implied that 22-24ths are pure gold, and 2-24ths alloy. In the process of assaying gold, the real quan- tity taken is very small, generally from 6 to 12 grains ; and this is termed the assay pound. It is subdivided into 24 carats, and each carat into 4 assay grains, and each grain into quarters; so that there are 384 separate reports for gold. "When the gold assay pound is only 6 grains, the quarter assay grain only weighs l-64th of a grain. 'This will give an idea of the accuracy required in the weights and scales used for such delicate operations. CAEBON in a perfectly pure state is the diamond : less pure forms are plumbago, graphite, coke, anthracite, and charcoal. For its various proper- ties, see these different heads. The soot and smoke of lamps, gas, and other substances of vegetable origin, is carbon almost pure. Carbon has many uses : it forms the base of a durable ink ; of crayons ; of the filtering substance, such as common charcoal, bone, and ivory black. It is an admirable manure for the soil : it is one of the best substances for reducing metals. When a piece of charcoal, which is very clean, and free from ash, is immersed in a solution of metallic salt, the metal itself is deposited on the charcoal with all its natural bril- i liancy. Salts of tin, copper, platina, sil- ver, and gold, furnish very beautiful i deposits. When the salts are too acid j these effects are not produced. The i weak salts of copper often yield upon | charcoal the most varied shades of color, j from the rich azure blue to the deep cop- per color. There are some parts of charcoal for which some metals exhibit a preference to that of others. In the three first forms it has a crys- talline arrangement. In the others it is amorphous, and generally presents itself as a black, brittle, hard substance, easily powdered, and quite unalterable at com- mon temperatures. CAEBON ATES. Salts containing car- bonic acid. They are recognized by the effervescence which is excited when they are put into dilute muriatic acid. Carbo- nate of lime is one of the most important of these compounds, forming the vari- eties of marble, limestone, calcareous spar, chalk, &c. Carbonate of lime con- sists of Lime 1 atom= ..28.. 56 Carbonic acid 1 " = . . 22 . . 44 1 50 100 Carbonate of potash and carbonate of soda are also important salts. (See Pot- ash, Soda.) Carbonate of ammonia is used in medicine ; it is a white pungent salt, commonly known under the name of smelling salt. Spirits of hartshorn is a solution of impure carbonate of am- monia, obtained by distilling bone or horn. CAEBONIC ACID. This important compound is obtained when any form of carbon, such as the diamond or pure charcoal, is burned in oxygen gas. It consists of 6 carbon -{-16 oxygen =22 carbonic acid ; or of Carbon . .1 atom 6 27-27 Oxygen.. 2 " ... .16.. . .72-73 1 22 100-00 100 cubical inches of carbonic acid gas Aveigh 47-3 grains. Under a pressure of 36 atmospheres, at the temperature of 32°, it becomes liquid; and when the pressure which retains it in the liquid state is removed, the rapidity of the evaporation, and the sudden and enor- mous expansion of the vapor, are such as to produce a degree of cold under which the acid solidifies, forming a white concrete substance possessed of very ex- traordinary properties. Mr. Faradav was the first who liquefied carbonic acid, but car] CYCLOPEDIA OF THE USEFUL ARTS. 79 it was first described as a solid by M. Thilourier. At common temperatures and pres- sures water absorbs its own volume of carbonic acid; under a pressure of two atmospheres it dissolves twice its vol- ume, and so on. Carbonic acid imparts briskness and a slightly pungent and sour taste to water thus impregnated with it : it also confers the effervescent quality upon many mineral springs. Car- bonic acid is recognised by its rendering lime-water turbid. It extinquishes flame and suffocates animals ; hence the miners call it choke damp. Carbonic acid is con- tained in marble, chalk, and all the va- rieties of lime-stone; from which it is extracted by strong heat, as in the pro- cess of burning lime ; or by the action of stronger acids, in which case the car- bonic acid escapes with effervescence. Mountains of lime-stone, therefore, are great natural repositories of carbonic acid. This gas is also produced during the respiration of animals, and is evolved in the process ot fermentation. CARBONIC OXIDE. A gas com- posed of Carbon . .1 atom 6 42-8 Oxygen.. 1 " .... 8 57-2 4 14 100-0 100 cubical inches weigh 30*2 grains. It is fatal to animals, and extinguishes flame ; but it burns in contact with air, and forms carbonic acid. It is obtained by passing carbonic acid over red-hot charcoal, or by heating a mixture of chalk or pounded marble and iron or zinc fil- ings to redness. It is not absorbed by water. CARBONIFEROUS. A geological term, generally applied to beds or strata containing coal. CARBOY. A large globular bottle of green glass protected "by basket-work, arboys are seldom used, except for con- taining certain acids and other highly corrosive liquids likelv to act upon stone- ware. A carboy of oil of vitriol usually contains about 160 lbs. of that acid, or 12 gallons of water. CARBUNCLE. The ancient name of a gem, probably corresponding with our precious aarnet. CARBURET OF SULPHUR. A lim- pid volatile liquid of fetid smell and acrid taste. It boils at 112° F., and eva- porates so rapidly as to congeal mercury in a vacuum. It is composed of two atoms of sulphur and one of carbon. It is used as a solvent for caoutchouc. CARBURETTED HYDROGEN. A generic name for the compounds of car- bon and hydrogen, of which there are several, viz. : oil and coal gas, oil of lem- ons, turpentine, naphtha, otto of rcses, &c. CARDS — Carding Machines. Instru- ments for arranging cotton and other fibres. After picking and disentangling, the cotton is in the form of a very clean, light, downy substance, consisting of short fibres thoroughly disentangled. But these fibres are not parallel: they lie across each other at every imaginable an- gle, and any attempt to combine them to- gether in this state would be fruitless ; they must be rendered parallel, and to effect this is the object of the beautiful operation of carding, one of those which have exercised such a large amount of in- ventive ingenuity. If we were to take two combs, and pass the teeth of one be- tween those of the other, we should have a rude idea of the process of carding, es- pecially if we had a few fibres of cotton entangled among the teeth : for the move- ment of the two combs would tend to ar- range the fibres in some degree parallel. A number of pieces of wire are inserted in a piece of wood or leather, so that all shall project to an equal distance and at an equal angle ; and if two such pieces of apparatuswere placed with their wires in contact, and moved in contrary direc- tions, a few fibres of cotton placed on the lower one would be combed out by the up- per one, and arranged parallel. In vari- ous stages of the history of the manufac- ture, the two cards have been arranged in different ways. Sometimes one was on a convex surface, and the other on a con- cave surface fitted to it ; sometimes one was on a cylinder, and the other on a flat surface ; sometimes both were on the surfaces of cylinders. But the principle of action is the same in all, and is nothing more or less than a process of combing. In some arrangements the cotton is brought into the" form of a " lap," or flat layer,' by the scutching-machine, and in that state transferred "to the carding-en- gine ; while in other cases the latter is fed by hand with cotton. These card-combs arc sometimes set on cylinders, and applied to the burring and carding of cotton and avooI. In 1848, letters patent were granted for the mode of constructing the hollow cy- linder, to which the teeth of burring or carding cylinders are to be attached. A light cylinder of tinned sheet metal is first 80 CYCLOPEDIA OF THE USEFUL ARTS. [car made, — wire, covered with tin, is then wound tight and spirally all over the con- vex surface of the cylinder. Metal pro- per for soldering is then poured over the surface thus formed, which renders the whole firm and compact, the surface is then turned true, and the cylinder is ready to receive the teeth of such charac- ter as may be desired. In the same year patents were granted for a new method of constructing burring cylinders. A proper cylinder is first con- structed for the reception of the teeth, wire of proper size is then rolled flat, and afterwards planed in such a manner as to leave a rib or shoulder its whole length on the one side, and a thin edge on the other. Notches are then filed into the thin edge at intervals, thus forming teeth. The convex surface of the cylinder is then grooved at proper intervals around its surface, and the toothed strips on the edge having the shoulder, are laid into I the groove, and the ridges of metal be- tween the grooves are forced down upon the shoulders to hold them in place ; or the toothed strips are wound upon the cylinder and soldered, and the cylinder is finished, the shoulders, &c, giving pro- per distance between the rows of teeth. A patent was also granted for a carding machine, in which a cylinder, like Park- hurst's burring cylinder, is made to work against the main cylinder. When cards are used the teeth will yield, and a knot, closely matted together, might be carried through the machine without being pro- perly opened ; but the cylinder above- mentioned would hold such a knot, and bring it successively in contact with the teeth of the main cylinder, until by de- priza it would be opened and carried for- ward. Another patent has been granted for improvements in this variety of machines, which consists principally in banding i*om the main cylinder, and thus giving a high speed to' the workers with little increase of power. Messrs. J. Lambert and J. Zimmerman, of Waterloo, New York, have made an improvement in the working of carding machines, for which they have taken mea- sures for a patent, and which is said to card double the quantity at least, in the same time, that has usually been done by the old mode of operation. The " workers," instead of carrying round the wool from the main cylinder, at once, by revolving in a contrary direction, re- volve with it, and carry the wool but a short distance to the strippers, and thus, by the way, they are geared ; the "work- ers" are rendered workers indeed, and not merelv in name. CAEM1NE. A brilliant lake, made of the coloring matter of the cochineal in- sect, combined with alumina and oxide of tin. It is of different shades, — either de- pendent on the amount of alumina pre- sent, or of the adulterations to which it is liable. Vermillion is a common one of these. It is always easy to discover the amount of impurity, as true carmine dis- solves in water of ammonia, and leaves the adulteration behind. Starch is a com- mon impurity. To make ordinary car- mine, take 1 lb. powdered cochineal, Si drachms of carbonate of potash, 1 oz. of alum, and 3£ drachms of fish glue ; boil the cochineal and potash together in thirty quarts of water in a copper, take it off the fire, and let it settle, then add the alum in powder : after fifteen minutes the liquor clears, and may be decanted from the sediment, — the bright clear fluid con- taining the carmine. This is next de- canted into another copper, the glue dis- solved in a large quantity of water added, and the whole boiled ; th*e carmine separ- ates from the liquid, and rises like a scum to the top ; this must be collected, and drained on a filter of canvas or linen. The China carmine is made by adding to the solution of cochineal and alum, when freed from sediment, a solution of tin (chloride), until the carmine ceases to be thrown down. Ordinary carmine may be brightened by dissolving in water of ammonia, and precipitating by acetic acid, washing in alcohol, and drying. Carmine, dissolved in ammonia, is used by painters, and called liquid carmine. Carmine is used in miniature painting, fine inks, water colors, and artificial flower tinting, because it is more transparent than the other colors. CAEPET. An ornamental covering for the floor. The manufacture of carpets is carried on to great perfection in this country. The principal varieties are the Brussels, Axminster, Wilton, Kidder- minster, and Venetian. They are gener- ally composed of linen and Avorsted. In some the pile is cut so as to give the car- pet the character of velvet, as in the Wil- ton carpets. Kidderminster or Scotch carpets are entirely fabricated of wool. The manufacture may be classed under two heads: that of double fabrics, and that cut to imitate velvets. The- Jacquard ■loom has lately been used in carpet manu- tacture. Plain Venetian carpets for stairs and car] CYCLOPEDIA OF THE USEFUL ARTS. 81 passages, are woven in simple looms, pro- vided with common heddles and reed. The warp should be a substance of wor- sted yarn so as to cover in the weft. Kid- derminsters are composed of two woollen webs which intersect each other, so as to produce definite figures. Brussels carpet- ing has a basis composed of a warp and woof of strong linen thread. In the warp there is added to every two threads of linen ten threads of woollen, of different colors. The use of the linen thread is to bind the worsted together, and is not visi- ble on the upper surface. The worsted yarn, which is raised to form the pile, is not cut ; in the Wilton it is cut. The following figure and description will ex- plain the construction of the three-ply imperial Scotch and two-ply Kiddermin- ster carpet-loom, which is merelv a modi- fication of the J acquard metier. The Brus- sels carpet-loom, on the contrary, is a draw-boy loom on the damask plan, and requires the weaver to have an assistant. Fig. a a a, is the frame of the loom, con- sisting of four upright posts, with caps and cross-rails to bind them together. The posts are about six feet high, c c, the cloth-beam, is a wooden cylinder, six- inches or thereby in diameter, of suffi- cient length to traverse the loom, with iron gudgeons in the two ends, which work in bushes in the side frame. On one end of this beam is a ratchet-wheel, with a tooth to keep it from turning round backwards by the tension of the web. r>, the lay, with its reed, its under and up- per shell, its two lateral rulers or swords, and rocking-tree above. There are grooves in the upper and under shell, in to which the reed is fitted, e, the hed- dles, or harness, with a double neck at- tached to each of the tower or card me • onanisms ff, of the Jacquard loom. The heddles are connected and work with the treddles u b, by means of cords, as shown in the figure, o g are wooden boxes for the cards. 11, the yarn or warp-beam. Mr. James Templeton, of Glasgow, Scotland, has taken out a patent in Eng- land for an improved method of manu- facturing carpets, the designs of which are produced from the weft threads, which are previously printed* to produce the design or pattern. He makes velvet- carpets by employing chenile weft, previ- ously printed, which weaves up into the Eatterns designed ; he also makes carpets y the printed weft, which work up into patterns on both sides of the carpet, like those of the ingrain carpet. The princi- ple of this important improvement in carpet-weaving to do away with the Jac- quard, lies in the mode of printing and preparing the weft previous to weaving. The most extensive manufacturers in the United States are at Thompsonville. They use 10,000,000 lbs. of wool, and 10,000 lbs. of flax-yarn per annum. They manufacture three-ply Brussels and Ax- minster carpeting ot the richest patterns, the weaving being mostly done at pre- sent on hand-looms. They have, how- ever, introduced power-looms into this factory, for weaving rugs and Axminster carpets. The wool for Axminster carpet- ing is first woven in a web, and afterwards cut in strips, forming what is called che- nile card ; this is done on a machine, in- vented by Messrs. Davidson and Parks, of Springfield, Vt., which is the first and only one of the kind, and has more than paid for itself in six months. This ma- chine has over 200 hundred cutters, or knives, which are attached to a cylinder, making some 300 revolutions, and cutting full two yards of the web per minute into strips, which being passed over a grooved cylinder, heated by having hot irons in- serted within it, it* is prepared for weav- ing. Besides the large carpet establish- ment, there is in the same village a fac- tory, 150 feet by 143 on the group, and five stories high, for the manufacture of knit shirts, drawers, and fancy ginghams. This establishment has 30 sets of wool cards, and 25 or 30 gingham rooms. CAKTHAMUS. {See Safflowek.) : 82 CYCLOPEDIA OF THE USEFUL ARTS. [< CASE. Is the receptacle for the types, from which the compositor gathers them separately, and arranges them in lines and pages to print from. They are al- ways in pairs ; one of which is styled the upper case, and is divided into ninety- eight boxes or recesses of equal size, in which are deposited the capitals, small capitals, accented letters, figures, &c. ; the other is styled the lower case, and is divided into fifty-four boxes or recesses, of unequal size, containing the small let- ters, spaces, &c, the letters most in use having the largest boxes assigned to them. The cases are two feet nine inches long, one foot four inches and a half broad, and a full inch deep. CASE HAKDENING. A process by which tools *and other iron articles have their surfaces converted into steel. This is sometimes effected by putting the arti- cles into an iron box filled with charcoal, and cemented together for some time ; by this means, a thin coating of steel is formed on the outside. Immersion of the articles in boiling water or boiling oil partially steels the" surface. Ferrocy- anide of potassium is used in powder for this purpose, thus : — the article when polished is made red hot, then rubbed with the powdered salt. It is decom- posed by the heat, and the iron is then quenched in cold water. Gas flame hard- ens iron verv well. CASHMERE SHAWLS. First im- ported from that province, now imitated in France to great perfection. They are made from the downy wool found about the roots of the hair of the Thibet goat. The oriental cashmeres are woven by slow processes, and bring from 500 tb 2000 dollars each, on sale, but with the draw loom and the jacquard loom the French shawls rival the oriental, and some of them have the advantage of be- ing woven without seam in a single piece. CASSAVA, or Tapioca, is obtained frincipaily from the Jatroplia Manioc. ts extraction is remarkable for the large quantity of hydrocyanic acid which the juice of that plant contains. When dis- tilled, it affords, as a first product, a li- quor which, in the dose of 30 drops, will cause the death of a man in the course of six minutes ; and it is well known that this acid does not pre-exist in the plant, but that it is generated in it, after it is grated down into a pulp. It would be interesting to discover in what state the substance exists, from which it proceeds. After the grating of the root, and washing of the pulp, this is dried upon hot plates, to agglutinate it into the form of concretions, constituting the tapioca of commerce. But the starch of the washed root floated in water, is spon- taneously deposited, and, when dried in the sun, forms Cassava flour, called mous- tache by the French. CASSIUS, PUEPLE OF. So called from its inventor. A beautiful purple used in porcelain painting, and for stain- ing glass. It is formed by immersing tin in a solution of gold. It is probably a mixture of oxide of tin and finely di- vided gold. CASTING— of Guns. A new method has been resorted to at the Cannon Foun- dry, near Pittsburgh, for the production of guns. Instead of bringing them from the mould solid, and afterwards boring them, they are cast with the proper bore, the core being carefully prepared so as to enclose a circle of cold water, which it receives and discharges in a continuous current, during the process of cooling, the object, probably, being to chill the inner surface more rapidly than the outer, and thereby give it a greater density and strength. The plan is the suggestion of Lieut. Rodman : and two guns — one cast on the old and the other on the new plan — having been subjected to the usual tests, the first exploded on the 84th, and the latter on the 255th round. This shows a great superiority over the com- mon mode of making cannon, and if fu- ture experiments substantiate this suc- cessful one, Lieut. Rodman's invention will come into general use. CASTING— in Metal. (See Foundry.) CATECHU. The extract of the Aca- cia Catechu, an astringent substance, consisting of tannin and extractive mat- ter imported from Bengal and Bombay. The tannin constitutes one-half of the extract, and unlike that from galls, is sol- uble in alcohol, and more soluble in water. It is much used for brown color in dye- ing and calico-printing. CATGUT. The strings of musical in- struments, clock cords, and a few other materials of support, are made of an ani- mal substance called catgut, which is the twisted muscular coat of the intestines of cattle and sheep. To separate the muscular from the peritoneal and mu- cous coats, the intestine is steeped, scour- ed, fermented, and inflated. It is then twisted, rubbed smooth with horsehair, bleached with sulphur, and dried. Tho bal] CYCLOPEDIA OF THE USEFUL MtTS. Italian catgut for violin and harp-strings is the finest. Lean animals furnish the best catgut ; hence this manufacture might in our Western States be made not only profitable, but of superior qual- ity. CAUSTIC, Lunar, is the salt obtained by evaporating gently the nitric acid so- lution of silver to dryness, in a silver vessel, continuing the neat until it melts ; and when in fusion, pouring it into moulds, or cast it into sticks, the size of the barrel of a common quill. CAVIAR. The salted row of the stur- geon : a manufacture confined to the Russians. CAULKING- SHIP consists in driving a quantity of oakum or old ropes un- twisted, and drawn asunder into the seams of the planks, or in the intervals, where the planks are joined together in the ships, deck, or sides, in order to prevent the entrance of water. After the oakum is driven into these seams, it is covered with hot melted pitch or resin to keep the water from rotting it. Among the Poles in Europe a sort of unctuous clay is used for the same pur- pose on their navigable rivers. CEDE A. The "fruit of a species of citron, having a thick peel, and an epi- dermis having a fragrant and essential oil. The peelis used in making liqueur. CELESTINE. Native sulphate of strontia; decomposed by ignition with charcoal into sulphuret of strontia, which is converted into nitrate by saturation with nitric acid, evaporation, and crys- tallization. The nitrate is used for fed light in theatres. CEMENTATION implies the imbed- ding of any solid substance in a pulve- rulent matter, and exposing both to ig- nition in an earthen or metallic case. Iron is thus cemented with charcoal to form steel, and bottle-glass with gypsum powder, or sand, to form Reaumur's porcelain. CEMENTS. Substances capable of taking the liquid form, and of being in that state applied between the surfaces of two bodies, so as to unite them by solidifying. They may be divided into two classes, those which arc applied through the agency of a liquid men- struum, such as water, alcohol, or oil, and those which arc applied by fusion with heat. The diamond cement for uniting broken pieces of china, glass, &c, which is sold as a secret at an absurdly dear price, is composed of isinglass soaked in water till it becomes soft, and then dissolved in proof spirit, to which a little gum resin, ammoniac, or galbanum, and resin mastic are added, each previouslv dis- solved in a minimum of alcohol. When to be applied, it must be gently heated to liquefy it ; and it should be kept for use in a well-corked vial. A glass stop- per would be apt to fix so as not to be removable. This is the cement cm- ployed by the Armenian jewellers in Turkey for glueing the ornamental stones to trinkets of various kinds. When well made it resists moisture. Shellac dissolved in alcohol, or in a solution of borax, forms a pretty good cement. White of egg alone, or mixed with finely sifted quicklime, will answer for uniting objects which are not ex- posed to moisture. The latter combina- tion is very strong, and is much em- ployed for joining pieces of spar and marble ornaments. A similar compo- sition is used by copper-smiths to secure the edges and rivets of boilers ; only bullock's blood is the albuminous matter used instead of white of egg. Another cement in which an analogous substance, the curd or caseum of milk is employed, is made by boiling slices of skim-milk cheeses into a gluey consistence in a great quantity of water, and then incor- porating it with quicklime on a slab with a muller, or in a marble mortar. When this compound is applied warm to broken edges of stoneware, it unites them very firmly after it is cold. A cement which gradually indurates to a stony consistence may be made by mixing 20 parts of clean river sand, two of litharge, and one of quicklime, into a thin putty with linseed oil. The quick- lime may be replaced with litharge. When this cement is applied to mend broken pieces of stone, as steps of stairs, it acquires after some time a stony hard- ness. A similar composition has been applied to coat over brick walls, under the name of mastic. The iron-rust cement is made of from 50 to 100 parts of iron borings, pounded and sifted, mixed with one part of sal- ammoniac ; and when it is to be applied, moistened with as much water as will give it a pasty consistency. Formerly flowers of sulphur were used, and much more sal-ammoniac in making this ce- ment, but with decided disadvantage, as the union is effected by the oxydize- ment, consequent expansion, and solidi- 84 CYCLOPEDIA OF THE USEFUL ARTS. fication of the iron powder, and any he- terogeneous matter obstructs the effect. The best proportion of sal-ammoniac is, I believe, one per cent of the iron bor- ings. Another composition of the same kind is made by mixing 4 parts of fine borings, or filings of iron, 2 parts of potter's clay, and 1 part of pounded pot- sherds, and making them into a paste with salt and water. When this cement is allowed to concrete slowly on iron joints, it becomes very hard. For making architectural ornaments in relief, a moulding composition is formed of chalk, glue, and paper paste. Even statues have been made with it, the paper aiding the cohesion of the mass. Mastics of a resinous or bituminous nature which must be softened or fused by heat are the following : Mr. S. Varley's consists of sixteen parts of whiting sifted and thoroughly dried by a red heat, adding when cold a melted mixture of 16 parts of black resin and 1 of bees'-wax, and stirring well during the cooling. Mr. Singer's electrical and chemical apparatus cement consists of 5 lbs. of resin, 1 of bees'-wax, 1 of red ochre, and two table-spoonsful of Paris plaster, all melted together. A cheaper one for cementing voltaic plates into wooden troughs is made with 6 lbs. of resin, 1 pound of red ochre, i of a pound of plaster of Paris, and j of a pound of lin- seed oil. The ochre and the plaster of Paris should be calcined beforehand, and added to the other ingredients in their melted state. The thinner the stratum of cement that is interposed, the strong- er, generally speaking, is the junction. Boiled linseed oil and red lead mixed gether into a putty are often used by cop- persmiths and engineers, to secure joints. The washers of leather or cloth are smear- ed with this mixture in a pasty state. The resin mastic alone is sometimes to- used by jewellers to cement by heat ca- meos of white enamel or colored glass to a real stone, as a ground to produce the appearance of an onyx. Mastic is like- wise used to cement false backs or doublets to stones, to alter their hue. Melted brimstone, either alone, or mixed with resin and brick dust, forms a tolerably good and very cheap cement. Plumber's cement consists of black resin one part, brick dust two parts, well incorporated by a melting heat. The bituminous or black cement for bottle corks, is pitch hardened by resin and brick dust. The following makes a good cement for mastic works : mix 50 parts of silicious sand, 50 parts of lime marl, or pulverized brown sand stone | and 8 parts of litharge. When the ce- ! ment is used it is to be ground up with j linseed oil. An excellent cement for resisting mois- J ture is made by incorporating thoroughly ! 8 parts of melted glue, of the consistence I used by carpenters, with 4 parts of lin- j seed oil, boiled into varnish with litharge. ] This cement hardens in about forty-eight i hours, and renders the joints of wooden ! cisterns and casks air and water tight. | A compound of glue with one-fourth its i weight of Venice turpentine, made as | above, serves to cement glass, metal, and j wood, to one another. Fresh made I cheese-curd, and old skim-milk cheese, j boiled in water to a slimy consistence, ! dissolved in a solution of bicarbonate of | potash, are said to form a good cement ; for glass and porcelain. The gluten of I wheat, well prepared, is also a good ; cement. White of eggs, with flour and ; water well mixed, and smeared over linen I cloth, forms a ready lute for steam joints in small apparatus. White lead ground upon a slab with linseed oil varnish, and kept out of con- tact of air, affords a cement capable of repairing fractured bodies of all kinds. It requires a few weeks to harden. When stone and iron are to be cemented toge- ther, a compound of equal parts of sul- phur with pitch answers very well. For hydraulic cement, see Mortar. Mr. Seating, of London, has patented a mode of combining ervpsum or other cement. calcareous substances with borax, for a Separate solutions of borax and crude tartar are made, and then mixed : cal- cined gypsum is then added in lumps to the liquor, and allowed to remain till it has absorbed all it will take up. It is then taken out and heated in an oven : again put in the solution and afterwards burned : when it is fit for use. CENTIGKADE DIVISION. The di- vision into grades or degrees by hun- dredth parts. A unity of any denomi- nation being divided into 100 equal parts, forms a centigrade scale ; but the term most frequently occurs in scientific works, in reference to the French divi- sion of the scale of the thermometer. The fixed points of the thcrmometric scale are the points at which water freezes on the one hand, and boils on the other ; the distance between these two points being divided into 100 degrees, the cen- cha] CYCLOPEDIA OF THE USEFUL ARTS. 85 tigrade scale is formed. In Fahrenheit's scale, which is usually applied to the thermometer in this country, the same distance is divided into 180 degrees ; a degree of the centigrade scale is there- fore greater than a degree of Fahrenheit in the proportion of 180 to 100, or of 9 to 5. Any number of degrees, therefore, on the centigrade scale, being multiplied by 9 and divided by 5, will give the equi- valent number of degrees of Fahrenheit. But in comparing temperatures express- ed by the two scales, it is necessary to recollect that the zero of Fahrenheit's scale is not placed at the freezing point, but 82° below it. An example will best show how this is to be taken into ac- count. Let it be required to express on Fahrenheit's scale the temperature corre- sponding to 10° centigrade. Here 10 X 9 -r 5 = 18 ; to this add 82, and we have 18 -+- 82 = 50 ; so that 10 degrees of the centigrade scale correspond to 50 degrees of Fahrenheit's. CENTK1FUGAL FORCE. The force by which a body in rotation tends to re- cede from the centre of motion : Centri- petal Force, that by which a body in motion is urged towards a centre, and compelled to describe a curve instead of a straight line. CENTRIFUGAL MACHINE. A ma- chine moved by the centrifugal force of water ; frequently called from its inven- tor, Barker's Mill. It consists of a hol- low metal cylinder or pipe of metal placed upright, and resting on a pointed steel pivot at A. The pipe is widened or ex- tended into a funnel shape at the top B, and is kept in its position by a vertical steel axis C D, passing through a frame at the top. Towards "the lower extrem- ity, two or more small pipes A E, A F, with closed external ends, are inserted at right angles to the axis. In the side of each of these an orifice is made as near as possible to the end, and on opposite sides, so that water from them may spout horizontally in opposite directions. Water is conveyed into the funnel at the top, through the pipe G, in such quantities that the tube is kept con- stantly full, while the discharge is going on at the orifice "near the extremities of the ho- rizontal pipes. In this state of things the re- sistance or reaction ge- nerated by the water issuing from the side-holes is such as to throw the vertical pipe, with its arms and axis, into rapid rotatory motion ; and this axis may communicate its motion or power to wheelwork or machinery, or to a mill-stone connected with its upper end. A machine of the same construc- tion, but having the arms at the upper end, and turned rapidly by means of a wheel and pinion, was invented by a Mr. Erskine for raising water. Centrifugal Machine is also used synonymously with Whirling Machime. CERAS1N. Cherry-tree gum : a name given to gums which swell and soften, but do not readily dissolve in water. CERATE. An ointment made of wax and oil, or spermaceti. CERATR1N. The bitter principle of Iceland moss. CEREAL GRASSES. Those which give flour fit for bread : such as corn, wheat, rye, barley, oats, rice, and millet. CERINE. One of the principles of wax : soluble in alcohol ; there is nearly 80 per cent, of it in bees-wax. It is white, melts at 134°, and is carbonized by sul- phuric acid. Cork grated and boiled in alcohol, furnishes a substance resembling cerine. CERITE. A siliceous oxyde of cerium. CERIUM. A metal named after the planet Ceres, and discovered in 1803 by Hisinger and Berzclius in a Swedish mi- neral termed cerite, and since found by Dr. Thompson in Allanite, a mineral from Greenland. It is said to be a white brittle metal, very difficult of fusion, and volatile when intensely heated ; but we are scarcely acquainted with it in its metallic state. Its equivalent number appears to be 48, on the hydrogen scale. CEROSTROTUM, or CESTROTUM. A species of encaustic painting, executed chiefly on horn or ivory with a particular sort of stylum called a cestrum, which was pointed at one end and flat on the other. The cestrum was heated, and with it the lines of the subject were burnt in, and wax introduced into the furrows made by the heated instrument. Doors Avere sometimes ornamented with this species of painting. CERULIN. Indigo dissolved in sul- phuric acid. CERUSE. Carbonate of lead. CETI NE. Pure spermaceti . CHABAZITE. A variety of Zeolite. CHAFF. The husk or withered calyx of grasses, and more especially of the bread corns. The term is also applied to straw or hay cut into very short lengths, 86 CYCLOPEDIA OF THE USEFUL ARTS. [CHA and used for mixing with corn, roots, or other food for horses or cattle. This kind of chaff, in greater lengths, is also used for mixing with mortar on some parts of the Continent, more particularly m Germany and Kussia ; and it is used as a substitute for hair in making plaster for rooms. Both stubble and cut hay were used by the ancient Egyptians in making bricks. CHAIN WORK. A peculiar style of fabric to which hosiery and tambouring belong. RAIL-CHAIR. Mr. Van Anden has secured a patent for a wrought iron chair, which displays much ingenuity, and is an useful invention. Figure, ISo. 1, is a view of the rail secured in the chair, and figure, No. 2, is a view of the chair it- self. Fie. i. D E are the sections of two rails placed together and secured at the joint on the chair by the jaws, B B. The chair is bolted down by the spikes, C C. In fig. 2 the chair is represented as made of a single block or plate, A, of wrought iron. The machine takes the bar of iron as it comes from the rolls — cuts it — forms the jaws, punches the holes, and completes the chair at a single blow. The chair is set in its proper place on the track, spiked down, and the ends of the two rails brought together within the jaws, Fig. 2. as represented in fig. 1. The jaws are then hammered down snug upon the bed plate of the rails, thus securing them in the most perfect manner. The advan- tages of the wrought over the cast iron rail chair admits of but little argument. CHALCEDONY. A semi-transparent silicious mineral, apparently formed by the infiltration of silicious matters origin- ally in a state of solution. It is of various colors, and often banded. The finest specimens are said to have been found at Chalcedon in Asia. CHALCOGRAPHY. The art of en- graving on brass and copper. CHALK. Earthy carbonate of lime. (See~Liuv.) CHALYBEATE. Medicines and min- eral waters containing iron are called chalvbeates. CHAMELEON MINERAL. A com- pound of manganesic acid and potash, which presents a variety of tints when dissolved in water. As it has of late been largely employed for whitening tal- low, palm oil, and" decoloring other or- ganic matters, it merits description. It exists in two states ; one of which is called by chemists the manganate of pot- ash, and the other the oxymanganate ; denoting that the first is a compound of manganic acid with potash, and that the second is a compound of oxymanganic acid with the same base. They are both prepared in nearly the same way • the former by calcining together, at a red heat, in a covered crucible, a mixture of one part of the black peroxide of manganese with three parts of the hydrate of potash (the fused potash of the apothecary). The mass is of a green color when cold. It is to be dissolved in cold water, and the solution allowed to settle, and become clear, but by no means filtered for fear of the decomposition to which it is very prone. When the decanted liquid is evaporated under the exhausted receiver of an air pump, over a surface of sul- phuric acid, it affords crystals of a beau- tiful green color, which should be laid on a clean porous brick to drain and dry. They may be preserved in dry air,, but should be kept in a well-corked bottle. They are decomposed by water, but dis- solve in weak water of potash. On dilut- ing this much, decomposition of the salt ensues, with all the chameleon changes of tint ; red, blue, and violet. Sometimes a green solution of this salt becomes red on being heated, and preserves this co- lor even when cold, but resumes its green hue the moment it is shaken. The ori- ohe] CYCLOPEDIA OF THE USEFUL ARTS. 87 ginal calcined mass, in being dissolved, always deposits a considerable quantity of a brown powder, which is a compound of the acid and peroxide of manganese com- bined with water. Much of* the potash remains unchanged, which may be reco- vered. A permanent oxymanganic salt may be made as follows : — Melt chlorate of pot- ash over a spirit lamp, and throw into it a few pieces of hydrate of potash, which immediately dissolve, and lorm a limpid liquid. When peroxide of manganese in fine powder is gradually introduced into that melted mixture, it immediately dis- solves, with the production of a rich green color. After adding the manganese in excess, the whole is to be exposed to a gentle red heat, in order to decompose the residuary chlorate of potash. It is now a mixture of manganate of potash, chloride of potassium and peroxide of manganese. It forms with water a deep freen-colored solution, which when oiled assumes a fine red color, in conse- quence of its becoming an oxymanganate, and it ought to be decanted off the sedi- ment while hot. By cooling, and still more after further evaporation, the oxy- manganate of potash separates in crystals possessed of great lustre ; but toward the end colorless crystals of chloride of potas- sium. CHARCOAL. A form of carbon, ob- tained by burning wood with the imper- fect access of air, or by heating or dis- tilling it in iron cylinders so constructed as to allow of the collection of the vola- tile products ; among which are tar, and pyroligneous acid, which is impure vinegar. Charcoal, exclusive of its im- portant use as a fuel, is possessed of some curious and valuable properties. It is a very bad conductor of heat ; and hence powdered charcoal is used to surround tubes and vessels which are required to retain their heat. It is not injured by air and moisture : hence stakes and piles are superficially charred to preserve them. It is infusible ; and provided air be care- fully excluded, it undergoes no change in most intense heats. It absorbs air and moisture, and also the coloring and odoriferous parts of many animal and ve- getable substances. Tainted flesh and putrid water are thus sweetened by the action of powdered charcoal, especially by what is called animal charcoal, ob- tained by burning bone, or the clippings of hides, leather, ~&c. Colored vegetable solutions filtered through well burned charcoal are materially decolored by it : when burned in oxygen or air, it is con- verted into carfomic acid. {See Diamond and Carbon.) Common charcoal, in- tended merely for fuel, is prepared by cutting pieces of wood from 1 inch to 3 inches in diameter, into lengths of from 1 foot to 3 feet, forming them into a coni- cal pile, and covering them with turf or clay ; leaving two or three small holes, close to the ground, for lighting the wood, and boring through the turf m the upper part of the cone a few other small holes for the escape of the smoke. The pile being lighted at the several holes along the bottom, continues burning with a slow smouldering flame for a week or two, and is allowed to cool before the turf is removed. In the case of very high winds, the holes to the windward, are stopped, to prevent combustion from going on with too great rapidity. Char- coal obtained by distilling beech- ivood, log-wood, willow, and other woods which are free from resin, is called cylinder charcoal. The charcoal employed in the manufacture of gunpowder is now always so prepared. It is not, however, by any means as good as that prepared by the burning of Eeat or turf. More charcoal is obtained y the slow combustion of the wood than by the quick. The quantity of charcoal obtainable from wood varies from 12 to 25 per cent. Animal charcoal is superior in its de- colorizing power to vegetable charcoal. In filtering ale through it, it was found to abstract all the bitter principle ; it has also the property of separating sulphate of quina, many salts of the alkaloids, as well as other saline matters from their solutions. Its absorbing power over gases is great- est when it is fresh. It acts with differ- ent energy on different gases ; thus, one cubic inch of charcoal will absorb of Ammoniacal Gas 90 cubic inches. Muriatic Acid 85 " Sulphurous Acid 65 " Sulphuretted Hydrogen ..55 " Carbonic Acid 35 " , Oyxgen 9i " Hydrogen \\ " Hence the great value of charcoal thrown into cesspools and privies, to ab- sorb odors ; hence its use, added to gua- na, fcecal matter, urine, or any substance giving off gases valuable for growth of vegetation. Its chief value as a manure depends on this property. Charcoal is occasionally used as a polishing powder. CHAKRED WOOD. Wood, the outer 88 CYCLOPEDIA OF THE USEFUL ARTS. [CHA surface of which has been carbonized by burning, in order to preserve it from de- cay when it is buried in the soil. CHARRING OF POSTS. The prac- tice of carbonizing by burning that por- tion of the surface of wooden posts which is to be inserted in the ground. The object is to prevent the posts from decaying, more especially at the surface of the ground, or, as the common phrase is, between wind and water. The prac- tice is common in most parts of Europe, and even in Russia and Sweden, though timber is there so abundant. Dipping the ends of the timber in oil of vitriol, diluted with four parts of water, chars the outside of the wood, and answers verv well for stakes and fence wood. CHASING. Embossing in metal. The work to be embossed as bassi relievi are punched out from the back, and then cut on steel blocks or puncheons, and cleared with small chisels or gravers. CHEESE consists of the curd of milk mixed with some of the fatty mat- ter and sugar of milk. Difference in the quality of the milk and the dairy man- agement determines endless variety in the produce. To separate the curd or casein it is necessary to acidify the milk, and adopt such other means as will sepa- rate the curd rapidly and effectually. The liquid portions have then to be expressed from the cake of curd. Any acid will coagulate milk, but rennet is the acidulous substance always used. Before adding rennet new milk should be heated up to 95° F. ; skim milk not so high. This separates the curd in a tougher and harder state. The milk should not be fire fanged in the heating. A naked fire is objectionable ; immersing the milk vessel in a larger one containing boiling water is the proper mode. Vessels with a double bottom might be used for this purpose. The rennet ought never to be putrid, nor added in too large quantity, ior then the curd is too tough. If too little, time islost. When acids, as vinegar, are used instead of rennet, the cheese is apt to have their flavor. The acid, formed by the addition of the rennet, should be separated slowly from the whey ? for if done hastily, the fat of the milk is squeezed out, and the cheese is poorer. The whey should, however, be completely removed, for as it contains sugar and lactic acid, if left behind, fer- mentation will set in. Curd-mills and cheese-presses arc used to effect this re- moval. The preservation of the fresh cake de- pends on the purity of the salt, and the mode of applying it. Cheese is then colored sometimes by saffron, but chiefly by annotto, in the proportion of i an oz. to 60 lbs. of cheese ; sometimes the marigold and carrot are boiled in milk, and used as coloring. In milk of average quality, there is from 4 to 5 per cent, of pure casein, which, if all extracted, would give, according to Professor Johnston, 6 to 7 lbs. of skim milk cheese, or 9 to 10 lbs. pure new milk cheese, in every 100 lbs. of milk ; and on an average, 8 to 10 lbs. of good milk in summer, will yield 1 lb. of whole milk cheese. The following abstract of Euro- pean cheeses, taken from Brandos Ency- clopedia, may be interesting : " The following are the principal British cheeses : Brickhat, formed of new milk and cream, chiefly in "Wiltshire, in the autumn, and sold in little square pieces about the size of brickbats. Cheddar, round thick cheeses, weighing about 150 or 200 lbs., with a spongy appearance, and the eyes or vesicles filled with a rich oil. Cheshire, large round thick cheeses, com- monly weighing from 100 to 200 lbs. each, — solid, homogeneous, and dry and friable rather than viscid. They are made from the whole of the milk and cream, the morning's milk being mixed with that of the preceding evening previously warmed. Derbyshire is a small white rich cheese. Bunfop, originally made in Ayrshire, but now general throughout Scotland, is large, round, white, buttery, and weighs from 30 to 60 lbs. This and the Derby- shire cheese are very much alike in form, color, and flavor. Gloucester, large, round, and mild; buttery rather than friable. There are two kinds, the single and dou- ble Gloucester : the single is made of the milk deprived of about half the cream, and the double of the milk with the whole of the cream. Green or Sage cheese may be made of any of the other kinds, by mixing the milk before it has curdled with a decoction of sage leaves, among which some put a few flowers of marigold and leaves of parsley. In the Highlands of Scotland the leaves or seeds of lovage are added to the sage, which communi- cate a very strong "flavor. Lincolnshire is made of new milk and cream; it is quite soft, not above 2 inches thick, and will not keep more than two or three months. Norfolk, the weight is generally from 30 to 50 pounds ; the curd" is dyed yellow with arnotto or saffron, and though not a rich cheese, it is considered a good keeper. Soft or Slipcoat is a small, soft, che] CYCLOPEDIA OF THE USEFUL ARTS. 89 rich cheese, which might almost be mis- taken for butter, if it were not white, and which must be eaten in a week or two after making. Stilton, so named from the town m Huntingdonshire where it was first brought into notice, but which is made principally in Leicestershire. It is solid, rich, buttery, and white, and, un- like all the other cheeses which have been mentioned, it is twice as high as it is broad. It is much improved by keeping, and is seldom used before it is two years old. It is the dearest of all English cheeses, the price being generally to~that of Chester as 2 to 1, or 2 to lj. In order to induce premature decay and the conse- quent appearance of age in these cheeses, it is said the makers sometimes bury them in masses of fermenting straw. Cotten- ham, so named from a town in Cambridge- shire ; it differs chiefly from the cream cheese of Stilton in being flat, broader, and superiorly flavored. The flavor is said to be owing to the rich grasses which grow on the fens. Suffolk, or skim-milk, is round and thin, weighing from 25 to 80 lbs. each, and is the best keeping cheese made in England. Wiltshire re- sembles the Cheshire, but is poorer, and of inferior flavor. It is apt to become scurfy, to prevent which it is generally coated over with red paint. Yorkshire, or cream cheese, is the same as the slip coat cheese, already mentioned. European Cheeses. — The most remark- able ot these are the following : Parmesan is chiefly made at Parma and other places in Lombardy, of the curd of skimmed milk hardened by heat. Its flavor is said to be owing to the rich pastures of that part of Italy, where all plants, from the greater quantity of bright sunshine than in Britain, have doubtless their aromatic properties greatly increased. Siviss cheese is of various kinds ; but the chief sorts are the Gruyere or Jura cheese, and Schabzieger or green cheese : the last is flavored with the seeds and leaves of the melilot (Mdilotis officinalis). German cheeses are of different kinds ; but none are celebrated, unless we except that of Westphalia, which is made up into round balls or short cylinders, under a pound weight each. The peculiar flavor which this cheese acquires, arises from the curd being allowed to become putrid before it is compressed. In Holland very good cheese is made, particularly the Edam and Gouda cheeses : the former is very salt, and keeps well at sea. In many parts of the Continent, and even in the interior of Poland and Russia, there are imitations of English cheese made ; but what may be called the indigenous cheese of the Russian empire is nothing more than salted curd put into a bag and powerfully pressed, and taken to market as soon as it is made, in the same manner as butter is. In some places, instead of a press, the whey is forced out of the curd by putting it into a long cloth midway be- tween the two ends, while a person at each end twists the cloth in an opposite direction, and thus wrings out the whey. In some miserable Russian villages the curd is exposed for sale in small lumps, retaining the marks of the fingers, which shows that no other pressure has been employed than what can be given with the hand. In France the Roquefort cheese is the most esteemed, and next that of Neufchatel. The former some- what resembles Stilton, but is much in- ferior, and the latter is a cream cheese, seldom exceeding a quarter of a pound in weight. The cheese manufacture is a large and important one in the Northern and West- ern States, and the exportation is great and increasing. New York is the chief station for export, and the quantity which reaches that city may be estimated from the following abstract from the Patent- Office Report for 1847. The Albany Journal gives the following statement of the amount of Cheese re- ceived at Albany and Troy during the past twelve years : 1836, pounds, 14,060,000 1S37, " 15,500,000 1838, " 13,810,000 1839, " 14,530,000 1840, " 18,S20,000 1841, " 14,170,000 1842, " 19,004,000 1843, " 24,331,000 1844, " 26,677,500 1845, " 27.542,861 1846, " 35,560,180 1847, " 40,S14,000 This last having a value of $2,860,854. The importation of cheese into Great Britain is larger than that of butter. The total quantity in 1846 from Europe amounted to 249,664 cwt., and from the United States to 91,901 cwt. The Ameri- can cheese, however, is said to have some faults which need to be corrected to ren- der it acceptable to the English market. These are stated by Mr. Coleman to be, first, the softness of the rind, which ren- ders them liable to crack, and which is imputed to their richness, and the remedy for which is to let the cheese, when taken from the press, remain in brine so strong 90 CYCLOPEDIA OF THE USEFUL ARTS. [cm that it mil take up no more salt, for four or five hours. It must not, however, be kept too long in the brine, as it may re- ceive injury. The second fault complain- ed of is the acid and sharp taste. This is imputed to some improper preparation of the rennek, and possibly to something wrong in the feed or pastures. Cheese of good quality is manufactured in Saxony from potatoes. These are boiled, peeled and pulpified with rasps. 1 lb. of sour milk is added to 5 lbs. of this pulp, mixed well and set aside for four days. It is then kneaded, the moisture drained off, and thev are potted. They improve by age. CHEMITYPE. A newly invented style of printing, the object of which is to su- persede, to a great extent, wood-cutting. By this method, an etching or engraving made in metal in the usual way, may be converted into a high relieve stamp, to be used for printing on an ordinary press, as is the case with common wood engravings. The following statement may in general illustrate the character of the invention: On a highly polished plate of pure zinc an etching or engraving is made in the usual manner, which, under common cir- cumstances, would be fitted for impres- sions on an engraver's press, having the same harmony and proportion of all the respective etched or engraved lines. The tracery thus deepened is now to be fused or melted down with a negative metal, and the original metal plate (zinc) cor- roded, or etched by means of a certain acid, thus making the characters of the former drawing appear in the shape of a high relieve stamp. This effect is only produced in consequence of the metal composition in the lines of the tracery not being acted upon by the acid on ac- count of the galvanic agency subsisting between the two metals, and the acid corroding only the zinc. As every drawing on the metal plate is completely exact on the relieve stamp, the practice is absolutely independent^ the exact and accurate representation of the original sketch is always to be expect- ed. Wood-engraving cannot, in most cases, be superseded by this novel me- thod; but in many other instances the new practice is preferable, chiefly when colored printing is required, in the repre- sentation of maps, plans, architectural drawings, &c, &c. At the same time, the correction or improvement of any drawing can be much better executed than in wood-engraving. CHIMNEY. (Fr. cheminee.) The place in a room where the fire is burnt, and from which the smoke is carried away by means of a conduit called a flue. Chimneys are usually made by projection from a wall, and recess in the same from the floor, ascending within the limits of the projection and recess. That part of the opening which faces the room is properly the fire-place, the stone or marble under which is called the hearth. That on a level with, and in front of it, is called the slab. The vertical sides of the opening are called jambs. The head of the fore- plate resting on the jambs is called the mantel; and the cavity or hollow from the fire-place to the top of the room is called the funnel. The part of the funnel which contracts as it ascends is termed the gathering, or by some the gathering of the wings. The tube or cavity of a paral- lelogrammatic form on the plan, from where the gathering ceases up to the top of the chimney, is called the flue. The part between the gathering and the flue is called the throat. The part of the wall facing the room, and forming one side of the funnel parallel thereto, on the part of the wall forming the sides of the funnels, where there are more than one, is the breast. In external walls, that side of the funnel opposite the breast is called the back. When there is more than one chimney in the same wall, the solid parts that divide them are called withs. And when several chimneys are collected into one mass, it is called a stack of chimneys. The part which rises above the roof for discharging the smoke into the air, is called a chimney shaft, whose horizontal upper surface is termed the chimney top. The covings were formerly placed at right angles to the face of the wall, and the chimney was finished in that manner; but Count Rumford showed that more heat is obtained from the fire by reflexion when the covings are placed in an oblique position. He likewise directed that the fire itself should be kept as near to the hearth as possible, and that the throat of I the chimney should be constructed much | narrower than had been practised, with j a view to prevent the escape of so much j heated air as happened with wide throats. ' If the throat be too near the fire, the j draught will be too strong, and the fuel will be wasted ; and if it be too high up, ; the draught will be too languid, and there I will be a clanger of the smoke being occa- sionally beat back into the room. Beforo Count Rumford directed his attention to this subject, smoky chimneys were very ' common ; but by studying his principles, : these at present seldom occur. chl] CYCLOPEDIA OF THE USEFUL ARTS. 91 Lieut. Mason, in a letter to the London Builder on the subject of smoky chim- neys, writes : " I have built many chim- neys in all possible situations, and have found one simple plan everywhere suc- ceeded, the secret being only to construct the throat of the chimney, or that part of it just above the fire-place, so small that a man or a boy can barely pass through it. Immediately above this the chimney should be enlarged to double its width, like a purse, to the extent of about two feet in height, and then dimin- ished again to its usual proportions. No chimney that I ever constructed thus, smoked." CHINA INK. The finest kind of this useful pigment is seldom met with in our market. According to a description in a Japanese book, it is made from the con- densed smoke or soot of burned camphor : and hence, when of the best quality, it has this odor. Most of the China ink is made from oil-lampblack occasionally dis- guised, as to smell, with musk, or with a little camphor black. The binding sub- stance is gelatine, commonly made from parchment or ass's skin; but isinglass answers equally well. A good imitation may be made by dissolving isinglass in warm water, with the addition of a very little alkali (soda), to destroy its gelatin- izing power, and incorporating with that solution, by levigation on a porphyry slab, as much of the finest lampblack as to produce a mass of the pi-oper consist- ence. The minute quantity of alkali serves also to saponify the oil which usu- ally adheres to lampblack, and thereby to make a pigment readily miscible with water. CH I NTZ. A peculiar pattern on print- ed calicos, in which flowers and other de- vices are printed in five or six different colors, upon white and colored grounds. A good chintz pattern in fast colors is one of the most surprizing and difficult efforts of the art. CHLORAL. A liquid, obtained by the action of chlorine eras upon alcohol. CHLORATE OF POTASH. A salt composed of chloric acid and potass. It is formed by passing chlorine gas through a solution of caustic potass till no more gas is absorbed, evaporating the liquor and crystallizing. By the action of the gas two salts are formed : a chloride of potassium and a chlorate of potass, — the former remains in solution, the latter crystallizes readily, and it may be separ- ated thus from the chloride. Washing and 1 ecrystallization are necessary to ob- tain a pure salt. Mr. Calvert's improved process consists in forming a mixture of 5s- ounces of burnt lime for 1 equivalent of caustic potash, and passing a current of chlorine through the not mixture. In this wa}' chloride of calcium and chlorate of potash are formed. The loss of potash is thus avoided. Chlorate of potash cry- stallizes in flat, pearly-looking plates, and has an unpleasant cool taste ; it does not bleach. It dissolves in six parts of cold water, and when heated to redness, gives out 39 per cent, of oxygen ; if rubbed hardly in a mortar, it crackles and gives off sparks. When rubbed with sulphur and phosphorus, it detonates danger- ously. A mixture of this salt with sugar and sulphuret of antimony, is used for tipping lucifer matches, as it explodes when rubbed on emery or sand-paper. It formed the detonating powder which was dropped in percussion caps ; but owing to trie rusting property of the gases pro- duced by explosion, fulminate of mercury is now preferred. Owing to its property of giving off oxy- gen readily when decomposed, it has been used to some extent in bleaching fats and oils. It contains 76 parts of chloric acid, and 48 of potassa, in 124 parts of the chlorate. CHLORATES. Combination of chloric acid with salifiable bases. CHLORIDE OF LIME— BLEACH- ING POWDER. Its composition is tot yet fully determined. The chief agent in bleaching appears to be the hypochlor- ite of lime, one of the constituents. It constitutes a large branch of chemical manufacture, which is carried on in con- nection with that of carbonate of soda. When hydrate of lime, very slightly moist, is exposed to chlorine gas, the lat- ter is eagerly absorbed, and a compound produced which has attracted a great deal of attention : this is the bleaching pow- der of commerce, now manufactured on an immense scale, for bleaching linen and cotton goods. It is requisite, in pre- paring this substance, to avoid, with the greatest care, all elevation of temperature, which may be easily done by slowly sup- ? lying the chlorine in the first instance, 'he product, when freshly and well pre- pared, is a soft, white powder, which at- tracts moisture from the air, and exhales an odor sensibly different from that of chlorine. It is soluble in about 10 parts of water, merely the unaltered hydrate being left behind ; the solution is highly alkaline, and bleaches feebly. When hy- drate of lime is suspended in cold water, 92 CYCLOPEDIA OF THE USEFUL ARTS. [CHL and chlorine gas transmitted through the mixture, the lime is gradually dissolved, and the same peculiar bleaching com- pound produced ; the alkalies also, either caustic or carbonated, may, by similar means, be made to absorb a large quan- tity of chlorine, and give rise to corres- ponding compounds ; such are the " dis- infecting solutions" of M. Labarraque. The most consistent view of the con- stitution of these curious compounds is that which supposes them to contain salts of hydrochlorous acid, a substance as remarkable for bleaching powers as Chlorine Lime j Oxygen I Calcium Chlorine Lime chlorine itself; and this opinion seems borne out by a careful comparison of tha properties of the bleaching salts with those of the true hypochlorites. Hypo- chlorous acid can be actually obtained from good bleaching powder, by distill- ing it with dilute sulphuric or nitric acid, in quantity insufficient to decompose the whole ; when the acid is used in excess, chlorine is disengaged. _ If this view be correct, chloride of cal- cium must be formed simultaneously with the hypochlorite, as in the following dia- gram : Chloride of calcium. Hyperchlorite of lime. When the temperature of the hydrate of lime has risen during the absorption of the chlorine, or when the compound has been subsequently exposed to heat, its bleaching properties are impaired, or altogether destroyed; it then contains chlorate of lime and chloride of calcium ; oxygen, in variable quantity, is usually set free. The same change seems to en- sue by long keeping, even at the common temperature of the air. In an open ves- sel it is speedily destroyed by the carbonic acid of the atmosphere. Commercial bleaching powder thus constantly varies in value with its age, and with the care originally bestowed upon its preparation ; the best may contain about 30 per cent, of available chlorine, easily liberated by lu. acid, which is, however, far short of the theoretical quantity. The general method in which this sub- stance is employed for bleaching is the following : The goods are first immersed in a dilute solution of chloride of lime, and then transferred to a vat containing dilute sulphuric acid ; the chlorine or hy- pochlorous acid thus disengaged in con- tact with the cloth, causes the "destruction of the coloring matter. This process is often repeated, it being unsafe to use strong solutions. White patterns are, on this principle, imprinted on colored cloth, the figures being stamped with tartaric acid thickened with gum-water, and then the stuff" immersed in the chloride bath, when the parts to which no acid has been applied remain unaltered, while the printed portions are bleached. For purifying an offensive or infections | atmosphere^ as an, aid to proper ventilation, I the bleaching powder is very convenient. The solution is exposed in shallow ves- sels, or cloths steeped in it are suspended in the apartment, when the carbonic acid of the air slowly decomposes the chloride. An addition of a strong acid causes rapid disengagement of chlo- rine. The value of any sample of bleaching powder may be easily determined by the following method, in which the loosely- combined chlorine is estimated by its ef- fect in peroxidizing a proto-salt of iron, of which two equivalents require one oi chlorine ; the latter acts by decomposing water and liberating a corresponding quantity of oxygen — 78 grains of green sulphate of iron are dissolved in about two ounces of water, and acidulated by a few drops of sulphuric or hydrochloric acid ; this quantity will require for per- oxidation exactly "l0 grains of chlorine. Fifty grains of the chloride of lime to be examined are next rubbed up with a little tepid water, and the whole transferred to the alkalimcter before described, which is then filled up to with water, after which the contents are well mixed by agitation. The liquid is next gradually poured into the solution of iron, with constant stirring until the latter has be- come peroxidized, which may be known by a drop ceasiug to give a deep blue precipitate with red ferrocyanide of pot- assium. The number of grain-measures of the chloride solution employed may then be read off, and since these must contain 10 grains of serviceable chlorine, the quantity of the latter in the 50 grains may be easily reckoned. Thus, suppose chl] CYCLOPEDIA OF THE USEFUL ARTS. 93 72 such measures have been taken, then Measures. Gms. chlorine. Measures. Gms. chlorine. 72 : 10 : : 100 : 13-89 The bleaching powder contains, therefore, 27*78 per cent. A partv of Germans have erected in Steubenville, Ohio, an establishment for the manufacture of soda ash and chloride of lime. It is the only one of the kind in the United States ; it is estimated that during the first year it will produce be- tween"$40,000 and $50,000 worth of soda ash, and nearly $20,000 in value of chlor- ide of lime. It is supposed that the amount of manufacture will be doubled the second year. CHLORIDES. Combinations of chlo- rine, corresponding with the oxides. Com- mon salt is a chloride of sodium ; that is, a binary compound of 'chlorine and sodi- um. Where there are two chlorides of the same base, the relative proportions of chlorine in them are almost invariably as 1 to 2 : hence the terms protochhride and bichloride. Calomel and corrosive subli- mate arc the protochloride and bichloride of mercury. The latter is frequently termed perchloride. In calomel, 200 of mercury are combined with 36 of chlo- rine, and in corrosive sublimate with twice 36, or 72. CHLORINE. This gas was discovered in 1774 by Scheele, who called it dephlo- gisticated muinatic acid • the French no- mcnclaturists afterwards termed it oxygen- ated muriatic acid, conceiving it to be a compound of oxygon and muriatic acid. This erroneous viow of its nature waa corrected in 1809 by Sir II. Davy, who gave it the present ntune, indicative i f its color. Chlorine is s. simple substanc ;, existing at common temperatures ar.d pressures in the gaseous state ; but wh^n subjected to a pressure of about fom at- mospheres, it become:! condensed iri) a yellow transparent liq aid, which io t. non- conductor of electricity. 100 cibical inches of chlorine, at mean temr/jiature and pressure, weign between 7c and 77 grains : water absorbs twice its volume, and acquires a yeJJow color, ur.d the pe- culiar suffocating odor of tho gas. When humid chlorine in exposed to a tempera- ture of 32°, it as* ames a crystalline form ; this hydrate of chlorine consists of 1 equi- valent of chlorine = 37 -f 10 of water — 9 •+• 10 or 90. Chlorine is not only unre- spirable, but very injurious when breath- ed, even if largely diluted ; a taper burns in it with a red smoky flame, and is soon extinguished. Some of the metals, when finely divided, spontaneously take fire in chlorine, such as brass leaf, or powdered antimony. A remarkable property ot chlorine is its power of destroying almost all vegetable and animal colors : hence the important application of this gas and of some of its combinations to the art oj bleaching. It also destroys the putrid odor of decomposing vegetable and ani- mal substances, and infectious effluvia of all kinds : whence its use in fumigation, and in preventing the spread of infecti- ous and contagious matter, and purifying noxious atmospheres. The great natural source of chlorine is common salt, which contains it in the pro- portion of about 60 per cent. It is pro- cured by decomposing common salt by the joint agency of sulphuric acid and peroxide of manganese. The best pro- portions are 3 parts of salt and 1 of oxide of manganese ; these are well mixed, and put into a retort with 2 parts of sulphuric acid previously diluted with 2 of water. Chlorine is evolved, and its extrication is quickened by the application of a gentle heat. Chlorine may also be obtained from a mixture of muriatic acid with half its weight of black oxide of manganese. The gas may be collected over water, and should be preserved in bottles with glass stoppers; if left in the contact of water, it is soon absorbed. (See Muriatic Acid.) CHLORIODINE, OR CHLORIODIC ACID. A compound of chlorine and iodine. CHLORITE. An earthy mineral of a green color, often found in the cavities and veins of slate rocks. CHLOROCARBONIC ACID. A com- pound formed by exposing a mixture of chlorine and carbonic oxide to the action ofliffht, CHLOROCYANIC ACID. A com- pound of chlorine and cyanogen. CHLOROFORM. A most valuable agent to the physician in producing tem- porary insensibility to pain : and a still more useful aid in the arts, where it has taken its place as a solvent for many resins, &c. It is obtained by distilling alcohol, woodspirit, or acetone with a so- lution of chloride of lime. One part of hydrate of lime is suspended m four parts of cold water, and chlorine passed through the mixture until nearly the whole lime is dissolved. A little more hydrate is then added to restore the al- kaline reaction, the clear liquid mixed with one part of alcohol or woodspirit, and, after an interval of 24 hours, cau- tiously distilled in a very spacious vessel. 94 CYCLOPEDIA OF THE USEFUL ARTS. [CHO A watery liquid containing a little spirit, and a heavy oil collect in the receiver ; the latter, in which is the chloroform, is agitated with water, digested with chlo- ride of calcium, and rectified in a water- bath. It is a thin, colorless liquid of agreeable ethereal odor, much resembling that of Dutch- liquid, and sweetish taste. Its density is 1*48, and it boils at 141° ; the density of its vapor is 4*1 16. Chloro- form is with difficulty kindled, and burns with a greenish flame. It is nearly in- soluble in water, and is not affected, by concentrated sulphuric acid. Alcoholic solution of potash quickly decomposes it with production of chloride of potassium and formiate of potash. Chloroform contains C* H CI 3 ; it is changed to formic acid by the substitu- tion of three eq. of oxygen for the three eq. of chlorine removed by the alkaline metal. It is difficult to obtain pure chloro- form. Gregory directs it to be agitated with oil of vitriol and filtered subse- quently through oxide of manganese : it will then be free from impurity and keep better. Chloroform has already been applied to many uses ; it is a valuable test for iodine and other bodies in the hand of the chemist : gutta percha dissolved in it, constitutes the collodion or artificial skin used by the surgeon in dressing abraded surfaces. It dissolves bro- mine and the essential oils, gun cotton, caoutchouc, copal and gum lac ; and if produced sufficiently cheap, would be a valuable substance in the manufacture of varnishes. The credit of first using sub- stances for producing insensibility, of which ether and chloroform are the chief, belong to this country — having been first applied by Dr. Jackson of Boston, and Mr. Morton. CHLOROMETER. An instrument for the purpose of testing the decoloring or bleaching powers of chloride of lime, by which the relative values of different samples of that important bleaching and disinfecting compound may be ascer- tained. CHLOROPHAlTE. A mineral, which, when recently broken, is green, but af- terwards becomes black. CHLOROPHANE. A species of fluor spar, which, when heated, shines with a beautiful pale-green light. CHLOROPHYLL. The green color- ing matter of the leaves of plants. CHOCOLATE is an alimentary prepa- ration of very ancient use in Mexico, from which country it was introduced into Europe by the Spaniards in the year 1520, and by them long kept a secret from the rest of the world. Linnaeus was so fond of it, that he gave the speci- fic name, iheobroma (food of the gods), to the cacoa-tree which produced it. The cacao-beans lie in a fruit somewhat like a cucumber, about 5 inches long and 3i thick, which contains from 20 to 30 beans, arranged in 5 regular rows with partitions between, and which are sur- rounded with a rose-colored spongy sub- stance, like that of water-melons. There are fruits, however, so large as to contain from 40 to 50 beans. Those grown in the West India islands, Berbice and De- marara, are much smaller, and have only from 6 to 15; their development being less perfect than in South America. After the maturation of the fruit, when their green color has changed to a dark-yel- low, they are plucked, opened, their beans cleared of the marrowy substance, and spread out to dry in the air. Like almonds, they are covered with a thin skin or husk. In the West Indies, they are immediately packed up for the market when they are dried ; but in the Caraccas, they are subjected to a species of slight fermentation, by putting them into tubs or chests, covering them with boards or stones, and turning them over every morning to equalize the operation. Dr. lire in his Dictionary of Arts, from which this article is condensed, gives an analysis of Guayaquil coco, made by him- self,' as follows : Concrete fat or butter of coco, dissolv- ed out by ether 87 Brown extractive, extracted by hot water, after the operation of ether. . 10 Ligneous matter, with some albumine 30 Shells 14 Water 6 Loss 3 100 Dr. U. thinks : " the solid fat of the coec I should be most intimately combined by i milling with the extractive, albumine, j and ligneous matter, in order to render ! it capable of forming an emulsion with water ; and, indeed, on account of the large proportion of concrete fat in the beans, some additional substance should be introduce to facilitate this emulsive union of the fat and water. Sugar, gum, and starch or flour, are well adapted for this purpose." The fatty matter is of the consistence of tallow, white, of a mild agreeable taste, called butter of cacao, and not apt to chr] CYCLOPEDIA OF THE USEFUL ARTS. 95 turn rancid by keeping. It melts only at 122° Fahr., ana should, therefore, make tolerable candles. It is soluble in boiling alcohol, but precipitates in the cold. It is obtained by exposing the beans to strong pressure in canvass bags, after they have oeen steamed or soaked in boiling water for some time. From 5 to 6 ounces of butter may be thus ob- tained from a pound of cacao. It has a reddish tinge when first expressed, but it becomes white by boiling with water. The beans, being freed from all spoiled and mouldy portions, are gently roasted over a fire in an iron cylinder, with holes in its ends for allowing the vapors to escape ; the apparatus being similar to a coffee -roaster. When the aroma begins to be well developed, the roasting is known to be finished; and the beans must be turned out, cooled, and freed by fanning and sifting from their husks. The kernels are then to be converted into a paste, either by trituration in a mortar heated to 130° F., or by the aid of an ingenious and powerful machine. The chocolate paste has usually in France a little vanilla incorporated with it, and a considerable quantity of sugar, which varies from one-third of its weight to equal parts. For a pound and a half of cacao, one pod of vanilla is sufficient. Chocolate paste improves in its flavor by keeping, and should therefore be made in large quantities at a time. But the roasted beans soon lose their aroma, if exposed to the air. CHEOMATYPE, is a new process of photography. It consists in washing f^ood letter-paper with the following so- ution : — Bichromate of potash, 10 grains • sulphate of copper, 20 grains ; distilled water, 1 ounce. Papers prepared with this are of a pale-yellow color, and may be kept for any length of time without injury, and are always ready for use. For copying botanical specimens, or en- gravings, nothing can be more beautiful. After the paper has been exposed to the influence of sunshine, with the object to be copied superposed, it is washed over in the dark with a solution of nitrate of silver of moderate strength ; as soon as this is done a very vivid positive picture makes its appearance, which then only requires washing in pure water. CHEOM1UM, {Chrome.) A metal dis- covered by Vauquelin in 1797. It exists chiefly in two native compounds ; the one formerly called red lead of Siberia, ; which is a chromate of lead ; the other, a '' compound of the oxides of chromium ! and iron. Chromium is a whitish, brit- tle, and very infusible metal ; sp. gr. 5-5. When heated with nitre, it is converted into chromic acid. Its equivalent num- ber is 28. It forms two compounds with oxygen, — a green oxide, and a red per- oxide ; the latter being sour, and com- bining with salefiable bases, is called chromic acid. The oxide consists of 28 chromium + 12 oxygen ; and chromic acid of 28 chromium -f 24 oxygen. Chro- mic acid is of a red color, and forms a variety of colored compounds, some of which are much used in the arts ; such as the chromate and bichromate of potash, largely manufactured for the use of cali- co-printers, and the chromates of lead, employed as yellow and red dyes and paints. The oxide of chrome is green, and furnishes a valuable color for porce- lain and in enamel. Chromic acid gives color to the ruby, and the green of the emerald is due to oxide of chrome. Chrome iron ore is found in abund- ance distributed over the United States. In Maryland, at the Bare Hills near Bal- timore ; and in Delaware county, Pa., it is found very plentifully. In that locality, one firm has upwards of 100 hands em- ployed, and are daily shipping the mi- neral to Baltimore. The proprietors of farms upon which it is found, receive $3 per ton for washed chrome — and in the rock state it is sometimes worth $5 per ton. Mr. W T ood's chrome iron ore mine, on the Eiver Ortorara, separating Chester and Lancaster counties, Pa., is probably the most extensive chrome mine in the world, being 170 feet deep — 200 feet long and 30 feet broad : the ore yields 93 per cent, of oxide of chrome. The mineral is also found in great abundance at vari- ous points east of the Mine Eidge, in Lancaster, Chester, and Delaware coun- ties, Pa., and is all, or nearly all, shipped to Baltimore, whence it is exported large- ly to Europe. This ore forms the basis of many of the colored preparations of chrome, for which see Dyeing. The chief application of this ore is to the production of chromate of potash, from which salt the various other prepa- rations of this metal used in the arts are obtained. The ore, freed, as well as pos- sible, from its gangue, is reduced to a fine powder, by being ground in a mill under ponderous edge-wheels, and sifted. It is then mixed with one-third or one- half its weight of coarsely bruised nitre, and exposed to a powerful heat, for seve- ral hours, on a reverberatory hearth, where it is stirred about occasionally. In CYCLOPEDIA OF THE USEFUL ARTS. the large manufactories of this country, the ignition of the above mixture in pots is laid aside, as too operose and expen- sive. The calcined matter is raked out, and lixiviated with water. The bright- J'ellow solution is then evaporated brisk- y, and the chromate of potash falls down in the form of a granular salt, which is lifted out from time to time from the bottom with a large ladle, perforated with small holes, and thrown into a draining- box. This saline powder may be formed into regular crystals of neutral chromate of potash, by solution in water and slow evaporation ; or it may be converted into a more beautiful crystalline body, the bichromate of potash, by treating its con- centrated solution with nitric, muriatic, sulphuric, or acetic acid, or, indeed, any acid exercising a stronger affinity for the second atom of the potash than the chro- mic acid does. Bichromate of potash, by evaporation of the above solution, and slow cooling, may be obtained in the form of square tables, with bevelled edges, or flat four- sided prisms. They are permanent in the air, have a metallic and bitter taste, and dissolve in about one-tenth of their weight of water, at 60° F. ; but in one- half of their weight of boiling water. Thev consist of chromic acid 13, potash 6 ; or, in 100 parts, 68-4 + 31-6. This salt is much employed in calico-printing and in dyeing ; which see. Chromate of lead, the chrome-yellow of the painter, is a rich pigment of vari- ous shades, from deep orange to the palest canary-yellow. It is made by add- ing a limpid solution of the neutral chro- mate (the above granular salt) to a solu- tion, equally limpid, of acetate or nitrate of lead. A precipitate falls, which must be well washed, and carefully dried out of the reach of any sulphureted vapors. A lighter shade of yellow is obtained by mixing some solution of alum, or sul- phuric acid, with the chromate, before pouring it into the solution of lead ; and an orange tint is to be procured by the additiorTof subacetate of lead, in any de- sired proportion. Lately great use has been made of the green oxyde to dyeing and painting on por- celain. This oxyde may be prepared by decomposing, with heat, the chromate of mercury, a salt made by adding to ni- trate of protoxyde of mercury, chromate of potash, in equivalent proportions. This chromate has a flne cinnabar red, when pure ; and, at a dull red heat, parts with a portion of its oxygen and its mer- curial oxyde. From M. Dulong's ex- periments it would appear, that the Surest chromate of mercury is not the est adapted for preparing the oxyde of chrome to be used in porcelain painting. he thinks it ought to contain a little oxyde of manganese and chromate of potash, to afford a green color of a fine tint, especially for pieces that are to re- ceive a powerful heat. Pure oxyde of chrome preserves its color well enough in a muffle furnace ; but, under a stronger fire, it takes a dead-leaf color. An improved method of making this valuable color for enamelling, is to mix intimately 45 parts of gunpowder with 240 parts of perfectly dry chromate of potash, and 35 parts of hydrochlorate of ammonia (sal ammoniac), reduce to pow- der, and pass through a fine sieve ; fill a conical glass or other mould with this powder, gently pressed, and invert so as to leave the powder on a porcelain slab of any kind. When set on fire at its apex with a lighted match, it will burn down to the bottom with brilliant corus- cations. The black residum, being elu- triated with warm water, affords a fine bright green oxide of chromium. CHROMIC ACID. As this substance is now much used by calico printers and bleachers, the following mode of obtaining it is subjoined. To 100 parts of yellow chromate' cf potash, add 136 of nitrate of barytes, each in solution. A precipitate of the yellow chromate of barytes falls, which being washed and dried would amount to 1 30 parts. But while still moist it is to be dissolved in water by the intervention of a little nitric acid, and then decom- posed by the addition of the requisite quantity of sulphuric acid, whereby the barytes is separated, and the chromic acid remains associated with the nitric acid, from which it can be freed by evapo- ration to dryness. On re-dissolving the chromic acid residum in water, filtering and evaporating to a proper degree, 50 parts of chromic acid may be obtained in crystals. This acid may also be obtained from chromate of lime, formed by mixing chro- mate of potash and muriate of lime ; washing the insoluble chromate of lime which precipitates, and decomposing it by the equivalent quantity of oxalic acid, or for ordinary purposes even sulphuric acid may be employed. Chromic acid is obtained in quadrangu- lar crystals, of a deep red color ; it has a very acrid and styptic taste. It reddens powerfully litmus paper. It is delique- chr] CYCLOPEDIA OF THE USEFUL ARTS. 97 scent in the air. When heated to red- ness it emits oxygen, and passes into the deutoxyde. When a little of it is fused along with vitreous borax, the compound assumes an emerald green color. CHRONOGRAPH, Locke's Electro C. This apparatus, for which an appropria- tion was made by Congress, has been put in operation at the National Observa- tory Washington. The clock case is of fine Italian marble, ornamented with glass panels, set in silver sashes. The dial and hands are like those of an ordinary clock, but the dial is cut out and made a skeleton, for the purpose of giving access to the elec- trical works behind it. The pendulum is made throughout of glass ; to compen- sate for the expansion even of glass by heat, the weight of the pendulum con- sists of four large glass tubes, placed side by side, like organ pipes, all filled four or five inches deep with quicksilver. The suspension of the pendulum con- sists of hardened steel cylinders, rolling on jewelled planes made of polished chrysolite. The mechanism by which the electrical contact surfaces are kept clean and bright is very ingenious and was suggested to Dr. Locke by Prof. House oi New York. It consists of a small platinum cylinder which is kept revolving with a wiper to keep it clean. Thts cylinder has also a longitudinal mo- tion, which by reciprocation makes the electrical contacts, which occur every second, travel in a spiral, which also re- volves. The result is, that the contacts are made every second for 36 days with- out occuring twice in the same place ; and even then it is a mere chance if the contacts are recommenced in the same track. Every time a contact is made a slight mark is left, by electrical action, on the platinum surface ; and when the spiral revolution has been completed, the cylin- der is mai-ked all over its surface by geo- metric intersections. The clock contains a duplicate interrup- ter or electrotome, which may be brought into action when desired. It consists of a little tilt-hammer, pivoted concentri- cally with the pendulum, and lifted by a little arm, or its equivalent, projecting from the pendulum itself. No less than four patents have been recently taken out in England for im- provements in Clocks moved by Electri- city. The first Electric Clock known was invented in 1815, by a German named Buzengeiger. This was a local clock. 6 The first Electric Clock to move in unison any number however distant, was inven- ted by Bain in 1840. Since then there have been a great number of modifica- tions such as combining a register with the clock, which is a most important im- provement. CHRONOMETER. A watch of pecu- liar construction, and great perfection of workmanship, used for determining geo- graphical longitudes, or other purposes where time must be measured with ex- treme accuracy. The chronometer differs from the ordinary watch in the principle of its escapement, which is so construct- ed that the balance is entirely free from the wheels during the greater part of its vibration ; and also in having the balance compensated for variations of tempe- rature. Marine chronometers generally beat half seconds, and are hung in gim- bals, in boxes about six or eight inches square. The pocket chronometer does not differ in appearance from the ordi- nary watch, excepting that it is generally a little larger. Chronometers are of im- mense utility in navigation ; and ships going on distant voyages are usually fur- nished with several, for the purpose of checking one another, and also to guard against the effects of accidental derange- ment in any single one. The accuracy whith which some of the better sort of chronometers have been found to perform is truly astonishing ; the error in a two months' voyage not exceeding two or three seconds. Chronometers, offered to the British Government to purchase, are placed in the Greenwich Observatory in the first or second week in January, and ranged on shelves round the chronometer room, and each is daily compared with the astro- nomical clock, and its rate carefully noted. This is continued until the mid- dle of July, during which time the tempe- rature of the room is much varied. In the coldest weather the room is thrown open, so that it is as cold inside as out ; and in summer the change is all of 70° of difference. The chronometers are also submitted day and night for about six weeks to 80 degrees heat, raised by fire. This is the usual trial. Chronometers are more in use in Ameri- can vessels than in those of any other na- tion. Mr. Loseby has introduced mercury into the chronometer to compensate for the loss of elasticity in the balance spring when subjected to heat. It acts equally by its fluidity and by its thermal expan- 98 OTCLOPEDIA OF THE USEFUL ARTS. [cm sion, and has been favorably reported on after trial, by the Astronomer Eoyal of England. CHRYSOBERIL. This mineral occurs in small rounded masses, and in crystals, it is very hard, transparent or translu- cent, and of different shades of greenish yellow. It is employed in jewelry. It has been brought from Brazil ; and is as- sociated in the sand of the Ceylonese rivers with rubies and sapphires. The cymo-pham of Kauy, which is a species of chrysoberil, consists of alumina 76*7, glucina 17*8, oxide of iron 5-5. CHRYSOLITE. A crystallized mineral, often of a golden yellow color. It is a ferriferous silicate of magnesia, and is sometimes used in jewelry. CHURN. An instrument used to sepa- rate the butter out of milk. So long as the milk is alkaline the butter will not separate, but when it becomes faintly acid the butter commences to gather on the top. Agitating the milk by in- troducing air hastens this by forming lac- tic and acetic acids in the milk. In 1850 Mr. Z. C. Robins of St. Louis, Mo., patented a telegraph churn, of which the following figure is an illustration. The nature of this invention is to agi- tate the cream or milk by the operation of the rotation of the beaters, (formed for that purpose) like to the actionproduced by knives for whipping eggs. The speci- fication says : — I produce this effect by forming the beaters on the agitator, of thin slats or boards, A A, secured to radial arms, B B, or discs, in such positions as to bring their sides at right angles, or nearly so, with the radii of the agitator. I generally construct the agitator of four series of beaters, as represented in the drawings, each series being composed of two, three or more beaters, one placed within the other, with narrow spaces be- tween each beater. Unless the agitator is driven at a high velocity, the particles of milk, &c, are not thrown off tangentially. It can operate in a round vessel as well as a square one, and produces butter at the usual temperature, in about ten minutes. When the butter has been made, it is collected into a roll in the centre, by reversing the motion. The wording of his claim is : " What I claim is the series of parallel floats or beaters A A, j formed and arranged within the agitator, substantially as above described, so that when their motion is reversed, their thick inclined rear edges will gather the butter into a roll in the centre of the agi- tator, substantially as herein set forth. CIDER. A fermented liquor made from the juice of apples. Cider is made in all the temperate climates of the world which are not sufficiently warm for ma- turing the grape, and where the cold is not so great as to reduce the inhabitant? to only the beer produced by a ferment- ed decoction of grain. Cider is formed by grinding or crushing the apples when ripe, either in a circular stone trough by a stone roller turned by a horse, or be- tween fluted or spiky, and afterwards between smooth rollers of wood or iron, driven by men. The apples, including the core and the seeds, being reduced to a pulp by crushing or grinding, the mass is put into a hair clotn and powerfully pressed ; and the liquor which runs from it is put into casks, where it is allowed to ferment, the casks being freely expo- sed to the air in the shade : the progress of the fermentation is then carefully watched, and as the sediment has subsi- ded the liquor is racked off; on the I proper time being chosen for doing this ' depends the excellence of the cider. The best cider, other circumstances being the same, is that in which the fermentation has gone on slowly, and where the vinous fermentation has not gone so far as to be- come acetous. The check to fermenta- tion consists in racking off from one cask to another. Before winter the casks are removed to a cellar, and by the following spring the liquor is fit for use, or bot- tling. The value of apples to produce this beverage of good quality is proportionate to the specific gravity of their juice. M. cla] CYCLOPEDIA OF THE USEFUL ARTS. 99 Couverchel has given the following tahle, illustrative of that proposition : — Juice of the green renette, queen apple (reinstte verte) . . . 1,084 English renette 1,080 Red renette 1,0 < 2 Musk renette 1,069 Fouilletrayd 1,064 Orange apple 1,063 Renette of Caux 1,060 Water 1,000 \\\ November,2, 340 kilogrammes of apples (2* tons English, nearly) are sup- posed to afford 1,000 litres (220* gallons) of pute eider; and 600 litres of a small ci- der made with the marc mixed with water and pressed. But many persons mix all together, and thus manuiacture 1,600 li- tres out of the ahove weight of fruit. In France, the fermented liquor, as soon as it is clear, is often racked off into casks containing the fumes of burning sulphur, whereby it ceases to ferment, and pre- serves much of its sugar undecomposed. It is soon afterwards bottled. Average cider should yield 6 per cent, of alco- hol on distillation. Cider-apples may be distributed into three classes, the sweet, the bitter, and the sour. The second are the best ; they afford a denser juice, richer in sugar, which clarifies well, and when fermented keeps a long time; the juice of sweet apples is difficult to clarify ; but that of the sour ones makes bad cider. Late ap- ples are in general to be preferred. Frederick Falkener, in the fourth vol- ume of the Royal Agricultural Journal of England, adverts judiciously to the ne- cessity of the presence of alkaline and earthy bases, in the soils of all deciduous trees, and especially of such as produce acid fruits. CINNABAE. An Indian name, given, according to Pliny, to a mixture of the blood of the dragon and elephant, and other substances of similar color. It is now exclusively applied to the red pig- ment called vermilion. It is a bisvlphuret of mercury, composed of 200 mercury-f- 32 sulphur. CINNAMON. The bark of the Cin- namomum zeylanicum. This tree is a na- tive of Ceylon, whence the finest cinna- mon is obtained ; it is of an astringent and highly aromatic and warm flavor, and yields by distillation an extremely fra- grant and pungent volatile oil, kept for pharmaceutical use under the name of oil of cinnamon. An inferior kind of cinnamon is often met with in commerce, which is remarkably deficient in flavor. CINNAMON STONE. (So called from its color.) A silicate of lime, alumine, and oxide of iron, from Ceylon. It oc- curs massive and in rounded pieces in the sand of rivers ; some of these are oc- casionally cut and polished for jewelry. CITRIC ACID. The acid of lime and lemon juice. It is largely made for do- mestic use and for calico printing. The juice is saturated with lime to separate the mucilage and extraneous matters. The citrate of lime so formed is treated with oil of vitriol, which taking the lime to form sulphate of lime sets the citric acid free : this is treated with water, and evaporated and crystallized. CIVET. A brown semifluid contained in a gland near the anus of the Viverra Civetta or civet cat. The odor, unless dilute, is very unpleasant, combined with other perfumes. CLARET. A term applied to several of the Bordeaux wines. An excellent claret is now manufactured in Texas from the Mustang grape. As many as five barrels have heen made upon a single plantation. The spontaneous production of this grape in Texas exceeds all belief. Thousands of hogsheads of wine, nowise inferior to French claret, could be manu- factured every year from this hardy, na- tive grape. CLAY. In chemistry, a term gene- rally applied to a variety of plastic earthy compounds of different colors, and hav- ing much attraction for water. They are essential in the manufacture of pottery, and consist of silica, with variable quan- tities of alumina, and generally some ox- ide of iron. Clay. In agriculture, one of the most common ingredients that enter into the composition of soils. Indeed, it may be as- serted that no soil whatever will maintain its fertility for any length of time without a due proportion of clay in its composi- tion. The most fertile soils in the world are the alluvial deposits on the banks of rivers ; and these, in an agricultural sense, all belong to clayey soil. In many cases the clays of agriculture are inti- mately united with calcareous earths, and in others with sands ; but in both cases these earths are in such a state of minute division, that the mixture has all the ap- pearance and the mechanical properties of a strong clay, and they are treated by cultivators accordingly ; and these, when examined, are found in many cases to contain a considerable proportion of lime, and in others of sand. The best wh*s,ts are every where grown on calcareous 100 CYCLOPEDIA OF THE USEFUL ARTS. [COA clays ; and also the best fruits and flow- ers of the Eosaceous kind, such as ap- ples, pears, plums, cherries, roses, &c. ; but it is remarkable that the grape, when grown on clayey soil, produces neither high-flavored fruit nor good wine. CLAYEY SOIL. Soil in which clay is the principal earthy ingredient. _ Soils of this description when first subjected to cultivation are expensive to labor, and uncertain in their produce; but after they have been drained, cultivated, limed, and manured for two or three ge- nerations, they become the most fertile of all soils, producing immense crops of wheat, beans, clover, rye-grass, &c. CLOCK. (See Watoh.) CLOTH. (See Textile Fabrics and Weaving.) Cloth, incombustible. At a late meet- ing of the British Association, Sir Da- vid Brewster read a paper " On a speci- men of incombustible cloth, for the dresses of ladies and children, manufac- tured in Dundee, Scotland, by Mr. Latts." This cloth is printed calico, of which several specimens were prepared by immersion in phosphate of magnesia. When inflamed it soon went out without the flame spreading, and Sir David stated that a spark of red coal would not ignite it. ' Cloth, Vulcanized IndiaEubber (pa- tented). Mix 15 parts of golden sulphuret of antimony with 100 parts of India rub- ber, and when it is thoroughly " masti- cated" as known to manulacturers, the articles are to be made up and then sub- mitted to heat in a boiler under pressure at a temperature varying from 260° to 280° Fahrenheit. Cloth, or Silk French Waterproof. The following is the process adopted by M. Collet :— Take 1 lb. of linseed oil, li lb. of white lead, 1 oz. of umber, and a little garlic; boil these ingredients for 12 hours over a slow fire, and when this composition acquires a skin upon its surface, it is fit for use. The cloth or silk is then to be immersed, being pre- viously spread over a frame, then hung up to dry, and afterwards rubbed smooth with pumice stone. The material is next to be coated with another composition, prepared in the fol- lowing manner : — Take 1 lb. of linseed oil, 1 oz. litharge, 4 drachms of sulphate of zinc, and 4 oz. of white lead, calcined to a yellow color : boil these in an iron pot until they assume the consistence of paste. This preparation is then to be spread over the cloth on the side of it, and then dried in a heated chamber. For covering of silk this operation should be repeated. Oil-skin cloth, perfectly flexi- ble and waterproof, is thus produced. COAL. This highly important sub- stance is found in beds or strata in that group of the secondary rocks which in- cludes the red sandstone and mountain limestone formations, and which is com- monly called the carboniferous group, or coal measures. From the peculiarities of their depositions they are often spoken of under the names of coal basins, and coalfields. There are two or three points, and those of much theoretical importance, respecting the origin of coal, on which geological authorities are nearly unani- mous . The one is, that our present coal is exclusively of vegetable origin, formed apparently from the destruction of vast forests ; and the prodigious quantities of timber drifted by some of the great rivers of the world into the present ocean render it not improbable that a similar formation may now be carrying on in the depths of certain parts of the sea. Secondly, from the nature of the preserved vegetables it appears probable that the climate of these parts was not merely tropical, but ultratropieal. It may also be inferred that the coal strata were deposited in the neighborhood, and often probably upon the very verge of exten- sive tracts of dry land ; for the trees that are found in coal strata are often like those of our submarine forests, as far as position goes. And, finally, the deposits of coal appear afterwards to have been elevated, and often singularly dislocated and contorted by forces acting from be- low, and probably of a volcanic nature. In some coal fields there are appear- ances which justify the term coal basin ; they are of limited extent, frequently dip as it were to a common centre, and con- sist of various beds of sandstone, shale, and coal, irregularly stratified ; and sometimes mixed with conglomerates, showing a mechanical origin. That "these deposites have taken place, and that the change of wood into coal has often been effected under great pres- sure, and often under the pressure of heat, seems evident from the appearance of some of the vegetable masses, and al- so from the manner in which the carbu- retted hydrogen escapes in the form of blowers and eructations from the strata, as if pent up in their cavities fender vast condensation, and even sometimes, per- haps, in a liquid form. Though there are often many bods and cob] CYCLOPEDIA OF THE USEFUL ARTS. 101 Beams of coal in one field, it is seldom that many of them are worked. They are generally of uniform thickness through a great extent, hut are some- times subject to irregularities. When less than two feet thick they are sel- dom worked to any great extent. The nature of the upper stratum, or stony matter of the roof, is very important : if compact, it is secure from falling, and keeps out water; if loose, the expenses incurred in supporting it absorbs the profits of the coal. The Beds of Coal in the U. S. are numer- ous and extensive, embracing the whole country from the border of New Bruns- wick to Tuscaloosa in Alabama, and from the Allcghanies to Vancouver's Island. The coal is of both kinds, anthracitic and bituminous. The former existing on the slope of the Alleghanies, where, by up- heaval of heated mineral masses, the bitu- men has been expelled, and the coal con- verted into anthracite. The bitumen in coal increases as the beds pass westward toward the Mississippi, where as well as on the Pacific shores, the quantity of bitumen is equal to that in English sea- coal. The geological survey of the state of New York has not brought to light any important deposit of coal in that state ; but it has been stated in the Al- bany livening Journal of 1850, that a seam of coal, four feet in thickness, has been discovered by Mr. J. N. Cutler, of that city, in Coeymans — a few miles only from Albany, on the farm of a Mr. Vanduzee. It is believed to extend through Albany, Green, and Schoharie counties. The three great coal-fields in the country are : — the Ohio, 740 miles long, and 180 wide, covering an area of 60,000 square miles ; the Illinois coal-field, covering 50,000 square miles ; and the Michigan, 15,000 square miles. Besides these, there are the numerous anthracitic basins in Pennsylvania and Virginia, the furthest being 100 miles S.E. of the margin of the Ohio coal-field. In passing across the coal-fields there is a gradual diminution of the bitumen eastward. The coal of every kind rests on the same basis of rock, with the same fossils distributed through it, and the particular coal-fields can be identified even when separated by an interval of 50 miles. The anthra- cite field is 5000 feet deep, and contains 50 seams of coal. The bituminous coal- field of Ohio is 2,800 feet deep, 3,000,000 tons of anthracite, and 1,000,000 tons of bituminous coal are raised yearly. The anthracite coal-mines on the Lehigh River, Pa., are worked like an open quar- ry on the slope of a mountain, rising 900 feet above the river. The coal is 60 feet thick, and surrounds the quarry in black glistening walls, capped by 40 feet of yel- low sandstone, and is conveyed by a self- acting railway for eight miles down a de- clivity, from 100 to 140 feet per mile, the whole of obtaining being about 4 cents a ton ; when quarried to some distance the bed splits up into branches. The anthra- cite district extends across two counties, Luzerne and Schuylkill. At Portsmouth, R. I., abed of anthracite has been worked for 25 years back. A mine of anthracite has been open in Worcester, Mass., at the head of the Blackstone Canal. The cost of transport of a ton of coal is — From Maunch Chunk to Philadelphia $1 93 From Maunch Chunk to New York . 2 42 From Penham to Philadelphia . . I 93 From Penham to New York . . 2 55 The value of coal exported in 1850 was $167,090. The coal imported in the same year was 180,439 tons, value $378,817. COBALT. From Kohold, " evil influ- ence," applied by the German miners, who considered it unfavorable to the presence of the more important metals. Cobalt is a brittle metal of a reddish gray color ; its specific gravity is 7*8. It fuses at a temperature a little below that required for the fusion of iron. It is magnetic. When heated red hot, and freely exposed to air, cobalt absorbs oxygen. Its equivalent number is 30 ; and the salifiable, or protoxide of cobalt, consists of 30 cobalt + 8 oxygen = 38 oxide of cobalt. The oxide of cobalt is nearly black ; but when in the state of hydrate', or when largely diluted by fusion with glass or borax, it produces its characteris-. tic blue color ; and as this color is perma- nent at very high temperatures, it is an invaluable article in the manufacture of porcelain and pottery, all the blue colors of which are derived from oxide of cobalt. When fused with glass it communicates a blue tint without impairing its trans- parency. A very deep blue glass of this kind when finely powdered acquires a pale and brilliant color, and is called smalt. Impure oxide of cobalt is known in com- merce under the name of zaffre. Cobalt is said by Stromeyer to exist in all mete- oric iron, although in very small quantity. In its ores it is always associated with ar- senic, and zaffre is prepared by roasting these native arseniurets of cobalt. COCCOLITE. A mineral of a concre- tional or granular texture. 102 QYCLOPEDIA OF THE USEFUL ARTS. [coc COCOON. The silken case which the larvae of certain insects spin for the purpose of a covering during the period of their metamorphosis, and which some spiders prepare as a protection to their ova during the development of the young. The cod or cocoon of the silk- worm is a well known example of the most valuable of these productions. COCCULUS INDICUS.^ The fruit of the Mervlspermum cocculus, imported from the East Indies. It contains a poisonous principle, which has been termed picro- toxia. It is often used to poison hshes ; a few handfuls of it ground into coarse powder, and thrown into a pond, bring the fish, in the course of a few hours, to the surface in an intoxicated or poisoned state ; but if quickly removed into fresh water, they recover. It is sometimes ad- ded to ale to increase its stupefying qua- lity. COCHINEAL. The Coccus cacti. This valuable insect was first introduced into Europe about the year 1523. It is im- Eorted from Mexico and New Spain. It jeds on several species of cactus. It is small, rugose, and of a deep mulberry color. They are scraped from the plants into bags, killed by boiling water, and dried in the sun. Those are preferred which are plump, of a peculiar silvery appearance, and which yield a brilliant crimson when rubbed to powder. Cochin- eal is sometimes adultered by the admix- ture of a manufactured article composed of colored dough. This is detected by the action of boiling water, which dis- solves and disintegrates the imitation, but has little effect upon the real insect. The principal component of cochineal is a peculiar coloring matter, which has been called carminium and cochinelia. It is obtained by digesting the powder of cochineal first in ether, which takes up fat, and then in alcohol, which dissolves the cochinelia. Acids change its color from crimson to an orange red, and alka- lies turn it violet. When mixed with re- cently precipitated aluminous earth, it forms a beautiful lake. Cochineal yields a brilliant scarlet dye, which is produced by fixing the coloring matter of the in- sect by a mordant of alumina and oxide of tin, and exalting the color by the ac- tion ot 3upertartrate of potash. {See Carmine and Dvking.) COCOA, MANUFACTURES FEOM. The cocoa manufactures are remarkable for simplicity of the process resorted to, and for the usefulness of the articles pro- duced, in many instances, from materials formerly thrown away as useless. The cocoa nut as it comes from the tree con- sists, first, of the outer husk, composed of fibres matted and adhering together ; secondly, the shell ; and thirdly, the ker- nel. The manufacturers up to the present time employed only the outer husk and kernel. Tlie natives of India have long used the fibres obtained by rotting the outer husk till the fibres can be separated by beating the husks. The fibres are spun into yarn by the native girls and women, by rubbing such fibres between the palm of the hand and the surface of the leg ; and in this manner is made the large quantity of Coir yarn brought into that country, and used for weaving-cloths for covering passages and rooms, and also matting for various uses. Notwith- standing this rude mode of spinning the fibres, up to the present time no better means have yet been introduced ; and the whole of the yarn employed in England is imported. This, however, may be ac- counted for, by reason of there having been no practical mode of obtaining the fibre in Britain from the husks till very lately. The husks are beaten to obtain the fibre, which consists 'of three descrip- tions : first, a light elastic fibre suitable for stuffing furniture ; secondly, a coarser fibre used for making mats ; and thirdly, a strong fibre used for brushes and brooms. The husks are soaked for some time, then subjected to the pressure of grooved rollers, and then by successive processes of carding, by revolving cylin- ders armed with bent teeth, the fibres are combed out, the separate descriptions of fibres being deposited in different re- ceivers. The uses of these fibres are for making brushes, brooms, mats, and mat- tresses. The kernels are dried in the sun, then pounded in mills to extract the oil ; but in more modern times the dried kernel has been pressed between mats in powerful presses. The oil for the most part is sent to England, and was formerly largely employed in the manufacturing of candles. The oil being, when it comes to London, of about the consistency of lard, requires pressing to separate the stearine from theelaine, and this is done between mats of cocoa nut fibre pressed in powerful presses. The stearine was used for candles at first alone, then in combination with stearic acid of tallow, producing what are called composite candles ; and it was the introduction of stearine of cocoa nut, combined with stearic acid, which constituted the first step to the great improvement which has com] CYCLOPEDIA OF THE USEFUL ARTS. 103 taken place in the manufacture of candles. The larger quantities of cocoa nut oil, however, are now exported to France to make soap, the use of such oil in candle making being now for the most part sub- stituted bv palm oil. It has lately been proposed m Ceylon, to employ the juice of the cocoa nut tree for the making of sugar, it being considered that each tree is capable of producing upwards of one hundred weight per annum, and that an acre of cocoa nut trees, requiring little cultivation, will produce at least twice as much sugar as an acre of sugar-cane re- quiring much more cultivation. COFFEE. The seed of an evergreen shrub, coffea Arabica, of the family liuhi- acem. It rises twenty feet high. The berry is imported from Arabia, the East and West Indies. In Java large quanti- ties are grown and exported. It grows upon large bushes, and the grains of coffee are formed two in a ber- ry, about the size and shape of our com- mon plum. The skin ot the berry is about as thick as that of the plum, and the color, when ripe, a pale scarlet. The bush is very productive. Every branch is loaded with the berries, which grow two in a place, on the opposite sides of each other, and about an inch and a half apart. When ripe, the skin bursts open, and the grains of coffee fall out upon the ground; but a more general way is to spread something tinder the bush, and shake the coffee down. After the outer skin is taken off there remains a kind of husk over each kernel, which is broken off (after being well dried in the sun) by heavy rollers. The coffee after this needs winnowing, in order to be freed from the broken particles of the bush. It has been said by some writers that one bush will not, with another, average more than a pound of coffee. Coffee might be cultivated with advan- tage in Florida. The analysis of the raw berry affords Cellular matter, 34 Moisture, 12 Fatty matters, 10 to 13 Glucose dextrin, 15*5 Legumen and casein, 3 Caffein, 3*5 to 5 Nitrogenized matters, 8 Essential oil and aromatic principles, - 005 Potash, lime, magnesia, phosphoric ) and sulphuric" acids, silica and V 6-697 chlorine, ) In 100 parts. The change coffee undergoes by roast- ing is not fully understood ; some of the essential oils are driven off, and the berry is charred ; the peculiar aroma is deve- loped, which is soluble in water, and is acid. COKE. The charcoal obtained by heating^ coal with the imperfect access of air, or by its distillation. The former is usually called oven coke; the latter gas coke, being abundantly produced in gas- works. The weight of coke usually amounts to between 60 and 70 per cent. of the coal employed. Coke is a valuable fuel for many purposes in the arts. COLCOT1IAE. Brown peroxide of iron. (See Rouge.) COLOPIIANY. The dark colored re- sin which remains after the distillation of oil of turpentine. COLUMBIUM. A metal discovered by Mr. Hatchett in 1801, in a mineral from Massachusetts in North America. It has since Deen found in a Swedish mineral called tantalite, but its ores are extremely rare. It is acidifiable, and hence the peroxide has been termed Co- lumbia acid. COLZA, OIL OF. The oil expressed from the seed of the Brassica oleracea, a species of cabbage. Colza oil is much used in France and Belgium for burning in lamps and other purposes. COMB. The name of an instrument made of a thin plate, either plane or curved of wood, horn, tortoise-shell, ivory, bone, or metal, cut out upon one or both of its sides or edges, into a series of somewhat long teeth, not far apart ; which is employed for disentangling, laying parallel and smooth the hairs of man, horses, or other animals. A thin steel saw bow, mounted in an iron or wooden handle, is the implement used by the comb-maker to cut the bone, ivory, and wood, into slices of from a twelfth to a quarter of an inch thiok, and of a size suitable to that of the comb. The pieces of tortoise-shell as found in commerce are never flat, or, indeed, of any regular curvature, such as the comb must have. They are therefore steeped in boiling water sufficiently long to soften them, and set to cool in a press between iron and brass moulds, which impart to them the desired form which they pre- serve after cooling. After receiving their outline shape and curvature, by proper flat files or fine rasps, the place of the teeth is marked with a triangular file, and then the teeth themselves are cut out with a double saw, composed of two 104 CYCLOPEDIA OF THE USEFUL ARTS. [com thin slips of tempered steel, such as the main-spring of a watch, notched with very iine sharp teeth. These slips are mounted in a wooden or iron stock or handle, in which they may be placed at different distances, to suit the width of the comb-teeth. A comb-maker, how- ever, well provided in tools, has an as- sortment ot double saws set at every or- dinary width. The two slips of this saw have their teeth in different planes, so that when it begins to cut, the most prominent slip alone acts ; and when the teeth of this one have fairly entered into the comb, the other parallel blade begins to saw. The workman, meanwhile, has fixed the plate of tortoise-shell or ivory between the flat jaws of two pieces of wood, like a vice made fast to a bench, so that the comb intended to be cut is placed at an angle of 45° with the hori- zon. He now saws perpendicularly, forming two teeth at a time, proceeding truly in the. direction of the first tracing. Dr. Ure mentions a much better mode of making combs, which is to fix upon a shaft or arbor in a lathe a series of circu- lar saws, with intervening brass washers or discs to keep them at suitable dis- tances ; to set in a frame like a vice, in front of these saws, the piece of ivory or horn to be cut ; and to press it forward upon the saws at an angle of 45 degrees, by means of a regulated screw motion. Wli en the teeth are thus cut, they are smoothed and polished with files, and by rubbing with pumice-stone and tri- p'oli. Mr. Bundy, of Camden Town, Eng- land, obtained a patent so long ago as 1796, for an apparatus of that kind, which had an additional arbor fitted with a se- ries of circular saws, or rather files, for sharpening the points of the comb-teeth. More recently, Mr. Lyne has invented a machine in which, by means of pres- sure, two combs are cut out at once with chisels from any tough material, such as horn or tortoise-shell, somewhat softened at the moment by the application of a heated iron to it. The piece of horn is made fast to a carriage, which is moved forward by means of a screw until it comes under the action of a ratchet- wheel, toothed upon a part of its circum- ference. The teeth of this wheel bring a lever into action, furnished with a chisel or knife, which cuts out a double comb from the flat piece, the teeth of which combs are opposite to each other. By this means, no part of the substance is lost, as in sawing out combs. The 1 same carriage may be used, also, to bear ' a piece of ivory in the hard state toward a circular saw, on the principles above explained, with such precision, that from J 80 to 100 teeth can be formed in the space of one inch by a proper disposition j of the tool. Bullocks' horns, after the tips are I sawed off, are roasted in the flame of a | wood fire, till they are sufficiently soft- I ened ; when they are slit up, pressed in i a machine between two iron plates, and [ then plunged into a trough of cold water, I whereby they are hardened. A paste of ! quicklime, litharge, and water, is used to ! stain the horn to resemble tortoise-shell. COMBINATION. A chem'-al term j which denotes the intimate union of dis- similar particles of matter into a homo- geneous-looking compound, possessed of properties generally different from those of the separate constituents. COMBUSTIBLE. Any substance which, exposed in the air to a certain temperature, consumes spontaneously with the emission of heat and light. All such combustibles as are cheap enough for common use go under the name of Fuel ; which see. Every combustible requires a peculiar pitch of temperature to be kindled, called its accendible point. Thus phosphorus, sulphur, hydrogen, carburetted nydrogen, carbon, each takes fire at successively higher heats. COMPASS. A name given to instru- ments contrived to indicate the magnetic meridian, or the position of objects with respect to that meridian. According to the purposes to which the instrument is chiefly applied, it becomes the mariner's compass, the azimuth compass, the varia- tion compass, each particular application requiring some peculiarity of construc- tion ; but whatever modifications it may receive, the essential parts are the same in all cases. These are a magnetized bar of steel, called the needle, having fitted to it at its centre a cap which is supported on an upright pivot, made sharp at the point in order to diminish the friction as much as possible, and allow the needle to turn with the slightest force. The mariner' 8 compass has a circular card at- tached to its needle, which turns with it ; and on the circumference of which are marked the degrees, and also the 32 points or rliomhs, likewise divided into naif and quarter points. The pivot rises from the centre of the bottom of the cir- cular box, called the compass box, which contains the needle and its card, and which is covered with a glass top to pre- coo] CYCLOPEDIA OF THE USEFUL ARTS. 105 vent the needle from being disturbed by the agitation of the air. The compass box is suspended within a large box, by means of two concentric brass circles or gimbals, the outer one being fixed by ho- rizontal pivots, both to the inner circle which carries the compass box, and also the outer box, the two sets of axes being at right angles to each other. By means of this arrangement the inner circle, with the compass box, needle, and card, al- ways retain a horizontal position notwith- standing the rolling of the ship. The principal requisites of a compass are intensity of directive force, and sus- ceptibility. The first of these is obtained by constructing the needle of the mate- rial and form best suited to receive and retain the magnetic virtue. A number of experiments on this subject were made by Coulomb, and more recently by Cap- tain Kater, an account of which, is given in the Phil. Trans, for 1821. Captain Kater found that the kind of steel capable of receiving the greatest magnetic force is shear steel ; and that the best form is that of a lozenge or rhomboid cut out in the middle, so as to diminish the extent of surface in proportion to the mass, it being found that the directive force of the needle, when magnetized to satura- tion, depends not on the extent of surface, but on the mass. Beyond a certain limit (about five inches) no addi- tional power is gained by increasing the length of the needle ; and needles ex- ceeding a very moderate length are apt to have several consecutive poles, the ef- fect of which is to produce a great dimi- nution of directive force. On this ac- count short needles, made very hard, are to be preferred. The azimuth compass, being intended to show the bearing of objects in respect of the magnetic meridian, has its circle divided merely into degrees, instead of the rhombs used in navigation, and is provided with sights to allow the angles to be taken more accurately. The variation compass, is designed to exhibit the diurnal changes in the devia- tion of the magnetic from the true me- ridian ; and the needle is generally made of much greater length than the mariner's compass, in order to render minute va- riations more sensible. Mr. Dent, of England, in 1845, made an improvement in the compass, which consists in placing the iv \gnetic needles and the card on an axis, instead of the 5* usual mode of suspension, the point be- ing higher than the centre of gravity, and subject when on shipboard to the law of pendulous bodies. Mr. Dent has also so improved the azimuth compass, that by turning an azimuth 180°, it effects the correction lor collimation ; and by in- verting the card, it being engraved on both sides, affords the means or determining the error of the zero on the ard, not co- inciding with the magnetic meridian. CONCRETE. In architecture and en- gineering a mass composed of stone chippings or ballast cemented together through the medium of lime and sand, usually employed in making foundations where the soil is of itself too light or bog- gy, or otherwise insufficient for the re- ception of the walls. The essential qual- ity of concrete seems to be that the ma- terials should be of small dimensions, so that the cementing medium may act in every direction round them, and that the latter should on no account be more in quantity than is necessary for that pur- pose. Architects and engineers nave much varied the proportions of lime and sand used. If the lime, which should be fresh and ground to powder, be good stone lime, it will bear three or four times its measure by bulk of sand. These, and the ballast or gallots, as the stone chippings are called, should, be thorough- ly turned over and mixed together. If the foundations be wet, the mixture will want very little, if any water; indeed, sometimes the ballast only is wetted, and then covered over with the lime and sand. It is then filled into the barrows, and run on to be dropped from a stage into the foundations. This latter opera- tion should be performed at as great a height as possible above the level of the trench, in order that the whole of the different particles of the composition may be compressed together so as to oc- cupy the least possible space. The stones employed should not exceed the size of a common hen's egg. The mass very quickly sets and becomes extremely hard. COOLEK. An apparatus used by brewers and distillers for cooling worts. The coolers generally consist of very shal- low vessels exposing great surface, and placed in the high and airy parts of the brewery: the cooling is sometimes as- sisted by fans, which agitate the air over their surfaces. Worts are also oc- casionally cooled by causing them to tra- verse metal pipes, which are surrounded by a counter-current of cold water. COP-SPINNER. A piece of machinery 106 CYCLOPEDIA OF THE USEFUL ARTS. [coi for this purpose was exhibited at the fair of the American Institute, N. Y., in 1849, which appears to combine the qua- lities of the throstle and mule in one frame. The rovings from bobbins, at the top of the frame, are drawn through drawing rollers, like the throstle-frame: and from the drawing rollers, the thread passes at once to a small traveller, mov- ing around a ring which surrounds the cop spindle, and the which ring has a coping motion up and down, to build the cop on the spindle, by a cam gearing be- low, connected by a rocking shaft to the main driving shaft. The whole of this machinery occupies no more room than the whole throstle frame ; no carriage, like the mule frame, is used ; the whole is compact and simple, and it does its work well. It is asserted that it will spin 100 per cent more yarn than the flyer spindle, with one half the power, com- pared to the quantity produced ; and that 2,820 spindles produces as much yarn as 4,600 spindles on the old machines. There can be no question about the su- perior and safe speed with which this machine can be driven. The inventors and proprietors are Mr. John C. Dodge and Sons, Dodgeville, Attleborough, Mnoa COPAIBA or COPIVI BALSAM. An exudation from the Copaifera officinalis, a South American tree : it is a liquid re- sin, and yields by distillation a consider- able quantity of a pungent volatile oil. A small teaspoonful taken twice a day in a glass of water proves diuretic, and is of use in the cure of gleet and the latter stages of gonorrhoea. A larger dose is aperient, and has been of service in the treatment oHhannorrhoids. COPAL. A generic name applied to clear gums? This substance is often improperly called gun copal. It is a pe- culiar resin, very difficultly soluble in alcohol ; hard, brittle, and inodorous ; its specific gravity varies from 1-04 to 1-13. It is the produce of the ETius copalinum and of the Elmocarpus copaliferm of the East Indies : a third kind ot copal is also brought from the coast of Guinea. It is used in varnishes. It dissolves in caoutchicine diluted with alcohol. COPPER. This metal was known at a very remote period ; and in the early ages of the world, before iron was in use, copper was the chief ingredient in do- mestic utensils and instruments of war. It is an abundant metal, and is found native, and in many ores ; of these the most im- portant are the varieties of pyrites, which are sulphurets of copper and iron. There are 19 principal ores of copper, and seve- ral subvarieties. There are no rules by which copper ores may be known exter- nally, but after fusion with nitre, water of ammona receives a deep blue tint from any cupreous ore. The ores are na- tive copper, sulphurets, oxides, silicates, carbonates, sulphates, phosphates, clo- rides, and arseniates. Native copper is found abundantly on the shores of Lake Superior, both in Canada and this coun- try, where it is found imbedded in trap, intruded through secondary rocks ; per- haps this is the largest district of native copper in the world. The mass disco- vered by Schoolcraft on the west bank of the river Onontagon weighs 12,200 lbs. It is now at Washington. "Large masses of pure copper are quarried at the several mines in that region fMinesota) to which attention was first called by Dr. Hutton. Some of these veins contain 10 per cent of silver, which brings its value up to between four and five thousand dollars per ton. The Eagle Harbor Mining Company drifted aiong a piece of na- tive copper ninety feet without finding its length and four feet downwards, without reaching its depth; its average thickness was 18 inches. The veins vary in thickness from 6 inches to 2 feet branching east and west, in small strings 2 inches thick, and 12 to 24 inches long. The trap in the interstices are charged with native copper to about 50 per cent. There are six very profitable veins in this shore. Dr. Jackson has shewn that these mines were worked by the native Indians many years back. Congress, in 1817, di- rected a survey of these mines to be made ; the report has not yet been sent in. In the working of the Cliff and Mine- sota mine the difficulty has been to get away pieces small enough. Seven pieces taken from the Cliff mine in 1850 weighed 29,852 lbs., and 4 from Minesota weighed 14,611 lbs. The latter company smelt their copper in New York. The copper is chiselled away with heavy hammers. The pyritic ores are the vitrious copper ore, which consists of 81 copper and 19 sulphur, found in the U. S. in old red sandstone. The purple copper ore con- tains iron with sulphur : it is not found in quantity. The grey copper ore con- sists of copper 52, iron 23, and 14 sul- phur. It occurs plentifully in Kussia, Chili, and Mexico. Yellow copper ore is the most abun- dant ore, found plentifully in this north- ern and southern continent. It contains copper 30, iron 32, sulphur 36 ; lead and arsenic 3. cot] CYCLOPEDIA OF THE USEFUL ARTS. 107 The red oxide, or tile ore, is the richest variety, containing 88-5 per cent of cop- per. It occurs in Peru and Chili. Azure copper and malachite are carbonates ; they are found in Pennsylvania and Lake Superior. The finest specimens of mala- chite are from the Siberian Ural Chain in Russia, where it occurs so massive that large doors 30 feet by 18 have been cut out of the mineral, and are now exhibited in the Crystal Palace, London. The ores are repeatedly roasted and fused to drive off the sulphur, and the oxide of copper is ultimately reduced by the joint agency of heat and carbon. Cop- per is distinguished by its color. Its spe- cific gravity is 8'6. It is ductile and mal- leable, and requires a temperature equal to about 2000° of Fahrenheit's scale for its fusion ; that is, nearly a white heat. Ex- posed to air and moisture, copper gradual- ly becomes covered by a green rust ; heated red-hot, it absorbs oxygen, and is super- ficially converted into a black oxide, which is the basis of the principal salts of cop- per ; it consists of 32 copper and 8 oxy- gen. It forms blue or green salts with the acids ; of these the sulphate of copper, or blue vitriol, is a good example. The salts of copper are poisonous ; and in consequence of the use of copper vessels for culinary purposes, food is sometimes contaminated by them. It is detected when in very minute quantities by the bright blue color produced by the addi- tion of liquid ammonia, and by a brown precipitate with ferrocyanate of potash. A clean plate of iron dipped into a solu- tion containing copper becomes covered with the latter metal in a metallic state. Two improvements in the smelting of copper ores have been suggested. One is to roast the sulphuretted copper ores with salt. The sulphur Is converted into sulphuric acid, which seizes on the soda of the salt. Its chlorine passes to the copper, forming a chloride, which can be dissolved out by water. The copper is separated from this solution by pieces of iron dropped into it. The other mode is by roasting to con- vert the ore into a sulphate of copper, and dissolve this in water. The copper is thrown down by iron as in the first instance. {See Metallurgy.) Bronze and Bell Metal are alloys of cop- per and tin. They are melted in cruci- bles, and cast in charcoal moulds. An alloy of 100 copper and 4 of tin makes a good metal for medals. Copper 100, and tin 14, affords a metal for edge tools equal in hardness to steel. Cymbal and Gong Metal consists of copper I 100, and tin 25. After being heated it ! should be suddenly cooled. Eor White Copper, «ee German Silver. Copper may be tinned by placing a sheet of tin on a well polished surface of copper, and subjecting them to a strong heat, a little resin or muriate of ammoni- um being sprinkled between the plates to prevent oxidation. COPPERAS. Green vitriol, or sul- phate of iron. COPPERPLATE. In engraving, a plate of copper highly polished on which an engraving is made. CORAL. A calcareous substance, the covering of the coral insect. It : ,s fished up in the Mediterranean, Red, and Indian sens ; mostly of a red tint, but also flesh colored, or white. It is used for making necklaces, crosses, &c, and is worked like precious stones. It is composed of carbonate of lime, with a trace of phos- phate. The debris of the coral animal washed on shore, or dredged up, forms a valuable manure. CORK. The bark of the Quercus liber, a species of oak which grows along the shores of Mediterranean Europe. It i9 removed from the tree by making circu- lar incisions, and connecting these by longitudinal ones; the bark is then Eeeled off, wetted to flatten it between oards ; it is then fire dried, which black- ens the surface. When burned, it forms a light black substance, known as Span- ish black. Corks are cut with the pores laterally; bungs have them downwards, hence they do not keep in the liquid as well. Cork is also used for inner soles, floats in water, models, and false limbs. Powdered cork, treated with alcohol, leaves 70 per cent of suberine ; treated with nitric acid, it is changed into resin, OXalic acid and suberic acid. CORROSIVE SUBLIMATE. The bi- cloride of mercury, composed of 200 mer- cury+72 chlorine. It is an acrid poison of great virulence : the stomach-pump and emetics are the surest preventives of its deleterious effects when accidental- ly swallowed ; white of egg has also been found serviceable in allaying its poison- ous influence upon the stomach. Its spe- cific gravity is 5*2. It requires 20 parts of cold water, but only two of boiling water, for its solution. {See Mercury.) CORUNDUM. A crystallized or mas- sive mineral of extreme hardness, and composed of nearly pure alumina ; it is usually almost opaque, and of a reddish color. It is allied to the sapphire. COTTON. The soft vegetable down in the seed vessels of the cotton plant 108 CYCLOPEDIA OF THE USEFUL ARTS. [cot (gossypium Tierhaceum), cultivated in this country, South America, the East and West Indies, and Egypt. It is an annual plant, which forms its seed in pods, which are triangular, and have each three cells ; in these lie the downy cotton. The fibres of cotton are very fine, delicate, and flexible ; under the microscope they are flat, triangular, and somewhat con- torted ; their sides are serrated, which explains the cause of their adhering to- gether, and enables them to be spun into thread. In the southern states, three kinds are cultivated : the nankeen cotton, the green seed, and the black seed cotton. The two first are upland and short staple variety. The last has a long fine staple. Two machines are used to clean the cotton from the seed, — the roller gin and the saw gin. The first consists of two small cylinders, between which the cotton is drawn, while the seed is prevented by its size from passing. The saw gin, in- vented by E. Whitney, is used for the black seed, which adhere too strongly to be separated by the rollers. His appa- ratus is a receiver, fitted on one side with wires an eighth of an inch apart; between these pass a number of circular saws, revolving on a common axis. The cotton is caught by the teeth of the saws, and drawn through the grating, which is too narrow to admit the seeds to pass. The cotton thus separated is swept off the saws by a revolving brush ; the seeds fall out at the bottom. The cot- ton crop of this country in 1848 was estimated at 1,066,000,000 lbs., value $74,620,000. The following is a tabular view of the value of raw and manufac- tured cotton for the last five years, with the amount of export to Britain and France. Raw Cottcn. Home Manufactured. Exported to Great Britain. Exported to France. Years. Raw Cotton. Manufac. Cotton. Cotton Wool. Manufac. Cotton. 1846 1847 1848 1849 1850 $42,707,341 53,415,848 61,998,294 66,396,967 71,984,616 $ 3,545,481 4,082,543 5,718,205 5,933,129 4,734,424 $27,707,717 35,841,265 41,925,258 47,444,899 48,884,453 $9,607 6,765 28 2,591 50 $10,080,485 10,381,318 11,428,850 10,185,713 14,395,449 $ 216 2,374 539 $296,563,066 $53,013,762 $201,803,592 $19,041 $56,471,798 $3,229 COTTON MANUFACTURE embraces so many operations, each of which is per- formed in various ways, and by mechan- ism variously termed, that it requires a volume of ordinary size to give a full de- scription of it. It is impossible, in the limits here assigned, to give more than a faint outline of the most common pro- cesses. The first process is that of separating and spreading it out in a light uniform mass, and is "termed batting and scutch- ing, or willeyingand spreading, according to the description of machinery employed for the purpose. This machinery consists, mainly, of revolving beaters which beat the cotton against gratings or screens, through which the dirt, sand and short broken fibres are blown by fans. The next process is that of carding, which serves to equalize the substance of the cotton, and dispose the fibres in a * The ginning operation is always |>ert'orine00 10.868,000 11,658,400 13,041,000 11,227,200 14,S20,000 16.796,000 18,772,000 4,368,000 4,680,000 4,836,000 4,805,000 5,148,000 4,304,000 6.240,000 6,864,000 7,176,000 7,800,000 8,4-M,000 '13,655,200 14,560,000 15,111,200 13,395,200 16,016,000 16,962,400 19,281,600 21,091,200 21,996,000 24,596,000 27,196,000 Total aggregate of males employed in eleven years, 208,800 ; females, 702,000. Total aggregate wages paid to females for eleven years, $138,715,200 ; males, $65,145,600. Total, $203,860,800. Average No. of males employed per year, for eleven years, 18,982 ; females, 63,818. Average aggregate paid females per year for eleven "years, $12,610,472; males, $5,922,327. Total, $18,532,800. The chief manufactures of cotton are carried on in the New England States : it cre] CYCLOPEDIA OF THE USEFUL ARTS. Ill is only of late years that manufactures have sprung up in the South ; at the pre- sent time in Georgia, there are 40 cotton mills working 60,000 spindles, and using 45,000 bales of cotton per annum. In Tennessee there are 30 factories, run- ning 30,000 spindles and 700 looms, and using 15,000 bales. In Alabama there are 12 lactones, working 15,580 spindles and 300 looms, and consuming 5,000 bales of raw cotton. A Table showing the number of Spindles run, and the annual increase of toorlc in U. 8. «! n^ m |NTo, of yiirds. Increase .»ji i maniifiietur- I of Xo. of J.'"** »!»*<**] „,. Ispin.Ji.s. No. ofyardB. 1838! 1.422.000 409.200,000 185,000 51,000,000 1839 ' 1.521 >,< !00 501 ,500,000 93,000 32,300,000 184011,530.000 51)4,900,000' 10,000 3,400,000 1841 1 1,375,000 45:-!,9(M>,000 decreas. decrease 1842ll.674.iM)0 552.5011,000, *97,000 *32,300,000 1843 ; 1,788,000 5s9,900,000j 114,000 37,400,000 1844:2,004,000 601,300,000 216,000 71,400,000 1845 12,174,000 717,400,000! 170,000 5(5,100,000 1846 j 2,207,000-748,000,000 1 93,000 30,600,000 1847 12,576,000 850,000,000,: 309,000 102,000,000 1848 2,800,000;918,000,000 ! 224,000! 68,000,000 * Gain after deducting what 1841 lost COURT PLASTEE. To make this, black silk is strained and brushed over ten or twelve times with the following preparation : — Dissolve £ an ounce of balsam of benzoin in 6 ounces of rectified spirits of wine ; and in a separate vessel dissolve 1 ounce of isinglass in as little water as may be. Strain each solution, mix them, and let the mixture rest, so that any undissolved parts may subside ; when the clear liquid is cold it will form a jelly, which must be warmed before it is applied to the silk. When the silk coated with it is quite dry, it must be finished off with a coat of a solution of 4 ounces of Chian turpentine in 6 ounces of tincture of benzoin, to prevent its cracking. CEANE. In Mechanics, a machine for raising heavy weights, and depositing them at some distance from their origi- nal place ; for example, raising bales from the hold of a ship, and depositing them on the quay. A jib or transverse beam, inclined to the vertical in an angle of 40° or 50°, is constructed, which, by means of a collar, turns on a vertical arbor. The upper end of the jib carries a fixed pulley, and the lower end a cylinder, which is put in motion by a wheel and pinion, or cog wheel, or merely with a handle. The weight is made fast to a rope which pas- ses over the pulley and is wound round the cylinder. On turning the cylinder, the weight is raised as far as necessary j the jib is then turned on its arbor till the weight is brought immediately over the spot where it is to be deposited ; when, by withdrawing the moving power, it is allowed to descend by its own gravity. Cranes may be constructed of immense Eower. They are generally turned by uman force ; sometimes, however, by a steam engine. CEANK. A mechanical contrivance for changing a revolving into an alternate motion. An iron axis is bent in some part of its length out of its rectilinear di- rection. As the axis turns, the bent part describes the circumference of a circle, and gives a reciprocating motion to a pis- ton rod attached to it. Crank. In Nautical language, a ship is said to be crank, when by the form of its construction, or by want of a sufficient quantity of ballast or cargo, or by being loaded too much above, it is incapable ? p carrying sail without being exposed to the danger of oversetting. CEAPE. A species of gauze made of raw silk woven without crossing. It is stiffened with gum-water. CRAYONS. Colored cylinders used for drawing upon paper ; they are usually made of a fine pipe-clay, colored with metallic pigments or carmine. Crayons containing plumbago are styled solid lead pencils. General Lomet proposes the following composition for red crayons : He takes the softest hematite, grinds it upon a por- phyry slab, and then carefully elutriates it. He makes it into a plastic paste with gum arabic and a little white soap, which he forms by moulding, as above, through a syringe, and drying, into crayons. The proportions of the ingredients require to be carefully studied. Crayons, Lithographic Various form- ulas have been given for the formation of these crayons. One of these prescribes, white wax 4 parts ; hard tallow soap, shellac, of each 2 parts ; lamp black 1 part. Another is, dried tallow soap and white wax, each 6 parts; lamp black 1 part. This mixture being fused with a gentle heat, is to be cast into moulds for forming crayons of a proper size. CEEAM. A semifluid yellowish sub- stance which collects on the surface of milk, and which is made into butter by the process of churning. When the milk of any animal is allowed to stand for some time, it spontaneously undergoes certaiD changes ; this substance rises to the sur- face and forms a thin stratum, which is 112 CYCLOPEDIA OF THE USEFUL ARTS. [CRO called cream, and which consists chiefly of oily particles ; while the milk below, which of course is thinner than it was before the cream separated from it, is of a pale, blueish color, and consists of curd, coagulum, or the matter of which cheese is made. When cream is kept for some days it gradually becomes thicker, and fmrtially coagulated ; and if put into a inen bag, and suspended from the ceil- ing of a cool room, it will acquire the consistence of cheese ; and this is one among other modes of making cream cheeses. When cream is shaken by churning, it is resolved into its compo- nent parts, and hence we have butter and buttermilk. In order to make butter it is not always necessary that the cream should be separated from the milk ; but whether separated or not, the process is facilitated by allowing the liquid to stand for some time, during which a part of the sugar contained in the serum is changed into an acid, which shortens the process of churning by facilitating the separation of the butter from the milk. When either cream or milk is churned without having previously become sour, the pro- cess is much more tedious; and some- times, from causes not easily accounted for by the dairy-maid, it is unsuccessful, and the milk is said to be bewitched. The true cause, however, is the want of acid- ity ; because it has been found that the addition of a small portion of vinegar will dissolve the charm, and cause the almost immediate appearance of butter. Cream, when separated from milk, and kept till it has become acid, is frequently mixed with milk newly drawn from the cow ; and this eaten with sugar is one of the most delicious preparations of the dairy. Common clotted cream is simply milk and cream in a coagulated state, and sour. When the clotted cream is broken and stir- red, and the whey drawn off, the mass may be turned into cheese by artificial pressure, by whioh the whey is separated instan- taneously ; or by suspending it in a po- rous bag, in a cool airy situation, when it will be separated by degrees. CEEOSOTE or KREASOTE. A color- less, transparent, oily liquid, separable from wood-tar and pyroligneous acid, by repeated distillation and rectification ; it appears to be the principle to which the antiseptic power or wood-tar, smoke, and crude pyroligneous acid is owing. Creosote dissolves several salts, particu- larly the acetates, and the chlorides of calcium and tin ; it reduces nitrate and acetate of silver. It also dissolves indigo blue ; a remarkable circumstance. Its action upon animal matters is very inter- esting. It coagulates albumen, and pre- vents the putrefaction of butchers' meat and fish. For this purpose these sub- stances must be steeped a quarter of an hour in a weak watery solution of creo- sote, then drained and hung up in the air to dry. Hence Riechenbach has in- ferred that it is owing to the presence of creosote that meat is cured by smoking ; but he is not correct in ascribing the effect to the mere coagulation of the albu- men, since jibrine alone, without creosote, will putrefy in the course of 24 hours, during the heat oi summer. It kills Slants and small animals. It preserves our paste unchanged for a long time. Creosote exists in the tar of beech- wood, to the amount of from 20 to 25 per cent., and in crude pyroligneous acid, to that of H. It ought to be kept in well-stoppered bottles, because when left open it becomes progressively yellow, brown, and thick. CROTON AQUEDUCT. This beauti- ful structure has been built after the plan of the Eoman buildings — that is, in chan- nels of masonry, rather than in metal pipes. The following account is abridged from Tower's work on the Crotpn Aque- duct: Dr. Brown, in 1798, first called attention to the necessity of a good supply of wa- ter for the city of New-York. In the next year the Manhattan Company sank wells of great depth. In 1834, an act passed the Legislature, authorizing five Water Commissioners to examine and consider ail matters relative to a supply of water to the city. These Commission- ers decided in favor of using the Croton River, and bringing it in a closed aque- duct of masonry, at an estimate of $5,412,336 72. The work was commenced in May, 1837, and the 22d June, 1842, the aqueduct received the water from the fountain reservoir on the Croton ; on the 27th it entered the receiving reservoir in the city, and on 4th July it was admitted into tne distributing reservoir. The sources of the Croton River are in Put- nam county, 50 miles from New-York ; they are about twenty lakes or ponds, oc- cupying about 3,800 acres. The water is so remarkably clear and pure, that the native Indians called it clear water. The dam on the Croton River is thirty-eight feet above the original level of the water- flow, and sets the water back about six miles, forming the fountain reservoir, which contains an area of 400 acres. This CRU] CYCLOPEDIA OF THE USEFUL ARTS. 113 large reservoir allows the water to settle before entering the aqueduct, and it has an available capacity of 600,000,000 gal- lons ; this has been looked on as sufficient store for one-third of a million of people for ninety days, a longer period than any drought would last. The minimum flow of water in the river where the aque- duct begins, is 27,000,000 gallons in twenty-four hours. The aqueduct itself is calculated to convey 60,000,000 gallons in that time. From the fountain reser- voir to the receiving reservoir is thirty- eight miles, the aqueduct for which is of stone, except where the Haarlem Kiver is crossed over, and in passing a deep valley in the island, where iron pipes are used. These pipes descend and rise again, so that they are always full. The surface of the reservoir is 166£ feet above the level of the tide at New-York ; that of the receiving reservoir is 119 feet, so that the fall of the river during its course through the 38 miles of aqueduct, is 47 & feet. From the receiving reservoir it is carried in iron pipes (two miles) to the distributing reservoir, where the surface of the water is 115 feet above the tide level. At suitable places on the line of aque- duct six waste weirs are constructed, to discharge surplus water in such a mode, that when the water reaches a certain level, it flows off at the side. For ventilation, hollow cylinders of stone are erected over the aqueduct, and rise 14 feet above the surface of the ground. These occur at every mile, and at every third mile there is one having a door to allow of entrance into the aque- duct ; these have a diameter of four feet, the former only of two ; the top is cov- ered by an iron grating. Besides these there are places marked at every quarter of a mile of the course, where opening can be made readily in cases of emergency. Where streams intersect the line of aque- duct, culverts are built to allow them to pass under. At each end of the aqueduct are gate chambers, with two sets ot gates, the regulating and the guard gates : the former of gun metal, the latter of cast iron. The height of the interior of the aque- duct is 8 feet 5? inches, and the greatest width 7 feet .5 inches. The velocity of the water is lft miles per hour when the water is two feet deep. The average depth is probably four feet. The foundations of the channel were formed with cement, the side walls of stone, and the bottom and inside faced with brick ; the top also covered with an arch of brick. In tunnel-cutting, the na- tural rock in some places served as roof. The bridge which crosses the Haarlem River is the most interesting work on the line ; its width is 21 feet, and it is 150 feet from the top of the work to the foundations in the river. The iron pipe conveying the water along this is 3 feet in diameter. In passing through the Manhattan valley two pipes are used, each 3 feet in diameter ; provision, how- ever, has been made for four such. The capacity of the receiving reservoir is 150,000,000 gallons when full. It is divided into two unequal parts, with a connecting pipe to sJIow of an equalizing of the level. The distributing reservoir is two miles lower down the island, and three miles from City Hall ; the water in it is 36 feet deep, and it is calculated to hold 20,000,000 gallons. It is 40£ miles distant from the fountain reservoir. The whole of the cost of the work, ex- clusive of the pipes in the city below the distributing reservoir, is about $9,000,000. It is a beautiful work of art, — a worthy rival of the finest of the Roman aque- ducts. The success of this undertaking in New- York has stimulated other Atlan- tic cities to supply themselves Avith abundance of pure water in a similar manner and the aqueduct which sup- plies Boston from the Cochituate pond is highly creditable. CRUCIBLES are small conical vessels, narrower at the bottom than the mouth, for reducing ores in docimacy by the dry analysis, for fusing mixtures of earthy and other substances, for melting metals, and compounding metallic alloys. They ought to be refractory in the strongest heats, not readily acted upon by the sub- stances ignited in them, not porous to li- quids, and capable of bearing considera- ble alternations of temperature without cracking ; on which account they should not be made too thick. The best cruci- bles are formed from a pure fire-clay, mixed with finely ground cement of old crucibles, and a portion of black lead or graphite. Some pounded coke may be mixed with the plumbago. The ' clay should be prepared in a similar way as for making pottery-ware ; the vessels af- ter being formed must be slowly dried and then properly baked in the kiln. Crucibles formed of a mixture of 8 parts in bulk of Stourbridge clay and cement, 5 of coke, and 4 of graphite, have been found to stand 23 meltings of 76 pounds of iron each, in the RoyarBerlin foundry. Such crucibles resisted the greatest possi- 114 CYCLOPEDIA OF THE USEFUL ARTS. [cup ble heat that could be produced, in which even wrought iron was melted, equal to 150° or 155° Wedgewood, and bore sud- den cooling without cracking. Another composition for brass-founding crucibles is the following : i Stourbridge clay, $ burned clay cement, I coke powder, | pipe clay. The pasty mass must be com- {>ressed in moulds. The Hessian cruci- >les of Germany are made from a fire- clay which contains a little iron, but no lime; it is incorporated with silicious sand. The dough is compressed in a mould, dried, and strongly kilned. They stand saline and leaden fluxes in docimas- tic operations very well ; are rather po- rous on account of the coarseness of the sand, but are thereby less apt to crack from sudden heating or eoohng. They melt under the fusing point of bar iron. Beaufay in Paris has lately succeeded in making a tolerable imitation oi the Hes- sian crucibles with a fire-clay found near Namur in the Ardennes. Berthier has published the following elaborate analysis of several kinds of cru- cibles : St. Etienne Hessian. Beaufay. English for for Glass Pots Bohemian Glass Pots Oast Steel. Cast Steel. at Nemours. Glass Pots. of Creusot. Silica, - - - - 70-9 64-6 63-7 65-2 67-4: 6S-0 68-0 Alumina, - - - 24-8 34-4 20-7 25-0 32-0 29-0 28-0 Oxide of Iron, - 3-8 1-0 4-0 7-2 0-8 2-2 2-0 Magnesia, - - trace — — trace trace 0-5 trace Water, - - - — — 10-3 — — — 1-0 Wurzer states the composition of the sand and clay in the Hessian crucibles as follows : Clay — silica 10*1, alumina 65-4, oxides of iron and manganese 1*2, lime 0-3, water 23. Sand — silica 95*6, alumina 2*1, oxides of iron and manganese 1*5, lime 0-8. Black lead crucibles arc made of two parts of graphite and one of fire-clay, mixed with water into a paste, pressed in moulds, and well dried, but not baked hard in the kiln. They bear a higher heat than the Hessian crucibles, as well as sudden changes of temperature, have a smooth surface, and are, therefore, pre- ferred by the melters of gold and silver. This compound forms excellent small or portable furnaces. CUDBEAR, OR PEESIO, is a powder of a violet red color, difficult to moisten with water, and of a peculiar but not dis- agreeable odor. It is partially soluble in boiling water, becomes red with acids, and violet blue with alkalies. It is pre- pared in the same way as archil, only to- wards the end the substance is dried in the air, and is then ground to a fine pow- der, taking care to avoid decomposition, which renders it glutinous. In Scotland they use the lichen tartareus, more rarely the lichen calcareus, and omphalodes, most of which lichens are imported from Sweden and Norway, under the name of rock moss. The lichen is suffered to fer- ment for a month, and is then stirred about to allow any stones which may be present to fall to the bottom. The red mass is next poured into a flat vessel, and left to evaporate till its urinous smell has disappeared, and till it has assumed an agreeable color verging upon violet. It is then ground to fine powder. During the fermentation of the lichen, it is wa- tered with stale urine, or with an equiva- lent ammoniacal liquor of any kind, as in making archil. CUPELLATION is a mode of analyz- ing gold, silver, palladium, copper, and platinum, by adding to small portions of alloys, containing these metals, a bit of lead, fusing the mixture in a little cup of bone earth called a cupel, then by the joint action of heat and air, oxidizing the copper, tin, &c, present in the pre- cious metals. The oxides thus produced are dissolved and carried down into the porous cupel in a liquid state, by the vi- trified oxide of lead. (See Assay, Gold, and Silver.) CURRYING is the art of dressing cow-hides, calf-skins, seal-skins, &c, principally for shoes : and this is done either upon the flesh or the grain. In dressing leather for shoes upon the flesh, the first operation is to soak the leather in water until it is quite wetted, then the flesh side is shaved on a beam about seven or eight inches broad, with a knife of peculiar construction, to a proper sub- stance, according to the custom of the country and the uses to which it is des- tined. This is one of the most curious and laborious steps of the whole process. The knife used is of a rectangular form, with two handles, one at each end, and a cut] CYCLOPEDIA OF THE USEFUL ARTS. 115 double edge. It is thrown into water again, and scoured on a board or stone commonly set apart for that use. Scour- ing is done by rubbing the grain or hair side with pumice-stone, or with some other stone of a good grit. These stones force out of the leather a white substance called the bloom, produced by the oak bark in tanning. The hide or skin is then conveyed to the shade or drying- place, where the oily substances are ap- plied termed stuffing, or dubbing ; when it is thoroughly dry, an instrument, with teeth on the under side, called a grain ing- board, is first applied to the fresh side, which is called graining, — then to the grain side, called bruising. The whole of this operation is to soften the leather to which it is applied. Whitening or paring succeeds, which is performed with a fine edge to the knife already described, ana used in taking off the grease from the flesh. It is then boarded up or grained again, by applying the graining- board first to the grain, and then to the flesh. It is then fit for waxing, which is now performed by coloring, which is done by rubbing with a brush, dipped in a composition of oil and lamp-black, on the flesh, until it be thoroughly black. It is then sized, called black-sizing, with a brush or sponge, dried and tallowed ; and when dry, this sort of leather called waxed, or black on the flesh, is curried. The currying leather on the hair or grain side, called blade, on the grain, is the same as currying on the flesh until we come to the operation of scouring it. Then the first black is applied to it while wet, which black is a solution of sul- phate of iron or copperas, in plain wa- ter, or in the water m which the skins as they come from the tanner have been soaked. This is first put upon the grain after it has been rubbed with a stone ; then rubbed over with a brush dipped in stale urine : the skin is then stufted, and when dry, it is seasoned — that is, rubbed over with a brush, dipped in cop- peras water, on the grain till it is per- fectly black. After this, the grain is raised with a fine graining-board : when it is thoroughly dry it is whitened, bruised again, and grained in two or three different ways, and when oiled upon the grain with a mixture of oil and tallow it is finished. CURRY POWDER. {See Turmeric.) CUTLERY, in the general sense, com- prises all edged tmls ; but it is now more particularly confined to the manufacture of knives and forks, scissors, pen-knives, razors, and swords. Those articles which do not require a fine polish, are made from blistered steel; while those which require the edge to possess great tenacity at the same time that hardness is not re- quired, are made from shear steel. The finer kinds of cutlery are made from steel which has been in a state of fusion, termed cast steel; no other kind being susceptible of a high polish — {see Steel.) It can then be made so as to be welded to iron with great ease. Table-knives are mostly made of shear steel. The blade is first rudely formed and cut off. It is next welded to a rod of iron about half an inch square, so as to leave as little of the iron part of the blade ex- posed as possible : of the iron attached to the blade enough is then taken off from the rod to form the bolster or shoulder and the tang. To give the bol- ster size, shape, and neatness, it is intro- duced into a die and a swage placed upon it : the swage has a few small dIows given to it by the striker. The die and swage are called prints. The blade is now heated, and the proper anvil finish is given to it : this is termed smithing. It is again heated red-hot, and plunged down into cold water. It thus becomes hardened and requires to be tempered down to a blue color, when it is ready for the grinder. Forks are a different branch, of manu- facture ; they are made of small rods of steel, drawn out flat at one end to about the length of the prongs. The shank and tang are heated, and the form given by a die and swage. The prongs are then formed at one blow by a stamp, which weighs about 100 lbs., and falls from a height of 7 or 8 feet upon the heated end of the rod: a fly-press re- moves the metal left between the prongs. The forks are then annealed, which sof- tens and prepares them for filing. The inside is then filed ; they are then bent into form and hardened, by heating and plunging them into cold water. The tempering is done by exposure to the degree of heat at which grease inflames. Almost all razors are made of cast steel, the quality of which should be very good, the razor's edge requiring great hardness and tenacity. The tempering is usually performed by placing them on the open fire, in a sand bath, or an oil bath, or a bath of fusible metal of 8 parts of bis- muth, 5 parts of lead, and 3 of tin heated up to 500° Fahr. Razors are ground crosswise, upon stones from 4 to 7 inches in diameter ; a small stone being needful 116 CYCLOPEDIA OF THE USEFUL ARTS. [CYA to make the sides concave : they are then smoothed and polished. Pen-knives have three stages in their manufacture : 1st, the forging of the blades, the spring, and iron scales ; the 2d, the grinding and polishing of the blades: and 3d, the handling, or fitting up of all the parts. The finest hind of cast steel is used in the manufacture of ladies' scissors ; the larger scissors have a blade of iron, with steel edge. The various processes of grinding and polishing are performed by machinery, moving in general by the power of steam, or a water-wheel. The grinding and polishing of, cutlery is the most ruinous occupation to health and life at which any man can be occupied : few who com- mence to work at it early in life, reach forty years of age. The manufacture of handles is carried on often in the same establishment with the steel work. According to the tech- nical phraseology applied, all handles are called hafts in which a tang of the knife passes into a hole in the handle, and is there fixed ; while the handles which are formed of two flat pieces riveted to a central plate, as in pen-knives, are called scales. The workmen who engage in this em- ployment confine themselves each pretty nearly to one kind of material. The pearl-handle makers procure the shells from the shores of India and Africa; these shells are about six inches in dia- meter, and are so extremely hard that they have to be wetted while being cut with a saw, to prevent the saw from be- ing softened by the heat. This is a dirty occupation, and is accompanied by a " very ancient and fish-like smell," elicited by the heat from the shell itself. The pearl, or rather mother-of-pearl, is cut up into thin slices, to be afterwards used tor the scales for pen-knives, razors, &c. Ivory handles are made by sawing up elephants' tusks into the most useful pieces they can make, by means of a cir- cular saw. If the ivory is for scales, it is cut into veneers ; but if for hafts, it is cut into small oblong pieces, which are afterwards brought to shape by hand, polished, and pierced for the reception of the tang. Bone handles are similarly made by cutting with a small circular saw, and then filing into shape ; and the same may be said of ebony and fancy wood handles generally. Saw-handles are cut out of wood, which, after being planed to the proper thickness, is fixed in a vice, cut with a very fine saw, smoothed with files and glass-paper, pierced with rivet-holes, and riveted to the saws. Metal handles are of course made in a way similar to other articles of metal. Horn handles have a peculiarity in their mode of manufacture, which places them in a distinct rank. When horn is made hot, it becomes so soft and ductile that it may be pressed into moulds ; and this circumstance is taken advantage of to give an ornamental device to horn handles, except stages horn, which is left in its natural state. The tips or solid parts of the ox-horn and buffalo-horn are made into hafts, while the other parts are made into scales. The mould for pressing is in two halves, which close together like a pair of pincers ; and this mould has the device on each of its halves. The mould is heated in a fire ; the piece of horn is cut nearly to the re- quisite size, and put into it ; and the mould is pressed in a powerful vice, whereby the horn receives the impress of the device. There is also a good deal of skill shown in staining horn, bone, and ivory, or in bleaching them ; as also in studding and ornamenting them in various ways. CYANIDE OF POTASSIUM. This salt, so much used now in the electrotype processes, is prepared, according to Lie- big's formula, oy mixing 8 parts of Sounded prussiate of potash, sharply ried, with 3 parts of pure carbonate of potash, fusing the mixture in an iron crucible, by a moderate red heat, and keeping it so, till the glass or iron rod with which the fluid mass should be oc- casionally stirred, comes out covered with a white crust. The crucible is then to be removed from the fire; and after the disengaged iron has fallen to the bot- tom, the supernatant fluid, still obscure- ly red hot, is to be poured off upon a clean surface of iron or platinum. After concretion and cooling, the white saline mass is to be pounded while hot, and then kept in a well-stopped bottle. It consists of about 5 parts of cyanide of potassium, and 1 of cyanate of potash. For most purposes, and the analysis of ores, the latter ingredient is in no ways detrimental. CYANITE. A massive and crystal- lized mineral. It has a pearly lustre, is translucent, and of various shades of blue : it is a silicate of alumina, with a trace of oxide of iron. Only found in pri- mitive rocks. dag] CYCLOPEDIA OP TUB USEFUL ARTS, 117 CYANOGEN. An essential ingredient of Prussian blue. Cyanogen is a gas of a strong and peculiar odor, resembling that of rubbed peach leaves ; it is ob- tained by heating cyanuret of mercury. Under a pressure of between three and four atmospheres it becomes a limpid liquid. It extinguishes a taper, is high- ly poisonous and unrespirable, and burns in contact of air with a rich purple flame. Water absorbs between 4 and 5 times its volume of the gas. It is composed of carbon and nitrogen in the proportions of 12 carbon+14 nitrogen=26 cyanogen; it is therefore a bicarburet of nitrogen. Mixed with oxygen it explodes by the electric spark, and is resolved into car- bonic acid and nitrogen gas. It com- bines with hydrogen to produce the hy- drocyanic or prussic acid : it forms with the metals cyanurets or cyanides. CYANOMETER. An instrument con- trived by Saussure for determining the cteepness of the tint of the atmosphere. A circular band of thick paper or paste- board is divided into 51 parts, each of which is painted with a different shade of blue, decreasing gradually from the deepest blue formed by a mixture of black, to the lightest formed by a mix- ture of white. The colored zone is held in the hand of the observer, who notices the particular tint which corresponds to the color of the sky. The number of this tint, reckoned from the lightest shade, marks the intensity at the time of observation. DAGUERREOTYPE. The art of im- pressing distinct and permanent images on polished metallic surfaces. It received its name from M. Daguerre, who disco- vered the mode in 1839, and from whom the French government bought the right to the discovery by giving him an annu- ity of 10,000 francs. Compared with the present processes his views were very meagre and incomplete. The views taken were of landscapes, and the process in his hands consisted in coating the silver plate with iodine to a gold color, expos- ing in the camera for ten minutes in full sunlight, then exposing the plate to the fumes of mercury, and washing in hypo- sulphate of soda. Dr. Draper (now of New York) made the plate more sensi- tive by exposing it to chlorine gas after it had received the iodine coating. Views could thus be taken in shade, and in a shorter time ; the impression also was more distinct. Chloride of iodine was soon after substituted for chlorine and io- dine separately ; and, still later, bromide of iodine was tried with much gi eater success. At the present time the art is practised with wonderful delicacy of manipulation, and perfection in result, in this country. It is acknowledged that American da- guerreotypes excel European in beauty of finish, with mellowness and depth of tint. Those taken in France are much better than English ones, which i3 no doubt due to the clearer and less cloudy skies of France. Perhaps it may be the same reason which causes to be produced better portraits in America than in west- ern Europe. The plate which receives the image is copper coated with silver, either by the ordinary process of plating, or by the electrotype method : the latter is prefer- able. The first step in the process is the cleansing the plate. Too much atk ntion cannot be devoted to this, as upon it de- pends subsequent success. It is impos- sible to take a picture on a dirty plate. The slightest trace of oxide, sulphuret, or even film of air adhering to the plate, is sufficient to prevent the appearance of an image. Various plans of cleaning plates are practised. Some use rotten stone and water, made acid by nitric acid ; others use alcohol and ammonia water. These are rubbed on to the plate with small pieces of Canton flannel. The rotten stone should be very fine, and the acid very dilute, else the plate will be streaked. It should be cleaned in the centre first, and then the edges wiped off. The acid may be. removed from the plate, by washing with alcohol, or weak solution of potass ; washing with a solu- tion of hydriodate of potass increases the sensitiveness. After being cleaned the plates are Imffed, or rubbed with a pad covered with' cotton, velvet, or buckskin leather. Great delicacy is employed in the application of the buff, which should remove all traces of the materials used for polishing, and give the final purity to the plate. The plate is now ready to re- ceive the coating, or films of iodine and bromine. Small boxes hold the ingre- dients in a glass saucer at the bottom, and the plates are placed on the sliding frame above, and passed over the surface of the saucers until they receive the due quantity of these ingredients. This quan- tity varies with the nature of the light and desired appearance of the picture. The depth of the coating is known by the co- lor of the plate, which is first straw yel- low, then orange, then rose color, violet, steel blue, indigo, and green. If the 118 CYCLOPEDIA OF THE USEFUL ARTS. [> coating be continued beyond this, it passes into yellow again, and^ through the same range of colors. The iodine in the box should be quite dry, as the slightest damp on the plate mars the coating. The Dromine is used as bromide of lime, made by mixing bromine with fresh slaked lime, till the whole is of an orange tint. As a rule, a good picture will be produced by coating with iodine to a dark orange yellow, then with the bro- mide of lime coat to a deep rose red, coat again with iodine one-tenth as long as at first coating. The plate now coated is very sensitive, the least exposure to light decomposing its surface. Hence it ir ne- cessary to shut the plate up in the tablet immediately : this is a close case with a a sliding lid. It is introduced into the camera, and the lid raised when we wish it to receive an image. The selection of a good camera is a tine qua nan with the daguerreotype artist. Generally those of Voigtlander of Germany have the best lenses, and are to be preferred. Daguer- reotypists, however, in this country pre- fer the American cameras. For taking views, the camera invented by Mr. Har- rison is by far the best yet made for such purposes. It has been found advanta- geous to blacken the inside of the came- ra, which absorbs the rays falling on the sides, and thus prevents their reflection and interference Avith the rays falling upon the plate. A room lighted from above is more suitable than a window or side light, the latter producing the sha- dows too deeply marked. A northern aspect is preferred, as the light is more uniform through the day, although light from the south has a greater chemi- cal influence. The sitter should^ not be placed too near the window, nor in front of it. The thus of exposure in the came- ra varies with the light, amount of coat- ing, and time of the day, from 10 se- conds to 1* minutes. The operator's judgment is the best guide. The plate is now removed from the camera in the closed tablet, and has to be exposed to the vapor of mercury, in order to bring out the image, for as yet no trace of any delineation is visible. The mercury bath is an iron vessel of an inverted conical form, the mercury occupying the lower part ; is heated with a spirit lamp until it reaches the temperature of 90 centigrade, when the plate is now placed on the frame attached to the upper part of the bath, where it receives the vapor of the quicksilver. A little window at the side allows the operator to observe the advancement of the process. The I image gradually is developed as the mer- | curial vapor coats the plate, and when j the greatest distinctness is produced (which is generally after two minutes), the plate is removed. As far as the image is concerned, nothing more is ne- cessary to be done. The picture is made, and has now to be preserved. It is necessary first to re- move the superfluous iodine and bro- mine from the sides of the picture, where the light has not produced any chemical action ; this is accomplished by washing with hyposulphate of soda, a salt which is capable of dissolving the iodide of sil- ver formed on the plate. The washing should be performed immediately after the exposure to the mercury. The plate is held by a pliers in the hand, and the hyposulphate solution is poured over the plate, and washed around it. The plate is then rinsed with water, and dried off by the heat of a spirit lamp applied underneath. The hyposulphate solution should be weak. The picture is now formed, and the su- Eerfluous coating removed : it has yet to degrees) during about ten minutes ; a longer time is necessary if the temperature be less elevated ; ten grammes of iodine to be used per square of 4 inches. The paper intended to re- ceive the impression is to be covered with a coat of paste, taking care previ- ously to have it moistened with water containing one degree of pure sulphuric acid. The proofs, after being pressed with a linen cloth, present a design of admirable purity. These impressions, taken on paste will, however, in drying, become vaporous ; but if taken on paper prepared with one or two layers of starch, the design will not only be clear, but will preserve much better. What is most extraordinary is, that many impressions may be taken from the same print with- out submitting it to a new preparation — the last proofs being always the clearest. Designs of various colors may thus be obtained according as the paste is more or less boiled, or according to the quanti- ty of acid used. Proofs may also be taken on different metals by observing the fol- lowing precaution. In submitting the engraving to the vapor of iodine, care should be taken to have it perfectly dry, in order that the white portions of it may become impregnated. In this case it should be exposed but a few minutes to the vapor. Let it be afterwards applied, without wetting it, to a plate of silver, and then placed under a press ; at the end of five or six minutes there will be a most faithful reproduction of the original. By afterwards exposing the plate to the va- por of mercury, a proof similar to that of a daguerreotype is obtained. It h.as been rumored, that at a meeting of the French Academy of Sciences, M. Niepce had declared iiis capability of taking the pictures in the natural colors ; his process has not yet reached this countrv. DAliLINE, the same as Inuline, the fecula obtained from elecampane, and analogous in many respect to starch. It is not employed in the arts. DAIRY. An apartment in a house, or a separate building, for the purpose of holding milk and "manufacturing it into butter, cheese, or other dairy produce. On a small scale, where butter only is made from milk, the dairy may be a room in the north side of the dwelling house ; or it may form one of the offices connect- ed with the kitchen court. The requi- sites for the room to contain the milk are — an equal temperature throughout, the year, viz : between 48° and 55° ; .suf- ficient ventilation to carry off all bad smells and impurities in the air; and the exclusion of flies and other insects. An equable temperature is maintained by thick or by hollow walls, and by double windows. In winter the temperature is somewhat raised by the warm milk, and in summer it is cooled to the degree required by ventilation and the evaporation of water poured on the floor. The ventilation is effected by opening the glazed sashes of the windows, and supplying their places by wire shutters, and indeed one of the best modes of arranging the windows of a dairy is to have wooden shutters out- side for closing in the most severe weather in winter ; next, a fixed frame of wire- work to exclude the flies ; and within this, at three or four inches distance, the glazed sash, which should be made to open. A dairy on a large scale is most conveniently arranged as a detached building; in which case, it contains a milk-room, a churning-room, and a dairy scullery, or place for scalding the utensils. If cheese is to be made, a room will be required for a cheese press and another for drying the cheeses. DAMASCUS BLADES, are swords or cimeters, presenting upon the surface a variegated appearance of watering, as white, silvery, or black veins, in fine lines, or fillets ; fibrous, crossed, inter- laced, or parallel, &c. They are brought from the East, being fabricated chiefly at Damascus, whence their name. Their excellent quality has become proverbial ; for which reason these blades are much sought after by military men, and are high priced. The oriental processes have never been satisfactorily described; but of late years methods have been devised in Europe to imitate the fabric very well. Clouet and Hachette pointed out the three following processes for producing Damascus blades: 1, that of parallel fil- lets ; 2, that by torsion; 3, the mosaic. The first, which is still pursued by some French cutlers, consists in scooping out with a graving tool the faces of a piece of stuff composed of thin plates of different kinds of steel. These hollows are by a subsequent operation filled up, and brought to a level with the external faces, upon which they subsequently form tress- like figures. 2. The method of torsion which is more generally employed at present, consists of forming a bundle of dec] CYCLOPEDIC OF THE USEUL ARTS. 121 rods or slips of steel, which are welded together into a well-wrought bar, twisted several times round its axis. It is re- peatedly forged, and twisted alternately ; after which it is slit in the line of its axis, and the two halves are welded with their outsides in contact ; by which means their faces will exhibit very various configura- tions. 8. The mosaic method consists in preparing a bar, as by the torsion plan, and cutting this bar into short pieces of nearly equal length, with which a fagot is formed and welded together; taking eare to preserve the sections of each piece at the surface of the blade. In this way, all the variety of the design is displayed, corresponding to each fragment of the cut bar. The blades of Clouet, independently of their excellent quality, their flexibility, and extreme elasticity, have this advant- age over the oriental blades, that they exhibit in the very substance of the metal, designs, letters, inscriptions, and, gener- ally speaking, all kinds of figures which had been delineated beforehand. Notwithstanding these successful re- sults of Clouet, it was pretty clear that the watered designs of the true Damas- cus cimeter were essentially different. M. Breant has at last completely solved this problem. He has demonstrated that the substance of the oriental blades is a cast-steel more highly charged with car- bon than our European steels, and in which by means of a cooling suitably con- ducted, a crystallization takes place of two distinct combinations of carbon and iron. This separation is the essential condition; for if the melted steel be suddenly cooled in a small crucible or ingot, there is no damascene appearance. DAMASKEENING. The art of inlay- ing iron and steel with gold and silver, originally practised at Damascus in Syria. DAMASSIN. A species of woven damask with gold and silver flowers. DAMPEE. An iron plate sliding back- wards and fowards in a groove, and so arranged as to enlarge or contract and occasionally close the chimneys of fur- naces, steam boilers, &c, so as to in- crease or diminish the draught of air through the fire, and consequently regu- late the intensity of the combustion. DAMPS. The noxious exhalations of mines and excavations. The carbu- retted hydrogen of coal mines is called Fire Damp ; carbonic acid is termed Choke Damp. D ATHOL1TE or DATOLITE. A mine- ral compound of lime, silica, and boracic acid, a boro silicate of lime. It becomes : opaqe when heated. DAVIT. A piece of timbei used in I managing the anchor. DAVITE. Fibrous sulphate of alumi- na, found near Bogota in Columbia. DEAD BEAT. In clock-work (called also dead scapement, or scapement of re- pose), a peculiar kind of scapement in- vented by Mr. George Graham about the year 1700, with a view to lessen the effect of the wheel-work on the motion of the pendulum ; and acquired its name from the circumstance that the seconds' index stands still after each drop, whereas the index of a clock with a recoiling scapement is always in motion, hobbling backward and forward. DEAD LIGHTS. Strong wooden prists or shutters, put over the glass-windows of the cabin in bad weather, as a defence against the sea. DEAD BECKONING. A term used in navigation to express the estimation that is made of a ship's place without having recourse to observation of the ce- lestial bodies. It is made by observing the way she makes by the log, and the course on which she lias been steered, making allowance for drift, leeway, &c. DECANTATION. The pouring off a clear liquid from its subsidence or resi- due ; it is often resorted to in the chemi- cal laboratory instead of filtration, the clear supernatant liquor being poured or syphoned off from precipitates, which may thus be repeatedly washed or edul- corated, so as to free them from all solu- ble matters. DECAEBONIZATION OF CAST IBON. This process is resorted to in order to convert cast iron into steel, or by a further decarbonization to reduce it to the state of malleable iron • hence, many articles which were formerly exclu- sively manufactured of wrought iron are now cast, and afterwards decarbonized — such as horseshoes, &c. ; and in other cases various cutting instruments are cast, and afterwards brought to a proper hardness by a similar process. The arti- cles to be decarbonized are packed in finely powdered haematite, or native oxide of iron, and exposed for a sufficient time to a high red heat. It is often necessary to mix iron filings or turnings with hae- matite : these substances, thus applied, gradually abstract the excess of carbon in cast iron, and reduce it to a state ana- lagous to that of steel ; or, by a longer continuance of heat, to that of soft iron. In some cases, however, the process 122 CYCLOPEDIA OF THE USEFUL ARTS. [det seems rather to affect the texture and mechanical properties than the composi- tion of the iron, and is therefore more analogous to annealing. DECOMPOSITION, is the separation of the constituent principles of any com- pound body. The following table, the result of important researches recently made by M. Persoz, professor of chemis- try at Strasburgh, shows the order in which decompositions take place among the successive substances, diminishing in power from above downwards. Nitric Acid. Muriatic Acid. Oxide of Magnesium Oxide of Magnesium — Silver — Cobalt — Cobalt — Nickel — Nickel Protox of Mercury Protox. of Cerium — Cerium Oxide of Zinc Oxide of Zinc Protox of Manganese Protox of Manganese Oxide of Lead — Iron — Cadmium — Uranium — Copper — Copper — Glucinum — Tin — Alumium Oxide of Glucium — Uranium — Alumium — Chromium — Uranium Protox of Mercury — Chromium Oxide of Mercury — Iron — Iron — Tin — Bismuth — Bismuth — — Antimony The study of the tables of decomposi- tion are of the utmost importance to the practical and manufacturing chemist, as they are the means of protecting him from much waste and loss. DECREPITATION, is the crackling noise, attended with the flying asunder of their parts, made by several salts and minerals, when heated. It is caused by the unequal sudden expansion of then- substance by the heat. Sulphate of bary- ta, chloride of sodium, calcareous spar, nitrate of baryta, and many more bodies which contain no water, decrepitate most violently, separating at the natural joints of their crystalline structure. DEFECATION. The freeing from dregs or impurities. DEFLAGRATION. The sudden blaz- ing up of a combustible ; as of charcoal or sulphur when thrown into melted nitre. DELPHIN1A. The vegeto-alkaliue principle of the Delphinium stapliysa- gria, or stavesacre. It is poisonous. DELIQUESCENT, is said of a solid which attracts so much moisture from the air as to become spontaneously soft or liquid; such as potash and muriate of lime. DEPILATORY, is the name of any substance capable of removing hairs from the human skin without injuring its tex- ture. They act either mechanically or chemically. The first are commonly glu- tinous plasters formed of pitch and resin, which stick so closely to the part of the skin where they are applied, that when removed, they tear away the hairs with them. This method is more painful, but less dangerous than the other, which consists in the solvent action of a men- struum, so energetic as to penetrate the pores of the skin, and destroy the bulb- ous roots of the hairs. This is com- posed either of caustic alkalies, sulphuret of baryta, or arsenical preparations. Cer- tain vegetable juices have also been re- commended for the same purpose ; as spurge and acacia. The bruised eggs of ants nave likewise been prescribed. But the oriental rusma yields to nothing in depilatory power. Gadet de Gassincourt has publish. ed in the Dictionnaire des Sciences Medicales, the following recipe for preparing it. Mix two ounces of quicklime with half an ounce of orpiment or realgar, (sulphu- ret of arsenic ; j boil that mixture in one pound of strong alkaline ley, then try its strength by digging a feather into it, and when the flue falls off, the rusma is quite strong enough. It is applied to the hu- man skin by. a momentary friction, fol- lowed by washing with warm water. Such a caustic liquid should be used with the greatest circumspection, beginning with it somewhat diluted. A soap is sometimes made with lard and the above ingredients; or soft soap is combined with them ; in either case to form a depi- latory pommade. Occasionally one ounce of orpiment is taken to eight ounces of quicklime, or two to twelve, or three to fifteen ; the last mixture being of course the most active. Its causticity may be tempered by the addition of one-eighth of starch or rye flour, so as to form a soft paste, which being laid upon the hairy spot for a few minutes, usually carries away the hairs with it. DESTRUCTIVE DISTILLATION. A term applied to the distillation of organic products at high temperatures, by which the ultimate elements are separated or evolved in new combinations. The de- structive distillation of coal is resorted to for the production of gas, and that of bone for the production of ammonia, and of wood for the formation of vinegar. DETONATING TUBE. A stout glass tube, used in the chemical laboratory for the detonation of gaseous bodies. It is dia] CYCLOPEDIA OF TTIE USEFUL ARTS. 123 generally, as represented in the annexed cut, graduated into centesimal parts, and perforated by two opposed wires, for the purpose of passing an electric spark through the gases which are introduced into it, and which are confined within it over water or mercury. When a detonating tube is used over eit ler of these fluids, the small- est possible quantity of explo- sive gas should be introduced ( into it, as in consequence of /—A the expansion which ensues, a portion is apt to be forced out at the moment of the explosion. The tube, when used, should be firmly held : a spring is sometimes substituted for the grasp of the hand, but it is inconvenient. DETONATING POWDER. A term applied in chemistry* to fulminating mer- cury and silver, and to other compounds which suddenly explode when struck or heated. Some of these compounds have lately been much used for the ignition of gunpowder in percussion locks. DETONATION. When chemical com- bination or decomposition is sudden and attended by flame and explosion, it is often said to be effected by detonation. If a mixture of hydrogen gas and oxygen be inflamed by the electric spark or by a taper, it burns rapidly and with explo- sion, and is said to detonate. When a grain or two of phosphorus is mixed with chlorate of potassa and struck witli a hammer, the mixture detonates. DETRITUS. A geological term applied to deposits composed of various sub- stances which have been comminuted by attrition. The larger fragments are usu- ally termed debris ; those which are pul- verized, as it were, constitute detritus. Sand is the detritus of siliceous rocks. D E U T X I D E, literally means the second oxide ; but is usually employed to denote a compound containing two atoms or two prime equivalents of oxy- gen to one or more of a metal. Thus we say deutoxide of copper, and deutoxide of mercury. Berzefius has abbreviated this expression by adopting the princi- ples of the French' nomenclature ot 1787 ; according to which the higher stage of oxydizement is characterized by the" ter- mination ic, and the lower by ous, and he writes accordingly cupric and mercuric, to designate the deutoxides of these two metals ; cuprous and mercurous, to de- signate their protoxides. DEXTRINE. This substance has ex- actly the same chemical composition as starch, consisting of 24 atoms of carbon, 20 of hydrogen, and 10 of oxygen (Du- mas) ; but it is distinguished from starch by its solubility in cold water, like gum, and not being affected by iodine. British gum, as it is called, or roasted starch, is merely dextrine somewhat discolored ; a substance apparently used for the paste on the queen's head British letter- stamps. A process discovered by M. Pay en, and patented in France by M. Henze, for making dextrine, consists in moistening one ton of dry starch with water containing 4i lbs. of strong nitric acid. The starch thus uniformly wetted, is made up into small bricks or loaves, and dried in a stove. It is then rubbed down into a coarse powder, and exposed in a stove-room to a stream of air heated to about 180° F. Being now triturated, sifted, and heated in a stove to about 228° F., it forms a perfect dextrine of a fair color ; because the acid acts as a substitute for the higher heat, used in making the British gum. Such an arti- cle makes a fine dressing for muslin and silk goods, and is much employed in French surgery, for making a stiff paste- support to the bandages of fractured limbs. DIALS are instruments known to and constructed by the ancients, for the mea- surement of time. In constructing a sun-dial, the object is to find, by means of his shadow, the sun's distance at any time from the meri- dian. When this distance is known, the hour is also known, provided we suppose the sun's apparent motion to be uniform, and that (Turing the whole course of a day he moves hi a circle parallel to the equator. Neither of these conditions is, in fact, accurately fulfilled, bnt the er- ror which this gives rise to is of small amount; and it is, moreover, sufficiently obvious that the use of a dial is not to indicate the hour with astronomical pre- cision, but merely to give such an ap- proximation as is necessary for the pur- poses of civil life. Dials are usually constructed on an immovable surface, and admit of an in- finite number of different constructions, all depending on the nature of the sur- face and its position with regard to the equator of the earth. The general prin- ciples, however, are the same in all, and depend on the simplest elements of geometry and astronomy. The first part that claims attention is the style or gno- mon, or axis of the dial, which is usually a cylindrical rod, or the edge of a thin 124 CYCLOPEDIA OF THE USEFUL ARTS. [dta plate of metal. The style must be di- rected perpendicularly to the terrestrial equator ; in which direction it may be considered, on account of the smallness of the earth's diameter in comparison of the distance of the sun, as coinciding with the axis of the diurnal rotation ; consequently the plane which passes through the style and its shadow on the surrounding surfaces, and which always passes through the centre of the sun, will be an hour plane, and turn with the sun as the sun turns round the style by the effect of the diurnal motion. All that remains to be done, in addition, is to dis- cover, and describe, for the different hours of the day, the intersections of this variable hour plane with the surface on which the dial is to be constructed. On these intersections the shadow of the style will be projected every day at the same hour ; because at the same hour the sun must have returned to the same hour plane, although his distance from the equator may be different. From these considerations it is mani- fest that the whole theory of dialling is comprehended in the solution of this general problem : — " Twelve planes all intersecting each other in the same straight line, and making with each other equal angles of 15°, being given in posi- tion; to find the intersections of those planes with any surface whatever, also given in form and position." The sur- face which intersects the hour planes may be of any kind whatever, but for obvious reasons it is generally a plane ; and when its position with respect to the common intersection of the hour planes (which is the style of the dial) and to any one of those planes is given, the traces or intersections, which are in this case all straight lines, are the hour lines on the dial, and easily calculated by the ordinary rules of trigonometry or geo- metry. According to the position of the dial with respect to the horizon of the place, the dial is horizontal, vertical, or inclined. The most com- mon construc- tion is the Hori- zontal Dial, or that in which the plane of the dial is parallel to the horizon, and consequent- ly makes with the style an an- gle equal to the ^jt> n '//\ V H \V IV x xi xn i u equo this is the same as th»; polar dial ; but at all other places, the hour lines inter- sect each other in the point in which the style intersects the plane of the dial, which point is called the centre, and the angles they make with one another, or with the xii hour line, depend on the latitude. After the horizontal dials, the construc- tion most frequently employed is that in which the plane of the dial is vertical ; for example, when fixed on the wall of a house. In this case, the positions of the different hour lines depend on the lati- tude of the place and on the aspect ot the dial ; that is to say, its position with re- spect to the meridian. _ If the dial is per- pendicular to the meridian, it is a smith dial, or north dial, according as it faces the south or north. (The vertical south dial is represented in the annexed figure.) When not perpendi- cular to the meridian, the vertical dial is said to be declined. The formula for the hour lines of a south verti- cal dial differs from that for a horizontal dial in no respect excepting that the sine of the latitude is changed into the co- sine, the cause of which' will be obvious when it is considered that the plane of the dial in passing from the horizontal to the south vertical direction preserves its inclination to the different hour planes unaltered ; while the angle which it makes with the style, or the axis of the earth, is the complement of the angle it made with the same line in its former position. Let y, therefore, be the hour angle at the centre of the dial ; and put- ting, as before, h = the hour from noon, and I = the latitude, the formula for the south vertical dial is tan. y = tan. h cos. I ; whence it follows that a horizontal dial constructed for any given latitude will be a south vertical dial for any place of which the latitude is the complement of the latitude of the former place, — a property which was discovered by the Arabians. The hour lines of the vertical north dial are found exactly in the same way as those of the south dial. DIAMOND. (A corruption of ada- mant). The most valuable of the pre- cious stones. Diamonds were originally discovered in Bengal, and in the Island of Borneo. About the year 1720 they were found in Brazil. One lately found dia] CYCLOPEDIA OF THE USEFUL ARTS. 125 at Bahia was worth $225,000, though sold hy the negro finder for $175. # They always occur in a detached state in allu- vial soil. The primitive crystalline form of the diamond is a regular octahedron, of which there are numerous modifica- tions. Diamonds are found of all colors : those which are colorless, or which have some very decided tint, are most es- teemed; the latter, however, are rare. Those which are slightly discolored are the least valuable. "The diamond is the hardest known substance, and can only be polished by its own dust or powder. The art of splitting or cutting and polish- ing this gem, though probably of remote antiquity in Asia, was first introduced into Europe, in 1486, by Louis Berghem, of Bruges, who accidentally discovered that by rubbing two diamonds together their surfaces might be abraded. They are cut chiefly into two forms, rose and. brilliant : the latter have the finest effect, but require a sacrifice of a larger portion of the gem ; so that the weight ot an or- dinary polished diamond often does not exceed half that of the rough gem. The largest known diamond is probably that mentioned by Tavernier, in possession of the great mogul ; it was found in Gol- conda in 1550; is of the size of half a hen's egg, and said to weiirh 900 carats. The next most valuable diamond in the world has lately come into the pos- session of Queen Victoria, and was exhibited in the World's Fair. It was brought from the East Indies, and pre- sented to the queen by the East India Company ; it is called the " Koh-i- Noor " (Mountain of Light). All the na- tives of Iliridostan have heard of it, and it has had a mythological lame for a number of centuries. Its possession by any prince was superstitiously held to be the type of dominion. It was discovered in the famous diamond mines of Golcon- da, but when is unknown. It was a state jewel of the Delhi Emperors until 1739. In that year the Persian warrior, Nadir Shah, conquered the Delhi mon- arch, and carried away as his most pre- cious trophy, the " Koh-i-Noor." It af- terwards came into the possession of the Meers of Affghan, and was an heir loom in the family of Ahmed Khan Abdali, and was carried to Lahore by the fugi- tive prince Shah Shooja, from whom it was extorted by the basest of means — starvation. This was the hospitality of the Sikhs. By the conquest ol the Sikh territory, in 1848, this diamond came in- to the possession of Lord Dalhousie, ac- cording to stipulation, to be presented to the queen. Its value is about eight mil- lions of dollars ; it weighs 280 carats, and is of the finest water. It never has been in a dealer's hands, but has descended, either by fraud or force, from one prince to another. Its shape is like the pointed Jialf of a hen's egg. Among the crown jewels of Russia is a magnificent diamond, weighing 195 ca- rats : it is of the size of a pigeon's egg, and was purloined from a brahminical idol by a French soldier; it passed through several hands, and was ultimately purchased by the Empress Catharine for the sum of 90,0002. and an annuity of 4,0002. Perhaps the most perfect and beautiful diamond hitherto found is a brilliant brought from India by a gentle- man of the name of Pitt, who sold it to the recent Duke of Orleans for the sum of 100,0002. It weighs about 136 carats, or 544 grains. That the diamond is combustible wa3 first proved by the Florentine academi- cians in 16?4,"who found that when ex- posed to the heat of the sun concentrated in the focus of a large lens, it burned away with a blue lambent flame. The products of its combustion were first examined by Lavoisier, in 1772, who showed that when it was burned in air or oxygen it produced carbonic acid; subsequent experiments have shown that nothing but carbonic acid is thus formed ; and hence it is proved that the diamond is charcoal or carbon in a pure and crystalline form. On the banks of the river Nik olaiefska, Tobolsk, in Siberia, in the midst of the auriferous sand washings, has been dis- covered a mine of stones resembling dia- monds ; they are a little less heavy and hard, but are harder than granite. It is proposed to call them Diamantoid. Dia- mond dust is used for working cameos, polishing brilliants, and sharpening cut- lery. Diamonds are valued by multiplying the square of their weight by the value of each carat. Allowing a rough diamond to weigh 4 carats, and the value of each carat is $8, then 4X4=16X8=1128, the value of a rough diamond. Manufac- tured or cut diamonds, have their values found by doubling the weight — for ex- ample, a cut diamond of two carats, dou- ble the 2, thus 4X4=16 ; multiply as be- fore 16X8=128, the value of a cut dia- mond 2 carats fine. r T air of dies are made of good steel duly lardencd and tempered, and are carefully used, they will sometimes yield from two to three hundred thousaud impressions before they become so far worn or injured as to require to be removed from the coh ing presses. DIFFERENTIAL THERMOMETER. An ingenious instrument of great use in experimental philosophy, for measuring very small differences of temperature ; invented and re-applied by Sir John Leslie, though the idea of an instrument of the same hind seems to have long be- fore been suggested by Sturmius. The differential thermometer is described by Leslie, in his Experimental Inquiry into the Nature and Propagation of Meat, nearly as follows : Two glass tubes of unequal lengths, each terminating in a hollow ball, and having their bores somewhat widened at the other ends, a small portion of sul- phuric acid tinged with carmine being in- troduced into the ball of the longer tube, are joined together by the flame of a blow- pipe, and afterwards bent into nearly the shape of the letter U; the one flexure being made just below the joining, where the small cavity facilitates the adjustment of the instrument, which, by a little dex- terity, is performed by forcing with the heat of the hand a few minute globules of air from the one ball into the other. The balls are blown as equal as the eye can judge, and from four-tenths to seven- tenths of an inch in diameter. To one of the legs of the thermometer a scale is attached ; and the liquid in the tube is so disposed that it stands in the gradu- ated leg opposite the zero of the scale, when both balls are exposed to the same temperature. From this construction of the instrument, it is easy to see that it is affected by the difference only of heat in the two balls. As long as both balls are of the same temperature, whatever this may be, the air contained in the one will have the same elasticity as that contained in the other; and consequently the inter- eluded colored liquid, being thus pressed equally in opposite directions, remains sta- tionary. But if, for instance, the ball which holds a portion of the liquor be warmer than the other, the superior elas- ticity of the confined air will drive it for- wards, and make it rise in the opposite branch above the zero, to an elevation proportional to the excess of elasticity or of heat. Sulphuric acid is chosen as the liquor best adapted to the purpose ; be- cause it is not vaporizable, and conse- quently does not by its vapor affect the pressure of the air above it. The car- mine is used to render it more easily visible. DIGESTER is the name of a strong kettle or pot of small dimensions, made very strong, and mounted with a safety valve in its top. Papin, the contriver of this apparatus, used it for subjecting bones, cartilages, &c, to the solvent ac- tion of high-pressure steam, or highly heated water, whereby he proposed to facilitate their digestion in the stomach. This contrivance is the origin of the French cookery pans, called autoclaves, because the lid is self-keyed, or becomes steam-tight by turning it round under clamps or ears at the sides, having been previously ground with emery to fit the edge of the pot exactly. In some auto- claves the hd is merely laid on with a fillet of linen as a lute, and then secured in its place by means of a screw bearing down upon its centre from an arched bar above. The safety valve is loaded either by a weight placed vertically upon it, or by a lever of the second kind pressing near its fulcrum, and acted upon by a weight which may be made to bear upon any point of its graduated arm. Chevreul has made a useful application of the digester to vegetable analysis. His instrument consists of a strong copper cylinder, into which enters a tight cylin- der of silver, having its edge turned over at right angles to the axis of the cylinder, so as to form the rim of the digester. A segment of a copper sphere, also lined with silver, stops the aperture of the sil- ver cylinder, being applied closely to its rim. It has a conical valve pressed with a spiral spring, of any desired force, esti- mated by a steelyard' This spring is in- closed w ; ithin a brass box perforated with four holes ; which may be screwed into a tapped orifice in the top of the digester. 128 CYCLOPEDIA OF THE USEFUL AUTS. [dis A tube screwed into another hole serves to conduct away the condensable vapors at pleasure into a Woulfe's apparatus. 1)1 MIT Y is a kind of cotton cloth ori- ginally imported from India, and now manufactured in great quantities in vari- ous parts of Britain, especially in Lanca- shire. Dr. Johnson calls it dimmity, and describes it as a kind of fustian. The distinction between fustian and dimity seems to be, that the former designates a common twilled cotton cloth of a stout fabric, which receives no ornament in the loom, but is most frequently dyed after being woven. Dimity is also a stout cot- ton cloth, but not usually of so thick a tex- ture ; and is ornamented in the loom, either with raised stripes or fancy figures ; is seldom dyed, but usually worn white, as for bed and bed-room furniture. The striped dimities are the most common ; they require less labor in weaving than the others ; and the mounting of the loom being more simple, and consequently less expensive, they can be sold at much lower rates. DIPPEL'S OIL. An empyreumatic oil, produced during the destructive dis- tillation of bone. DIPPER. A name commonly given to the water-ouzel and other species of the genus C Indus. DIPPING NEEDLE. An instrument for showing the direction of the magnetic force of the earth. It is a magnetic nee- dle, furnished with an axis at right angles to its length, and passing as exactly as possible through its centre of gravity, about which it moves in a vertical plane. When a needle thus mounted is placed any where not on the magnetic equator, it dips, or points downwards : and if the vertical plane in which it moves coincides with the magnetic meridian (which is al- ways known by means of a variation com- pass), the position which it assumes shows at once the direction of the mag- netic force ; and the intersection of two or more directions, found by making the experiment at different places, indicates the place of the magnetic pole. Though the principles on which the dipping needle acts are abundantly simple, its practical construction is found to be exceedingly difficult. It must be accurately balanced on its axis ; the axis must be placed ex- actly horizontal ; the friction must be diminished to the utmost extent possible ; and the adjustments can only be made when the needle is perfectly free from magnetism, and also secured from the effects of the magnetic influence of the earth. It must be subsequently magne tized, and during this process much care is required to guard against derangement. The simple construction is represented in the annexed figure. The needle D d consists of a flat oblong piece of steel, tapering to a point at both ends, and hav- ing a slender cylindrical axis passed through its centre of gravity. The axis moves freely in circu- lar holes made in the lateral horizontal bars II A, which support a vertical circular C C, graduated for the pur- pose of showing the in clin ation of th e nee- dle to the horizon. The stand S. T, to which the circle is fixed, is provided with levels, and ad- justed to horizontality by means of screws. But in the most improved form of construction of the dipping needle, the axis, instead of being a cylinder, is a knife edge, resting perpendicularly, like the supports of a pendulum, on two agate planes. A needle thus supported, how- ever, must necessarily make small oscil- lations ; consequently it must be so ad- justed that when it points in the direc- tion of the magnetic force, the knife edges may be perpendicular to the agate planes. The mean value of the angle of the dip must therefore be known previously to its construction ; but it is the best adapt- ed, on account of its delicacy, for ascer- taining the minute variations of the dip at the same place. The angle of the dip, like that of the variation, changes its value even at the same place, following of course the motion ot the magnetic poles, which, from the observations made by Scoresby, Parry, Eoss, and others, in high latitudes, appear to have a motion westward, the annual amount of which is about 11' 4". In the summer of 1831, Commander Ross, in an excursion from the vessel in which his party were so long detained in the polar seas, reached a spot on the continent of North Ameri- ca, which had been calculated to be the position of the magnetic pole. There he found the dip of the needle to be S9° 59', within one minute of the vertical ; and i compass-needles suspended in the most delicate manner possible exhibit no pol- arity whatever. The latitude of this spot is 70° ;V 17" north, and its longitude 96° 46' 4.">" west. DISTILLATION. The evaporation DIS] CYCLOPEDIA OF THE USEFUL ARTS. 129 and subsequent condensation of liquids by means of a still and refrigeratory, or of a retort and receiver. The discovery of the art of distillation is generally ascribed to the alchemists ; but it was doubtlessly known in more re- mote ages to the Arabians, and by them probably derived from nations further east. The process of distillation, though in continual use in the chemical and phar- maceutical laboratory, is carried on upon the most extensive scale for the produc- tion of ardent spirits in the distilleries. Under the words Alcohol, Brandy, Fer- mentation, Wine, &c, will be found some details bearing upon the nature, sources, and production of spirituous liquors. There are two distinct operations in the production of ardent spirits ; the one is the conversion of certain vegetable prin- ciples into alcohol ; and the other, the separation of the alcohol from the other substances with which it is necessarily blended during its production. All those species of corn which are em- ployed in breweries answer for distil- leries ; as wheat, rye, barley, and oats ; as well as buckwheat, and maize or In- dian corn. The product of spirits which these different grains afford, depends upon the proportion of starch they con- tain, including the small quantity of un- crystallizable sugar present in them. Hermstaedt, who has made exact experi- ments upon the subject, reckons a quart, (Trussian or British) of spirits, contain- ing 80 per cent, of the absolute alcohol of Kichter, for two pounds of starch. Hence 100 pounds of starch should yield 35 pounds of alcohol ; or 4-375 gallons imperial, equal to 7.8 gallons of spirits, excise prool. 100 pounds of the following grains afford in spirits of specific gravity 0.9427, containing 45 per cent, of absolute alco- hol, (= 9-11 ot British proof,) the follow- ing quantities : — Wheat, 40 to 45 pounds of spirits ; rye, 36 to 42 ; barley, 40 ; oats, 36 ; buck- wheat, 40 ; maize, 40. The mean of the whole may be taken at forty pounds, equal to 4j gallons imperial, of 0-9427 specific gravity = 3-47 gallons, at excise proof. The chief difference in these sev- eral kinds of corn consists in their differ- ent bulks under the same weight ; a mat- ter of considerable importance ; for since a bushel of oats weighs little more than the half of a bushel of wheat, the former becomes for some purposes less conve- 6* nient in use than the latter, though it affords a good spirit. Barley and rye are the species of grain most commonly employed in the Euro- pean distilleries for making whiskey. On this continent corn and potatoes are the chief materials used for producing alcohol. The vegetable principle which is es- sential to the formation ot alcohol is sugar ; and this is sometimes used directly, as where molasses and analogous saccharine products are subjected to immediate fer- mentation 5 or it is indirectly obtained by subjecting amylaceous grains to certain processes, by* which the starch they contain is first converted into sugar, and then that sugar afterwards alcoho- lized. In distilleries the latter alternative is adopted ; and various kinds of grain, but chiefly barley, wheat, and rye, with more or less malt, are subjected to the opera- tion of mashing. For this purpose the § round grain and the bruised malt are uly mixed, and infused under constant agitation in a proper quantity of hot water in the mash-tub ; the wort is then run off, and fresh water added, till the soluble materials of the grain are ex- tracted. In this way the mixed worts or wash is obtained, which is afterwards to be sub- jected to fermentation ; but in the dis- tilleries of Great Britain the operator is not, as in the brewery, left to his own judgment or convenience, but enforced to conform to the excise laws, which are of a very peremptory and often of a very unscientific character. By these laws the distiller is restricted in the density of his worts to specific gravities between 1050 and 1090 ; and in Scotland between 1030 and 1075. It is presumed that as those specific gravities, which are called 50 and 90, and 30 and 75, the actual quan- tity of saccharine or saccharifiable matter contained in each barrel (or 36 imperial gallons) amounts respectively to from 47 £ lbs. to 85 lbs., and from 28 lbs. to 79 3-10 lbs. In this country the distiller is untrammelled. When the wash above alluded to is ad- justed as to density, it is run into the fermenting vats, where, mixed with a small quantity of yeast, it is subjected to the process of fermentation, which con- tinues from six to ten or twelve days, the time required for its completion vary- ing with the mass of liquid and with the temperature of the atmosphere. 130 CYCLOPEDIA OF THE USEFUL ARTS. [dis During mashing, as well as during fer- mentation, the starch passes into sugar, and the sugar into alcohol ; the conse- Suence of which is that the wash gradu- ily decreases in density or attenuates; and. as soon as this attenuation has reach- ed its maximum, which may be deter- mined by the hydrometer, it should be distilled, in order to prevent the access of acetous fermentation. In all large distilleries there are two sets of stills : one for the purpose of dis- tilling from the wash a weak spirit, tech- nically called low wines; and the other for redistilling (or rectifying) the low wines. In these distillations there passes over along with the first and last portions of the spirits a peculiar volatile oil of a disagreeable flavor and odor, and render- ing the weaker spirit milky. These por- tions are c&MedJaints, and are carefully turned into separate receivers as soon as the appearance of the runnings from the worm-end indicates their presence. The quantity of alcohol which may be obtained from a given quantity of sugar will depend upon the skill and care with which mashing, fermentation, and distil- lation have been respectively conducted ; theoretically, 100 pounds of sugar are convertible into about 51 of alcohol and 49 of carbonic acid. The quantity of al- cohol to be procured from different kinds of grain will also depend upon the same causes, and upon the quantity of sugar, and of starch and gum convertible into sugar, which each may contain. Sometimes malt only is used ih the dis- tillery, in which case the distiller calcu- lates in obtaining two gallons of whiskey of proof strength from each bushel of malt. In some distilleries as much as 3000 gallons per day are produced, and the wonn of the still is passed into the body of a second still, so that the heat arising from the condensation ha the worm raises the temperature in the second still, and thus economises fuel. There is a kind of ardent spirits man- ufactured in Holland, vulgarly called Dutch gin, Hollands, and sometimes geneva, from genievre, the French for juniper, a plant with the essential oil of whose berries it is flavored. One cwt. of ground malt mixed with two cwts. of rye meal are mashed for two hours, with about 450 gallons of water at the temper- ature of 160° F. The mash drawn off is reduced with cold water till the liquid part has the density of 45 lbs. per barrel, = specific gravity 1*047; and is then put altogether into the fermenting back at the temperature of 80° F. One or two gallons of yeast are added. The fermen- tation soon becomes so vigorous as to raise the heat to 90° and upwards, but it is not pushed far, being generally over in two days, when the gravity of the wash still indicates 12 lbs. of saccharurn per barrel. By this moderate attenua- tion, like that practised by the contra- band distillers of the Highlands of Scot- land, it is supposed that the fetid oil of the husks is not evolved, or at least in very small quantity. The grains are put into the alembic along with the liquid wash*, and distilled into low wines, which are rectified twice over, some juniper ber- ries and hops being added at the last dis- tillation. But the junipers are some times bruised and put into the mash. The produce of worts so imperfectly fer- mented, is probably little more than one half of what the British distiller draws from the same quantity of grain. But the cheapness of labor and of grain, as well as the superior flavor of the Skie- dam spirits, enables the Dutch distiller to carry on his business with a respecta- ble profit. In opposition to the above facts, Dubrunfaut says that about one third more spirits are. obtained in Hol- land from grain than in France, because a very _ calcareous spring water is em- ployed in the mashing operation. Were this account well founded, all that the dis- tillers of other countries would have to do would be merely to introduce a portion of chalk into their mash tubs, in order to be on a par with the Dutch. But the statement is altogether a mistake. In the vine countries, the inferior wines, or those damaged by keeping, as also a fermented mash of the pressed grapes, mixed with water, are distilled to form the eau de vie de Cognac of the French, called Brandy in tins country. It contains less essential oil, and that of a more agreeable flavor, than corn spirits. Of making wliisJcey from potatoes. — This root, in certain localities where it abounds at a moderate price, is an ex- cellent material for fermenting into al- cohol. When sound, it possesses from 20 to 25 per cent, of solid substance, of which starch constitutes at least three- fourths ; hence 100 pounds contain from 16 to 22 pounds of starch susceptible of being saccharified. In the expressed juice there is a small quantity of tartaric acid. As potatoes readily pass into the ace- tous fermentation, the admixture of the malt, the mashing and the cooling should Div] CYCLOPEDIA OF THE USEFUL ARTS. 131 be rapidly performed, while the utmost cleanliness must be observed. The fermentation is brisk, probably from the agency of the albumen, and fur- nishes a good head of barm, which an- swers well for the bakers ; 100 pounds of potatoes yield from 18 to 20 pounds measure of spirits, nine-elevenths of our excise-proof; or about 16 pounds mea- sure of proof = about 1| gallons. It has been observed that after the month of December potatoes begin to yield a smaller product of fermented spirits; and when they have once sprout- ed or germinated, they afford very little indeed^ From the difficulty of keeping and transporting potatoes, distillation from them, can never become general till some plan be adopted for overcoming these disadvantages. When acetic ether is added to well pu- rified or clean spirits, such as the distil- lers call silent whiskey, it gives it some- what of the flavor of brandy. For this purpose, also, the spirits are rectified from bruised prunes, or the lees of the cognac distilleries, whereby they acquire additional flavor. The astringent taste of old brandy is imitated by "the intro- duction of a little catechu into the British spirits. Burned sugar is employed as a coloring in these imitations. Butyric ether gives a pine-apple flavor. DIVING BELL. An apparatus by means of which persons are let down and enabled to remain under water, and execute various operations ; such as le- velling or clearing the bottoms of har- bors, preparing a foundation for build- ings, bringing up sunken materials, &c. The principle of the diving bell depends on the impenetrability of atmospheric air, and may be illustrated by a very fa- miliar experiment. Bring the edge of an inverted tumbler, or any close vessel, to the surface of water, and, keeping the mouth horizontal, press it down in the water. It will be seen that, though some portion of water ascends into the tumbler, the greater part of the space remains empty, or only filled with air; and any object placed in this space, though surrounded on all sides with j water, would remain perfectly dry. In I fact, the quantity of air remains the j same, but it is compressed into a smaller j volume, in proportion to the depth to i which it is made to descend. Isow, if we conceive a vessel of wood or iron, { sufficiently capacious to hold several men, | to be suspended by a chain, and lowered | by means of weights attached to it, to i any moderate depth under water, it is evident that they may remain there for a considerable time, and perform any ope- ration that could be executed on land in the same confined space. The machine, however, as thus described, is liable to two great defects, which must be obvi- ated by other contrivances before any great advantage can be derived from it. In the first place, as the air by its compressibility allows the water to enter the lower part of the bell, the dry space is not only diminished, but the bottom on which the bell rests, and where the operations are to be carried on, is also covered with water to a proportional depth. In the second place, the air within the bell, by repeated respiration, soon becomes mephitic, and unfit to sup- port life ; so that it is necessary to ele- vate the apparatus after short intervals, to admit a fresh supply. It is not known at what period the diviner bell was invented. Beckmann, in his History of Inventions, mentions that at Toledo, in the sixteenth century, two Greeks, in the presence of the emperor Charles V. and several thousand specta- tors, let themselves down under water in a large inverted kettle with a burning light, and rose again without being wet. George Sinclair, the author of Satan's In- visible World Displayed, in his work en- titled Ars Nova et Magna Gravitatis et Levitatis, mentions some attempts that were made about 1665 to raise, by means of a diving bell, the treasure from the ships of the Invincible Armada that went to the bottom near the Isle of Mull in the Hebrides, and describes the kind of bell that was employed. But, on account of the defects to which we have alluded, the diving bell continued to be of very little use till the time of Dr. Halley, who contrived a means of introducing fresh air into the bell while under water, and of allowing the mephitic or breathed air to escape. The bell he made use of he describes as having been of wood, con- taining about 60 cubic feet in its cavity, and of the form of a truncated cone, whose diameter at the top was three feet, and at the bottom five. This was coated with lead, so heavy that it could sink empty, ana the weight so distri- buted about its bottom that it could only descend in a perpendicular direction In the top a clear glass was fixed, to let in the light from above, and a cock to let out the air that had been breathed. To supply the air to the bell he caused a couple of barrels, of about 36 gallons 132 CYCLOPEDIA OF THE USEFUL ARTS. [div each, to be cased with lead so as to sink empty, each of them having a bung-hole in its lowest part, to let in the water as the air in them condensed on their de- scent, and to let it out again when they were drawn up full from below. To a hole in the uppermost part of the barrels a trunk or hose was fixed, long enough to fall beloAV the bung-hole, and kept down by a weight, sothat no air could escape by the hose till its end was raised up. The barrels thus prepared were let down by the side of the bell. A man stationed on a stage suspended from the bell was ready to take up the hose ; and, as soon as their ends were brought t^ the surface of the water in the barrels, all the air that was included in the upper f>arts of them was blown with great vio- ence into the bell, while the water en- tered at the bung-holes below and filled the barrels. By means of this contriv- ance the air was not only kept fresh, but another great advantage was gained ; namely, that by admitting a sufficient quantity of it the whole of the water was expelled from the inside of the bell, and the bottom of the sea laid dry. By means of this contrivance for the admission of fresh air, it was now pos- sible to remain for any length of time Tinder water ; but the use of the appara- tus was still found to be attended with some inconveniences, and even consider- able danger. The divers within the bell having no power over it, its rising or sinking depends entirely upon the peo- ple at the surface of the water ; and as the bell, even when in the water, has a considerable weight, there is always a possibility of the chain by which it is raised breaking, which would inevitably be attended with the destruction of the divers. Another danger, still more to be apprehended, is, that if the mouth of the bell in its descent should come upon a sunken ship, or a roek projecting ab- rup:ly from the bottom, it might be overset before any signal could be given to those above. These defects were ob- viated by the very ingenious contrivances of Mr. Spalding of Edinburgh. In order to avoid the risk of being upset when the bell descends on a rocky or uneven bottom, he suspended a considerable weight, which is called a balance weight, below the bell, by a rope passing over a pulley fixed in the inside ; and the other weights attached to the bell being so adjusted that they could not sink it without the balance weight, as soon as the latter rested on the ground the bell remained suspended in the water. In case of the mouth of the bell being caught by any obstacle, the balance weight is immediately lowered, till it rests on the bottom ; and as the bell, when thus relieved, is buoyant, the di- vers, having disengaged it from the rock, have it in their power either to descend by pulling in the rope, or by allowing it to run to ascend to the surface. Another contrivance of Mr. Spalding deserves mention. He divided the bell into two compartments, the one above the other, and communicating by means of a stop- cock. The divers are stationed in the lower one, and the weights are so ad- justed that when the cavity above is empty the bell is buoyant; when it is filled with water, the bell sinks. Imme- diately above the partition are some slits in the sides of the bells ; and at the top is an orifice, which can be opened or shut at pleasure. Suppose now, this orifice being open, the bell is required to be lowered ; as it descends, the water enters at the slits, and the air escapes by the orifice. When the apparatus is en- tirely under water, and the cavity conse- quently completely filled, let the orifice be shut. The bell will now continue to descend ; but if the stopcock communi- cating with the upper compartment be opened, the air will rush from the under to the upper, and displace a quantity of the water, and the apparatus will be lightened by the whole of the water so displaced. The divers have it thus in their power to regulate the descent or rise as they please. By admitting a cer- tain quantity of air into the upper cavity, the descent of the bell is arrested; by admitting a greater quantity it becomes buoyant, and rises to the top. This me- thod of constructing the diving bell has not, however, been adopted. The greatest improvement on the div- ing bell, since that of Halley, was made by the celebrated Mr. Smeaton, and con- sists in forcing down a continued stream of air by means of an air-pump through a flexible tube ; and this plan is now al- ways adopted. In the year 1788, Smea- ton constructed a diving bell to be used in the operations then contemplated at Bamsgate harbor on a new and improved plan. Instead of a bell-shaped vessel sunk by weights, his apparatus consisted of a square chest of cast iron, four and a half feet long, four and a half feet high, and three feet wide, affording sufficient room for two men under it. It was cast of such a thickness that its own weight DIV] CYCLOPEDIA OF THE USEFUL ARTS. 133 was sufficient to sink it ; and its thick- ness was greatest near the mouth or lower part, to prevent it from being easily overset. Thi3 construction of the diving bell gave the men jyithin it no power of raising or sinking it ; but as the apparatus was made to be used at a place where the nature of the bottom was known, this advantage was not con- sidered of great consequence ; and, in fact, it is found by experience that it is better to leave the bell to be entirely guided from above. On account of the facility with which water conveys sound, the strokes of a hammer on the inside of the bell can be heard at a great distance ; and the sound coming through the water has a peculiar character, which cannot be mistaken. By previous ar- rangements any directions can be given in this manner. For instance, one blow may denote more air ; two, stand fast ; three, heave up ; four, lower down, and so on. With these successive improve- ments, the diving bell is found to be a most important machine in all the great operations to be performed under water. It was used with great advantage by Mr. Kennie in the construction of the various harbors he projected ; and it has recently been successfully employed in deepening the Clyde between Glasgow and Green- ock, and improving the condition of the river. DIVING. The art of descending in water. Independently of the valuable native productions which are found at the bottom of the sea, such as pearls, coral, sponges, &c, the treasure which is so frequently carried down in wrecked vessels makes it an object of importance to be able to descend'to the bottom and remain there long enough to execute the operations necessary to recover it. But without the assistance of some mechani- cal apparatus, it is extremely little that even the most practised divers can per- form. A minute and a half, or two minutes, is the longest time that a diver, in general, can remain under water. Be- sides, on account of the loss of weight in water, the power which a man can exert is extremely small, unless borne down by a load which would entirely prevent him from rising again to the top. For these reasons, numerous projects have been brought forward to assist the natural powers of the body, and render diving an art of more extensive utility. In all these projects, the principal object aimed at is to supply the diver with fresh air and light, and leave him the free use of his arms, and the power of walking within a moderate range at the bottom. Borelli contrived an apparatus which he called a diving bludder; the bladder be- ing of brass or copper, about two feet in diameter, to contain the diver's head, and fastened to a goat-skin covering ex- actly fitted to the shape of the head. An apparatus of this kind was successfully used by Mr. Deane on the west coast of Scotland, at Spithead, and at Donagha- dee, where he brought up an immense number of dollars and various other ar- ticles from a vessel which had been wrecked there more than thirty years before. The principal part of Mr. Deane's ap- paratus consists of a helmet of thin sheet copper, which covers the head of the diver, large enough to admit of free mo- tion, and furnished with three eye-holes, covered with glass protected by brass wires. The helmet comes pretty well down over the breast and back, and is fastened by rivets to a waterproof can- vass jacket so tightly that no water can penetrate. A leather belt passes round the diver, to which are attached two weights, one before and the other be- hind, each about 40 lbs. The belt is supplied with a buckle in front, which, in case of any accident happening, can be instantly undone. The diver is sup- plied with fresh air by means of a flexi- ble water-proof pipe, which enters the helmet, and communi- cates with an air-pump, wrought above m the barge" from which he de- scends. This pipe pas- ses under the left arm of the diver, and enters the back of the helmet, being so contrived that the fresh air is made to impinge on the glasses ; which in a great measure prevents their being dimmed by the moisture of the breath. From the back part of the helmet there is also led an eduction pipe, to allow the escape of the breathed air. A single line passes under the right arm to" communicate with attendants at the surface. The diver descends from the side of the ves- sel, either by means of a rope or wooden ladder, loaded at the lower end, the weight being kept at a little height above the ground. When the diver descends to the bottom, the weight is let down, and the rope allowed to become slack, to prevent the motion of the boat from ob- structing him. His motion is rendered 134 CYCLOPEDIA OF THE USEFUL ARTS. |dra steady by heavy weights attached to his feet : and he carries a line in his hand, that he may, when necessary, guide him- self back to the rope. A waterproof dress covers his body entirely ; and he is thus enabled to remain under water five or six hours at once, all the while per- fectly drv. DIVISIBILITY. The property which all bodies possess of being separable into parts. It was a question formerly much agitated among philosophers, whether matter is divisible in infinitum ; or whether a certain term does not exist beyond which the particles are reduced to simple atoms incapable of further di- vision. The question is incapable of di- rect solution, and fortunately is of no importance to science ; but the extent to which the actual subdivision of bodies has been carried in many cases in the arts may well be considered as prodigious. "In the gilding of buttons, 5 grains of gold, which is applied as an amalgam with mercury, is allowed to each gross ; so that the coating left must amount to the 110,000th part of an inch in thick- ness. If a piece of ivory, or white satin, be immersed in a nitro-muriate solution of gold, and then exposed to a current of hydrogen gas, it will become covered with a surface of gold hardly exceeding in thickness the ten-millionth part of an inch. " The solution of certain saline bodies, and of other colored substances, exhibits a prodigious subdivision and dissemina- tion of~matter. A single grain of the sulphate of copper, or blue vitriol, will communicate a fine azure tint to five gal- lons of water. In this case the copper must be attenuated at least ten million times ; yet each drop of the liquid may contain so many colored particles, dis- tinguishable by our unassisted vision. Odors are capable of a still wider diffu- sion. A single grain of musk has been known to perfume a room for the space of twenty years. Animal matter like- wise exhibits in many instances a won- derful subdivision. The milt of a cod- fish when it begins to putrefy has been computed to contain a billion of perfect insects, so that thousands of these living creatures could be lifted on the point of a needle. But the infusory animalcules display in their structure and functions the most transcendant attenuation of matter. The Vibrio undvla,, found in duck weed, is computed to be ten thou- sand million times smaller than a hemp seed. The Vibrio lineola occurs in vege- table infusions, every drop containing myriads of these oblong points. The Monas gelatinosa, discovered in ditch wa- ter, appears in the field of a microscope a mere ator^ endued with life, millions of them playing like sunbeams in a single drop of liquid." DOCTMASTIC ART. The art of as- saying minerals or ores, with a view of determining the quantity of metal which they contain. DOCK. An artificial basin for the re- ception of ships. Docks are of two sorts, wet and dry : the former are used for the purpose of loading and unloading a ship^s cargo out of the influence of the tide, and are constructed with gates, which when shut keep the ship con- stantly on float at low water ; the latter are intended for the building, repairing, or examination of ships, which ar. ad- mitted into them at flood tide, and are so called because they are either left dry by the ebbing of the sea, or rendered so by the use of great flood gates or of pumps. A naval dock is a place provided with all sorts of naval stores, timber, and all the requisite machinery for ship- building. DRAGON'S BLOOD is a resinous substance, which comes to us sometimes in small balls of the size of a pigeon's- egg, sometimes in rods, like the finger, and sometimes in irregular cakes. Its color, in lump, is dark brown red; in powder, bright red : friable ; of a shining fracture; sp. grav.,' 1-196. It contains a little benzoic acid, is insoluble in water, but dissolves readily in alcohol, ether, and oils. It is brought from the East Indies, Africa, South America, as the Sroduce of several trees, the Dracana h-aco, the Pterocarpus santalinus, the Pterocarpus Draco, and the Calamus Bo- tang. Dragon's blood is used chiefly for tingeing spirit and turpentine varnishes, for preparing gold lacker, for tooth tinc- tures and powders, for staining marble, &c. According to Herbenger, it consists of 9-07 parts ofred resin, 2 of fat oil, 3 of benzoic acid, 1-6 of oxalate, and 3-7 of phosphate of lime. DRAINING. The art of freeing the surface of the soil from superfluous wa- ter, considered with reference to culti- vated vegetables, and the health of man and animals. "Water may become super- fluous by being collected in the natural hollows on the surface, and thus form- ing bogs ; by being retained in the sur- face stratum, in consequence of a reten- dra] CYCLOPEDIA OF THE USEFUL ARTS. 135 tive subsoil ; or by oozing through a moist subsoil to the surface stratum, in consequence of supplies from subter- raneous sources. Water collected in bogs, or marshy places, remains there, because it has no natural outlet, neither by an opening or hollow along the natural sur- face, nor by the porosity of the subsoil, in consequence of which the water might sink into it and disappear. The obvious mode of draining in the first case is by a trench or drain, so deep as to draw the water from the lowest parts of the hollow, bog, or marsh. Where water is retained in the surface soil in conse- quence of a retentive subsoil, as in the case of clays and many loams, the most effective mode is to cut a number of small drains parallel to and at short distances from one another ; and by the tops of these drains reaching within an inch or two of the bottom of the surface soil, which in cultivation is turned over by the plough, they absorb the superfluous water that passes through this soil and carry it off. Or, should the land be in pasture, the tops of the drain should be brought within an inch or two of the grassy surface, so as to intercept the water, both oozing laterally from the sur- face soil, and vertically from among the leaves of the grass. It may be observed also that pasture lands on this descrip- tion of retentive soil may be more rea- dily drained when laid into ridges, and an underground drain formed under each furrow or surface drain. This, however, is not essential ; and though furrows or surface drains would be no deformity in field culture, yet in lawns and parks the appearance of furrows would destroy the continuity and evenness of surface, which in lawns is one chief source of beauty. To drain the surface soil, where it is supplied by water from the subsoil, re- quires some knowledge of the strata of which the subsoil is composed. In gene- ral the strata composing the subsoil lie over one another in a direction more or less approaching to horizontal ; and when the natural inclination of the surface is every where parallel to this strata be- neath, the water, if it oozes out of the subsoil at all, will generally do so equally throughout the subsoil; and in such cases numerous drains at no great dis- tance are required to carry it off, pre- cisely as in the case of draining soils with retentive subsoils. Bat when the line of surface does not correspond with the line of substrata, but intersects this line, then water will generally be found oozing out at the line of intersection, technically called the cropping out of the strata. The quantity of water which will issue from these sections or cropping3 out of broken strata will depend on a great variety of circumstances, into which it is unnecessary here to enter ; be- cause in all cases the mode of draining is the same, viz., that of forming a drain parallel to the line of fracture of the strata. This drain in some cases is not required to extend the whole length of the line of the fracture ; because if the strata have a double inclination, so as it were to conduct the water to one angle or point, a drain at that angle or point will carry off the whole of the superflu- ous water contained in the strata. The subsoil in some cases is composed of strata in a nearly vertical position, and in others of strata alternately depressed and elevated, so that a section through them would form a serpentine line ; and sometimes the subsoil is composed of strata the layers of which have been broken up and jumbled together. All these, and other cases, are to be drained in one or more of the above described modes ; that is, accumulated water, whe- ther in the soil or above it, is to be let off by cuts or drains made at the lowest points of accumulation ; and surface soil saturated with water, whether from greater atmospherical supplies than can be carried off by evaporation or can sink into the subsoil, or whether it arise from sources in the subsoil, is to be carried off by numerous drains close to one another, and the tops of which are the cultivated soil, or the permanent cloth- ing of grass or other herbage. Draining is not required in this coun- try as much as in England ; yet in very many instances, as in heavy clay soils and "on low swamp lands, it should be the first step in the cultivation of the land. When the soil is porous, light, and sandy, drains are not required ; or if so, need only be placed far apart and at great depth (below 5 feet) : on clay lands they require to be closer, and about the depth of 30 or 36 inches. Draining tools and tiles are now coming into much use ; and when it is considered that it raises the produce of the land to one third more, few intelligent farmers n r ho cultivate well will neglect it. Pipe drains are better for general use than arch drains with flat soles, as the water is de- livered quicker in its channel, and the latter is kept clean, not choking up : the latter, however, hold better in clay soils. 136 CYCLOPEDIA OF THE USEFUL ARTS. [dry The top of every drain should be suf- ficiently far below the surface that the plough in passing over will not touch it. DRILL. In mechanics, a small instru- ment of steel for perforating metals or hard substances. Its action is produced by communicating to it a very rapid ro- tation by means of a drill-bow. Drill. In Agr., a machine for sowing agricultural seeds in rows ; sometimes worked by the hand alone, and some- times bv the addition of a horse. DKILL HUSBANDRY. In Agr., the cultivation of arable land, by sowing the crops in rows ; the advantage of which is, that it admits of destroying the weeds, and stirring the soil in the intervals be- tween the lines of plants. As this mode of cultivation requires some implements and machines not in use in the com- moner kinds of farming, and as it is be- sides better adapted for some soils than for others, it is not so generally used as the obvious advantages attending it would lead us to expect. DROSOMETER. Any instrument for measuring the quantity of dew that col- lects on the surface of a body exposed to the open air during the night. The first instrument for this purpose was Eroposed by Weidler. It consisted of a ent balance which marked in grains the preponderance which a piece of glass of certain dimensions, laid horizontally in one of the scales, had acquired from the settling and adhesion of the globules of moisture. A simpler and more con- venient drosometer would be formed on the principle of the rain gauge ; and in order to facilitate the descent of the dew down the sides of the funnel into the tube, a coat of delicate salt of tartar may be spread over the shallow surface. Dr. Wells, in making his celebrated experi- ments on dew, exposed a small quantity of wool to the open sky, and the differ- ence in its weight when laid down and taken up showed the quantity of mois- ture it had imbibed in the interval. DRUGGET. A coarse and flimsy woollen texture, chiefly used for covering carpets. It was formerly extensively employed as an article of clothing by the poorer classes, more especially of fe- males ; but this and similar fabrics are now almost wholly superseded by cotton goods, which induce greater cleanliness, and are less liable to retain infectious and contagious poisons. DRY DISTILLATION. This term is applied to the distillation of substances per se, or without the addition of water : thus if we put wood into a retort or other distillatory apparatus, and subject it to heat, it yields tar, vinegar, water, and various gaseous and other matters, which are called the products of its dry or de- structive distillation. DRYING OIL. This term is generally applied to linseed and other ofls which have been heated with oxide of lead: they are the bases of many paints and varnishes. DRY ROT. A disease which attacks wood, rendering it brittle, and destroy- ing the cohesion of its parts, is known by thisname. It occurs among the tim- bers of ships, where it sometimes com- mits the most serious damage,' jnd in damp ill-ventilated houses. It is usually ascribed to the attacks of fungi, espe- cially to such as Poly-porm destructor and Merulius lachrymans, whose filamen- tous spawn or thallus appears upon the surface, overspreading it like a tough thick skin of white leather ; and there is no doubt of its being often connected with appearance of such fungi. But dry rot is certainly, in some cases, to be identi- fied with the presence of a fungi of a more simple kind than those just men- tioned ; especially of such as belong to or resemble the genus Sporotrichum. The destruction of timber by such plants is effected in part by the disin- tegration of the tubes of the weed, in consequence of the introduction between them of the fine filamentous spawn of the fungi, and in part by the dampness which is thus conveyed to the interior of the wood, where it soon produces de- composition. It is not, however, certain that dry rot is always caused in this manner ; on the contrary, the term ap- pears to be frequently applied to cases of spontaneous decomposition of timber without the presence of fungi, or when the appearance of the latter takes place long after the commencement of the dis- ease. When dry rot produced by fungi has once made its appearance, there is no means of arresting its progress without removing the whole of the diseased and neighboring parts ; and even then it will probably again break out, unless means can be taken to introduce a circulation of fresh air among the parts liable to the affection. For if timber is allowed to remain in a damp situation, and in the dark, it affords so favorable a nidus foi the seeds of fungi, that they are almost certain to vegetate upon it ; unless some means have been previously taken to ouc] CYCLOPEDIA OF THE USEFUL ARTS. 137 render the timber permanently unsuited to their growth. This end appears to have been attained by Mr. Kyan, who obtained a patent for pickling timber, as a preventive of the dry rot, and who employed for this purpose a solution of corrosive sublimate. This salt of mer- cury is a well-known vegetable poison : if any animal jelly, upon which fungi will quickly appear in the form of mouldi- ness, is mixed with a minute quantity of corrosive sublimate, no fungi will in that case be produced ; so that both theory and experience are in favor of Mr. Ev- an's process. It is not improbable that the progress of dry rot might even be arrested in the buildings where it occurs, if the timbers could be got at and well washed with the same solution. Although dry rot generally fixes itself upon timber, it will also attack any form of vegetable matter. The paper hang- ings of rooms, chiefly composed of cot- ton and linen thread, are occasionally overrun in houses which have been long shut up and neglected ; and the mildew which destroys the strength of canvas is only another" form of dry rot, the ap- pearance of which is altered by the special circumstances under which the fungus is developed, or by the species of the fun- gus itself. (See Wood, Preservation of.) DRYSALTER. A dealer in salted or dried meats, and in the materials used in pickling, salting, and preserving various kinds of food ; hence drysalters usually sell a number of saline substances and miscellaneous drugs. DRYSTOVE. A glazed structure for containing the plants of dry arid cli- mates ; such as the cactuses, mesembry- anthemums, aloes, and other succulents of Africa. DUCTILITY. A property of certain bodies, in consequence of which they can be drawn out at length without suf- fering any interruption of the continuity of their constituent particles. The term ductility is frequently confounded with malleability, or that 'property of bodies through which different forms can be given to them by pressure or percussion. In general ductility depends, in a greater or less degree, on the temperature. Some bodies — wax for example — are rendered ductile by a small degree of heat ; while glass requires a violent heat before it acquires ductility. Some of the metals — for example, gold, silver, lead, &c. — are ductile under all kno;vn tempera- tures. " The ductility of some metals far ex- ceeds that of any other substance. The goldbeaters beerin their operations with a riband an inch broad and 150 inches long, which had been reduced, by passing it through rollers, to about the 800th part of an inch in thickness. The riband is cut into squares, which are disposed between leaves of vellum, and beat by a heavy hammer till they acquire a breadth of about three inches, and are thus ex- tended to ten times their former sur- face. These are again quartered and placed between the folds of goldbeater's skin, and stretched out by the operation of a lighter hammer to the breadth of five inches. The same process is re- peated, sometimes more than once, by a succession of lighter hammers ; so that 376 grains of gold are thus finally ex- tended into 2000 leaves of 3-3 inches square, making in all 80 books, contain- ing each of them 25 leaves. The metal is consequently reduced to the thinness of the 282,000th part of an inch, and every leaf weighs rather less ■ than the fifth part of a grain. A particle of gold, not exceeding the 500,000th part of a grain, is hence distinctly visible to the naked eye. "It has been asserted that wires of pure gold can be drawn of only the 4000th part of an inch in diameter ; but Dr. Wollaston, by an ingenious procedure, has lately advanced much farther. Tak- ing a short cylinder of silver, about the third part of an inch in diameter, he drilled a fine hole through its axis, and inserted a wire of platinum only the 100th part of an inch thick. This silver mould was now drawn through the suc- cessive holes of a steel plate, till its di- ameter was brought to near the 1500th part of an inch ; and consequently the internal wire, being diminished in the same proportion, was reduced to between the 4000th and 5000th part of an inch. The compound wire was then dipped in warm nitric acid, which dissolved the silver, and left untouched its core, or the wire of platinum. By passing the in- crusted platinum through a greater num- ber of holes wires still finer were ob- tained, some of them only the 30,000th part of an inch in diameter. The te- nacity of the metal, before reaching this limit, was even considerable ; a platinum wire, of the 18,000th part of an inch in diameter, supporting the weight of a grain and a third." Glass, when well softened by the fire, becomes as ductile as soft wax, and may be spun out into threads of greater fine- 138 CYCLOPEDIA OF THE USEFUL ARTS. [i ness than any hair, and which bend and wave like hair in the wind. The method of producing these threads is exceedingly easy. Two workmen are employed ; the first holds the glass over the flame of a lamp ; the second applies a hook to the metal in fusion, which, when drawn back, brings with it a thread of glass, still adhering to the mass ; the hook is then fitted on the circumference of a wheel, which, being turned round, draws out the thread, and winds it about its rim. Some of these threads are scarcely larger than that of a silkworm, and are surprisingly flexible. DUNGING. One of the processes of dyeing and calico printing. The steeping the goods in a bath of cowdung. Experience has proved that dunging is one of the most important steps in the process of calico printing, and that if it be not well performed the dyeing is good for nothing. Before we can assign its peculiar function to the dung in this case, we must know its composition. Fresh cows' dung is commonly neutral when tested by litmus paper ; but some- times it is slightly alkaline, owing, proba- bly, to some peculiarity in the food of the animal. The total constituents of 100 parts of cow dung are as follows: Water, 69-58; bitter matter, 0*74; sweet substance, 0-93 ; chlorophylle, 0-28 ; albumine, 0-63; muriate of soda, 0*08 ; sulphate of pot- ash, 0*05 ; sulphate of lime, 0-25 ; car- bonate of lime, 0*24; phosphate of lime, 0-46 ; carbonate of iron, 0*09 ; woody fibre, 26-39; silica, 1-14: loss, 0-14. In dunging calicoes the excess of un- combined mordant is in part attracted by the. soluble matters of tne cow's dung, and forms an insoluble precipitate, which has no affinity fur the cloth, especially in presence of the insoluble part of the dung, which strongly attracts alumina. The most important part which that insoluble matter plays, is to seize the excess of the mordants, in proportion as they are dis- solved by the water of the bath, and thus to render their reaction upon the cloth impossible. It is only in the deposite, therefore, that the matters carried off from the cloth by the dung are to be found. M. Camille Kcechlin ascribes the action of cow dung chiefly to its albuminous constituents combining with the alumina and iron, of the acetates of these bases dissolved by the hot water of the bath. The acids consequently set free, soon be- come evident by the test of litmus paper, I after a few pieces are passed through, and require to be got rid of either by a fresh bath, or by adding chalk to the old one. The dung thus serves also to fix the bases on the cloth, when used in moderation. It exercises likewise a dis- oxydating power on the iron mordant, and restores it to a state more fit to com- bine with coloring matter. DWARFING TREES. Dwarf trees may be produced in three different ways : by grafting on dwarf slow-growing stocks, as, for example, the pear on the quince • by planting in pots of small size filled with poor soil, by which the plant is starved and stunted; and by causing a portion of the extremity of a branch to produce roots, and then cutting it off and planting it in a pot or box of poor soil. This last is the Chinese method, and is thus performed: — The extremity of a branch two or three feet in length, in a fruit or flower-bearing state — for exam- ple, the points of the branches of a fir tree bearing cones, or of an elm bearing blossom buds — being fixed on, a ring of bark is taken off at the point where it is desired that the roots should be pro- duced. The space thus laid bare is co- vered with a ball of moist clay, which is kept moist by being covered with moss, which is occasionally watered. In the course of two or three months in some trees, and of a year or two in others, roots are protruded into the ball of clay. The branch may then be cut off below the part from whence the roots have been protruded, and the branch being ] ilanted in a pot of poor soil, and kept pparingly supplied with water, it will re- main nearly in its present state for many years ; producing leaves, and perhaps flowers, annually, but never shoots longer than a few lines. DYEING. The object of this beauti- ful art is to fix certain coloring matters uniformly and permanently in the fibres of wool, silk, linen, cotton, and other substances. The moderns have obtained from this Continent several dye-drusrs unknown to the ancients ; such as cochi- neal, quercitron, Brazil wood, logwood, annatto; and they have discovered the art of using indigo as a dj-e, which the Romans knew only as a pigment. But the vast superiority of our dyes over those of former times must be ascribed principally to the employment of pure alum and solution of tin as mordants, either alone or mixed with other bases ; substances which give to our common dye-stuffs remarkable depth, durability, dye] CYCLOPEDIA OF THE USEFUL ARTS. 139 and lustre. Another improvement in dyeing of more recent date is the appli- cation to textile substances of metallic compounds, such as Prussian blue, chrome yellow, manganese brown, &c. There are a few dyeing materials which impart their color to different stuffs with- out any previous preparation, and these have been technically termed substantive colors ; by far the greater number, how- ever, of coloring materials, only impart a fugitive tint under such circumstances, ami require that the stuff to be dyed should undergo some previous prepara- tion, in order to render the color perma- nent ; that is, capable of resisting the ac- tion of air, light, and water. The sub- stance applied with this intention is called a base or mordant, and must possess an affinity for the fibre of the stuff on the one hand, and for the coloring materials on the other. The mordant often effects another important object; that of chang- ing or exalting the color at the same time that it fixes it. The principal mordants are aluminous earth and oxide of iron, and these are usually applied in the state of acetates. Oxide of tin is a valuable mordant ; it is generally applied as ni- trate or chloride. .As an instance, we may mention the mode of dyeing calico red by means of madder, a decoction of which, if applied to the unprepared goods, would only give them a dirty red tinge, neither agreeable nor permanent. If the calico be previously passed through a weak solution of acetate of alumina, and then dried at a high temperature, and afterwards washed, a portion of the alumina is retained in chemical combina- tion with the fibre of the calico ; and when thus prepared and submitted to the action of a hot decoction of madder, and again washed, it comes out of a fine red, which is fixed in consequence of the at- traction of the alumina for the peculiar principle which gives color to the mad- der. If the mordant be oxide of iron in- stead of alumina, the color which is then produced is purple • and various shades and colors are obtained by mixing mor- dants, by using more or* less of them, and by applying the colored solutions in various states of concentration. Some- times articles are dyed by a similar pre- cipitation of colored metallic oxides in the fibre ; thus yellow is obtained by passing cloth impregnated with acetate of lead through a solution of chromate of potash : a double decomposition ensues, and yellow chromate of lead is precipi- tated in and combined with the vegetable or animal fibre. Blues are produced by passing the goods previously mordanted with iron through an acidulated solution of ferrocyanate of potash ; these are gene- rally called chemical colors, though not in fact more so than the others. Scarlet is exclusively produced by the coloring matter either of the cochineal or of the lac insect, which is fixed by oxide of tin, or by alumina, and heightened by the action of tartar. Indigo. This dye-drug, when tolera- bly good, contains half its weight of in- digotine. The cold vat is prepared com- monly with water, copperas, indigo, lime, or sometimes carbonate of soda, and is used almost exclusively for cotton and linen ; immersion in acidulated water is occasionally had recourse to for removing a little oxyde of iron which attaches it- self to the cloth dyed in this vat. The indigo vat for wool and silk is mounted exclusively with indigo, good potashes of commerce, madder, and bran. In this vat, the immediate principles with base of carbon and hydrogen, such as the extracts of madder and bran, perform the disoxydising function of the copperas in the cold vat. The pastel vats require most skill and experience, in consequence of their complexity. The greatest diffi- culty occurs in keeping them in a good condition, because they vary progressive- ly as the dyeing goes on, by the abstrac- tion of the indigotine, and the modifica- tion of the fermentable matter employed to disoxygenate the indigo. The alkaline matter also changes by the action of the air. By the successive additions of indi- go, alkali, &c, this vat becomes very difficult to manage with profit and suc- cess. The great affair of the dyer is the proper addition of lime ; too much or too little being equally injurious. Sulphate of indigo, or Saxon blue, is used also to dye silk and wool. If the wools be ill sorted, it will show their dif- ferences by the inequalities of the dye. Wool dyed in this bath put into water saturated with sulphureted hydrogen, be- comes soon colorless, owing to the disox- ygenation of the indigo. The woollen cloth when exposed to the air for some time resumes its blue color, but not so intense- ly as before. Logwood. The properties of hema- tine explain the mode of using logwood. When stuffs are dyed in the infusion or decoction of this wood, under the influ- ence of a base which acts upon the hema- tine in the manner of an alkali, a blue dye, bordering upon violet, is obtained. 140 CYCLOPEDIA OF THE USEFUL ARTS. [dye Such is the process for dyeing cotton and wool a logwood blue by means of verdi- gris, crystallized acetate of copper, and acetate of alumina. When we dye a stuff yellow, red, or orange, we have always bright tints : with blue, we may have a very dark shade, but somewhat violet; the proper black can be obtained only by using the three colors, blue, red, and yellow in proper proportions. Hence we can explain how the tints of yellow, red, orange, blue, green, and violet, may be browned, by applying to them one or two colors which along with themselves would produce black ; and also we may explain the na- ture of that variety of blacks and grays which seems to be 'indefinite. Nutgails and sulphate of iron, so frequently em- ployed for the black dye, give only a vio- let or bluish gray. The pyrolignite of iron, which contains a brown empyreu- matic matter, gives to stuffs a brown tint, bordering upon greenish yellow in the pale hues, and to chestnut brown in the dark ones. By galling cotton and silk, and giving them a bath of pyrolignite of iron, we may, after some alternations, dye them black. Galls, logwood, and a salt of iron, produce merely a very deep vio- let blue ; but by boiling and exposure to the air, the hematate of iron is changed, becoming red-brown, and favors the pro- duction of black. Galls and salts of cop- per dye stuffs an olive drab, logwood and salts of copper, a violet blue ; hence their combination should produce a black. In using: sumach as a substitute for galls, we should take into account the proportion of yellow matter it con- tains. When the best possible black is wanted upon wool, we must give the stuff a foundation of indigo, then pass it it into a bath of logwood, sumach, and proto-sulphate of iron. The sumach may be replaced by one third of its weight of nutgails. The compound or mixed colors, are such as result from the combination of two differently colored dye-stuffs, or from dyeing stuffs with one color, and then with another. The simple colors of the dyer are red, yellow, blue, and black, with which, when skillfully blended, he can produce every variety of tint. Ber- haps the dun or fawn color might be ad- ded to the above, as it is directly ob- tained from a great many vegetable sub- stances. 1. Bed with yellow, produces orange; a color which, upon wool, is given usual- ly with the spent scarlet bath. To this shade may be referred flame color, pome- granate, capuchin, prawn, jonquil, cassis, chamois, cafe au lait, aurora, marigold, orange peel, mordores, cinnamon, gold &c. Snuff, chestnut, musk, and other shades are produced by substituting wal- nut peels or sumach for bright yellow. If a little blue be added to orange, an olive is obtained. The only direct orange dyes are annotto, and subchromate of lead (see Silk and "Wool Dyeing). 2. Bed with blue produces purple, vio- let, lilac, pigeon's neck, mallow, peach- blossom, bleu de roi, lint-blossom, ama- ranth. 3. Bed with black; brown, chocolate, marone, &c. 4. Yellow with blue ; green of a great variety of shades, such as nascent green, gay green, grass green, spring green, laurel green, sea green, celadon green, Sarrot green, cabbage green, apple green, uck green. 5. Mixtures of colors, three and three, and four and four, produce an indefinite diversity of tints ; thus, red, yellow, and blue, form brown olives, and greenish grays ; in which the blue dye ought al- ways to be first given, lest the indigo vat should be soiled by other colors. Bed, yellow, and gray, (which is a gradation of black), give the dead-leaf tint, as well as dark orange, snuff color, &c. Bed, blue, and gray, give a vast variety of shades ; as lead gray, slate gray, wood- pigeon gray, and other colors, too nume- rous to specify. The following list of dyes, and the co- loring substances which produce them, may prove useful. Bed. Cochineal, kermes, lac, madder, archil, carthamus or safiiower, Brazil wood, logwood, periodide of mercury, alkanet. Yellow. Quercitron, weld, fustic, (yel- low wood) annotto, sawwort, dyer's broom, turmeric, fustic, {rhus cotlnus) Persian and Avignon berries, (rTiamnus infectorius) willow, peroxide of iron ; cliromate of lead, (chrome yellow) sul- phuret of arsenic, hydrosulphuret of an- timony ; nitric acid on silk. Blue. Indigo, woad or pastel, Prus- sian blue, turnsole or litmus, logwood with a salt of copper. Blade. Galls, sumach, logwood, wal- nut peels, and other vegetables which contain tannin and gallic acid, along with ferruginous mordants. The anacardi- um of India. Green. These are produced by tho blue and yellow dyes skillfully combined ; ear] CYCLOPEDIA OF THE USEFUL ARTS. 141 with the exception of the chrome green, and perhaps the copper green of Schwein- furt. Orange. Annotto, and mixtures of red and yellow dyes; subchromate of lead. Fawn, Dun, Hoot. Walnut peels, su- mach, birch-tree, henna, sandal wood. The chemical principles of the art of calico printing are the same as those of dyeing, but the details are more difficult and complicated ; and in consequence of the combination of a great variety of co- lors upon the same ground, the process is sometimes extremely refined and intri- cate ; so that a rich, varied, and pleasing pattern, thus effectively produced, may be considered as a triumph of practical skill over theoretical difficulties, which is scarcely rivalled, and certainly not. ex- celled, *in any other of the arts. It is ob- vious that calico printing is in the abstract a topical dyeing ; and much discrimina- tion and taste are requisite in the con- trivance of the pattern, its general de- sign, and the colors in which it is exhib- ited. In this art the mordant^, and sometimes the colors, are applied either by blocks, upon which the pattern is de- signed in relief, or by copperplates, which are engraved, or by cylinders or rollers. If the aluminous mordant be printed by one block and the iron mordant by ano- ther, and the mixture of the two by a third, and the piece thus prepared be then passed through a madder bath, and properly cleansed and bleached, the color will only adhere to the mordanted places, and it will be red where the aluminous earth only has been applied, purple with the mixed mordant, and black with the iron ; if the same three mordants be used with a decoction of quercitron bark, the resulting colors will be yellow, olive, and brown ; and in this way a great variety of colors may be produced. Sometimes copperplate and block printing are com- bined ; a fine running pattern being printed by the plate or cylinder over the whole surface, which serves as a ground work, and upon which other figures are printed by blocks. Sometimes the mor- dant and color are both applied at once by means of a block, and rendered fixed and permanent by exposing the goods for some time to steam. Beautiful effects are produced by printing the patterns on a mordanted ground with some substance which will resist the color, and so pro- duce a white pattern on a colored ground. (See Calico Pkentlng.) DYKE. In geology is a term applied . to a mass of igneous rock, as granite, trap, greenstone, or lava, which is thrown up or injected through and into the rents and fissures of a stratified, or even an ig- neous rock. Dykes are of frequent oc- currence in districts where primary rock prevails. Dyke is also a mound of earth or stone, or other material intended to prevent the sea inundating contiguous low coasts, such as in Holland. DYNAMOMETEK. An instrument for measuring power of any kind, as the strength of men and animals, the force of machinery, the magnifying power of a te- lescope, &c. An instrument for measur- ing animal force was invented by Mr. Graham many years ago, and afterwards improved by Desaguliers ; but as it con- sisted of wooden works, it was too heavy and bulky to be conveniently used for ordinary purposes. Leroy, of the Aca- demy of Sciences of Paris, proposed a dynamometer, which consisted merely of a tube of metal of ten or twelve inches in length, placed vertically on a stand, an^ containing a spring in its interior, which indicated by its compression the amount of the force applied. The instrument was in fact the same in principle as the common spring balance. The most convenient dynamometer is that of Regnier, which is described in the Journal de VEcole Polyteclinique. It con- sists of an elliptical steel spring of about 12 inches in circumference, and the force is applied either by pressing the two ver- tices of the axis minor against each other, or by drawing in opposite directions the two ends of the axis major. In both cases the sides of the spring are made to approach each other ; and. thus they move an index which marks the degree of approximation on a semicircular scale. By means of this machine the mean force is ascertained which a man can exert with the right hand, or with the left, or with both together, and in various positions of his body. Some interesting results re- lating to the average strength of men at different ages, and of different weights and sizes, have been deduced by M. Quetelet of Brussels, from numerous ex- periments with his dynamometer. In testing the value of ploughs, the dynam- ometer should be used, instead of plough- ing a sriven space of land. EARTHEN WAEE. See Pottery. EARTH. Modern science has demon- strated that the substances called primi- tive earths, and which prior to the great electro-chemical career of Sir H. Davy, I were deemed to be elementary matter, 142 CYCLOPEDIA OF THE USEFUL ARTS. EBU are all compounds of certain metallic ba- ses and oxygen, with the exception of silica, whose base, silicon, being analo- gous to boron, has led that compound to be regarded as an acid ; a title character- istic of the part it extensively performs in neutralizing alkaline bodies, in mine- ral nature, and in the processes of art. Four of the earths, when pure, possess decided alkaline properties, being more or less soluble in water ; having (at least three of them) an acrid alkaline taste, changing the purple infusion of red cab- bage to green, most readily saturating the acids, and affording thereby neutro-saline crystals. These four are baryta, strontia, lime, and magnesia. The earths proper are five in number ; alumina, glucina, yttria, zirconia, and thorina: These do not change the color of infusion of cab- bage or tincture of litmus, do not readily neutralize acidity, and are quite insolu- ble in water. The alkalis are soluble in water, even when carbonated ; a property which distinguishes them from the alka- line earths. Lithia must for this reason be considered to be an alkali. See the above substances in their alphabetical places. EAU DE COLOGNE. This prepara- tion has long possessed great celebrity, in consequence chiefly of the numerous virtues ascribed to it by its venders ; and is resorted to by many votaries of fashion as a panacea against ailments of every kind. It is however nothing more than aromatized alcohol, and as such, an agreea- ble companion of the toilet. Numerous fictitious receipts have been offered for preparing eau de Cologne ; the following may be reckoned authentic, bavins: been imparted by Farina himself to a friend. Take 60 gallons of silent brandy ; sage, and thyme, each 6 drachms ; balm-mint and spearmint, each 12 ounces ; calamus aromaticus, 4 drachms ; root of angelica, 2 drachms • camphor, 1 drachm ; petals of roses and violets, each 4 ounces ; flow- ers of lavender, 2 ounces ; flowers of orange, 4 drachms ; wormwood, 1 ounce ; nutmegs, cloves, cassia lignia, mace, each 4 drachms. Two oranges and two lemons, cut in pieces. Allow the whole to mace- erate in the spirit during 24 hours, then distil off 40 gallons by the heat of a water bath. Add to the product : Essence of lemons, of cedrat, of balm- mint, of lavender, each 1 ounce 4 drachms ; neroli and essence of the seed of anthos, each 4 drachni3 ; essence of jasmin, 1 ounce ; of bergamot, 12 ounces. Filter and preserve for use. Cadet de Gassincourt has proposed to prepare eau de Cologne by the following recipe ; Take alcohol at 32° B., 2 quarts ; neroli, essence of cedrat, of orange, of lemon, of bergamot, of rosemary, each 24 drops ; add 2 drachms of the seeds of lesser cardamoms, distil by the heat of a water bath , a pint and a half. "When pre- pared as thus by simple mixture of essen- ces without distillation, it is never so good. EAU DE LUCE is a compound formed of the distilled oil of amber and water of ammonia. EAU DE JAVELLE. Solution of hy- pochlorite of soda. EBULLITION. When the bottom of an open vessel containing water is ex- posed to heat, the lowest stratum of fluid immediately expands, becorm s therefore specifically lighter, and is forced upwards by the superior gravity of the superin- cumbent colder and heavier particles. The heat is in this way diffused through the whole liquid mass, not by simple com- munication of that power from particle to particle as in solids, called the conduction of caloric, but by a translation of the several particles from the bottom to the top, and the top to the bottom, in alter- nate succession. This is denominated the carrying power of fluids, being com- mon to both liquid and gaseous bodies. These internal movements maybe render- ed very conspicuous and instructive, by mingling a little powdered amber with water, contained in a tall glass cylinder, standing upon a sand-bath. A column of the heated and lighter particles will be seen ascending near the axis of the cylin- der, surrounded by a hollow column of the cooler ones descending near the sides. That this molecular translation or loco- motion is almost the sole mode in which fluids get heated, may be demonstrated by placing the middle of a pretty long glass tube, nearly filled with water, ob- liquely over an argand flame. The upper half of the liquid will soon boil, but the portion under the middle will continue cool, so that a lump of ice may remain for a considerable time at the bottom. W T hen the heat is rapidly applied the liquid is thrown into agitation, in consequence of elastic vapor being suddenly generated at the bottom of the vessel, and being as suddenly condensed at a little distance above it by the surrounding cold columns. These alternate expansions and contrac- tions of volume become more manifest as the liquid becomes hotter, and constitute the simmering vibratory sound which is egg] CYCLOPEDIA OF THE USEFUL ARTS. 143 the prelude of ebullition. The whole mass being now heated to a pitch com- patible with its permanent elasticity, be- comes turbulent and explosive under the continued influence of tire, and emitting more or less copious volumes of vapor, is said to boil. The further elevation of temperature by the influence of caloric, becomes impossible in these circumstan- ces with almost all liquids, because the vapor carries off from them as much heat in a latent state as they are capable of re- ceiving from the fire. Thetemperature at which liquids boil in the open air varies with the degree of atmospheric pressure, being higher as that is increased, and lower as it is di- minished. Hence boiling water is colder by some degrees in bad weather, or in an elevated situation, with a depressed bar- ometer, than in fine weather, or at the bottom of a coal-pit, when the barometer is elevated. A high column of liquid, also, by resisting the discharge of steam, raises the boiling point. In vacuo, all li- quids boil at a temperature about 124° F. lower than under the average atmospheric pressure. The following is a table of the boiling points of a few substances, on Fahren- heit's scale : Ether, 100° Alcohol, 173° Nitric Acid, 210° Water, 212° Solution of Salt, 224° Chloride of Calci- Muriatic Acid, 222° um, 285° Oil of Turpentine, 815° Sulphuric Acid, 600° Phosphorus, 554° Sulphur, 570° Linseed Oil, 640° Mercury, 662° M. Marcet has shown, that whatever the nature of the boiler, the temperature of the steam is invariably lower than that of the water from which the steam is generated. In glass vessels, this differ- ence amounts, on an average, to 1,908 de- grees, — in metal vessels, only to between 0.27 and 0.36 of a degree. There is but one exception to this rule, viz: where the inside of the boiler is coated with a thin layer of sulphur, gum lac, or any other matter possessing "an adhesion for water. In that case the boiling water and the steam have the same temperature. Thus, contrary to the generally received notion, it is not in metal vessels that the boiling point is lower under a stronger pressure, but in glass vessels; if the latter are coated with sulphur, gum lac, &c. EDULCOEATION. A chemical term applied to the cleansing of substances, especially pulverulent precipitates, by the repeated affusion of water, so as to re- move all soluble matters, and render them free from taste and smell. EFFEEVESCENCE. The escape of gaseous matter from liquids, as in the act of fermentation. All liquids from which bubbles of gas rapidly escape, so as to resemble boiling, are said to effer- EFFLOKESCENCE. Is the spontane- ous conversion of a solid, usually crystal- line, into a powder, in consequence either of the abstraction of the combined water by the air, as happens to the crystals of sulphaoe and carbonate of soda ; or by the absorption of oxygen and the forma- tion of a saline compound, as in the case of alum schist, and iron pyrites. Salt- petre appears as an efflorescence upon the ground and walls in many situa- tions.' EDGE-TOOLS. (See Cutlery and Steel.) EGG. The ovum of birds and other oviparous animals. The changes which the hen's egg undergoes during incubation have been described by Sir E. Home in the Philosophical Transactions for the year 1822, page 339, and illustrated by a beautiful scries of plates after Bauer's drawings ; the same volume also contains a vamable paper by Dr. Prout on the same subject, but chiefly in reference to the chemical changes of the egg during that process. The specific gravity of new-laid eggs at first rather exceeds that of water, varying from 1080 to 1090 ; h\\t they soon become lighter, and swim on water, in consequence of evaporation through the pores of the shell. When an egg is boiled in water and suffered to cool in the air, it looses about 32 hund- redths of a grain of saline matter, to- gether with a trace of animal matter and free alkali. The mean weight of a hen's egg is about 875 grains, of which the shell and its inner membrane, weigh 93-7 grains, the albumen, or white, 529*8 grs., and the yolk 251*8 grs. The shell con- tains about 2 per cent, of animal matter and 1 per cent, of the phosphates of lime and magnesia, the remainder being carbo- nate of lime, with a trace of carbonate of magnesia. When the yolk of a haid- boiled egg is digested in repeated por- tions of strong alcohol, there remains a white residue haviug the leading charac- ters of albumen, but containing phospho- rus in some peculiar state of combina- tion ; the alcoholic solution ib yellow, and deposits a crystalline fatty matter, and when distilled leaves a yellow oil The albumen of the egg contains sulphur The use of the phosphorus is to yield phosphoric acid to form the bones of the 144 CYCLOPEDIA OF THE USEFUL ARTS. [ela chick ; but the source of the lime with which it is combined is not apparent, for it has not been detected in the soft parts of the egg, and hitherto no vascular com- munication has been discovered between the chick and the shell. EGGS, HATCHING. (See Incubation, EIDER-DOWN is a kind of precious down, so called because it is obtained from the Eider-duck. These birds build their nests among precipitous rocks, and the female lines them with fine feathers plucked from her breast, among which she lays her five eggs. The natives of the districts frequented by the eider- ducks let themselves down bv cords among the dangerous cliffs, to collect the down from the nests. It is used to fill coverlets, pillows, cushions, &c. ELAINE is the name given by Chev- reul to the thin oil which may be expel- led from tallow, and other fats, solid or fluid, by pressure either in their natural state, or after being saponified, so as to harden the stearine. It may be extracted also by digesting the fat in 7 or 8 times its weight of boiling alcohol, spec. grav. 0-798, till it dissolves the whole. Upon cooling the solution, the stearine falls to the bottom, while the elaine collects in a layer like olive oil, upon the surface of the supernatant solution, reduced by evaporation to one-eighth of its bulk. If this elaine be now exposed to a cold tem- perature, it will deposit its remaining stearine and become pure. See Fat, Oils, and Stearine. ELASTICITY. In Physics, that prop- erty which certain bodies possess of re- covering their primitive form and dimen- sions after the external force by which they have been dilated or compressed or bent is withdrawn. The theory of elasticity must be deduct- ed from some hypothesis respecting the constitution of matter. The simplest and most general view which can be taken of the subject is ? that all matter is compo- sed of indefinitely small parts or molecules acted upon by attractive and repulsive forces. The attractive forces result from the action of the molecules on each other ; the repulsive forces from the caloric with which the molecules are combined. From the combined action of these two forces, the attraction of matter and the repulsion of caloric, the different forms of matter and its varied physical proper- ties may be explained. This view of the constitution of bodies supposes that the molecules are not in contact, but at a certain distance from each other, which, though it is to be re- garded as indefinitely small in compari- son of any distance appreciable by our senses, admits nevertheless of increase and diminution. When a body is in a state of rest, the opposite forces which any two of its contiguous molecules exer- cise on each other are in equilibrium. The energy of the forces also depends on the distance between the two molecules, or, in mathematical language, is a func- tion of that distance. If the distance be increased within the limits of the action of the forces, both forces are diminished ; and if the distance is diminished, both are increased, but not in the same pro- portion. If the interval at which the two forces balance each other be diminished, the repulsive force becomes stronger than the attractive force, and the two mole- cules are repelled from each other; on the contrary, if the distance be increased, the attractive force acquires the superiority, and the molecules are drawn towards each other. Elasticity is perfect when the body ex- actly recovers its primitive form, after the force by which it is bent or compressed or dilated has been removed, in the same time as was required for the force to pro- duce the alteration. This perfect elasti- city is, however, not found in any of the boclies of nature ; the aeriform fluids or gases are those whose elasticity approach- es the nearest to it. Hard bodies, even tempered steel and ivory, possess it in a less degree ; in fluid substances the elas- tic force is greatly diminished; and in soft bodies, as butter, moist clay, it en- tirely disappears. In solid bodies the elastic force is, in general diminished by use, or by a long continued application of a straining force. A bow which has been long bent, or a spring which has been long compressed, will not entirely recover its original form. In many cases the elasticity of a body can "be augmented by producing a closer aggregation of the molecules. The metals, for example, are rendered more elastic by hammering them cold, or by alloys. Iron and steel acquire a greater elasticity by ternfering ; that is, by producing a sudden contraction of their volumes when they have been ex- panded by heat. The principal phenomena of elastic bodies are the following :—-l, That an elastic body (the elasticity being sup- posed perfect) exerts the same force in endeavoring to restore itself, as that with which it was compressed or bent. 2, The ele] CYCLOPEDIA OF THE USEFUL ARTS. 145 force of elastic bodies is exerted equally in all directions, but the effect chiefly takes place on the side on which the re- sistance is the least. 3, When an elastic solid body is made to vibrate by a sudden stroke, tlie vibrations are performed in equal times, to whatever part of the body the stroke may be communicated. Thus, sonorous bodies always emit sounds of the same pitch ; and the difference of the pitch depends on the greater or less fre- quency of the vibrations of the sonorous body. 4, A body perfectly incompressi- ble cannot be elastic, therefore bodies perfectly solid can have no elasticity ; and hence, also, the small degree of elasticity belonging to the liquids which are emi- nently incompressible. ELASTIC BANDS. The manufacture of braces and garters, with threads of caoutchouc, either naked or covered, sterns to have originated, some time ago, in Vienna, whence it was a few years since imported into Paris, and thence into this country. At first the pear- shaped bottle of Indian rubber was cut into long, narrow strips by the scissors ; a single operative turning off only about 100 yards in a day, by cutting the pear in a spiral direction. He succeeded next in separating with a pair of pincers the several layers of which the bottle was composed. Another mode of obtaining fine threads was to cut them out of a bottle which had been rendered thin by inflation with a forcing pump. All these operations are facilitated by previously steeping the caoutchouc in boiling water, in its moderately inflated state. More recently, machines have been success- fully employed for cutting out these fila- ments ; but for this purpose the bottle of caoutchouc is transformed into a disc of equal thickness in all its parts, and per- fectly circular. This preliminary opera- tion is executed as follows : 1st, the bot- tle, softened in hot water, is squeezed between the two plates of a press, the neck having been removed beforehand, as useless in this point of view ; 2d, the bottle is then cut into two equal parts, and is allowed to consolidate by cooling before subjecting it to the cutting instru- ment. When the bottle is strong enough, and of variable thickness in its different points, each half is submitted to power- ful pressure in a very strong cylindrical mould of metal, into which a metallic plunger descends, which forces the caout- chouc to take the form of a flat cylinder with a circular base. This mould is plunged into hot water during the com- pression. A stem or rod of iron, which goes across the hollow mould and piston, retains the latter in its place, notwith- standing the resilience of the caoutchouc, when the mould is taken from the press. The mould being then cooled in water, the caoutchouc is withdrawn. The transformation of the disc of caoutchouc into fine threads is perform- ed by two machines ; the first of which cuts it into a riband of equal thickness in its whole extent, running in a spiral direction from the circumference to the centre ; the second subdivides this riband lengthwise into several parallel filaments much narrower, but equally thick. The threads, when brought to this state of slenderness, are put success ively into tubs filled with cold water ; they are next softened in hot water, and elongated as much as possible in the following man- ner : — They are wound upon a reel turn- ed quickly, while the operative stretches the caoutchouc thread with his hand. In this way it is rendered 8 or 10 times longer. The reels when thus filled are placed during some days in a cold apart- ment, where the threads become firm, and seem to change their nature. This state of stiffness is essential for the success of the subsequent operations. The threads are commonly covered with a sheath of silk, cotton, or linen, by a braiding machine, and are then placed as warp in a loom, in order to form a nar- row web for braces, garters, &c. If the gum were to exercise its elasticity during this operation, the different threads would be lengthened and shortened in an irregular manner, so as to form a puckered tissue. It is requisite there- fore to weave the threads in their rigid and inextensible, or at least incontractile condition, and after the fabric is woven to restore to the threads of caoutchouc their appropriate elasticity. This re- storation is easily effected by passing a hot smoothing iron over the tissue laid smoothly upon a table covered with blanket stuff. ELECTIVE AFFINITY, denotes the order of preference, so to speak, in which the several chemical substances choose to combine ; or really, the gradation of at- tractive force infused by Almighty Wis- dom among the different objects* of na- ture, which determines perfect uniformity and identity in their compounds amidst indefinite variety of combination. The discussion of this interesting subject be- longs to pure chemistry. ELECTRICAL WAVES, Velocity of. 146 CYCLOPEDIA OF THE USEFUL ARTS. [• Some ingenious experiments have been performed at the Cincinnati Observatory, in connection with the magnetic tele- fraph, to ascertain if there be any sensi- le time occupied in the transmission of the wave or current of electricity between the two points where relative longitudes are required. If there be a sensible velo- city, it must involve a correction for the difference of longitude as determined by star signals passed along the waves or through the ground by electrical cur- rents "between the two observatories. Thus far, Professor Mitchell says, all re- sults tend to the conclusion that there is no sensible wave time. Other methods may lead to a different conclusion. Ex- periments performed some months since, by Mr. Walker, lead that gentleman to believe he had detected and measured a wave time. The subject is interesting, and now becomes important as an ele- ment in the determination of longitudes by the magnetic telegraph. ELECTRIC CLOCK. The first public clock of this kind in the United States was placed above the chief entry of the Bank of Louisiana, New Orleans. It is a beautiful object to look at from the street, but there is something still more interesting connected with it. This con- sists of the method employed for setting the hands in motion, which is by elec- tricity. At the Bank of Louisiana there is no- thing but the dial and the hour and mi- nute hands ; the clock is in Mr. Foster's bfcore, where also is the galvanic pile from which the conducting wire leads to the Bank, past the adjoining houses, and along which the electric current travels that moves the hands. A person stand- ing in the street can see both by day and by night the progress of the minute hfT\ Iftheelec- ^KpSfcb fire be twist- "' •] CYCLOPEDIA OF THE USEFUL ARTS. 147 net; if of pure soft iron, it becomes a temporary magnet, so long as the electric current is in motion, and s and n are powerfully opposed poles. If the bar be bent, as m the annexed cut, a power- ful horse-shoe magnet is ob- tained when the ends t n of the copper wire twisted round U are connected with the vol- taic circle ; and a single pair of plates is sufficient for the purpose. ELECTRO-MAGNETIC ORE SEPA- RATOR. Mr. Ransom Cook has pa- tented a machine for separating the mag- netic iron from the rock with which lit is associated. He employs a revolving cylinder or drum with electro-magnetic poles on its circumference. When the crushed ore passes underneath the re- volving cylinder, the oxide of iron is at- tracted^ to the cylinder, leaving the im- purities behind : when the drum is charged with ore, the cylinder is freed from connection with the battery, and the ore then losing its attractive force, drops off into the receiving-box. ELECTRO-MAGNETISM. (Motive Powek of.) Numerous attempts have been made to apply electro-magnetism as a power for moving machines, and parti- cularly by the apparatus employed by Jacobi, I3al Negro, M'Gauley, Wheat- stone, and the machines recently con- structed by Mr. Hjorth. However, not- withstanding the talent which has been devoted to this interesting subject, and the large amount of money which has been spent in the construction of ma- chines, the public are not yet in posses- sion of any electro-magnetic machine which is capable of exerting power eco- nomically. The most remarkable experiments are those of Professor Jacobi, who, in 1838 and '39, succeeded in propelling a boat upon the Neva at the rate of four miles an hour. Mr. Hjorth's engine embraces many new features that promise to render the power more effective than hitherto. One of the electro-magnets made for the large engine, in a recenl trial, supported near- ly 5000 lbs., and its attractive force at \ of an inch was equal to nearly 1500 lbs. As this force can be multiplied without limits, it is reduced to a question of econ- omy and convenience. The power of electro-magnets can be increased without limitation. A voltaic current produced by the chemical distur- bance ot the elements of any battery no matter what its form may be, is capable of producing by induction a magnetic force, this magnetic force being always in an exact ratio to the amount of matter (zinc, iron, or otherwise) consumed in the battery. The greatest amount of magnetic force is produced when the chemical action is most rapid. Hence, in all machines, it is more economical to employ a battery of intense action, than one in which the chemical action is slow. It has been proved by Mr. Joule, and most satisfactorily con- firmed by Mr. R. Hunt, that one-horse power is obtainable in an electro-magnetic engine, the most favorably constructed to prevent loss of power, at the cost of 45 lbs. of zinc, in a Grove's battery, in 24 hours, while 15 lbs. are consumed in the same time to produce the same power in a battery of l)aniell's construction. The intensity of Darnell's battery being | that of Grove's. The cause of this was referred to the necessity of producing a high degree of excitement, to overcome the resistance which the molecular forces offer to the electrical perturbations, on which the magnetic force depends. What amount of magnetic power can be obtained from an equivalent of any material consumed ? Tne following, re- garded as the most satisfactory results yet obtained : — 1. The force of voltaic current being equal to 673, the number of grains of zinc destroved per hour was 151, which raised 9000 lbs. one foot high in that time. 2. The force of current being, relatively, 1300, the zinc destroyed in an hour was 291 grains, which raised 10,030 lbs. through the space of one foot. 3. The force being 1000, the zinc con- sumed was 223 grains ; the weight lifting one foot 12,672 lbs. The estimations made by Messrs. Scoresby and Joule, and the results obtained by Oersted, and more recently by Mr. Hunt, very nearly agree ; and it was stated that one grain of coal consumed in the furnace of a Cor- nish engine lifted 143 lbs. one foot high, whereas one grain of zinc consumed" in the battery lifted only 80 lbs. The cost of 1 cwt. of coal is under 9d. ; the cost of 1 cwt. of zinc is above 216d. There- fore, under the most perfect conditions, magnetic power must be nearly 25 times more expensive than steam power. But the author proceeded to show that it was almost proved to be an impossibility ever to reach this, owing, in the first place, to the rate with which the force diminishes through space. As the mean of a great 148 CYCLOPEDIA OF THE USEFUL ARTS. [ele many experiments on a large variety of magnets, of different forms and modes of construction, the following result was given : Magnet and armature in contact, lbs. lifting force - - 220 " distant 1-250 of an inch 90 6 " 1-125 " 50 7 " " 1-63 " 50 1 " 1-50 " 40 5 Thus at one-fiftieth of an inch distance four-fifths of the power is lost. This great reduction of power takes place when the magnets are stationary. Mr. E. Hunt has also shown that the moment they were set in motion a great reduction of the original power immediately took Slace : that, indeed, any disturbance pro- ucecl near the poles of a magnet dimin- ished, during the continuance of the mo- tion, its attractive force. The attractive force of a magnet being 150 lbs. when free of disturbance, fell to one-half, by occasioning an armature to revolve near its poles. - Therefore, when a system of magnets which had been constructed to produce a given power is set in revolu- tion, every magnet at once suffers an im- mense loss of power, and consequently their combined action falls in practice very far short of their estimated power. This fact has not been before distinctly stated, although it is well known that Jacobi observed it. And not merely does each magnet thus sustain an actual loss of power, but the power thus lost is converted into a new form of force, or or rather becomes a current of electri- city, acting in opposition to the primary current by which the magnetism is in- duced. Erom an examination of all these results, Mr. Hunt is disposed to regard electro-magnetic power as impracticable, on account of its cost, which must neces- sarily be, he conceives, under the best conditions, fifty times more expensive than steam power, and i3 at present at least 150 times as expensive. On the other hand, in opposition to the foregoing conclusions, Protessor Page, of Washington, has constructed a ma- chine either for locomotion or station- ary work. He has exhibited it in the Smithsonian Institute, and a Washington paper thus describes the circumstance : " He then exhibited his engine, of be- tween four and five horse power, operat- ed by a battery within the space of three cubic feet. It looked very unlike a mag- netic machine. It was a reciprocating engine of two feet stroke, and the whole battery and engine weighed about one ton. When the power was thrown on by the motion of a lever, the engine started off magnificently, making one hundred and fourteen strokes per min- ute ; though when it drove a circular saw ten inches in diameter, sawing up boards an inch and a quarter thick into laths, the engine made but about eighty strokes per minute. There was great anxiety on the part of the spectators to obtain speci- mens of these laths, to preserve as tro- phies of this great mechanical triumph. The force operating upon his magnetic cylinder throughout the whole motion of two feet, was stated to be six hundred pounds when the engine was moving very slowly, but he had not been able to ascertain what the force was when the engine was running at a working speed, though it was considerably less. The most important and interesting point, however, is the expense of the power. Professor Page stated that he had reduced the cost so far, that it was less than steam under many and most conditions, though not so low as the cheapest steam engines. With all the imperfections of the engine, the consumption of three pounds of zinc per day would produce one horse power. The larger his engines (contrary to what has been known before), the greater the economy. Professor Page was himself surprised at the result. There were yet practical difficulties to be overcome ; the battery had yet to be improved : and it remained to try the experiment on a frander scale, to make a power of one undred horse, or more. (^Locomotive.) ELECTRO METALLURGY. By this elegant art the most exact copies of any natural or artificial object can be obtained, or the surface of any body non-metallic or metal may become coated with a thin layer or film of copper, gold, and silver, or a few other metals. The practical de- tails of the arrangement is all that can find a space in these pages. On the Forms and Arrangement of Ap- paratus. — In the deposition of metals where voltaic electricity is the power em- ployed, there are two descriptions of ar- rangement : the first where the surface on which the deposit is formed is itself a part of the apparatus whence the power is generated ; the other in which the ob- ject receiving the deposit forms no part of the apparatus, but where the power is procured from a battery ; the former is termed the single cell, the latter the bat tery process. The forms of voltaic bat- teries used are numerous, and in most cases known by the names of their re- kle] CYCLOPEDIA OF THE USEFUL ARTS. 149 spective inventors ; such as Daniell's, Smee's, and Grove's batteries. The con- stant battery of Professor Daniell will be found most generally useful ; it is termed constant from its possessing the power of continuing in action for any lengthened period : it may be made in various forms, and consists of a copper cell, divided into two parts by a porous diaphragm or par- tition, which may be formed of wood, paper, plaster of Paris, earthenware, or animal membrane. The outer cell is filled with a saturated solution of sul- phate of copper, a perforated shelf sup- plied with crystals of this salt is placed at the upper portion, as that part of the solution is soonest weakened, the spe- cific gravity retaining the stronger por- tion below. The inner cell is filled with water, to which a few drops of sulphuric acid are added, and in which a rod or plate of amalgamated zinc is placed, to which, and to the copper of the outer cell, wires are attached. This battery may be generally employed for the pur- poses of plating, gilding, and platinizing, and is one of the most economical modes of reducing copper. The simplest form of apparatus used for the deposition of me- tal, more particularly copper, is the single cell ; it resembles in the number of its parts a Daniell's battery ; the surface to be deposited on repre- senting the copper of the outer cell. The diaphragm may be formed of plaster of Paris, brown paper, or thin wood ; but the action is almost rapid when the diaphragm is thinnest ; if a mould of metal or other sub- stance be attached to the zinc in the cell containing the acid and water, and intro- duced into the sul- phate solution, if tha metallic communica- tion between the mould and the zinc be complete, after a short immersion the former will become coated with a depo- sition of metallic copper, which goes on increasing in thickness as long as the strength of the cupreous solution is kept up, which may be done by placing a few crystals^ of sulphate in the solu- tion. Within a few months past, mag- neto-electric machines have been em- ployed for the deposition of metals ; and in Birmingham, plating is carried on to a considerable extent by machines, formed by peculiar arrangements of compound magnets, one of which, lately manufac- tured by Mr. Woolrich, is capable of de- positing from 300 to 500 ounces of silver Ser week ; but as such machines are dif- cult in management, and expensive in construction, they are not well suited for the purposes of experiment. On the production of Moulds. — Moulds may be formed either of metallic or non- metallic substances ; in the latter case it is absolutely necessary that the surface of the mould submitted for deposition should be a conductor of electricity, and the best conductors are metals and car- bon. Moulds for small objects, as coins or medals, may readily be made of lead or fusible metal : a very simple plan is to place the object between two strips of the former metal, scraped perfectly clean, subjecting the whole to the action of a press. Moulds may be formed of wax, stearine, tallow, plaster of Paris, sealing wax, &c, &c. : the surfaces of either of these materials may be covered with good plumbago, after fixing a metal wire into the mould to be deposited on ; the pow- der should be rubbed Lghtly over with a soft brush, taking care that it adheres to all parts. The deposition takes place at the wire by which the article is con- nected with the battery or cell, and spreads gradually from that point till the whole surface is covered ; but this pro- cess is limited to the deposition of cop- per only, as gold and silver will not spread to any extent on a black-leaded surface. Wood may be prepared to re- ceive a deposit in the following manner : — The surface of the block or piece in- tended to be deposited on is dipped in a weak solution of nitrate of silver, con- tained in a flat vessel, remaining for a few minutes in order that by capillary attraction the nitrate of silver may be drawn into the wood : a small portion of a solution of phosphorus in spirits of turpentine being poured into a watch- glass, and placed on a sand-bath, is al- lowed, gradually to evaporate ; on hold- ing the surface of the wood over the va- por an immediate change occurs, the nitrate of silver is converted into metallic silver, and the object may at once be placed in the battery to receive a deposit of copper. In this manner the interior of a plaster mould may be rendered a conductor ; but as this plan can only be adopted with substances which can be wetted with the solution of nitrate of sil- ver, an improvement has lately been in- 150 CYCLOPEDIA OF THE USEFUL ARTS. [ele troduced, by the adoption of a solution of phosphorus instead of the vapor of that substance. The best known solu- tion is bisulphurct of carbon, which easily dissolves a considerable portion of phos- phorus. If the article to be coated is dipped for a moment in a solution of one part of phosphorus to twelve parts of bisufphuret of carbon, on Avithdrawing it the bisul- phuvet of carbon, which is very volatile, will evaporate, leaving a film of phos- phorus on the surface ; the article is then immersed in a dilute solution of nitrate of silver, or sulphate of copper ; a pre- cipitate of silver or copper is immediately formed, and thus becoming an electric conductor it may be introduced into the galvanic cell, and the process will proceed in the same manner as it does when plumbago is used in the first instance. By this simple and elegant method the most delicate articles, as feathers, flow- ers, fruit, insects, &c, may be coated with metal. The surface should in all case3 be free from moisture before it is introduced into the solution of phos- phorus, which should be used with the greatest care, being highly inflammable. Phosphorus added to wax and stearine form an excellent coating for casts, as the surface becomes a conductor. Moulds of plaster of Paris being very porous, re- quire to be saturated with wax, oil, var- nish, or tallow, before receiving a coating of plumbago, otherwise when placed in the solution they will absorb the liquid, and the air which previously filled up the pores will be driven out, covering the surface of the mould with small bubbles. Flexible moulds for copying objects which are undercut, or overhung, may be made of a mixture of glue and treacle ; this mixture is easily removed from the pro- jecting parts, immediately regaining its proper form. The color of bronze is given to copper articles deposited by voltaic action by different methods. A very simple plan is to rub the article with plumbago immediately, or as soon as practica- ble, after its removal from the battery ; afterwards heating it, and rubbing it with a hard brush. A lighter tint may be obtained by covering the surface with oxide of iron, and giving it a considera- ble heat. Hydrosulphate of ammonia produces a fine color, and a dilute solu- tion of chloride of platinum gives the object an agreeable tint. On, Electro- Gilding, Plating, Platiniz- ing. — The metals reduceable by voltaic agency for purposes of utility are gold, sil- ver, platinum, copper and zinc ; these may be precipitated from their salts, or from the solutions of their salts in any material capable of dissolving them, and any de- sired deposit may be made by adjusting the strength and temperature of the so- lution to the intensity and power of the current of electricity employed. Gold may be deposited from its chloride, bro- mide, cyanide, iodide, sulphite, and hy- posulphite ; but for all purposes of gild- ing, it is well to use a solution of the cyanide, which may be prepared by ad- ding oxide of gold to the solution of cya- nide of potassium. The most eligible Proportions may be stated as follows : 'wo pounds of cyanide of potassium dis- solved in one gallon of water, to which are added one ounce and a half of oxide of gold ; but if heat is employed, and the solution is raised to the boiling point, the quantity of water may be doubled. A single pint battery of Daniell's pos- sesses sufficient intensity to gild any specimen, even large ores — the articles to be gilt must of course be attached to the zinc of the battery, and a plate of gold, of corresponding or greater dimensions, to the copper. The surfaces of all ob- jects to be gilt, plated, or deposited on, must be thoroughly cleansed before being introduced into the solution ; oxide, grease, or other impurities, may be re- moved by immersion in dilute sulphuric acid. The gold thus deposited may be colored to produce the red tint so gene- rally admired, by being coated with a mixture of acetate of copper, sulphate of alumina, and bees'-wax, and exposed to heat till the whole is consumed ; and a rich orange color may be obtained by gently boiling the following ingredients together in water till they have a creamy consistency :— Five parts of nitrate o'f potassa, two parts of sulphate of alumina, one part of sulphate of zinc, and one part of sulphate ot iron. The gilt object should then be dipped three or four times in the composition, and allowed to become nearly dry, and afterwards re- moved to a stove, when, according to the length of exposure to heat the depth of color will be increased : it should finally be well washed, and cleaned with soap and water and a brush. Silver can be precipitated from its cya- nide, acetate, sulphate, sulphite, or hypo- sulphite solutions. A solution of one pound and a half of cyanide of potassium in one gallon of water, to which two ounces of oxide of silver are abided, answers ad- eleJ CYCLOPEDIA OF THE USEFUL ARTS. 151 mirably for all purposes of plating. For some time after the introduction of elec- tro-gilding and plating, complaints were made of defective adhesion between the original and the deposited metal, and it was asserted by the manufacturers of similar articles on the old principle, that such plating and gilding would soon wear away, and exhibit the baser metal in all its original nakedness. There was, it must be admitted, some justice in this remark, though articles plated three years ago have been in daily use without showing any traces of the copper beneath. This defect was occasioned by the ab- sence of an alloy, but the objection has lately been altogether removed by the use of mercury, for the purpose of alloy- ing the two metallic surfaces ; for this purpose, nitrate of mercury is dissolved in water, and the copper article to be gilt or plated is plunged in the solution, and immediately withdrawn, then washed in water, and placed in the gold or silver solution. A thin film of mercury is by this means distributed over the object, and amalgamating with both metals, completely alloys them. The articles after being gilt or silvered should be heated to 600° Fahr., which dissipates the mercury. Another complaint against electro-plating was, that the articles ra- pidly tarnished on account of the purity of the- metal deposited. This may be obviated by brushing them over after re- moval from the vat with a saturated so- lution of biborate of soda, allowing them to dry so that a film of the salt may re- main, repeating the process a second or third time, till a slight but regular coat- ing of borax covers every part ; they should then be exposed to a red heat, and after being allowed to cool, immersed in dilute sulphuric acid, and dried in heated saw-dust. The metals - to which plating are most applicable are copper, brass, pewter, iron, steel, and erold ; the process is also extensively employed for severing articles formed "of the alloy of nickel, known as German silver. -. Platinum may be reduced from solu- tions of its bromide, iodide, and bi-chlo- ride, and the double chloride of platinum and sodium. The chloride is the salt- commonly employed, but as considerable difficulty exists in depositing this metal in a ductile state, a very feeble current of electricity should be employed, and the plate of metal introduced as an elec- trode should be very small ; it is of great advantage to have the solution neutral, and some therefore recommend soda be- ' ing added to it, thus forming the chic- ; ride of sodium and platinum. Zinc may be deposited from its iodide, I acetate, sulphate, and chloride ; also from i the solution of oxide of zinc in potassa, or muriate of ammonia. Copper may be thrown down from a considerable range of its salts ; those commonly used are the sulphate, nitrate, and cyanfde. Probably the most enormous applica- tion of the electrotype art is made in the sculpture of the Cathedral of St. Isaac in Petersburgh. Seven doors of the ca- thedral are of bronze and electrotype, the framework being of the former "and the scultured posts of the latter. Three of these doors are 30 feet high and 44 feet wide, the four others 17 feet 8 inches wide. They contain 51 bas reliefs, 63 statuettes, and 84 alto relievo bvsts of religious subjects. The gilding of tht ca- thedral was also done by this process. The quantity of metal employed in the dome was as follows : — Ducat gold, 247 lbs. ; copper, 521 tons ; brass, 32l£ tons ; wrought iron, 5241 tons ; cast iron, 1068 tons ; total, 1,966s tons. Casts in cop- per have been taken from the daguerreo- type plate, and impressions from these casts produced by electrotype by Dr. Paterson of Glasgow, Scotland. Smooth as a daguerreotype appears, the cast taken serves as a mould from which al- most any number of impressions may be taken, which are as bold and as clear as the original type. EL EMI is a resin which exudes from in- cisions made during dry weather through the bark of the amyris etimifera, a tree which grows in South America and Bra- zil. It comes to us in yellow, tender, transparent lumps, which readily soften by the heat of the hand. They have a strong aromatic odor, a hot spicy taste, and contain 12? per cent, ot ethereal oil. The crystalline resin of elemi has been called Elemine. It is used in mak- ing lacker, to give toughness to the var- nish. ELEMENTS. The ancients consider- ed fire, air, water, and earth, as simple substances, essential to the constitution of all terrestrial beings. This hypothe- sis, evidently incompatible with modern chemical discovery, may be supposed to correspond, however, 'to the four states in which matter seems to exist ; namely, 1st, the unconfinable powers of fluids — caloric, light, electricity ; 2d, ponderable gases, or elastic fluids ; 3d, liquids; 4th, solids. The three elements of the al- 152 CYCLOPEDIA OF THE USEFUL ARTS. [' chemists, salt, earth, mercury, were, in their sense of the word, mere phantasms. EMBALMING. A process adopted by the ancient Egyptians, chiefly for the preservation of dead bodies from putre- faction. The term is derived from the use of balsamic substances in the opera- tion ; in addition to these, saline sub- stances and tanning materials seem also to have been used. EMBANKMENT. In territorial im- provement, an embankment is a mound of earth or a wall, or a structure com- posed partly of a wall or partly of a bank of earth, to protect lands from being overflown by rivers or the sea. Em- bankments appear to have been coeval with the culture of corn crops ; because these, it appears, were first grown on the alluvial soils which border large rivers, and to protect the crops from the over- flowing of these rivers after heavy or long-continued rains, the cultivator would naturally throw up a bank of earth. This appears to have Deen done in Egypt at the most remote period of which there is any record. In modern times, embank- ments are employed, not merely to pro- tect land under cultivation, but to en- close land that is occasionally overflown by rivers or the sea, and render it fit for the purposes of husbandry. This has been done to a greater extent in Holland than in any other country. There are also immense embankments in Italy, par- ticularly in Lombardy. In Britain, there are the embankments of the Thames near London, which have been in exist- ence since the time of the Komans ; many in Lincolnshire, formed during the time of Cromwell, and some of them many centuries before ; and one of the most recent is that at Tre Madoc in Caer- narvonshire, by which upwards of 4000 acres were recovered from spring tides, and in great part rendered fit for the plough. Embankments are attended with immense expense ; but as the soil gained or protected is generally of the best quality, a judicious embankment is commonly" considered as paying about the same rate of interest as a landed estate. The levees of the Mississippi are numerous examples. EMBOSSING WOOD. Raised figures upon wood, such as are employed in pic- ture-frames and other articles of orna- mental cabinet work, are usually pro- duced by means of carving, or by casting the pattern in plaster of Paris, or other composition, and cementing, or other- wise fixing it on the surface of the wood. The former mode is expensive ; the lat- ter is inapplicable on many occasions. The invention of Mr. Streaker may be used either by itself, or in aid of carv- ing , and depends on the fact, that if a depression be made by a blunt instru- ment on the surface of the wood, such depressed part will again rise to its ori- ginal level by subsequent immersion in the water. The wood to be ornamented having been first worked out to its propos- ed shape, is in a state to receive the drawing of the pattern ; this being put on, a blunt steel tool, or burnie?er, or die, is to be applied successively to all those parts of the pattern intended, to be in relief, and, at the same time, is to be driven very cautiously, without breaking the grain of the wood, till the depth of the depression is equal to the intended prominence of the figures. The ground is then to be reduced by planing or filing to the level of the depressed part ; after which, the piece of wood being placed in water, either hot or cold, the part pre- viously depressed will rise to its former height, and will then form an embossed pattern, which may be finished by the usual operations of carving. EMBROIDERY. The name given to the art of working figures on stuffs or muslins with a needle and thread. All embroider}' may be divided into two sorts, embroidery on stuffs and^ on mus- lin : the former is used chiefly in church vestments, housings, standards, articles of furniture, &c, and is executed with silk, cotton, wool, gold and silver threads, and sometimes ornamented with span- gles, real or mock pearls, precious or imitation stones, &c. ; the latter is em- ployed mostly in articles of female appa- rel, as caps, collars, &c, and is perform- ed only with cotton. In Germany this division is indicated by the expression weisse hvhite or muslin), and bunte Sticke- rei (colored or cloth) embroidery. Th# embroidery of stuffs is performed on a kind of loom or frame ; that of muslin by stretching it on a pattern already de- signed. The modes of embroidering stuffs or muslin with the common needle are extremely various ; but a minute de- scription of these processes would be as difficult as it would be uninteresting to the general reader. They consist for the most part of a combination of ordinary stitches ; but no limit can be assigned to their number or variety. The art of em- broidery was well known to the ancients. As early as the time of Mobcs we find it EMP] CYCLOPEDIA OF THE USEFUL ARTS. 153 practised successfully by the Hebrews ; and long before the Trojan war the wo- men of Sidon had acquired celebrity for their skill in embroidery. At a later pe- riod, this art was introduced into Greece, probably by the Phrygians ^by some considered the inventors) ; and to such a degree of skill did the Grecian women attain in it, that their performances were said to rival the finest paintings. In our own times the art of embroidery has been cultivated with great success, more especially in Germany and France ; and though for a long period it was practised only by the ladies of these countries as an elegant accomplishment, it is now regard- ed as a staple of traffic, and furnishes em- ployment for a large portion of the popu- lation. EMBROIDEEING MACHINE. This art has been till of late merely a handi- craft employment, cultivated on account of its elegance by ladies of rank. But a few years ago M. Heilmann of Mulhause invented a machine of a most ingenious kind, which enables a female to em- broider any design with 80 or 140 nee- dles as accurately and expeditiously as she could formerly do with one. A brief account of this remarkable invention will therefore be acceptable to many readers. It was displayed at the national expo- sition of the products of industry in Paris for 1834, and was unquestionably the object which stood highest in public esteem ; for whether at rest or in motion, it was always surrounded with a crowd of curious visitors, admiring the figures which it had formed, or inspecting its movements and investigating its mecha- nism. 130 needles were occupied in copying the same pattern with perfect regularity, all set in motion by one person. Several of these machines are now mounted in France, Germany, and Swit- zerland. There exists one factory in Man- chester, where a great many of them are doing beautiful work. The price of a machine having 130 nee- dles, and of consequence 260 pincers or fingers and thumbs to lay hold of them, is 5000 francs, or £200 sterling ; and it is estimated to do daily the work of 15 expert hand embroiderers, employed upon the ordinary frame. It requires merely the labor of one grown-up person, and two assistant children. The operative must be well taught to use the machine, for he has many things to attend to ; with the one hand he traces out, or rather follows the design with the point of the pentograph ; with the other he turns a 7* handle to plant and pull all the needles, which are seized by pincers and moved along by carriages, approaching to and receding from the web, rolling all the time along an iron railway ; lastly, by means of two pedals, upon which he presses alternately with one foot and the other, he opens the 130 pincers of the first carriage, which ought to give up the needles after planting them in the stuff, and he shuts with the same pressure the 130 pincers of the second carriage, which is to receive the needles, to draw them from the other side ? and to bring them back again. The children have nothing else to do than to change the needles when all their threads are used, and to see that no needle misses its pincers. EMEE ALD. A mineral of a beautiful green color, which occurs in prismatic crystals, and is much valued for orna- mental jewelry. The finest are obtain- ed from Peru. It consists of 65 silica, 16 alumina, 13 glucina, about 3 oxide of chromium (which is the coloring matter), and a trace of lime. The mines from which the ancients obtained emeralds are said to have existed in Egypt, near Mount Zabarah. EMEEY. (From Cape Emeri, in the island of Naxos.) A variety of corun- dum ; amorphous, compact, and gene- rally opaque. It is characterized by ex- cessive hardness ; and its powder is used for cutting and polishing glass, gems, and all hard substances : it scratches and wears down nearly all minerals except the diamond. EMETIC TAETAE. A triple salt, composed of oxide of antimony, potassa, and tartaric acid. It is soluble in eigh- teen parts of cold and in three of boiling water. In the dose of from half a grain to two grains it operates as a powerful emetic and sudorific ; in smaller doses, it acts upon the bowels, and is diapho- retic. EMETINE. A substance discovered in 1817 by Pelletier in ipecacuanha. It is white, pulverulent, and bitter ; easily soluble in hot water and alcohol, and in- tensely emetic. It exists in ipecacuanha to the amount of about 16 per cent., and appears to be the sole cause of its emetic property. EMPYEEUMA means the offensive smell produced by fire applied to organic matters, chiefly vegetable, in close ves- sels. Thus, empyreumatic vinegar is obtained by distilling wood at a red heat, and empyreumatic o s il from many animal substances in the same way. 154 CYCLOPEDIA OF THE USEFUL ARTS. [ena ENAMELS are varieties of glass, gene- rally opaque and colored, always formed by the combination of different metallic oxides, to which certain fixed fusible salts are added, such as the borates, fluates, and phosphates. The simplest enamel, and the one which serves as a basis to most of the others, is obtained by calcining first of all a mix- ture of lead and tin, in proportions vary- ing from 15 to 50 parts of tin for 100 of lead. The _ middle term appears to be the most suitable for the greater number of enamels ; and this alloy has such an affinity for oxygen, that it may be cal- cined with the greatest ease in a flat cast- iron pot, and at a temperature not above a cherry red, provided the dose of tin is not too great. The oxide is drawn off to the sides of the melted metal according as it is generated, new pieces of the alloy being thrown in from time to time till enough of the powder be obtained. Great care ought to be taken that no me- tallic particles be left in the oxide, and that the calcining heat be as low as is barely sufficient ; for a strong fire frits the powder, and obstructs its subsequent comminution. The powder when cold is ground in a proper mill, levigated with water, and elutriated, as will be described, under lied lead. In this state of fineness and purity, it is called calcine, or flux, and it is mixed with silicious sand and some alkaline matter or sea-salt. The most ordinary proportions are, 4 of sand, 1 of sea-salt, and 4 of calcine. Chaptal states that he has obtained a very fine Eroduct from 100 parts of calcine, made y calcining equal parts of lead and tin, 100 parts of ground flint, and 200 parts of pure subcarbonate of potash. In either case, the mixture is put into a crucible, or laid simply on a stratum of sand, quicklime spontaneously slaked, or wood-ashes, placed under a pottery or porcelain kiln. This mass undergoes a semi-vitrification ; or even a complete fusion on its surface. It is this kind of frit which serves as a radical to almost every enamel ; and by varying the pro- portions of the ingredient, more fusible, more opaque, or whiter enamels are ob- tained. The first of these qualities de- pends on the quantity of sand or flux, and the other two on that of the tin. The sea-salt employed as a flux may be replaced either by salt of tartar, by pure potash, or by soda; but each of these fluxes gives peculiar qualities to the enamel. A patent was granted to Thomas and Charles Clarke, of England, in 1839, for a method of enamelling or coating the in- ternal surfaces of iron pots and sauce- pans, in such a way as shall prevent the enamel from cracking or splitting off from the effects of fire. The specification prescribes the vessel to be first cleansed by exposing it to the action of dilute sul- phuric acid, (sensibly sour to the taste) for three or four hours, then boiling the vessel in pure water for a short time, and next applying the composition. This consists of 100 lbs. of calcined ground flints ; 50 lbs. of borax calcined, and finely ground with the above. That mixture is to be fused and gradually cooled. 40 lbs. weight of tbe above product is to be taken with 5 lbs. weight of potter's clay ; to be ground together in water until the mixture forms a pasty-consis- tenced mass, which will leave or form a coat on the inner surface of the vessel about one-sixth of an inch thick. When this coat is set, by placing the vessel in a warm room, the second composition is to be applied. This consists of 125 lbs. of white glass (without lead), 25 lbs. of borax, 20 lbs. of soda (crystals), all pul- verized together and vitrified by fusion, then ground, cooled in water, and dried. To 45 lbs. of that mixture, 1 lb. of soda is to be added, the whole mixed together in hot water, and when dry. pounded; then sifted finely and evenly over the internal surface of the vessel previously covered with the first coating or compo- sition, while this is still moist. This is the glazing. The vessel thus prepared is to be put into a stove, and dried at the temperature of 212° Fahr. It is then heated in a kiln or muffile, like that used for glazing china. The kiln being brought to its full heat, the vessel is placed first at its mouth to heat it gradually, and then put into the interior of the infusion of the glaze. In practice it has been found advantageous also to dust the glaze powder over the fused glaze, and apply a second fluxing heat in the oven. The enamel, by this double application, becomes much smoother and sounder. ENAMEL, foe Pins, Hooks and Eyes, &c. The articles to be enamelled, after being thoroughly cleaned and freed from dust and dirt are spread or placed in a basin, dish, or other fit receptacle, where they are wetted with the spirit or oil of turpentine ; they are then dried, if re- quired, by artificial means : when dry, the enamel or japan is applied, it tak- ing effect and spreading a coat upon the EQU] CYCLOPEDIA OF THE USEFUL ARTS. 155 whole of those parts of the articles pre- viously covered by the turpentine ; should it be required to give the articles more coats than one, the same process of ap- plying the enamel is to be repeated, but omitting to apply the spirit of turpen- tine. The compositions are as follows : for blue, the best varnish or gums, three quarters of a pint- of spirits of turpen- tine, half a pint; flake white, 1 lb., and prussiate of iron, 1 oz. For red, Per- sian vandyke, 1 lb. ; varnish or gums, half a pint; spirits of turpentine, quar- ter of a pint. For green, pale chrome, | lb. ; varnish or gums, half a pint; spi- rits of turpentine, quarter of a pint. Other colors or tints may be composed and applied in like manner by varying or altering the proportions of the mate- rials. ENCAUSTIC PAINTING. In paint- ing, a method of painting used by the ancients, the precise mode of executing ■which is by no means sufficiently ex- plained. From Pliny's account, it seems that the colors were made up into cray- ons through a medium of wax, and, the subject being previously traced with a metal point, were melted on the picture as they were used. The picture being finished, a varnish of melted wax was spread over all. The colors thus not only obtained considerable brilliancy, but the work was also protected from the weather. It was lastly well polished. The attempts to revive this art, which, after all, if we may draw our conclusion from Pliny's account, seems to have been but a clumsy process, have not been at- tended with success. EQUATOK1AL. An astronomical in- strument, contrived for the purpose of directing a telescope upon any celestial object of which the right ascension and declination are known, and of keeping the object in view for any length of time, notwithstanding the diurnal motion. For these ^purposes, a principal axis (J D, resting on firm supports, is placed parallel to the axis of the earth's rotation, and consequently pointing to the poles of the heavens. On this polar axis there is fixed, near one of its extremities, a graduated circle A B, the plane of which is perpen- dicular to the polar axis, and therefore parallel to the earth's equa- tor. This circle is called the equatmnal circle, and measures by its arcs the hour angles, or differences of right ascension. The polar axis is pierced at E F, and penetrated by the axis of a second circle G II, at right angles to it. The axis of the second circle has consequently no connection with any external support, but is sustained entirely by the polar axis. The plane of the second circle G H, which is called the declination, cir- cle, and carries the telescope K, is thus in all positions at right angles to the plane of the first or equatorial circle A B. Now it is easy to conceive, from this general description, that when the tele- scope is pointed to a star, the angle be- tween the direction of the telescope and the polar axis is equal to the polar dis- tance of the star ; consequently, when a motion is given to the polar axis without altering the position of the telescope on the declination circle, the point to which the telescope is directed will always lie in the small circle of the heavens coinci- dent with the star's diurnal path ; and hence, if the motion communicated to the polar axis be just equal to the earth's diurnal rotation, the star will remain constantly, and as long as we please, in the field of the telescope, at least while above the horizon. In many observa- tions this is indispensable, and it is an advantage which attaches to no other in- strument. The polar axis may be moved by a peculiar kind of clock machinery, adjusted to sidereal time ; and the best and largest equatorials are now furnished with such an apparatus. Besides reliev- ing the observer from the fatigue of turning the instrument, the motion thus given "is perfectly equable, and all those jerks avoided which, when the instru- ment is turned by the hand, often prove fatal to an observation. EQUIVALENTS, CHEMICAL. A term introduced into chemistry by Dr. Wollaston to express the system of defi- nite ratios in which substances recipro- cally combine, referred to a common standard of unity. If we assume hydro- gen as unity, it being the substance which combines with others in the smal- lest relative weight or proportions, then all other substances may be represented by certain multiples of that unit, ex- pressed with sufficient precision for all ordinary purposes by whole numbers. Thus, upon this system, the equivalent number of oxygen will be 8, and that of water will be 'J, for 8 oxygen + 1 hydro- gen = 9 water ; and the equivalent of potassium will be 40, and of potassa or oxide of potassium 48, for 40 potassium 156 CYCLOPEDIA OF THE USEFUL ARTS. [eng + 8 oxygen = 48 potassa. Upon the same principle the equivalent of hydrochloric acid, which is a compound of chlorine and hydrogen, is 37, for it consists of 1 part by weight of hydrogen and 36 of chlorine; or, in other words, of an atom of hydrogen = 1 + an atom of chlorine = 36. The equivalent of sulphur is 16 : to form sulphuric acid one atom of sul- phur = 16 combines with 3 atoms of oxy- gen (8 X 3) = 24 ; hence the equivalent of an atom of sulphuric acid is 16 + 24 = 40. These equivalents are often ex- pressed by certain abbreviations, termed chemical symbols ; which, as far as single equivalents of the simple substances are concerned, are represented, together with their equivalent numbers, in a table in the article Atom. ENGKAVING ON WOOD, or Xy- lography. In'this branch of art the ma- terial used is a block of box or pear-tree wood, cut at right angles to the direction of the fibres, the thickness being regu- lated by the height of the type in the form. The subject is either transferred from a previous print, or else drawn on the block with a black lead pencil, or with Indian ink. The whole of the wood is then cut away except where the lines are drawn, which are left as raised parts. In this it differs from copper-plate en- graving, where the lines are cut out, or sunk m the metal. The impressions from wood blocks are taken in the same manner as from printing types. Copper Engraving is performed by cutting lines representing the subject on a copper plate with a steel instrument, ending in an unequal sided pyramidal point, such instrument being called a graver, or burin, without the use of aquafortis : which mode is described further on. Besides the graver there are other instruments used in the pro- cess, viz., a scraper, a burnisher, an oil stone, and a cushion for supporting the plate. In cutting the lines on the copper the graver is pushed forward in the di- rection required, being held in the hand at a small inclination to the plane of the copper. The use of the burnisher is to soften down lines that are cut too deep, and for burnishing out scratches in the copper: it is about three inches long. The scraper, like the last, is of steel, with three sharp edges to it, and about six inches lontr, tapering towards the end. Its use is to scrape off the burr, raised by the action of the graver. To show the appearance of the work dur- ing its progress, and to polish off the burr, engravers use a roll of woollen oi felt called a rubber, which is put in ac- tion with a little olive oil. The cushion, which is a leather bag about nine inches diameter filled with sand for laying the plate on, is now rarely used except by writing engravers. Eor architectural subjects, or in skies, where a series of parallel lines are wanted, an ingenious machine was invented by the late Mr. Wilson Lowry, called a ruling machine, the accuracy of whose operation is ex- ceedingly perfect. This is made to act on an etching ground by a point or knife connected with the apparatus, and bit in with aquafortis in the ordinary way. Etching is a species of engraving on copper or other metals with a sharp point- ed instrument called an etching needle. The plate is covered with a ground or varnish capable of resisting the action of aquafortis. The usual method is to draw the design on paper with a black-lead pencil ; the paper being damped and laid upon the plate, prepared as above, with the drawing next the etching ground, is passed through the rolling press, and thus the design is transferred from the paper to the ground. The needle then scratches out the lines of the design ; and aquafortis being poured over the plate, which is bordered round with wax, it is allowed to remain on it long enough to corrode or bite in the lines which the etching needle has made. Etching with a dry point, as it is called, is performed entirely with the point without any ground, the burr raised being taken off by the scraper. Etching with a soft ground is used to imitate chalk or black- lead drawings. For this purpose the ground is mixed with a portion of tallow or lard, according to the temperature of the air. A piece of thin paper being at- tached to the plate at the tour corners by some turner's pitch and lying over the ground, the drawing is made on the pa- per and shadowed with the black-lead pencil. The action of the pencil thus de- taches the ground which adheres to the paper, according to the degree to which the finishing is carried ; the paper being then removed, the work is bit in the ordinary way. Stippling is also executed on the etching ground % dots instead of lines made with the etching needle, which according to the intensity of the shad- ow to be represented, are made thicker and closer. The work is then bit ir. Etching on Steel is executed much in the same way as in the process on copper. The plate is bedded on common glazier's eng] CYCLOPEDIA OF THE USEFUL ARTS. 157 putty, and a ground of Brunswick black is laid in the usual way, through which the needle scratches. It is then bit in, in the way above desctibed. Mezzotinto Engraving. In this species of engraving the artist, with a knife or instrument made for the purpose, roughs over the whole surface ot the copper in every direction, so as to make it suscep- tible of delivering a uniform black, smooth, or flat tint. After this process the outline is traced with an etching nee- dle, and the lightest parts are scraped out, then the middle tints so as to leave a greater portion of the ground, and so on according to the depth required in the several parts of the work. Aquatinta Engraving, whose effect somewhat resembles that of an Indian- ink drawing. The mode of effecting this is, (the design being already etched) to cover the plate with a ground made of resin and Burgundy pitch or mastic dis- solved in rectified spirit of wine, which is poured over the plate lying in an in- clined position. The spirit of wine, from its rapid evaporation, leaves the rest of the composition with a granulated text- ure over the whole of the plate, by which means a grain is produced by the aqua- fortis on the parts left open by the evapo- ration of the spirit of wine. The margin of the plate is of course protected in the usual way. After the aquafortis has bitten the lighter parts they are stopt out, and the aquafortis is again applied, and so on as often as any parts continue to require more depth. Formerly the grain used to be produced by covering the copper with a powder or some substance which took a granulated form, instead of using the compound above mentioned ; but this process was found to be both uncertain and imperfect. In the compound the grain is rendered finer or coarser, in pro- portion to the quantity of resin intro- duced. This mode of engraving was invented by a Frenchman of the name of St. Non, about 1662. He communicated it to Jean Baptiste le Prince, who died in 1781, from whom it was acquired by Paul Sandby, who introduced it through the medium of Mr. Jukes into Eng- land. Etching on Glass. The glass is covered with a thin ground of beeswax : and the design being drawn with the etching nee- dle, it is subjected to the action of sul- phuric acid sprinkled over with powder- ed flour of Derbyshire spar. After four or five hours this is removed, and the glass cleaned off with oil of turpentine, leaving the parts covered with the bees- wax untouched. This operation may be inverted by drawing the design on tho glass with a solution of beeswax and tur- pentine, and subjecting the ground to the action of the acid. Engraving on Stone or Lithography. — A modern invention, by means whereof impressions may be taken from drawings made on stone. The merit of this di»- covery belongs to Aloys Senefelder, a musical performer of the theatre at Mu- nich about the year 1800. The following are the principles on which the art of lithography depends : First, the facility with which calcareous stones imbibe water ; second, the great disposition they have to adhere to resinous and oily sub- stances ; third, the affinity between each other of oily and resinous substances, and the power they possess of repelling water or a body moistened with water. Hence, when drawings aro made on a polished surface of calcareous stone with a resinous or oily medium, they are so adhesive that nothing short of mechanical means can effect their separation from it, and whilst the other parts of the stone take up the water poured upon them, the resinous or oily parts repel it. Lastly, when over a stone prepared in this manner a colored oily or resinous substance is passed, it will adhere to the drawings made as above, and not to the watery parts of the stone. It was formerly thought that England did not possess a sort of stone like that of Germany, suitable to the purposes of lithography ; this, how- ever, is now known to be erroneous, as the neighborhood of Bath abounds with it, being the white lias, which lies imme- diately under the blue. It is also found in Scotland. The ink and chalk used in lithography are of a saponaceous quality : the former is prepared in Germany from a compound of tallow soap, pure white wax, a small quantity of tallow, and a portion of lamp-black, all boiled together, and when cool dissolved in distilled wa- ter. The chalk for the crayons used in drawing on the stone, is a composition consisting of the ingredients above men- tioned, but to it is added when boiling, a small quantity of potash. After the drawing on the stone has been executed and is perfectly dry, a very weak solution of vitriolic acid is poured upon the stone, which not only takes up the alkali from the chalk or ink, as the case may be, leaving an insoluble substance behind it, but it lowers in a very small degree that part of the surface of the stone not drawn 158 CYCLOPEDIA OF THE USEFUL ARTS. [• upon, and prepares it for absorbing wa- i ter with greater freedom. Weak gum water is then applied to the stone, to close its pores and keep it moist. The stone is now washed with water, and the daubing ink applied with balls as in printing ; after which it is passed in the usual way through the press, the process of watering and daubing being applied for every impression. There" is a mode of transferring draw- ings made with the chemical ink on pa- per prepared with a solution of size or gum tragacanth, which being laid on the stone ana passed through the press leaves the drawing on the stone, and the pro- cess above described for preparing the stone and taking the impression is carried into effect. In Germany many engravings are made on stone with the burin, in the same way as on copper ; but the very great inferi- ority of these to copper engravings makes it improbale that this method will ever come into general use. Perhaps one of the greatest advantages of the art of lithography is the extraordi- nary number of copies that may be taken from a block. As many as 70,000 copies 01 prints have been taken from one block, and the last of them nearly as good as the first. Expedition is also gained, inas- much as a fifth more copies can be taken in the same time than from a copper- plate : and as regards economy the ad- vantages over every other species of en- graving is very great. Zincography. This art, which is of very recent introduction in this country (so much so, indeed, that but few specimens are as yet to be seen), is similar in princi- ple to lithography, the surface of the plates of zinc on which it is executed being bit away, leaving the design promi- nent or in relief. We have seen some beautiful examples of this art, but vary- ing little in their appearance from those of stone engraving. Mr. J. II. Friny, of England, has pro- posed a mode of engraving on steel and other metals by means of electricity. He employs six of Smee's batteries, in each the size of the platinized silver plate was about three square inches. The steel plate to be engraved was connected to the zinc end of the batteries ; a long covered wire is placed between the steel plate and the zinc. The wire in communication with the platinized silver, was used as an etch- ing point on the steel plate. The wire, i which served as a graver, was made of J platina; when held a glass tube protected | it from the hand. In proportion to the intensity of the current is the depth of the engraving. ERIOMETER. An optical instrument proposed by the late Dr. Young for measuring the diameters of minute par- ticles and fibres, by ascertaining the di- ameter of any one of the series of colored rings they produce. " The eriometer is formed of a piece of card or a plate of brass, having an aperture of about a fiftieth of an inch in diameter in the centre of a circle about half an inch in diameter, and perforated with about eight small holes. The fibres or particles to be measured are fixed in a slider ; and the eriometer being placed before a strong light, and the eye assisted by a lens ap- plied behind the small hole, the rings of colors will be seen. The slider must then be drawn out or pushed 1 11 the limit of the first red and green rug (the one selected by Dr. Young) coincides with the circle of perforations, and the index will then show on the scale the size of the particles cr fibres. ERVA LENTA. The farina or meal of the common lentil, the Ervum Lens. ERMINE. The winter hair of the com- mon weasel an animal indigenous through the whole states. The fur is white, long, thin, and silky. The animals are very abundant about Hudson's Bay. The fur is in great request, and was formerly one of the insignia of magistrates. When used to line cloaks, the black tuft of the tail is sewed to the skin at irregular inter- vals. ESSENTIAL OILS or VOLATILE OILS. Under this term are included all those peculiar compounds obtained by distilling vegetable substances with wa- ter, and which pass over along with the steam, and are afterwards condensed in the liquid or solid form. They appear to constitute the odoraus principles of vegetables. Their specific gravity fluctu- ates on either side that of water ; they are very sparingly soluble in water, and these solutions constitute the medicated waters : rose, peppermint, and other wa- ters being such solutions of the respect- ive essential oils. They dissolve in alcohol and form essences, many of which are used as perfumes. When these oils are pure, they evaporate from paper when held before the fire ; but if adulterated with fixed oils, they leave a greasy stain, and seldom dissolve perfectly in alcohol. The more expensive of these oils are frequently adulterated with the cheaper ones, and this fraud can only be eth] CYCLOPEDIA OF THE USEUL ARTS. 159 detected by an experienced nose. Their chief use is in perfumery, on account of their odour, and in medicine they form valuable stimulants. They are inflam- mable, and are, with a few exceptions, compounds of hydrogen, oxygen, and carbon. The essence of turpentine, of lemons, and a few others, are hijdro- carbons. ETHER. In Chemistry, this term is applied to a highly volatile, fragrant, in- flammable, and intoxicating liquid, pro- duced by distilling a mixture of equal weights of sulphuric acid and alcohol. When these liquids mutually act on each other, a series of complicated changes ensue, which terminate in the conversion of alcohol into ether. Ether, like alco- hol, may be regarded as a compound of hydrocarbon and water; and if alcohol be considered as consisting of one equiva- lent of oletiant hydrocarbon=14, and one of water=9, either may be regarded as constituted of tawolefiant hydrocarbon (14X2)=28, and one of water=9 : hence, the equivalent of alcohol being 14-f9=23, that of ether will be 14X2=28+9=37; and the process of etherification may bo stated to consist in the abstraction trom alcohol of one half of its elemental water. By some, ether is regarded as the oxide of a peculiar hydrocarbon, which they term ethule, composed of 4 equivalents of carbon and 5 equivalents ot hydrogen ; and alcohol must in that case be consid- ered as hydrate of ether. Ether, or, as it is often called, to dis- tinguish it from analogous products ob- tained by the intervention of other acids, sulphuric ether, is a limpid colorless fluid, of an agreeable odour, and a hot pungent taste. Its specific gravity is about 0-713, though that of the shops is usually heavier ; it boils at about 98°, and freezes at the low temperature of 46° below 0°. The specific gravity of ethereal vapor compared with atmospheric air is as 258 to 100. Ether is sparingly soluble in wa- ter, which takes up about a tenth of its bulk; it dissolves in all proportions in alcohol. The principal use ot ether is in medicine. When taken internally, it is stimulant; and it is sometimes applied externally, by reason of the cold produced during its evaporation, as an ingredient in refrigerating lotions. The most profitable way of manufac- turing ether has been pointed out by Boullay. It consists in letting the alco- hol drop in a slender stream into the acid, previously heated to the etherifying tem- perature. If the acid in this case were concentrated to 1*846, the reaction would be too violent, and the ether would be transformed into bicarbureted hydrogen (dihydrate of carbon). It is therefore necessary to dilute the acid down to the density of 1-780; but this dilution may be preferably effected with alcohol, in- stead of water, by mixing three parts of the strongest acid with two of alcohol, specific gravity 0-830, and distilling off a portion of the ether thereby generated ; after which the stream of alcohol is to be introduced into the tubulure of the re- tort through a small glass tube plunged into the mixture ; this tube being the prolongation of a metallic syphon, whose shorter leg dips into a bottle filled with alcohol. The longer leg is furnished with a stop-cock, for regulating at plea- sure the alcoholic streamlet. The dis- tilled vapors should be transmitted through a worm of pure tin, surrounded by cold water, and the condensed fluid received in a glass bottle. The quantity of alcohol which can be thus converted into ether by a given weight of sulphuric acid, has not hitherto been accurately de- termined ; but it is at least double. In operating in this way, neither sulphurous acid nor sweet oil of wine is generated, while the residuary liquid in the retort continues limpid and of a merely brown- ish yellow color. No sulphovinic acid is formed, and according to the experiments of Geiger, the proportion of ether ap- proaches to what theory shows to be the maximum amount. In fact, 57 parts of alcohol of 0-S3 sp. grav. being equivalent to 46-8 parts of anhydrous alcohol, yield, according to Geiger, 33£ parts of ether ; and by calculation they should yield 37J. The ether of the first distillation is ne- ver pure, but always contains a certain quantity of alcohol. The density of that product is usually 0*78, and if prepared by the first of the above methods, con- tains, besides alcohol, pretty frequently sulphurous acid, and sweet oil of wine ; impurities from which it must be freed. Being agitated with its bulk of milk of lime, both the acid and the alcohol are removed at the same time ; and if it be then decanted and agitated, first with its bulk of water, next decanted into a re- tort containing chloride of calcium in coarse powder, and distilled, one third of perfectly pure ether may be drawn over. ETHER, ACETIC, is used to flavor si- lent corn spirits in making imitation brandy. It may be prepared by mixing 20 parts of acetate of lead, 10 parts of al- 160 CYCLOPEDIA OF THE USEFUL ARTS. [EVA cohol, and Hi of concentrated sulphuric acid; or 16 of the anhydrous acetate, 5 of the acid, and 4£ of absolute alcohol; distilling the mixture in a glass retort into a very cold receiver, agitating along ■with weak potash ley the liquor -which comes over, decanting the superaatant ether, and rectifying it by re-distillation over magnesia and ground charcoal. Acetic ether is a colourless liquid of a fragrant smell and pungent taste, of spec, grav. 0-866 at 45° F., boiling at 166° F., burning with a yellowish flame, and disen- gaging fumes of acetic acid. It is soluble m 8 parts of water. ETCHING VARNISHES. The var- nishes of Mr. Lawrence, an English art- ist resident in Paris, is made as follows : Take of virgin wax and asphaltum, each two ounces, of black pitch and burgundy pitch each half an ounce. Melt the wax and pitch in a new earthenware glazed pot, and add to them, by decrees, the as- phaltum, finely powdered. Let the whole boil till such time as that, taking a drop upon a plate, it will break when it is cold, on bending it double two or three times betwixt the fingers. The varnish, being then enough boiled, must be taken off the fire, and after it cools a little, must be poured into warm water that it may work the more easily with the hands, so as to be formed into balls, which must be kneaded, and put into a piece of taf- fety for use. Care must be taken, first, that the fire be not too violent, for fear of burning the ingredients, a slight simmering being suf- ficient ; secondly, that whilst the asphal- tum is putting in, and even after it is mixed with the ingredients, they should be stirred continually with the spatula ; and thirdly, that the water into which this composition is thrown should be nearly of the same degree of warmth with it, in order to prevent a kind of cracking that happens when the water is too cold. The varnish ought always to be made harder in summer than in winter, and it will become so if it be suffered to boil longer, or if a greater proportion of the asphaltum or brown resin be used. The experiment above mentioned, of the drop suffered to cool, will determine the de- gree of hardness or softness that may be suitable to the season when it is usea. Preparation of the hard varnish used by Callot, commonly called the Florence Varnish : — Take four ounces of fat oil very clear, and made of good linseed oil, like that used by painters ; heat it in a clean pot of glazed earthenware, and af- terwards put to it four ounces of mastick well powdered, and stir the mixture briskly till the whole be well melted, then pass the mass through a piece of fine linen into a glass bottle with a long neck, that can be stopped very securely ; and keep it for the use that will be ex- plained below. Method of applying the soft varnish to the plate, and of blackening it : — The plate being well polished and burnished, as also cleansed from all greasiness by chalk or Spanish white, fix a hand-vice on the edge of the plate where no work is intended to be, to serve as a handle for managing it when warm ; then put it upon a chailng-dish, in which there is a moderate fire, and cover the whole plate equally with a thin coat of varnish; and whilst the plate is warm, and the varnish upon it in a fluid state, beat every part of the varnish gently with a small ball or dauber made of cotton tied up in taffety, which operation smooths and distributes the varnish equally over the plate. EUDIOMETER. This term is gene- rally applied to instruments for facilitat- ing the analysis of atmospheric air, or ra- ther for determining the quantity of ox- ygen contained in a given volume of air ; under the idea that the salubrity of the air depended upon its relative quantity of oxygen. We now know, however, that this is not the case, and that the re- lation of the oxygen to the nitrogen in the atmosphere is not subject to any dis- cernible fluctuation. EVAPORATION. The conversion of substances into vapour is one of the most important and general effects of heat. During this process, a considerable quan- tity of sensible heat passes into the latent or insensible state. When a vessel of water is placed upon the fire, its temper- ature gradually rises till it attains 212° ; then, although it remains upon the fire, and of course receives heat as before, it does not become hotter, but is gradually converted into steam or vapor ; so that the effect of heat is not to elevate tem- perature, but to change state or form : that is, in the case of water, to convert it into steam. Hence we assume that steam, though not hotter than water, contains a much larger quantity of heat, and this heat again makes its appearand when the steam is condensed or re-con- verted into water. At whatever temper- ature vapour is produced, it is similarly constituted ; and that which escapes from water at ordinary temperatures, by the '] CYCLOPEDIA OF THE USEFUL ARTS. 161 process usually called spontaneous evapo- ration, resembles the former in all re- spects : hence it is that evaporation is to surrounding bodies a cooling process ; and that in the converse change, or the return of the vapor to the liquid state, heat is evolved and rendered sensible. The same general phenomena are ob- served with all other liquids, and those which evaporate rapidly at common tem- peratures often give rise to the produc- tion of a great degree of cold ; such as spirit of wine, or ether. If the latter flu- id be suffered to dribble over the bulb of a thermometer, it will cause it to sink below the freezing point of water ; and by accelerating similar cases of evapora- tion, we obtain most intense degrees of artificial cold. The circumstances that principally in- fluence the process of evaporation are, extent of surface, and the state of the air as to temperature, dryness, stillness, and density. In evaporating by surfaces heated with ordinary steam, it must be borne in mind that a surface of 10 square feet will eva- porate fully one pound of water per min- ute, or 725X10=7250 gr., the same as over a naked fire ; consequently the con- densing surface must be equally exten- sive. Suppose that the vessel is to re- ceive of water 2500 lbs., which corres- ponds to a boiler 5 feet long, 4 broad, and 2 deep, being 40 cubic feet by mea- sure, and let there be laid over the bot- tom of this vessel 8 connected tubes each 5 inches in diameter and 5 feet long, pos- sessing therefore a surface of 5 feet square. If charged with steam, they will cause the evaporation of half a pound of wa- ter per minute. The boiler to supply the steam for this purpose must expose a sur- face of 5 square feet to the fire. It has been proved expei-imentally that 10 square feet surface of thin copper can condense 3 lbs. of steam per minute, with a differ- ence of temperature of 90 degrees Fahr. In the above example, 10 square feet eva- porate 1 lb. of water per minute ; the temperature of the evaporating fluid be- ing 212° F., consequently 3 : 1 : : 90: O During this evaporation the difference of the temperature is therefore =30°. Consequently the heat of the steam placed in connection with the inte- rior of the boiler, to produce the calcu- lated evaporation, should be, 212+30= 242°, corresponding to an elastic force of 53-6 inches of mercury. "Were the tem- perature of the steam only 224. the same boiler in the same time would produce a diminished quantity of steam, in the pro- portion of 12 to 30 ; or to produce the same quantity the boiler or tubular sur- face should be enlarged in the proportion of 30 to 12. In general, however, steam boilers employed for this mode of evapo- ration are of such capacity as to give an unfailing supply of steam. EXPANSION. One of the most com- mon and obvious effects of heat, which expands or enlarges the bulk of all the forms of matter. The expansion of sol- ids by increase of temperature is compar- atively small ; but it may be rendered sensible by carefully measuring the di- mensions of any substance when cold, and again when heated : an iron bar, for example, fitted to a gauge, which shows its length and breadth", will no longer pass through the apertures when heated. Among solids the metals are most expans- ible and contractile by heat and cold ; but they vary much in this respect, as shown in the following table, which ex- hibits the change of dimensions which several of them undergo when heated, from the freezing to the boiling point of water : — Temperature. Platinum Steel . Iron . Copper 120000 Tin Lead Zinc 212° 120104 120147 120151 120204 120230 120290 120345 120360 The average expansion of glass is very nearly the same as that of platinum. The expansibility of different Liquids is also very variable: ether, for instance, and alcohol, are more expansible than wa- ter, and water more than mercury. The expansibility of mercury is applied to a very useful purpose in the construc- tion of the common thermometer. In general all liquids expand and contract in proportion as they are heated and cooled ; but to this law there is a remarkable and anomalous exception with regard to wa- ter. When a large thermometer tube is filled with water of the temperature of 60°, and placed in a cold situation, or in a freezing mixture of ice and salt, the water goes on shrinking in the tube, till it has attained the temperature of about 40° ; and then, instead of continuing to contract till it freezes (as is the case with equal liquids), it slowly expands, and ac- tually rises in the tube" until it conceals. In this case the expansion above 40° and 162 CYCLOPEDIA OF THE USEFUL ARTS. b below 40° seems to be equal ; so that the water will be the same bulk at 48° and 32°. This anomalous expansion of water by cold is productive of some important consequences, considered as a natural operation ; for if water, like other fluids, went on increasing in density till it froze, the consequence would be that large bodies of water, instead of being only superficially frozen in winter, would be converted throughout into solid mass- es of ice. Let us take a fresh water lake as an example. The earth being in win- ter warmer than the air, the heat is with- drawn from the surface of the water by the cold breezes that blow over it ; and the whole body of water has its tempera- ture lowered to 40°, which is the point of its greatest density, and a temperature perfectly congenial to fish and most other aquatic animals. The cold now continues to operate upon the surface of the water ; but, instead of diminishing its bulk, and therefore rendering it heavier than the warmer water beneath, it expands it, and renders it lighter ; so that under these circumstances a stratum of ice-cold wa- ter (at 32°) will be found lying upon the mass of warmer water beneath it (at 40°). The influence of the cold continuing, the surface of the lake will soon freeze, but the water immediately below the super- ficial covering of ice will be found com- paratively warm ; and as water is almost a non-conductor of heat, it will be a long time before the ice attains any thickness ; and the whole body of water, if of any depth, can never freeze throughout. In- deed, it will be obvious that the retarda- tion of freezing will be proportional to the depth of water which has to be cooled, and hence some very deep basins or lakes are scarcely ever even covered by ice. As liquids are enlarged and consequent- ly rendered specifically lighter by heat, very different effects are produced by ap- plying heat to different parts of the ves- sels containing them. If the heat be ap- plied to the bottom of the vessel, it as Boon heated equally throughout, and made to boil ; but if "the surface only be heated, it may then be boiled and evapo- rated, while the lower parts remain quite cold. Aeriform bodies and vapors are the most expansible forms of matter, and they present an important peculiarity: for "in other substances each individual has its own degree of expansion and con- traction, whereas all pure aeriform bodies expand and contract alike ; so that if we accurately determine the expansion and contraction of any one of them, that knowledge applies to all the rest. 100 measures of air, when heated from the freezing to the boiling point of water, suffer an increase of bulk equal to 37*5 parts ; so that 100 cubic feet of air at 32° become dilated to 137i cubic feet at 212°. EXPLOSION. In natural philosophy, a sudden and violent expansion or the parts of any object. Explosion differs from expansion in this, that whereas the former is always sudden, and only of mo- mentary duration, the latter is the effect of some gradual and continued power, acting uniformly for some considerable time. EXTRACTS. The older apothecaries used this term to designate the product of the evaporation of any vegetable juice, infusion, or decoction ; whether the latter two were made with water, alcohol, or ether; whence arose the distinction of aqueous, alcoholic, and ethereous extracts. Fourcroy made many researches upon these preparations, and supposed that they had all a common basis, which he called the extractive principle. But Chev- reul and other chemists have since E roved that this pretended principle is a eterogeneous and very variable com- pound. By the term extract, therefore, is now meant merely the whole of the soluble matters obtained from vegetables, reduced by careful evaporation to either a pasty or solid consistence. The wa- tery extracts, which are those most com- monly made, are as various as the vege- tables which yield them ; some contain- ing chiefly sugar or gum in great abund- ance, and are therefore innocent or inert ; while others contain very energetic im- pregnations. The conduct of the evapo- rating heat is the capital point in the pre- paration of extracts. They should be al- ways prepared, if possible,' from the juice ot the fresh plant, by subjecting its leaves or other succulent part, to the action of a powerful screw or hydraulic press: and the evaporation should be effected by the warmth of a water-bath, heated not beyond 100° or 120° F. Steam heat may perhaps be applied advantageously in some cases, where it is not likely to decompose any of the principles of the plant. But by far the best process for making extracts is in vacuo. It is much easier to fit up a proper apparatus of this kind, than most practical men imagine. The vacuum may either be made through the agency of steam, as there pointed out, or by means of an air-pump. One uowerful air-pump may form and main- FAl] CYCLOPEDIA OF THE USEFUL ARTS. 163 tain a good vacuum under several re- ceivers, placed upon the flat-ground flanges 01 so many basins, each provided with a stop-cock at its side for exhaus- tion. The airless basin containing the juice being set on the shelf of a water- bath, and exposed to a proper tempera- ture, will furnish, in a short time, a large quantity of medicinal extract, possessing the properties of the plant unimpaired. For exceedingly delicate purposes, the concentration may be performed in the cold, by placing saucers filled with the expressed juice" over a basin containing sulphuric acid, putting a glass receiver over them, and exhausting its air. FAINTS. An impure spirit, which comes over at the commencement and termination of distillation. The first is called strong, and the last weak faints. Faints are impregnated with fetid vola- tile oils, which are unwholesome, and re- quire to be separated by rectification. FALLING, or weight of bodies ; an important phenomenon, which used to be ascribed to gravitation, a translation of the word weights ; so that, according to this wordy philosophy, weight was ow- ing to weight. But it is now con- sidered as well proved, that all central force in planets is a necessary result of the simultaneous orbit, or progressions, and the rotary motions, and that the di- rection to the centre is the constant dia- gonal of those motions, and the increase in the diagonal the exact quantity fallen in a given time. The rotation is a de- flection from the line of the orbit motion, and this being much greater, the body deflected by the rotation is carried by the greater motion obliquely to the com- mon centre of both motions. This is ob- vious in the equatorial plane, but, in lat- itudes, the diagonal is compounded of the orbit motions as one force, and of the sine and co-sine as to the rotatory or de- flective force ; and the square of the sine and co-sine being equal to the square of the radius, every where alike, the fall in direction and quantity agrees with that at the equator. The orbit velocity in a se- cond is 98,132 feet, the equatorial circle is 1525 feet nearly, or in the perpendicu- lar 970-85 feet, that 101-1 to 1, and this inversely, as 6.28318 the circle to the ra- dius 1, the resulting force in the radius is 16-08725 feet as the mean fall. Or, taking the two motions as 9S132 to 1525, and inversely as 4, the square of the di- ameter to 1, we also get 16-08725. The squaring the forces, and extracting the root of their sum, gives an analagous re- sult, but, for popular explanation, the preceding may suffice. FALLOW. In agriculture, lands are said to be under fallow when they are without a regular crop of corn or pulse. A naked fallow is one in which the soil remains a whole year without any crop whatever; and a turnip or green crop fallow is one in which the lands after be- ing without a crop from harvest till the beginning of summer, and being proper- ly labored during that period, ure sown with turnips or other similar crops in rows, and the grounds cultivated in the intervals. Fallowing was practised by the Romans on all soils whatever, and has been continued through the dark ages, in all the cultivated parts of Eu- rope, so as to have become, till lately, a f general habit in the treatment of arable ands. The practice of taking two corn crops, and then allowing the land to rest or he fallow, was, till the commencement of the present century, prevalent through- out Europe, and it is still a very common fa-actiee in most parts of that Continent. t appears to have been first broken through by the Flemings about the end of the 16th century ; and subsequently in Britain, with the culture of turnips, above a century and a half later. Fal- lows, under the most improved systems of agriculture, are no longer had recourse to in the case of free and easily worked soils, where turnip fallows are made, or drill crops of legumes are substituted; but in very strong clays they are still found necessary, and this will probably continue to be the case till by the " fre- quent drain system," and long-continued culture, the strong clays become friable and fit for the drill husbandry, like the sandy loams and other free soils. A perfect system of agriculture will com- pletely dispense with fallow ; under clover and green crops the ground recovers its mineral ingredients, and acquires an ad- dition of vegetable matter; it is thus richer after clover or green cropping than before, or than it would be by naked fal- low. FAN, FANNERS, or FANNING MA- CHINE. A machine for separating the chaff, husks, dust, or other light matters from seeds which are to be preserved for sowing, or for some other purpose in ge- neral or domestic economy. The air is put in motion by a wheel, commonly driv- en by hand with leaves or fans instead of spokes, directed in a stream against the seeds to be fanned; which seeds are placed in a hopper, so regulated as to 164 CYCLOPEDIA OF THE USEFUL ARTS. fFAT proportion their descent through the stream of air to the force of the current created by the fan wheel. Before fan- ners were invented the process was per- formed by hand in a manner the reverse of what it is now by machinery ; that is, the seeds and refuse to be separated from them were taken up in shovelfulls, and thrown to as great a distance as possible, through the calm air ; when the full-bo- died seeds, being the heaviest, were found at the greatest distance, and the chaff and other matters nearer, according to their degree of lightness. With the progress of the arts, a system of screens and sieves was added to the fanning ma- chine, in consequence of which, as it se- parated the seed from every kind of re- fuse, it is called a winnowing machine ; and in that case, it not only separates the chaff and other light matters generally from the heavy matters, but it parts both, according to their bulk and weight; so that the seed comes from the winnowing machine fit for being measured up for the market or store-room, and the vari- ous kinds of inferior products in a state fit for immediate use. FARINA. The flour of any variety of corn or starchy root, as the potato, arrow root, &c. It is only a species ot pure btarch. FATS occur in a great number of the animal tissues, being abundant under the skin in what is called the cellular mem- brane, round the kidneys, in the folds of the omentum, at the base of the heart, in the mediastinum, the mesenteric web, as well as upon the surface of the intest- ines, and among many of the muscles. They vary in consistence, color, and smell, according to the animals from which they are obtained ; thus, they are generally fluid in the cetaceous tribes, soft and rank-flavored in the carnivorous, solid and nearly scentless in the rumi- nants, usually white and copious in well- fed young animals ; yelloAvish and more scanty in the old. Their consistence va- ries also according to the organ of their production ; being firmer under the skin, and in the neighborhood of the kidneys, than among the moveable viscera. Fat forms about one twentieth of the weight of a healthy animal. But as taken out" by the butcher it is not pure, for being of a vesicular structure, it is always enclosed in membranes, mixed with blood, blood- vessels, lymphatics, &c. These foreign matters must first be separated in some measure mechanically, after the fat is minced small, and then more completely by melting it along with hot water, pass- ing it through a sieve, and letting tho whole cool very slowly. By this means a cake of cleansed fat wiirbe obtained. Many plans of purifying fats have been proposed ; one of the best is to mix two per cent of strong sulphuric acid with a quantity of water, in which the tallow is heated for some time with much stirring ; to allow the materials to cool, to take off the supernatant fat, and re-melt it with abundance of hot water. More tallow will thus be obtained, and that consider- ably whiter and harder than is usually procured by the melters. Fat is deposited in cells in the cellular tissues of the animal ; when viewed un- der the microscope they are partly poly- gonal, partly reniform particles, which are connected together by very thin mem- branes. These may be ruptured by me- chanical means, then separated by tritu- rating the fresh fats with cold water, and passing the unctuous matter through a sieve. The particles float in the water, but eventually collect in a white granular crystalline appearance, like starch. Each of them consists of a vesicular integu- ment, of the nature of stearine, and an interior fluid like elaine, which afterwards exudes. The granules float in the water, but subside in spirits of wine. When digested in strong alcohol, the liquid ?art dissolves, but the solid remains, hese particles differ in shape and size, as obtained from different animals ; those of the calf, ox, sheep, are polygonal, from i to -j.l_. of an inch in diameter ; those of the sow are kidney-shaped, and from ^ to -i ; those of a man are polygon- al, and from ' to -g~; those of in- sects are spherical, and at most _* of an inch. Fats all melt at a temperature much under 212° F. When strongly heated with contact of air, they diffuse white Eungent fumes, then blacken, and take re. When subjected to distillation, they afford a changed fluid oil, carbureted hydrogen, and the other products of oily bodies. Exposed for a certain time to the atmosphere, they become rancid, and generate tne same fat acids as they do by saponification. In their fresh state they are all composed principally of stearine, margarine, and oleine, with* a little color- ing and odorous matter. Fats are true chemical salts, being com- ?osed of a fatty acid united to a base, his base is generally glycerine. The acids are either stearic acid, which is fea] CYCLOPEDIA OF THE USEFUL ARTS. 165 found abundantly in the hard fats, as suet and tallow, Margaric acid, also a solid, found in the crystalline portion which cold throws out of olive oil ; it is also found in ani- mal fats and oleic acid, which is found abundantly in olive oil, and all liquid fats and oils. The properties of stearine and claine, or of stearic and oleic acids vary at dif- ferent seasons and under various circum- stances ; thus, butter, in summer, con- sists of 60 of oleine and 40 of stearine ; in winter, of 37 of oleine, and 63 of stear- ine ; the former substance being yellow, and the latter white. It differs, however, as produced from the milk of different cows, and also accordiug to their pas- ture. Animals oils and fats differ only in fluidity, and may be treated of together. Of animal oils, whale oils, and sperm oils are the most generally known in this coun- try : the fats are spermaceti, butter, tallow, lard, and suet. Whale or train oil is ex- tracted from the blubber of the whale, principally the oalena mystieetes ; origi- nally it is a firm solid fat. To obtain the oil, the blubber is melted in large copper vessels, a large quantity of water sepa- rates, and on the surface there floats a solid matter called fenks, which is proba- bly coagulated albumen ; the more mode- rate the heat, and the shorter its dura- tion, the paler and better the oil. The deep color is owing to too much boiling, and perhaps to blood and impurities mix- ed with it. The Greenland oil is pale and free from smell, and burns with a Sure and bright flame. By adding cold rawn oil it is made more fluid and com- bustible. Chloride of lime deprives it of its offensive odor. It boils at 600°, and may be distilled, but it then is an altered oil. Sperm oil forms part of the oily sub- stance in the cranium of the spermaceti whale (physeter macrocephalus). The oil is separated by putting the mass in a woollen bag and pressing it, when the oil runs out. This kind of oil is purer than train, and burns away without leaving charcoal on the wicks. The manner of obtaining the solid fats has been given ; when soft it is called lard, when hard taUow. It is insoluble in water and alcohol, melts at 90° or 100° ; by raising the heat it becomes acrid, and gives off a pungent vapor. In close ves- sels it is decomposed, and among other substances yields a large quantity of ole- fiant gas. It is inflammable, and affords by combustion water and carbonic acid. FEATHERS, the peculiar covering of birds, consist of the tube, the shaft, and the barbs. The tube is a hollow, trans- parent, horny cylinder, constituting the root of the feather ; the shaft is elastic, and contains a white, dry, and very light pith. The tube contains a vascular sub- stance, composed of numerous cells, join- ed together, and communicating with each other. This is enveloped by the tube, but communicates with the skin by a small opening at the root of the tube, and is probably the organ by which the feather is nourished. Two sides of the shaft are covered with the barbs, running in a uniform direction ; and each barb forms, of itself, a little shaft, which is covered, in a similar manner, with little barbs on each edge. On the wing-fea- thers, the barbs are broader on one side than on the other ; but on the other fea- thers, they are equal on both sides. The barbs are provided with barbules, by which they are bound so firmly to each other, as to appear to adhere together, although they are, in fact, entirely sepa- rate. The feathers of birds are periodi- cally changed. This is called moulting. T?he best method of curing feathers is to lay them in a room exposed to the sun, and, when dried, to put them in bags, and beat them well with poles. Fea- thers, when chemically analyzed, seem to Eossess nearly the same properties as air. FEATHERS. (Purification of.)— The following is an outline of Heal's pro- cess : — " The feathers are first placed in what is termed a steam-cistern, a chamber of iron, having its floor formed of perforat- ed metal, through which a current of steam is made to enter with considerable force, to fill every portion of the cistern, and thoroughly saturate the mass which it contains. This continues for some time, the effect upon the feathers being analogous to that produced upon metallic substances when exposed to the red heat of a furnace. Every particle of animal matter they contain is fused and driven off, being carried away by the steam as it rushes through the mass and escapes by an aperture for the purpose in the roof of the cistern. The feathers, now of course in a damp state, are next placed in a large hollow cylinder of iron, into which by means of a blowing machine, is carried a rapid current of air, heated by a fur- nace to a temperature of 300°. This, like the first cylinder, contains a revolving in- strument of iron, but having arms or bars 166 CYCLOPEDIA OF THE USEFUL ARTS. [> of iron ; and these, driven at a great velo- city, pass through and through the mass, thoroughly separate it, and keep the fea- thers constantly in motion : thus allow- ing the current of hot and drying air to permeate them freely, and effectually separating every fibre of them, while through a floor of wire- work passes away a large quantity of dust and refuse, which must be disengaged. Lastly, the feathers are placed in a hollow cylinder of perfor- ated metal, in which revolves a 'fan,' composed of four plates of metal, fixed at equal distances from each other, into a horizontal bar. This is driven with im- mense velocity, making about 900 revo- lutions in a minute, and carrying round the feathers with it; the dust, not al- ready removed in the drying cylinder, is separated by the powerful current of air which is driven through them, and, pass- ing the perforations of the cylinder, is carried away by a drain beneath. By this means the feathers are rendered perfectly sweet, pure, and dry." FELSPAR. An important mineral composed of silica, alumina, and potash, with traces of lime, and often of oxide of iron. Common felspar is of various shades of white and red ; it forms an in- gredient in granite, and is the base of some other rocks. It is often crystalized, and cleaves into rhomboidal fragments. FELTING. The process by which different kinds of fur or wool are blended into a compact texture for the manufac- ture of hats. The anatomical peculiari- ties of the different hairs or furs are much concerned in the perfection of the felt ; they must be such as to enable them to interlace and intertwine with each other. Hare and rabbit fur, wool, and beaver are the chief materials used ; they are mixed in proper proportions, and arc tossed about by the strokes of a vibrating string or bow till they become duly mat- ted together. The rapid alternations of its motion being peculiarly well adapted to remove all irregular knots and adhe- sions among the fibres, and to dispose them in a very light and uniform arrange- ment. This texture, when pressed under cloths and leather, readily unites into a mass of some firmness. This muss is dipped into liquor containing a little sul- phuric acid ; and, when intended to form a hat, it is first moulded into a large con- ical figure, and this is afterwards reduced in its dimensions by working it for seve- ral houre with the hands." It is then formed into a flat surface, with several con- centric folds, which are still further com- pacted, in order to make the brim, and the circular part of the crown, and forced on a block which serves as a mould for the cylindrical part. The nap, or outer por- tion of the fur, is raised with a fine win brush, and the hat is subsequently dyed, and stiffened on the inside with glue. FENCE. Any continuous line of ob- stacle interposed by art between one por- tion of the surface of land and another, for the purpose of separation or exclu- sion. The land of obstacle or material differs according to the animals which are to be separated, excluded, or confin- ed, and the nature of the soil and situa- tion. All fences are either live or dead, or a compound of these. Live fences are hedges ; that is, tows of shrubs placed close together, and pruned on the sides, so as toform a sort of living wall. Dead fences are either stone walls, mounds of earth, or structures of wood or of other materials raised above the ground's sur- face, or upon ditches excavated in it. The latter are sometimes filled with water. Mixed fences are those in which some kind of dead fence is used with some kind of live fence ; for example, a ditch with a bank of earth on one side, or a ditch with a wall or a hedge on one side ; the latter the commonest of all fences. The introduction of fences into agricul- ture was about as great an improvement in the progress of that art, as that of the principle of the division of labor into the art of manufacture. FERMENTATION. When certain vegetable substances are dissolved in water, and subjected to a due tempera- ture (between 65° and 85°), they undergo a series of changes which terminate in the production of alcohol or spirit ; these changes constitute the phenomena of vinous fermentation. Sugar and some ferment are essential to the process ; and during the formation of the alcohol the sugar" disappears, and carbonic acid is more or less abundantly evolved. The simplest ease of fermentation is that of must, or of the expressed juice of the grape, which, when exposed, either in close or open vessels, to a temperature of about 70*, soon begins to give off car- bonic acid, and to "become turbid and frothy ; after a time a scum collects upon the surface, and a sediment is deposited ; the liquor, which had grown warm, gra- dually cools and clears, loses its sweet taste, and is converted into wine. The chief compoueut parts of must are water, sugar, mucilage, gluten, and tartar. During the fermentation carbonic acid fer] CYCLOPEDIA OF THE USEFUL ARTS. 167 escapes, the sugar disappears, and with it the greater part of the mucilage : the gluten chiefly forms the scum and a por- tion of the sediment ; and the tartar, ori- ginally in solution, is thrown down in the form of a colored deposit. It appears, therefore, that the new products, which are alcohol and carbonic acid, are princi- pally formed at the expense of the sugar ; and Gay Lussac's experiments have shown that 45 pounds of sugar are re- solved, in the process of fermentation, into 23 of alcohol and 22 of carbonic acid. Sugar and water alone will not ferment; the ingredient requisite to the commence- ment of the change is the gluten, which absorbs in the first instance a little oxy- gen from the air, becomes insoluble, and induces the subsequent changes. The reason why grapes never ferment till the juice is expressed, seems to depend upon the exclusion of air by the husk or mem- branes ; and if grapes be bruised in a perfectly close vessel, carefully excluding oxygen, the juice undergoes no change ; so that the mere breaking down of the texture of the fruit is insufficient. But a very short exposure of the pulp to air is sufficient to induce that change in the juice which leads on to fermentation, and which is afterwards independent of the further contract of air, the evolution of carbonic acid being exclusively refera- ble to the decomposition of sugar. In beer the alcohol is derived from the sugar, original and produced, of the malt. When wine is exposed to air and a due temper- ature, a second fermentation ensues, which is called acetous fermentation, and Avhich terminates in the production of vinegar. During this process oxygen is absorbed, and more or less carbonic acid in most cases evolved ; but the apparent cause of the formation of vinegar is the abstract of hydrogen from the alcohol, so as to leave the remaining elements in such proportions as to constitute acetic acid. Thus alcohol is theoretically constituted of charcoal, water, and hydrogen ; and acetic acid of charcoal and water only ; the oxygen of the air, therefore, con- verts the hydrogen of the alcohol into water, and so effects the change into vinegar. Essential to fermentation are : 1. Sugar, or an equivalent convertible into it. 2. Water. 3. Heat, or increase of atomic activity. 4. Leaven, or yeast. 5. Air. Without a saccharine substance the fer- mentation is acetic, or vinegar; with it the fermentation is vinous, or spiritu- ous. These are followed by decomposi- tion or putrescence, called the ultimate, or putrefactive fermentation. It is most rapid from 70° to 100°. No vinous or beer fermentation takes place below 55° ; and above 100° the acetous precedes the vinous while the alcohol evaporates as formed. It is slower as the heat, or atomic activity, descends towards 55°, and quicker as it advances towards 100°. Again, heat should rise inversely vs quantity ; 100 gallons will do best at 94° ; 450 gallons at 72°, and 2000 gallons at 63°. Small vessels part with heat more rapidly than great ones ; and the time is inversely as the heat ; 100 gallons' at 63° would take 8 days instead of 2. Again, fermentation generates from 2° to 22° of heat, as quantity and strength, and the sinking of this internal heat to that of the surrounding atmosphere, is the signal for the termination of the fermentation. No operation should be attempted where the atmosphere is less than 50°, and, when less, doors and vents should be closed, and fires lighted. If the atmosphere is 80° or 90°, the liquid must be set to work at 70° or 80° and smaller vessels used in summer than in winter. By regulating the heats, fermentation may be conducted with success in every season. When fermentation is arrested, bottles or casks of hot water must be immersed, or water added to raise the temperature, When the fermentation is too rapid, it can be checked either by adding a strong solution of wort or syrup, or cooling with jets and ventilation, or by evaporation from the outside of the fermenting vessel. Whatever diminishes the strength of the wort, or must, increases the fermen- tation ; whatever increases the strength diminishes the fermentation. Heat also increases it, and cold dimi- nishes it. No fermentation takes places in a va- cuum, or in carbonic acid gas, and air is essential ; but, it is not necessary to leave the fermenting liquor uncovered, since the air penetrates and has saturated all the materials. When the fermentation has commenced, air favors the acetous more than the vinous fermentation. Much mixture with air converts the fer- ment to vinegar ; and while the fermenta- tion lasts, the liquor is protected by a stratum of carbonic acid gas lying over it. FERN BOOT. The root of the Aspi- di/amfilix mas, or male fern. About two drachms of the dried root, in powder, followed up by a brisk purge, is occasion- 168 CYCLOPEDIA OF THE USEFUL ARTS. [fil ally given as a vermifuge. It was Madame Noutfer's celebrated specific. FEEROCYANIC ACID. A compound of 3 atoms of cyanogen, 2 of hydrogen, and 1 of iron. It is the ferrochyazic acid of Mr. Porrett, the term chyazic being composed of the initials of carbon, hy- drogen, and azote, which are the ultimate elements of hydro-cyanogen. FIBRE. One of the two bases of all vegetable structures. It may be com- pared to hair in inconceivable fineness, its diameter often not exceeding 1-1200 of an inch; also the name of the finer divisions of roots. FIBRIN. A term applied by chemists to the muscular fibre when cleansed by washing from all adhering impurities ; or to the coagulum of the blood when the whole of the coloring matter is washed out of it. It is white, insipid, and inodor- ous ; its ultimate elements are, according to Gay Lussac and Thenard — Carbon .... 53-36 Hydrogen . . . 7*02 Nitrogen . . . 19-93 Oxygen .... 1969 It is merely a form of albumen. FIBROLltE. A rare mineral of a pe- culiar fibrous texture, accompanying co- rundum from the Carnatic and from China. FILE. This instrument is formed by cutting teeth upon a plate or tool of soft steel by the repeated blows of a straight- edged chisel. These teeth either form a single series of straight lines, or they are crossed by a second series ; the former are called "single cut, the latter double cut files. Files are required to be extremely hard ; and unless they are carefully and skilfully hardened, they are apt to warp. The best files are made exclusively of cast steel, and are cut by hand, none of the file-cutting machines producing un- exceptionable tools. FILLIGREE WORK. This work is a kind of enrichment on gold or silver, wrought delicately in the manner of little threads or grains, or both intermixed. In this kind'of work, fine gold and silver wire are often curled in a serpentine form and braided through each other, or form- ed into festoons and various ornaments, entwisting the threads to give them a very beautiful effect. This art is very ancient, and was brought into Europe from the east. It was formerly much used for decorating images and the tombs of saints. The Hindoos and Chinese make some beautiful works of this kind, with tools which are very coarse and olumsy. The Malay jewellers make a great deal of silver filligree work, and gold also. They either melt their gold in an earthen rice pot or in a clay crucible. They blow their fires with their mouth, through bamboo tubes, and they draw their wire much as we do ourselves ; after having drawn it sufficiently fine, they flatten it on the anvil, and give it a pecu- liar twist by rubbing it on a block with a flat stick. They then form it into leaves and flowers by handiwork, until they have the number to form the pattern they wish to execute on the plate. They always have the pattern beside them of the full size they wish to form on thp gold plate. They fix their work with a gluti- nous substance made of a berry ground on a stone. They keep this substance on a piece of cocoa nut. After all the leaves of the filligree is laid on the plate — stuck on bit by bit — a solder is prepared of gold filings and borax moistened with water, which they strew over the plate, then put it in the fire till the whole becomes united. In making open work the foliage is stuck on a card with the berry paste, then the work is strewn over with the solder and put into the fire, when the card burns away and the whole remains united. If the piece is very large it is soldered seve- ral times. When the filligree is finished, they cleanse it by boiling it in common salt water and alum, and they give it a fine purple color by boiling it in water with sulphur. Except in India, China, and some parts of Turkey, this art is much neglected at present/ FILTRATION is a process purely me- chanical, for separating a liquid from the undissolved particles floating in it, which liquid may be either the useful part, as in vegetable infusions, or of no use, as the washings of mineral precipitates. The filtering substance may consist of any porous matter in a solid, foliated, or pul- verulent form ; as porous earthenware, unsized paper, cloth of many kinds, or sand. The white blotting paper sold by the stationers, answers extremely well for filters in chemical experiments, pro- vided it be previously washed with dilute muriatic acid, to remove some lime and iron that are generally present in it. Fil- ter papers are first cut square, and then folded twice diagonally into the shape of a cornet, having the angular parts round- ed off. Or the piece of paper being cut into a circle, may be folded fan-like from the centre, with the folds placed exteri- orly, and turned out sharp by the pres- sure of the finger and the thumb, tokeep intervals between the paper and the fun- CYCLOPEDIA OF THE USEFUL ARTS. 169 uel into which it is fitted, to favor the percolation. The diameter of the funnel should he ahout three fourths of its height, measured from the neck to the edge. If it be more divergent, the slope will be too small for the ready efliux of the fluid. A filter covered with the sedi- ment is most conveniently washed by spouting water upon it with^ a little syringe. A small camel's-hair paint brush is much employed for collecting and turning over the contents in their soft state. Agitation or vibration is of singular efficacy in quickening percola- tion, as it displaces the particles of the moistened powders, and opens up the pores which had become closed. Instead of a funnel, a cylinder vessel may be em- ployed, having its perforated bottom covered with a disc of filtering powder folded up at the edges, and made tight there by a wire ring. Linen or calico is used for weak alkaline liquors ; and flan- nels, twilled woollen cloth, or felt-stuff, for weak acid ones. These filter bags are often made conical like a fool's cap, and have their mouths supported by a woollen or metallic hoop. Cotton wool put loose into the neck of a funnel an- swers well for filtering oils upon the small scale. In the large way, oil is filtered in conical woollen bags, or in a cask with many conical tubes in its bottom, filled with tow or cotton wool. Stronger acid and alkaline liquors must be filtered through a layer of pounded glass, quartz, clean sand, or bruised charcoal. The al- carrhazas are a porous biscuit, of stone- ware made, in Spain, which are conve- nient for filtering water, as also the po- rous filtering-stone of Teneriffe, largely imported into England at one time, but now superseded in a great measure by the artificial filters patented under many forms, consisting essentially of strata of gravel, sand, and charcoal powder. FIREARMS. (See Gun, 230.) A new gun has been invented by Mr. M. Cass, of Utica, N. Y. This gun "is loaded at the breech with ball cartridge, having cham- bers for twenty-six charges. It is also capped at the same time that it is charg- d. These twenty-six charges can be red in about three minutes without using any particular haste. The car- tridge is introduced in the barrel of the gun through the breech-pin, which is constructed something in the manner of a common faucet, being turned one quar- ter round by a small lever underneath the barrel, and thus admitting the charge, which is thrust forward from its chamber I by a small ramrod operating from behind by means of another smalllever. A new breech-loading musket has been invented in Prussia, which may be short- ly described thus : — " The musket has no lock, and is load- ed at the stock end of the barrel. The barrel is slightly rifled, but the grooves are perfectly straight, and not spiral, as in the American gun. The common charge is one-half of that used in the old per- cussion gun, and is said to carrj the ball to its mark nine hundred yards. None of the powder is wasted, the fire being communicated from the side of the bar- rel, and not from the breech. This is effected by an ingenious contrivance. The part of the cartridge next the ball is filled with an explosive substance similar to that in a percussion cap. This is made to explode by the contact of a piece of steel about the length of an eight-penny nail, which passes from the outside of the barrel through the cartridge. The gun is called the " nail firer." It can be discharged by a common soldier eight times in a minute, and need not be taken from the shoulder to be reloaded. FIRE BLAST. A term of very doubt- ful meaning, like the word blight. In agriculture it is sometimes applied to plants which are suffering from the mil- dew fungi, or from minute insects ; but its legitimate use would appear to be ap- plicable only when the delicate parts of plants are too suddenly exposed to a brilliant sun, and the rapid transpiration which takes place in consequence dries up and shrivels their leaves. FIREDAMP. The carburetted hydro- gen gas of coal mines. FIRE ENGINE. This most useful machine is constructed in a variety of forms, which all, however, agree in one principle. It generally consists of a dou- ble forcing pump communicating with the same air vessel ; and instead of a force-pipe a flexible leathern hose is used, through which the water is driven by the pressure of the condensed air in the air vessel. The an- nexed diagram repre- sents a section of the apparatus. The pipe T descends into a re- ceiver or vessel con- taining a supply of water. This pipe communicates with two suction valves V, which open into the pump barrels of two 1T0 CYCLOPEDIA OF THE USEFUL ARTS. forcing pumps A, B, in which solid pis- tons r, are placed. The piston rods of these are connected with a working beam F, elongated so that a number of persons may work at both ends of it at once. Force-pump barrel above the valves V, and pipes t, t, proceed from the sides of the they communicate with an air vessel M, by means of forcing valves V, which also open upwards. The pipe descends into the air vessel near the bottom. This pipe is connected with the flexible leath- ern hose L, the length of which is adapt- ed to the purposes to which the machine is to be appfied. The extremity of the hose may be carried in any direction, and may be introduced through the doors and windows of buildings. By the alter- nate action of the pistons, water is drawn through the suction valve, and propelled through the forcing valves, until the air in the top of the vessel M is highly com- pressed. The pressure acts on the sur- face of the water in the vessel, and forces it through the leathern hose in a con- tinued stream, so as to spout from its extremity with a force depending partly on the degree of condensation, and partly on the elevation of the extremity of the hose above the level of the engine. It is to be considered that the pressure of the condensed air has, in the first in- stance, to support a column of water, the height of which is equal to the level of the end of the tube above the level of the water in the air vessel ; and until the pressure exceeds what is necessary for this purpose, no water can spout from the end of the hose ; and, consequently, the force with which it will so spout will be proportional to the excess of the pres- sure of the condensed air above the weight of the column of water, whose height is equal to the elevation of the end of the hose above the level of the water in the air vessel. A steam fire-engine has been built by Mr. Braithwaite, of London, for the King of Prussia. It is intended to be exclu- sively employed for the protection of the public buildings of Berlin. The combustion is promoted by means of an exhauster, instead of a bellows ; the flue is in two lengths, and the greatest diameter 5 inches. The steam-cylinder is 12 inches in diameter, with a 14 inch stroke. The water cylinders are lOi inch, in diameter, with also a 14 inch stroke. The steam from the eduction -pipe is con- veyed through two coils of tubing laid in the water tank, and imparts a consider- able degree of heat to the water before it is transferred to the boiler. The feed pump is equal to the supply of from 20 to 25 cubic feet of water per hour. The steam is got up (in 20 minutes.) and the pressure in the boiler is at 70 lbs. the square inch. The height to which the water is ejected is not less than from 115 to 120 feet. The number of strokes per minute is 18, which gives for the quantity of water thrown 1 ton 7 cwt. 13 lbs. per minute. The water cylinder being 10i in dia- meter, the area of the water piston must be 86-6 square inches ; And a 14- inch stroke of the engine gives for the length of the stroke in the water cylinder 56 inches ; Therefore, 86-6 X 56 = 4849-6 cubic inches of water each stroke = 2-8 cub. ft. Deduct for back-water through the valves 1 cub. ft., leaves for the efiectual result 2-7 cub. ft. And, multiplying 2-7 by 18, the num- ber of strokes per minute, we have 48-6 cubic feet per minute = 3037 lb.s = 1 ton 7 cwt. 18 lbs. Two pipes were afterwards substituted, of 7-8 inch in diameter ; then four of 5-8 inch in diameter; and the effects pro- duced in each instance was as nearly as possible equivalent to that obtained by the 1\ inch jet. The average working power of the en- gine is between 80 ana 90 tons of water per hour. The consumption of coke is about three bushels. For the supply of the great quantity of water necessary for the engine, cast- iron suction-pipes are to be laid under the pavement, with plugs to which the suction of the engine may be fixed. In consequence of this arrangement, the en- gine may be used as well for extinguish- ing fire itself as for supplying other en- gines with water. As there are 400 ft. of hose belonging to it, the water may even by that means be conveyed to great dis- tances ; and a large plane may be protect- ed by placing the engine into a circle, the radius of which is 400 feet. This power- ful engine requires an engineer, a stoker, and 1 to 4 men to attend to the hose. It saves the strength of 42 to 105 men, ac- cording to its size from 6 to 15 horse f)ower. It does not tire, works regu- arlv, and requires no relief. Cooper's Jiotatory Fire Engine is on the rotative principle, worked by 16 men, with 11 inch lever. It discharges through a 4 inch pipe, more water than three 8 , inch cylinders, with 9 inch strokes, fir] CYCLOPEDIA OF THE USEFUL ARTS. 171 and 15 inch lover, worked by 34 men — and as much water as four 61 inch cylin- ders, 9 inch strokes, worked by 36 men with 24 inch lever. This experiment was made at New-York, in September, 1827. The same engine with 12 men, 11 inch lever, threw more water than 2 en- gines, worked by 36 men, with 24 inch lever. A rotative engine, with 20 men, exert- ing an estimated power of 35 lbs. per man, with 7 inch lever, has thrown from an inch pipe, 156 ft. horizontal, and 109 ft. in height. A rotative engine, with 8 men, exert- ing an estimated power of 50 lbs. per man, has thrown from a half-inch pipe, 148 ft. horizontal, and 103 ft. in height. The quantity of water discharged by the first engine was 525 gallons for each 1 to revolutions. By the second, 304 gal- lons, each 100 revolutions. By the third, 128 gallons, each 100 revolutions. In the first engine the revolving cylin- der was 13 inches long and 8 inches in diameter, and the surface acting upon the water was 40 square inches. In the second the revolving cylinder was 12 inches long and 6i inches in diameter, and it had a surface of 30 square inches. The third cylinder was 9 inches long, 5 inches in diameter, and 18 square inches acting surface. It raised double -the quantity of water, since in working the old engines, to dis- charge the chamber or cylinder once, the piston must pass twice through it; an ascending stroke to create a vacuum, and a descending one to force the water. Half the time is consequently lost. In the rotative, a continued vacuum is created, and a continued discharged effected. > It works with one-half the power, since the air-vessel is totally dispensed with ; and the power is applied directly upon the water. It operates on no more than it discharges. On the other hand, as a consequence of the alternating mo- tion of the piston engines twice the sur- face is acted on, and the friction of course is comparatively twofold. FIEE ESCAPE. Any machine or ap- paratus for the purpose' of enabling per- sons to escape from the upper stories of houses on fire. The contrivances which have been proposed for accomplishing this desirable object are very numerous, and are of two kinds ; the first kind com- prising those by means of which the escape is effected without external aid, and the second those requiring the as- sistance of persons without. Of the first kind the most obvious is a rope-ladder, which may be kept in a sleeping apart- ment, and used upon occasion by fasten- ing one end of it to a window-sill or bed- post. Mr. Maseres contrived an apparatus which consists of a long rope and an as- semblage of cordage or belts, so disposed as to form a seat; the person about to descend binds himself into the seat, and then lowers himself to the ground by al- lowing the rope which is fastened to the window-sill to slide slowly through his hands ; and in order that this may be done easily, the rope is made to pass through a series of holes in a block. But unfortunately contrivances of this kind can rarely be expected to be of any use ; for supposing them at hand when the alarm of danger is given, few persona can command the coolness and attention which are requisite for fixing and adjust- ing the apparatus ; and even then it is only the strong and active who could safely descend by such means from a considerable height. With regard to escapes of the second kind, the object is to enable persons without to establish speedily a commu- nication with an upper room, so as to afford the inmates the means of safe de- scent ; or to remove them if necessary, as in the case of the feeble or children. A very portable sort of ladder, invented by Mr. Young, is described in the Trans- actions of the Society of Arts for 1 813. It consists of a number of cross bars or rounds, connected with ropes, which form the sides of the ladder ; the end of the rounds are fitted into each other, so as to form a pole, which is readily ele- vated to a window ; and at the extremity is an iron frame terminating in hooks which can be lodged in the window-sill. When the hooks are properly fixed, a sudden jerk suffices to separate the rounds, which immediately fall into their places when the ladder is formed and suspended from the frame. But this ap- paratus only answers the same purpose as a rope-ladder, and is therefore liable to the same objections. Mr. Brady's fire- escape, described in the 34th vol. of the same Transactions, consists of a car oi cradle, which is made to slide on a slip of plank fixed to a pole, and is governed by a rope. Mr. Ford's escape consists of a spar of timber about 35 or 40 feet long, having two projecting arms at the top furnished with prongs, by which a firm bearing against the wall of a house is ob- tained. A grooved pulley is mortised into the spar near the top, and another m CYCLOPEDIA OF THE USEFUL ARTS. [fir near the bottom ; over the pulleys runs an endless rope, to which is attached at one point a main rope, and at another the semicircular brace of a large grooved roller, which traverses up and down the space between the pulleys. This brace carries on the under side of the spar a hook, to which a cradle is attached, whereby persons can be easily lowered to the ground. FIRE, GREEK. This fire, which was employed in the wars of the Christians ana Saracens in the middle ages, is said to have been invented during the reign of Constantine Pogonatus in the year 668 by Callinicus, an architect of Helio- polis. Naphtha was probably is princi- pal ingredient, which, if skilfully pro- jected and inflamed, creates great havoc and dismay, in consequence of its ex- treme combustibility and the difficulty of quenching its flame. FIRE-LOCK, or FUSIL. A musket or small gun, which is fired with a flint and steel; and thereby distinguished from the old musket, or match-lock, which was fired with a match. The date of the invention of fire-locks is uncertain. FIRE- WORKS. Artificial preparations made of gunpowder, sulphur, and other inflammable ingredients, displayed at public rejoicings and on other occasions. (See Pybotechny.) FISH-HOOKS, are constructed with simple tools, but require great manual dexterity in the workmen. The iron wire of which they are made should be of the best quality, smooth, and sound. A bundle of such wire is cut in lengths, either by shears or by laying it down upon an angular wedge of hard steel fixed horizontally in a block or anvil, and striking off the proper lengths by the blows of a hammer. In fashioning the barbs of the hooks the straight piece of wire is laid down in the groove of an iron block made on purpose, and is dex- terously struck by the chisel in a slant- ing direction, across so much of the wire as may be deemed necessary. A sharp- pointed little wedge is thus formed, whose base graduates into the substance of the metal. The end of the wire where the line is to be attached is now flattened or screw- tapped ; the other end is sharp-pointed, and the proper twisted curvature is given. The soft iron hooks are next case-hard- ened, to give them the steely stiffness and elasticity, by imbedding them in animal charcoal contained in an earthen or iron box; (s^Case-Hardening;) after which they are brightened by heating and agitating them with bran, and finally tempered by exposure to a regulated tem- perature upon a hot iron plate. Hooks for salt-water fishing are frequently tinned, to prevent them wearing rapidly away in rust. {See Tin Plate.) FIXED OILS. There are two speci- mens of oil in vegetables, agreeing in the common properties of unetuosity and in- flammability, but essentially different in many of their chemical qualities. The one capable of being volatilized without decomposition, is named volatile oil, the other is fixed oil. The latter is generally contained in the seeds and fruits of vegetables, and varies in its properties, according to the plants from which it is obtained by pressure, and frequently called expressed oils. When the process is aided by heat, the action of which is to render the oil more fluid, the product is esteemed less pure. The purest fixed oils are those expressed from the fruit of the olive, or the seeds of the almond ; others, less pure, come from the flax-seed and hemp-seed. These oils are usually fluid, but of a somewhat thick consistence, and liable to congeal at very moderate colds ; palm-oil is even, na- turally, concrete. When fluid, they are transparent, of a yellow or yellowish- green color, and capable of being render- ed quite transparent by the use of animal charcoal. They are inodorous and in- sipid, at least if they have been obtained with due care ; and free from the muci- laginous and extractive matter of the f)lants from whence they come ; are ighter than water, with which they do not unite, and are very sparingly soluble in alcohol, with the exception of castor- oil. At a temperature below 600° Fahr., they remain unchanged. Near this temperature, however, they begin to boil, and to disengage an in- flammable vapor; but the oil thus con- densed is altered in its properties ; it loses its mildness, becomes more limpid and volatile, a portion of carbon being likewise deposited. Transmitted through an ignited tube, fixed oil is convert id into carbonic acid and carbureted hydro- gen, with a small portion of acid liquor, and a residuum of charcoal. In the open air, it burns with a clear white light, and formation of water and car- bonic acid gas. Accordingly, the fixed oils are capable of being employed for the purposes of artificial illumination, as well in lamps as for the manufacture of | gas. Fixed oils undergo considerable pla] CYCLOPEDIA OF THE USEFUL ARTS. 173 change by exposure to the air. The ran- cidity which then takes place is occa- sioned by the mucilaginous matters which they contain becoming acid. From the operation of the same cause, they gradually lose their limpidity, and some of them, which are hence called drying-oils, become so dry, that they no longer feel unctuous to the touch, nor give a stain to paper. This property, for which linseed-oil is remarkable, may be communicated quickly, by heating the oil in an open vessel. The drying-oils are employed for making oil-paint, and, mixed with lamp-black, constitute print- ers' ink. During the process of drying, oxygen is absorbed in considerable quantity. This absorption of oxygen is, under certain circumstances, so abundant and rapid, and accompanied with such a free disengagement of caloric, that light, Jjorous, combustible materials, such as amp-black, hemp, or cotton-seed may be kindled by it. Many instances of spontaneous combustion have occurred from this cause. It appears that if hemp, flax, or linen cloth, steeped in linseed- oil, lie in a heap, and be somewhat press- ed together and confined, its temperature rises, a smoke issues from it, and, at length, sometimes within 24 or even 12 hours, it takes fire. The same thing happens with mixtures of oil and fine charcoal, and with lamp-black wrapped up in linen ; from whence it is conjec- tured, that many extensive fires, which have broken out in cotton manufactories, and for which no cause could be assigned, must have arisen from this spontaneous inflammability of oils. Fixed oils unite with the common me- tallic oxides. Of these compounds, the most interesting is that with the oxide of lead. When linseed-oil is heated with a small quantity of litharge, a liquid re- sults which is powerfully drying, and is employed as oil-varnish. Olive-oil, com- bined with half its weight of litharge, forms the common diachylon plaster. The fixed oils arc readily attacked by alkalies. With ammonia, they form a soapy liquid, to which the name of volatile liniment is applied. They are oxidated by a number of the acids. Sulphuric acid soon renders them black ; the oxygen of the acid attracting part of the hydrogen of the oil, and causing the deposition of charcoal ; and, if heat is applied, a large portion of sul- phurous acid is disengaged, and even sulphur is evolved. Nitric acids renders them thick ; if heat is applied, the action is more rapid, and a yellow color is com- municated, the oil being rendered con- crete. Chlorine thickens oil, and renders it white. When boiled in sulphur, a compound is formed of a brown color, a very fetid smell, and acrid taste. It like- wise, when heated, dissolves phosphorus, forming a liquid which becomes lumi- nous, when exposed to the air. Olive- oil consists of carbon77'213, oxygen 9-427, and hydrogen 13-360. FLAKE WHITE, is the name some- times given to pure white-lead. FLAME, is the combustion of an ex- plosive mixture of an inflammable gas or vapor with air. That it is not, as many suppose, combustion merely at the ex- terior surface, is proved by plunging a fragment of burning phosjiiorus or sul- phur into the centre of a large flame of alcohol. Either of these bodies will con- tinue to burn there with its peculiar light ; thus proving that oxygen is mixed with the whole of the burning vapor. If we mix good coal gas with as much at- mospheric air as can convert all its carbon into carbonic acid, the mixture will ex- plode with a feeble blue light ; but if we mix the same gas with a small quantity of air, it will burn with a rich white flame. In the latter case the carbona- ceous particles are precipitated, as Sir H. Davy first showed, in the interior of the flame, become incandescent, and consti- tute white light : for from the ignition of solid matter alone can the prismatic rays be emitted in that concentrated union. Towards the interior of the flame of a candle, a lamp, or a gas jet, where the air is scanty, there is a deposition of solid charcoal, which first by its ignition, and afterwards by its combustion, in- creases in a high degree the intensity of the light. If we hold a piece of fine wire gauze over a jet of coal gas close to the orifice, and if we then kindle the gas, it will burn above the wire with its natural brilliancy ; but if we elevate the gauze progressively higher, so as to mix more and more air with it before it reaches the burning point, its flame will become fainter and less white. At a certain dis- tance it becomes blue, like that of the above explosive mixture. Since the com- bustion of all the constituents is in this case direct and complete, the heat be- comes greatest in proportion nearly as the light is diminished. If a few platina wires be held in that dim flame they will grow instantly white hot, and illuminate the apartment. On reversing the order 174 CYCLOPEDIA OF THE USEFUL ARTS. [fla of this experiment, by lowering progres- sively a fhuxpiece of wire gauze from the summit towards the base of a gas flame, we shall And no charcoal deposited at its top, because plenty of air has been intro- duced there to convert all the carbon of the gas into carbonic acid, and therefore the apex is blue ; but as we descend, more and more charcoal will appear upon the meshes. At the very bottom, in- deed, where the atmospheric air impinges upon the gauze, the flame is again blue, and no charcoal can therefore be depo- sited. The fact of the increase of the bril- liancy and whiteness of flame by the de- velopment and ignition of solid matter in its bosom illustrates many curious phenomena. We can thus explain why olefiant gas affords the most vivid illumi- nation of all the gases ; because, being surcharged with charcoal, its hydrogen lets it go in the middle of the name, as it does in an ignited porcelain tube, whereby its solid particles first get igni- ted to whiteness, and then burn away. When phosphorus is inflamed it always yields a pure white light, from the igni- tion of the solid particles of the snowy acid thus produced. In the blowpipe the inner blue flame has the greatest heat, because there the combustion of the whole fatty vapor is complete. The feeble light of burning hydrogen, carbonic oxide, and sulphur, may, upon the principles now expound- ed, be increased by simply placing in them a few particles of oxide of zinc, slender filaments of amianthus, or fine f)latina wire. By narrowing the top of a ong glass chimney over anargand flame either from oil or coal gas, the light can be doubled at the same cost of material. The very tall chimneys used by the Pa- risian lampists are very wasteful. The light of a name may be increased by di- minishing its heat, or the intensity of its combustion ; and conversely the heat of flame may be increased by diminishing its light. FLATTING. In architecture, a coat of paint, which, from its mixture with turpentine, leaves the work flat, or with- out gloss. FLAX. An annual plant, the Imum usitatiwimum, grown extensively, from remote antiquity, over Europe, Asia, and Northern Africa. It is believed to be indigenous to Persia. It rises between two and three feet high, and is chiefly grown either for the seeds, which lie in capsules of ten cells, each cell containing one seed, or for the fibre yielded by the bark, of which linen cloth is made. The use of linen is so ancient that there is no tradition of its introduction. The Scan- dinavian and other northern tribes knew its use, and the mummies of Egypt are covered with it. Immense quantities arc still made at the mouth of the Nile, where it forms almost the sole clothing. It supplies most of Africa and Italy to a great extent. From Egypt its use passed into Greece, and thence into Italy. Be- sides being used as apparel, the rags when worn out and made into a paste, are converted into paper. The seeds of the flax are mucilaginous and emollient, and an infusion constitutes a medicinal drink. They also yield an oil, well known in commerce as Unseed oil, which differs from most expressed oils, as in congealing in water, and not forming a solid soap with fixed alkaline salts. The oil has no remarkable taste, and is used in lamps, and occasionally in cookery, and also forms the base of all the oily varnish made in imitation of China var- nish. It is much used in coarse painting, as where there is not much exposure to weather. Lime water and linseed oil constitutes one of the best applications to recent burns. The cakes which re- main after the oil is expressed are used for fatting cattle and sneep, for which they are very serviceable : they are occa- sionally used as manure. Flax-seed has been used instead of cereal grains in years of scarcity, but it is a heavy and unwholesome food. By attention and careful cultivation good flax may be grown on various soils : the soil best suited is a sound, dry, deep loam, with a clay subsoil. Draining is almost necessary for flax lands, for on too damp grounds good flax will not grow. In Flanders flax is grown in the year of a seven course shift, or the fifth year of a ten course shift. It is hardly advisable to cultivate it more frequently than once in seven years. It is usually grown after a grain crop, as oats coming after old lea, or a green crop ; or it grows well after potatoes coming after lea. The ground should be ploughed two or three times, once in autumn and twice in spring; it should be harrowed twice early in spring, to bring the land into good tilth, and clean it thoroughly from weeds and roots. The Kiga and Dutch seeds produce the finest flax. The seed of this country, though it gives an abun- dant crop, yet produces a coarse branchy stem, and should only be used on deep fla] CYCLOPEDIA OF THE USEFUL ARTS. 175 loamy soils. Two "bushels, or a little over per acre, is the fair quantity for sow- ing. It is better to sow thickly, for the stems grow taller and straighter, with only two seed capsules rt top, and the fibre is superior in fineness and length. Grass-seed and clover should not be sown with it, but carrots may be drilled in between the rows, if flax be so sown. The ground should be wed fre- quently, and pulled carefully. The best time for pulling is before the seed is quite ripe ; if pulled two soon there is Waste in the after preparation ; if too late, the fibre is coarse. When the seeds begin to change from green to pale brown, then the flax should be pulled. The separation of the seed from the stem is called rippling. It should be done on the field, and the ripple is a comb or row of iron teeth screwed into a block of wood; this is screwed on a plank resting on stools. A sheet is spread underneath, and by drawing the flax across the comb, the seeds are sepa- rated, and fall upon the sheet ; these are afterwards riddled and fanned, to sepa- rate chaff, &c, and then dried. Hereto- fore flax has hecn prepared by cold steep- ing in river water, the flax* being fully immersed. Here the soft parts of the plant ferment, and the fibre separates away. The time of steeping varies from eight tc fourteen days. The plant is then removed, and spread on grass to dry. It is now fit tor breaking and skutching. The treatment of flax and hemp should be carried on alike, the fibre of both being capable of being ob- tained in same way. There can be no doubt that chemical processes, and steam with warm water, will completely super- sede the cold water and grass processes. Breaking is sometimes performed by beating the flax with the hand and ham- mer, which bruises the wood and sepa- rates the fibres; a rude machine, called a hand-brake, is sometimes used for this purpose. The machines do this work more effectually. They consist of many deeply fluted rollers of wood or iron, whose teeth work into each other, and thus break the wood across, while the yielding fibre is not injured. By the operation of heckling a three- fold object is gained. 1st. The parting j of the filaments into their finest fibrils ; j 2d. The separation of short fibrils, which | are unfit for spinning ; 3d. The equable i and parallel arrangements of long fila- j ments. The instrument for accomplish- I ing these was a tool called the heckle ; a surface studded more or less thickly with metal points called heckle teeth: over which the flax is drawn in such a way that the above three required operations may be properly accomplished. The operation is simple, but requires expert- ness to work well. The operative seizes a flock of flax by the middle with the right hand, throws it on the points of the coarse heckle, and draws it to him, while he holds the left hand on the other side of the heckle, so as to spread the flax, and to prevent it from sinking too deeply among the teeth. The short fibres, or tow, are removed occasionally. When one half the length of the strake of flax is heckled, it is turned to heckle the other half. 100 lbs. of well cleaned flax, 45 or 50 lbs. of heckled flax, may be ob- tained by hand labor of 50 hours ; the rest being tow, with a small waste of fibre of wood. Machinery has not yet heCn made to effectually supersede hand labor in heckling. To aid the heckle in splitting the filaments, three methods have been had recourse to. 1. Beating, brushing, and boiling with soap water or an alkaline ley. This boiling dissolves that portion of the glutinous cement which had resisted the rotting, and com- pletes the separation of the fibres, and is an excellent plan of improving flax. ^Ma- chines driven by steam "have been employed for the heckling, combing, and scutching of the fibres. Scutching is effected in the heckling machine by means of four arms projecting from a ho- rizontal axle arranged so as to strike the boom in a slanting direction, until the hark and other useless parts of the plant are beaten away. In the spinning of flax, compared with cotton and wool, It possesses several cha- racteristic properties. While cotton and wool are naturally presented as insulated fibres, the former requiring to be merely separated from the seed, and the latter to be purified before delivery to the spin- ner, flax must have its filaments sepa- rated from each other by tedious treat- ment. In reference to the spinning and subsequent, operations, it may be said that good flax should have a bright silver gray, or yellow color, inclining neither tc green or black. It should be long, firm, soft, and glistening, like silk, and contain no broad, tape-like portions from undis- severed filaments. Tow is different in having shorter fibres of very unequal length, and entangled. The manufacture of linen and hemp yarn, and the tow of cither, may be 176 CYCLOPEDIA OF THE USEFUL ARTS. [fli effected by different processes; by the distaff, the hand-wheel, and spinning ma- chinery. In the language or flax mills, the flax ceases to be so called after it has passed through the heckling machine. The great portion is then called line, and the inferior tow. Both of these are after- wards spun into yarn, but the yarn so produced has different degrees of excel- lence. Other machines are used, by which tow is converted into slivers, by carding analogous to cotton and wool processes. When the slivers, whether of line or tow, have been brought to the desired breadth, thickness, and equality, they are carried to the 'roving machines,' where they are transformed to the state of a soft, small, cylindrical cord. There are two combined movements whereby this is effected; the sliver is drawn out or elongated, and it has a slight twist imparted to it as a means of enabling it to cohere and to bear the subsequent ac- tion of the spinning-machines. These spinning-machines we have next to notice. They are on the ' bobbin-and- fly ' principle ; ' mule-spinning ' not hav- ing, we believe, been introduced in the flax manufacture. Flax, unlike cotton, silk, wool, or worsted, is spun wet, as a means of obtaining a finer and smoother yarn ; and within the last few years the use of warm water, instead of cold, has been introduced for this purpose. The same flax, prepared in the same way, can be spun to a much higher number, or much greater degree of fineness, with hot wa- ter than with cold ; and this is doubtless one of the improvements to which the recent progress of the flax manufacture may be attributed. The spindles by which the yarn is spun revolve some thousands of times in a minute, and the wet yarn thus throws off a continuous spray by the centrifugal force thereby ge- nerated ; the girls and young women who attend the machines wear therefore a thick apron to protect themselves from the spray. The water is contained in a kind of oblong trough attached to each machine, and steam is admitted by a small pipe as a means of bringing the water to the required temperature. When the yarn is spun, it is destined either for weaving or for thread. If for weaving, the yarn is reeled into hanks on a hexagonal reel, to be afterwards made up into bundles of twenty hanks each, containing sixty thousand yards ; but if the yarn is to be made into thread, it is carried to other machines, by means of which two yarn-threads are twisted to- gether, and converted into the hard and firm thread used in needlework and lace- making. Here, then, the operations of a flax- mill terminate. If the flax-yarn is wov- en into any kind of linen or flaxen fabric, that is an additional feature. At most flax-mills the operations cease when the yarn and thread are produced. FLEXIBILITY. That property of bodies in virtue of which, when a suffi- cient force is applied to them, they change their form, and are bent. Flexi- bility is opposed to stiffness on the one hand, and to brittleness on the other ; stiff bodies being such as resist bending, and brittle those that cannot be bent without a disruption of their parts. FLINT. Common flints are nearly pure silica. They usually occur in irre- gular nodules in chalk. Their origin is an unsolved geological problem. FLINT GLASS, or CKYSTAL. A species of glass which derives its name from flint, because that substance was formerly employed in its manufacture. It is very extensively used for domestic purposes ; but is chiefly interesting to the philosopher on account of the pro- perty which it possesses of causing a greater dispersion of the rays of light which pass through a prism or lens form- ed of it than any other of the vitreous compounds. This property renders it invaluable in the manufacture of the ob- ject glasses of telescopes and micro- scopes ; for by combining a concave lens of flint glass with one or two convex lenses of crown glass, which possesses a much less dispersive power, a compound lens is formed, in which the prismatic colors arising from a simple refraction are destroyed, and the lens rendered achro- matic. This construction of object glasses was first discovered by a Mr. Hall, a coun- try gentleman in Worcestershire, about 1729 ; but the discovery was forgotten, and no farther notice taken of it for near- ly 30 years, when it was again brought to light by John Dollond, after a long-con- tinued course of experiments under- taken for the purpose of perfecting the telescope. It is, however, very difficult to prepare flint glass fit for the purposes of achromatic telescopes. This difficulty arises not from the want of sufficient dis- persive power in the substance, but from the want of purity or homogeneity ; the slightest impurity or inequality of com- position in the glass giving rise to a streaked or imperfect image By reason of the unequal refraction of the Kiys. The FLO] CYCLOPEDIA OF THE USEFUL ARTS. Ill composition of pure flint glass long re- mained a secret in the family of the Dol- londs, and its manufacture formed a very profitable article of exportation ; for till about the beginning of the present cen- tury, no flint glass of good quality was made on the Continent. Of late years, however, a great change has taken place in this respect, and glass of the best quality has been manufactured, both in France and Germany, in much larger masses than the English artists have yet succeeded in obtaining. This result has been mainly produced by the experimen- tal researches of D' Artigues, Fraunhofer, Cauchoix, Guinand, and Korner. For- merly, an object-glass exceeding five inches in diameter could scarcely be pro- duced. Fraunhofer succeeded in making them of nine, and even twelve inches. The object-glass of the large parallactic telescope belonging to Sir James South, at Campden Hill, was manufactured by Cauchoix ; it exceeds twelve inches, and is throughout of the utmost purity. The exact proportion of the ingredients which enter into these choice specimens is not known, and probably their excellence de- pends in part on some accidental circum- stances in the preparation. Korner pro- duced some of his best specimens by employing the following ingredients : 100 parts of quartz, first treated with mu- riatic acid ; 80 parts of litharge, or red lead ; and 80 parts of the bitartrate of potash. Flint glass for common pur- poses is usually made of 120 parts of fine white sand, 40 parts of well purified pearl ash, 35 parts litharge or minium, 13 parts nitre, and a small quantity of the black oxide of manganese ; the latter ingredient being used to correct the green color occasioned by the presence of oxide of iron in the sand. FLINT-GRINDING is a mechanical process indispensable in the manufacture of earthenware and porcelain. The flint nodules, derived from the chalk forma- tions, are calcined in small kilns (formed similarly to lime-kilns). While hot they are thrown beneath the stampers, a set of vertical beams, whose ends are shod with iron, and which are lifted up by the crank or shaft, and fall on the nodules, the fractured portions falling through a grate. These are thrown into a circular vat, 10 to 15 feet in diameter, the bottom pav- ed with blocks of chert-stone, the horn- stone of Jameson. In a step in the cen- tre is placed the axis of a vertical strong wooden shaft, on the upper end of which is a crown spur-wheel, lor the requisite 8* motion from a steam-engine or water- wheel. At right angles this shaft has an arm, each with a ledge, to bear other blocks of chert. The whole being put in motion, the abrasure of the calcined flints" is promoted by that of the chert among the water, and is continued until the mass is a pulpy fluid, and a pint measure of it weigns not less than 32 oz. The Cor- nish stone is ground in a similar manner, and the pulpy fluid is not less than 33 oz. the pint measure. One ton of good nod- ules should grind into 120 pecks of flint *ti Flints are also reduced to fine powder, by heating them red hot and quenching them in water. FLOAT BOAEDS. The boards fixed to the rim or outer circumference of un- dershot wheels, which receive the im- pulse of the water and communicate the motion to the wheel. FLOATED LATH AND PLASTER. In architecture plastering of three coats, whereof the first is pricking up ; the second, floating or floated work ; and the last of fine stvff. FLOATED WORK. In architecture, plastering made of a perfectly plane sur- face, by means of a tool (which is a long rule with a straight edge) called a float. FLOATING MEADOWS. Meadow lands, the surface of which is flat, ad- joining a river or other source of water, with which they can be flooded or cover- ed at pleasure. ^ The water is turned on chiefly in the winter season, when it is more or less muddy, and leaves a deposit that serves as a kind of manure. It is also useful to vegetation, by preserving a higher temperature in the surface soil than it could maintain through the win- ter, if fully exposed to the action of the atmosphere; because, wherever water is in a fluid state, its mean temperature, and that of the bodies immediately in contact with it, must be above 32°, and at that temperature the grasses common in Bri- tish meadows will grow. There are pro- bably other benefits which grass lands receive from being covered with water during a portion of the winter season, but these have not yet been satisfactorily explained by science. FLOATING SCREEDS. In architec- ture, strips of plaster arranged and nicely adjusted for guiding the floating-rule. See Floated Work. FLOATSTONE. A porous variety of flint, which floats upon water. FLOSS-SILK is the name given to the portions of ravelled silk broken off in the 178 CYCLOPEDIA OF THE USEFUL ARTS. [flu filature )f the cocoons, which is carded like cot *>n or wool, and spun into a soft coarse J arn or thread, for making bands, shawls, 30cks, and other common silk fa- brics. The floss or fleuret, as first ob- tained, must be steeped in water, and then subjected to pressure, in order to extract the gummy matter, which renders it too harsh and short for the spinning- wheel. After being dried, it is made still more pliant by working a little oil into it with the hands. It is now ready to be Bubmitted to the carding engine. It is spun upon the flax wheel. FLOUR OF WHEAT (Adultera- tions of, to detect). The first method is by specific gravity. If potato flour be added, which is frequently done in France, since a vessel which contains one pound of wheat flour will contain one pound and a half of the fecula, the proportion of ibis adulteration may be easily estimated. 2f gypsum or ground bones be mixed with the flour, they will not only increase its density still more, but they will re- main after burning away the meal. The second method is by ascertaining the quantity of gluten which the suspect- ed sample will afford, by the process pre- scribed under the article Bread. The two following chemical criteria may also be employed. 1st. Nitric acid has the property of coloring wheat flour of a fine orange yel- low, whereas it affects the color neither of fecula nor starch. 2d. Pure muriatic acid colors good wheat flour of a deep violet, but dissolves fecula or starch, and forms with it a light, eolorless, viscous fluid, decomposable by alkalis. It may also be observed, that as fecula absorbs less water than flour, this affords a ready means of detection. The adulteration with bean or pea flour may be detected by pouring boiling water upon it, which developes the peculiar smell of these two substances. FLOWERS (Artificial). The art of representing by flowers, leaves, plants, &c, vegetable nature in her ornamental productions, constitutes the business of the artificial florist. The Italians appear to have been the first people in Europe who excelled in the art of making artifi- cial flowers ; but of late years the French have been most ingenious in this branch of industry. Ribbons folded in different colors were originally employed for imi- tating flowers, by being attached to wire stems. This imitation soon gave way to that of feathers, which are more delicate in texture, and more capable of assuming a variety of flower-like figures. But a great difficulty was encountered in dye- ing them with due vivacity. The savages of South America manufacture perfect feather flowers, derived from the bril- liant plumage of their birds, which close- lv resemble the products of vegetation. The blossoms and leaves are admirable, while the colors never fade. The Italians employ frequently the cocoons of the silk- worm for this purpose ; these take a brilliant dye, preserve their color, and possess a transparent velvety appearance, suitable for petals. Of late years, the French have adopted the finest cambric for making petals, and the taffeta of Flo- rence for the leaves. Tissue paper, twisted on wire, consti- tute the stem and branches. The lea* »s are made from muslin, cambric, velvet, and gold and silver lama muslin, which are stamped out with a die, having the form and outline of the leaf. The flowers are made from velvets and muslin stamp- ed out as the leaves, and tinted with transparent colors ; occasionally the fine variations on the surface are painted with pencil and paint. The greater amount of artificial flowers, and the richer kinds, are imported from France. The manufacture of the com- mon kinds in this country is, however, very extensive. M. de Bernardiere employs whalebone in very thin leaves for artificial flowers ; and by bleaching and dyeing them of vari- ous colors, he has succeeded in making his imitations of nature to be very re- markable. The coloring matters used in flower dyeing are the following : For red : carmine dissolved in a solu- tion of salt of tartar, or in water of am- monia. For blue : indigo dissolved in sulphurk acid, diluted and neutralized in part by Spanish whitening or chalk. For bright yellow : a solution of tur- meric in spirit of wine. Cream of tartar brightens all these colors. For violet : archil, and a blue bath. For lilach : archil. Some petals are made of velvet, and are colored merely by the application of the finger dipped in the dye. FLUATES, more properly fluorides, compounds of fluorine and the metals, as fluor spar, for example, which consists of fluorine and calcium. FLUKE is also applied in navigation to the broad part of the anchor, which takes hold of the ground. FLU] CYCLOPEDIA OF THE USEFUL ARTS. 179 FLUOttORIC ACID. A gas obtained by heating to redness a mixture of dry boracic acid and powdered fluor spar. Its specific gravity is 2*36. It is color- less, pungent, and produces a dense white cloud when it escapes into a moist atmosphere; it is resolved by the action of water into boracic and hydrofluoric acids. It acts with great energy upon animal and vegetable substances, and chars them. It is probable a compound ot 20 parts of boron and 108 of fluorine, or of one atom of boron and 6 atoms of fluorine. FLUORIC ACID. See Htdboflttokic Acid. FLUORINE. The hypothetical base of the hydrofluoric acid; it has not yet been obtained in a separate state. FLUOR SPAR. This is a common mineral product, found in great beauty in Derbyshire; hence known in this country under the name of the Derby- shire spar. It is generallv crystallized in cubes, but its primitive form is an octa- hedron. ^ It is of various colors, and often beautifully banded, especially when in nodules, which are much piized for the manufacture of vases, and occasionally used for beads, brooch stones, and other ornamental purposes. It is probably a compound ot fluorine and calcium, hence a. fluoride of calcium. The term Jt nor is derived from the fusibility of this sub- stance, on which account it is sometimes used as a flux to promote the fusion of certain refractory minerals. It is manu- factured at Matlock and Derby into a great varietv of articles. It abounds m N. Jersey. FLUOSILICIC ACID. A gas obtain- ed by applying a gentle heat to a mix- ture of one part of powdered fluor spar, one of silica, and two of sulphuric acid in a retort. It is colorless, pungent, fumes when it escapes into a humid air, and is rapidly absorbed by water. Its specific gravity is about 3-6 ; 100 cubic niches weighing nearly 112 grains. It is decomposed by water, and forms silica and hydrofluric acid. It consists of 8 Earts by weight of silicium, and 18 of uoride, its equivalent (upon the hydro- gen scale) being 26. FLUIDITY is that state of a substance in which its constituent particles are so slightly cohesive that they yield to the smallest impressions. The term is usual- ly confined to express the condition of the nonelastic fluids ; and hence it de- notes one of the three states in which matter exists ; namely, the solid, the fluid or liquid, and the gaseous. The state of fluidity is best defined as that in which bodies tend to form drops, as this disposition does not belong either to bodies in a gaseous form, or to solid bodies reduced to fine powder. The for- mation of drops arises from this, that the molecules of fluid bodies adhere to each other with a certain force, at the same time that they glide over one another without any sensible resistance. It is in- correct to say that the molecules of bodies in a state of fluidity offer no resistance to separation ; for, on bringing a flat disc of glass or metal into contact with the sur- face of a liquid, a very sensible degree of force is required to separate them. That adhesion exists among the molecules of fluid bodies is also proved by various other phenomena. Water or mercury on a flat plate of metal collects in glo- bules, and when slowly poured into a wine glass will remain heaped up, as it were, above the level of the edge. Various hypotheses have been framed by philosophers to explain the different states in which matter is found to exist. Confining ourselves to the most general views, we may regard all bodies as "assem- blages of particles constantly maintained in equilibrium between two forces, an attractive force which tends to unite the particles, and a repulsive force which tends to increase the distance between them. The solid state results from the preponderance of the attractive force. Conceive the repulsive force to receive an augmentation until it becomes equal to, or forms an equilibrium with, the at- tractive force. When the two forces are thus balanced, the particles exert on each other neither attraction nor repulsion, and the body is in the fluid state. Last- ly, if the repulsive energy be still increas- ed, the particles will be separated from each other to such distances that their mutual attractions will cease altogether to be sensible, and then the body passes Into the gaseous state. Hence we may pronounce that there is no natural state of body ; and that fluidity, solidity, the state of vapor, and the aeriform state are only accidental, and determined by the temperature of the medium in which the body is placed. FLUX. A substance which is mixed with metallic ores, or other bodies, to promote their fusion, just as an alkali is mixed with silica to form a glass. From the property which the borates possess of fusing metalic oxides, they are used by braziers, tinmen, &c. It Is this salt which is chiefly used in the fusion of 180 CYCLOPEDIA OF THE USEFUL ARTS. [foo minerals before the blow-pipe. White flux, is made by mixing 2 parts of nitre and 1 of cream tartar, and deflagrating them in a crucible ; it is carbonate of potash. Black flux is obtained when equal parts of the same ingredients are used : beside the carbonate of potash, it contains charcoal: this last aids in the reduction of metallic oxides. Limestone, fluor spar, borax, and several earths and metallic oxides are used as fluxes in metallurgy. FLY. In mechanics, an appendage given to machines for the purpose of re- gulating and equalizing the motion, as in the windlass, jack, pile-engine, &c. ; and sometimes for collecting force in order to produce a very great instantaneous im- pression, as in the coining press. Gene- rally it is formed of a heavy disc or hoop at right angles to the axis ; sometimes of heavy knobs at the extremities of a bar having the same position. The fly is of great use in all cases where the power, or the resistance, acts unequally in the dif- ferent parts of a revolution. FLYING BUTTRESS. In Gothic ar- chitecture, a buttress in the form of an arch, springing from a solid mass of ma- sonry, and abutting against the spring- ing of another arch which rises from the upper points of abutment of the first. It is seen in most ancient cathedrals, and its office is to act as a counterpoise against the vaulting of the nave. If flying but- tresses were built solid from the ground, it is obvious that they would interfere with the vista along the aisles of the church ; hence the project of continuing a resistance by means of arches. Their stability depends on the resistance afford- ed by the weight of the vertical buttress from whence they sprinsr. FLY POWDEE. An imperfect oxide of arsenic, formed by the exposure of na- tive arsenic to the air ; when mixed with sugar and water it is used to kill flies. FOIL. A term generally applied to a varnished metal. Common foil is thus made : a copper plate covered with a thin layer of silver is rolled out into sheets under the flatting mill. The sil- ver surface is then highly polished, or covered with a colorless varnish. The colored foils are similarly prepared with oolored varnishes. FOOD. All substances susceptible of digestion and assimilation may come under the denomination of food ; but the proximate principles of organic bodies on which their mitritive powers depend are comparatively few. Hence, although, the j articles employed in different countries | for the support of animal life are almost 1 infinitely various, their sustaining powers may be referred to certain substances capable of being separated and identified by chemical analysis and tests. Among the proximate elements of vegetable food gluten and its modifications, starch, gum, sugar, oil, wax, and lignin or woody fibre, are by far the most important ; and among those of animal food albumen, gelatin, and their modifications, together j with fats and oils, which are common to both kingdoms of nature. To illustrate the actual simplicity of our food as compared with its apparent multi- fariousness and complexity, it may suffice to state, that wheat and almost "all the esculent grains consist principally of starch and gluten; that the same ingre- dients are found in many fruits and roots ; that sugar, gum or a relation of gum which is called vegetable jelly, together with minute traces of aromatic principles which give flavor, and more or less abundance of water, and of vegetable acids, are the chief component parts of apples, pears, peaches, currants, gooseberries, and all analogous tribes of fruits ; a very few also contain oil. Then, as regards animal food, the muscular fibres of various ani- mals closely resemble each other in com- position and nutritive power ; in some cases texture merely, and in others mi- nute additions of foreign matters, confer upon them their relative digestibilities, and their different aspects and flavors; albumen or fibrine, and gelatin, small proportions of saline bodies, and a large quantity of water are found in them all. It often happens that the truly nutri- tious part of food is so combined with or protected by indigestible matters, as to escape the solvent powers of the stomach, unless previously prepared and modified by various chemical and mechanical agents. Indurated woody fibre, tor in- stance, or lignin, as chemists call it, will often resist the joint action of the stomach and bowels, and pass through the ali- mentary canal with scarcely any altera- tion. The husks of many seeds and fruits are composed almost exclusively of this material. This is the case with the kernels of the apple, pear, &c; the seeds of the currant, gooseberry, melon, and so on ; the skin or husk of peas, beans, &c, and of wheat, barley, and oats ; so that unless the woody part is either broken down by the teeth or previously removed, the food which it envelops is protected from the solvent action of the secretions FOo] CYCLOPEDIA OF THE USEFUL ARTS. 181 of the stomach. This is in some respects a wise and curious provision in nature ; for birds in this way become the carriers of seeds, which pass through them not only undigested, but even retaining their vegetative powers ; and in this way un- inhabited and sterile portions of the globe may gradually become clothed with verd- ure, and shrubs, and trees. Bones are highly nutritive ; but unless broken into very small fragments by the masticatory powers of the animals which eat them, they too would elude digestion. In refer- ence, however, to the food of man, much of its digestibility and nutritious power is referable to the important chemical operations preparatory to its use which are carried on in the kitchen ; in other words, cookery is essentially a chemical art ; and substances totally unfit, in their raw state, for reception into the stomach, are ren- dered palatable, digestible, and nutritious by the skill of the cook. And here salt, and a variety of condiments, as they are called, and which are aromatic and stimu- lant substances, chiefly of vegetable ori- gin, play an important part ; nor must the mere effect of heat be overlooked, for it is most important. Meat, by boiling and roasting, is not only softened in its fibre, but new substances are generated in it. Among these a peculiar extractive matter, and osmazone, or the principle which gives an agreeable flavor and odor to dressed meat, are especially recognized. Nor are the changes which vegetables suffer under the influence of heat less obvious. There is another important point in the history of our food, namely, its ultimate composition. We have spoken of starch, sugar, gum, albumen, and other substan- ces as the proximate principles upon which we live ; but what is the ultimate consti- tution of these secondary products, what are their true elements? It is curious that four elements only are principally con- cerned in the production of our food. These are, carbon, hydrogen, oxygen, and nitrogen. Among vegetable sub- stances gluten (including vegetable albu- men) is the only one which abounds in nitrogen; gum, sugar, starch, and the rest are constituted of carbon, hydrogen, and oxygen only ; and what is very re- markable is, that in all these important principles, and also in lignin, the oxygen and hydrogen bear to each other the same relative proportions as in water, so that they may be figuratively, perhaps truly, described as compounds of charcoal and water. Now there are two very curi- ous points in reference to that part of the chemical history of our food which has been adverted to; the one is, that no animal can subsist for any length of time upon food which is destitute of nitrogen ; and the other, that a certain mixture of different kinds of food is absolutely es- sential. An animal fed exclusi/vely on starch, or sugar, or albumen, or jelly, soon begins to suffer in health ; peculiar diseases" make their appearance, and his existence is painful and brief; but mix these together and occasionally modify their proportions, and he then thrives and fattens. Magendie's experiments on this subject, together with those of Tiedemann and Gmelin, well illustrate this fact. Thus, geese fed upon gum died on the 16th day, those fed upon starch on the 24th, and those fed on the boiled white of egg on the 46th; in all these cases they dwin- dled away and died as if from starva- tion. Habit, as is well known, will do much in accustoming the stomach to particular descriptions of food ; many persons live exclusively, or almost so, on vegetable, others on animal matters, and particular kinds of diet are forced on the inhabi- tants of many regions of the globe; but, as far as we are concerned, a due mixture of vegetable and animal matter is not only most palatable, but most conducive to health. The variety in our teeth and the structure of the alimentary canal, point out a mixed food as the most ap- propriate. The shortness of the intesti- nal canal shows that man was not intend- ed to live solely on vegetable diet. Nothing is fit for food which has not already undergone organization ; and wa- ter, though an essential part of the food of all annuals, is obviously not in itself nutritious, though it performs the ex- tremely important function of dissolving nutritive matter, so as to render it con- veyable by the lacteals and other absorb- ents into the blood. No compound then of nitrogen, hydrogen, carbon, and oxy- gen, which can be formed artificially, can constitute food. Air, water, and char- coal, though involving the elements of our nutriment, are themselves unfit for our support ; and it is only by passing through the hidden processes which are carried on in the vessels of living things, that they are so recombined and modified as to be rendered capable of supporting animal life. It is the vegetable world which commences this wonderful operation. Plants absorb their nutriment from the air and from the soil ; they assimilate in- 182 CYCLOPEDIA OF THE USEFUL ARTS. [FOO inorganic as well as organic matter ; they become the food of the graminivorous tribes, and from these man derives the great bulk of his animal food. Animals cannot create food ; they cannot form any one of these proximate principles we have mentioned ; this is the office of the plant. The plant is a creating being, the animal only assimilates what the plant had formed. In speaking of the composition of food, that ot milk, the most important of all food, must not be forgotten ; in it nature has wonderfully provided a mixture which, though secreted by an animal, partakes also of the nature of vegetable rood, and it presents a perfect analogy to that combination of vegetable and animal matter which has been mentioned as most congenial to the palate and stomach. The albumen or curd of milk is a highly elaborated animal principle, abounding in nitrogen, yet, from its attenuated and soluble state, easy of digestion. A second principle of milk is what is termed sugar of muk: in composition and properties it resembles a vegetable product, and is intermediate between gum and sugar. The third component of milk is butter, partaking of the nature of vegetable oil and animal fat; there are certain saline and acid substances in small proportion: and all these matters are either dissolved or suspended in a large relative propor- tion ot water. I. Table showing the average quantity of nutritive matter in 1000 parts of seve- ral varieties of ajvimal and vegetable food. Blood 215 Veal 250 Pork 240 Chicken 270 Haddock 180 Bones 510 White of egg 140 Bice 880 Bye 792 Potatoes 260 Turnips 42 Beetroot 148 Pears 160 Gooseberries 190 Plums 290 Peaches 200 Melon 80 Tamarind 340 Morels 896 The above table represents the relative proportions of solid digestible matter contained in 1000 parts of the different articles of food which are enumerated. When blood, for instance, is evaporated to dryness, at a temperature not exceed- Beef 260 Mutton 290 Brain 200 Cod 210 Sole 210 Milk 72 Wheat 950 Barley 920 Oats 742 Carrots 98 Cabbage 73 Strawberries 100 Apples 170 Cherries 250 Apricots 260 Grapes 270 Cucumber 25 Almonds 650 ing 212°, the residue amounts to 215 parts in 1000, and may be regarded as almost entirely composed of digestible matters ; it consists of albumen and coloring mat- ter, with small proportions of saline sub- stances. The different kinds of meat were dried in the same way. The loss of weight during their desiccation is al- most wholly referable to water ; and the dry residue composed of albumen or fibrine, with some gelatine, and perhaps traces of fat and of saline matters, repre- sents the true nutritive value. Upon an average, therefore, the nutritive matter in a pound of meat is not more than four ounces. This, however, only applies to raw meat ; for when dressed a consider- able portion of its constituent water is often dissipated. The nutritive matter of wheat is chiefly starch and gluten, and in this species of grain the gluten is in much greater relative proportion to the starch than in barley, oats, or rye. Iii rice there is little else than starch. There can be little doubt that the great value of wheat as an article of food depends upon this excess of gluten, which is a nitro- genous substance, and has not inaptly been termed the vegeto-animal princi- ple. In the esculent roots, such as car- rots, &c.j but especially turnips, sugar is the leading nutritive matter ; and the common fruits contain sugar, gum, albu- minous matter, and acids, together with a highly attenuated form of woody fibre, or lignm, which, in that state, is probably digestible. The following table shows the ultimate composition of those proximate princi- ples which have been above adverted to as constituting the nutritive part of food. II. Table showing the ultimate elementary composition in 1000 parts of the following proximate principles in animal and vegetable food. £ i S j 1 © s o n Albumen 516 76 258 150 Gelatin 483 80 276 161 Fat 780 609 122 73 98 116 Curd of milk... 208 Sugar of milk.. 454 61 485 Gluten 557 78 220 145 Starch 438 62 500 Gum 419 444 68 62 513 494 Sugar Lignin 500 56 444 CYCLOPEDIA OF THE USEFUL ARTS. 183 Tables like the above have been used to point out the nutritive values of food ; those which contain the greatest amount of nitrogen being esteemed the most nutri- tious ; this view must not, however, be too hastily adopted. If the nitrogen exist in the form of albumen, gluten, fibrin, or casein, any of the forms of what Mulder has termed Protein, the composition of which is, carbon 54-37, hydrogen 7*12, nitrogen 15*93, and oxygen 22-58, in 100 parts, it is undoubtedly true. But many substances contain nitrogen in other forms, as the mushroom tribe ; in these it exists as ammonia, which does not in any way contribute to the nutrition of an animal. Such substances therefore have not a nutritive value at all equal to what the percentage of nitrogen in them would indicate. The uses of these proximate principles to the animal frame are different. The substances containing nitrogen go to form the solid parts of the blood and muscle of the animal ; the starch, gum, and sugar assist in respiration and in producing animal heat; the oils and fat serve the same end, and are occasionally stored up as fat in the animal frame to meet the wants of the system when it may require it. FORCE, in mechanics, denotes that combination of matter and motion which produces a change in the state or position of a body. According to this definition, the muscular power of animals, as like- wise pressure, impact, gravity, &c, are considered as effects of motion in other bodies ; it being evident, from daily ex- perience, that bodies exposed to any free action have force imparted to them, or are themselves thereby imbued with power. All forces, however various, are measured by the effects which they pro- duce in like circumstances, whether the effect be creating, accelerating, retarding, or deflecting motions. When we say that a force is represent- ed by a right line, A B, it is to be under- stood that it would cause a material body, situated at A, to run over the line A B, which is called the direction of the force, so as to afrive at B at the end of a given time, while another force would cause the same body to have moved a greater or less distance from A in the same time. The force of a body in motion is a power residing in that body, so long as it continues its motion : by means of which, it is able to move other bodies lying in its way, or to lessen, destroy, or overcome the force of any other moving body, which meets it in an opposite direction ; or, to surmount the largest dead pressure or resistance. Force is quantity by velocity, before or after impact ; and if quantity is increased, velocity is diminished. Nature and art is a display of the transfer and reception of force, ad infinitum, and what is lost by one body, is gained by other bodies, by these transferred again, and Fometimes collected or concentrated, and at othei times scattered and diffused. To trace the sources and distribution, is to analyze nature ; but it is the most general of all laws, that wherever there is force, there is some matter, in some fit motion ; and wherever there is matter in motion, there is resulting force. Of course, there are no innate, or mir- aculous forces — no attraction — no repul- sion — no elastic force — no vital force — all are derived from previous motions in other bodies, and the phenomena depend on the quantities of the agents and pa- tients, on the direction of their velocity, and on various reactions. Composition of forces takes place when two or more forces, differently directed, act upon the same body at the same time. As the body then cannot obey them all, it will move in a direction somewhere between their line. This is called the composition and resolution of forces or of motion. But, if the bodv be impelled by equal force, acting at right angles to each other, it will move in the diagonal of a square, and instances in nature, of mo- tion produced by several powers acting at the same time, are innumerable. All machines are impelled either by the exertion of animal force, or by the appli- cation of other powers of nature. The latter comprise the elements of water, air, and fire. The former is more com- mon, yet so variable as hardly to admit of calculation. It is derived from the muscular lever of the animal acting against the ground, and the power of the muscles to act is derived from the gas fixed by respiration. It depends not only on the vigor of the individual, but on the different strength of the particular muscles employed. Every animal exer- tion is attended by fatigue of the muscles ; it soon relaxes, and would speedily pro- duce exhaustion. The most profitable mode of applying the labor of animals is to vary their "muscular action, and revive its tone by short and frequent intervals of repose.* The ordinary method of com- puting the effects of human labor is, from the weight which it is capable of elevat- 184 CYCLOPEDIA OF THE USEFUL ARTS. [for ing to a certain height, in a given time, the product of these three numbers ex- pressing the absolute quantity of perfor- mance. This was reckoned by Bernoulli and Desaguliers, at 2,000,000 lbs. avoir- dupois, which a man could raise one foot in a day. But, our civil engineers have gone much further, and are accustomed, m their calculations, to assume that a laborer will lift 10 lbs. to a height of 10 feet every second, and is able to continue such exertion for 10 hours each day, thus accumulating the performance of 3,600,- 000 one foot. Coulomb has furnished the most accu- rate and varied observations on the mea- sure of human labor. A man will climb a stair, of from 70 to 100 feet high, at the rate of 45 feet in a minute. Beckoning his weight at 155 lbs., the animal exer- tion for one minute is 6975 lbs., and would amount to 4,185,000, if continued for 10 hours. A person may clamber up a rock 500 ft. high, by a ladder-stair, in 20 minutes, and, consequently, at the rate of 25 feet each minute ; his efforts are thus already impaired, and the perfor- mance reaches only 3875 in a minute. But, under the incumbrance of a load, the quantity of action is still more re- markably diminished. A porter, weigh- ing 140 lbs., was found willing to climb a stair, 40 ft. high, 266 times in a day ; but he could carry up only 66 loads of firewood, each of them 163 lbs. weight. In the former case, his daily performance was very nearly 1,500,000; while, in the latter, it amounted only to 808,000. The quantity of permanent effect was hence only about 700,000, or scarcely half the labor exerted in mere climbing. In the driving of piles, a load of 42 lbs., called the ram, is drawn up H ft. high 20 times in a minute ; but the work has been considered so fatiguing, as to endure only three hours a day. This gives about 530,000 for the daily performance. Near- ly the same result is obtained by comput- ing the quantity of water, which, by means of a double bucket, a man drew up from a well. He lifted 36 lbs. 120 times in a day, from a depth of 120 ft., the total effect being 518,400. A skilful laborer, working in a field with a large hoe, creates an effect equal to 728,000. When the agency of a winch is employed in turning a machine, the performance is still greater, amounting to 845,000. In all these instances, a certain weight is heaved up, but a much smaller effort is sufficient to transport a load horizontally. A man could, in the space of a day, I scarcely reach an altitude of two miles. ; by climbing up a stair, though he will ! easily walk over 30 miles, on a smooth I and level road. But he would, in the j same time, carry 130 lbs. only to the 1 fourth part of that distance, or 71 miles. Assuming his own weight to be 140 lbs., the quantity of horizontal action would amount to 42,768,000, or 28 times the vertical performance ; but the share of it, in conveying the load, is 20,961,780, or about 30 times what was spent in its elevation. The greatest advantage is ob- tained by reducing the burthen to 102 lbs., the length of journey being augmented in a higher ratio. According to some experiments of th« late Mr. Buchanan, the exertions of a man in working a pump, in turning a winch, in ringing a bell, and in rowing a boat, are as the numbers 100, 167, 227, and 248. A man's force, in fact, is such, that he can raise 10 lbs. 10 ft. in a second, for 10 hours in a day, or 100 lbs., or 10 imperial gallons, 1 ft. per second, or in 10 hours, (36,000 seconds) 3,600,000 lbs. one ft., or 360,000 gallons one ft. The labor of a harse in a day is com- monly reckoned equal to that of five men; but then he works only eight hours, while a man easily continues nis exertions for ten hours.* Horses, like- wise, display much greater force in carry- ing than in pulling ; and yet an active walker will beat them on along journey. Their power of drawing seldom exceeds 144 lbs., but they are capable of carrying more than six times as much weight. With regard to the ordinary power of draught, the formula (12 — w) 2 , where i denotes the velocity in miles an hour, will perhaps be found sufficiently neai the truth. Thus, a horse beginning hit pull with the force of 144 lbs., would drav» 100 lbs. at a walk of two miles an hoar, but only 64 lbs. when advancing at double that rate, and not more than 38 lbs. if he quickened his pace to six milea an hour. His greatest performanca would hence be made with the velocity of 4 miles an hour. The accumulated effort in a minute will then amount to 22,528. The measure generally adopted for computing the power of steam-en- fines is much higher, the labor of a horse eing reckoned sufficient to raise, every minute, to the olevation of one ft. ? the weight of 32,000 lbs. Wheel-carnages enable horses, on level roads, to draw, at an average, loads about 15 times greater than the power exerted. FOu] CYCLOPEDIA OF THE USEFUL ARTS. 185 FORCER. In Mechanics, a solid pis- ton applied to pumps for the purpose of producing a constant stream, or of rais- ing water to a greater height than it can be raised by the pressure of the atmo- sphere. See Pump. FORGE. The workshop in which iron is hammered and shaped by the aid of heat. The term is generally applied to the places in which these operations are carried on upon the comparatively small scale ; the great workshops in which iron is made malleable for general purposes being called a shingling mill. A common forge consists of the hearth or fireplace, which is merely a cavity in masonry or brickwork well lined with fine clay or brick, upon which the ignited fuel is placed, and upon the back or side of which a powerful blast of air is driven in through the nozzle of a double-blasted bellows, which, in a common forge, is generally worked by a hand lever. Forges are sometimes constructed so as to be portable, when the bellows is most con- veniently placed under the hearth : these are used in ships, and for various jobs on railways, &c. FORMIC ACID. A sour liquor which ants eject when irritated, and which was formerly obtained by bruising the in- sects and distilling them, mixed with water ; a peculiar volatile acid passed over. It has been ascertained by Dobe- reiner, that an analogous acid may be ar- tificially obtained by distilling, from a capacious retort, a mixture of 2 parts of tartaric acid, 3 of peroxide of manganese, and 3 of sulphuric acid diluted with 5 of water. The tartaric acid acquires oxy- gen from the oxide of manganese, and is resolved into water, carbonic acid, and formic acid. From the analysis by Ber- zelius, of formiate of lead, it appears that formic acid is a compound of 2 atoms of carbon, 3 of oxygen, and 1 of hydrogen ; or of 2 atoms of carbonic oxide, and 1 of water. This acid decomposes the salts of a few Yuetals. Silver is readily thrown out in the state of bright metal on glass sur- faces, by means of formic acid. FOUNDING, of Ikon. The opera- tions of an iron foundry consist in re- melting the pig-iron of the blast furnaces, and giving it an endless variety of forms, by casting it in moulds of different kinds, prepared in appropriate manners. Coke is the only kind ot fuel employed to effect the fusion of the cast-iron. The essential parts of a well-mounted iron foundry are, Magazines for pig-irons of different qualities, which are to be mixed in cer- tain proportions, for producing castings of peculiar qualities; as also for coal, coke, sands, clay, powdered charcoal, and cow-hair for giving tenacity to the loam mouldings. One or more coke ovens. A workshop for preparing the pattern and materials of the moulds. It should contain small edge millstones for grind- ing and mixing the loam, and another mill for grinding coal and charcoal. A vast area, called properly the foun- dry, in which the moulds are made and filled with the melted metal. These moulds are in general very heavy, con- sisting . f two parts at least, which mus* - - be separated, turned upside down seve- ral times, and replaced very exactly upon one another. The casting is generally effected by means of large ladles or pots, in which the melted iron is transported from the cupola, where it is fused. Hence, the foundry ought to be provided with cranes, having jibs movable in every direction. A stove in which such moulds may be readily introduced as require to be en- tirely deprived of humidity, and where a strong heat may be uniformly main- tained. Both blast and air furnaces, capable of melting speedily the quantity of cast- iron to be employed each day. A blowing machine to urge the fusion in the furnaces. The mode of casting metal pipes will serve to illustrate many different varie- ties of iron-founding. There is formed, in the first place, a core or central pat- tern of cast-iron, with alternate grooves and ridges extending from end to end. Round this is wrapped a covering of hay or straw rope, and this rope is plastered with a layer of wet loam or clay, worked until the exterior surface becomes cylin- drical, and corresponding in diameter with the internal dimensions of the pipe to be made. From this mode of forma- tion it follows that there are hollow chan- nels or gutters beneath the straw-rope, and these serve for the exit of heated air in the subsequent processes. The core, when formed, is sprinkled with powder- ed charcoal, and placed in a heated oven to harden. Meanwhile, the mould for giving the external form of the pipe is being prepared. A model, or pattern, is made, corresponding exactly with the exterior of the pipe to be made, and with this pattern a mould, or cavity, is form 186 CYCLOPEDIA OF THE USEFUL ARTS. [fou ed in a smooth oed of sand, in two halves. Then, when the core is placed and sup- ported concentrically in this mould, there is a cylindrical space between the two, equal to the thickness of the intended pipe. Holes for the admission of the melted metal, and others for the exit of the heated air, are provided, and the metal is poured in from the ladles or vessels before alluded to. It will be plain, on a little consideration, that the exterior of the core must give the in- terior form to the pipe, while the interior of the mould must give the exterior form to the pipe. In casting pipes of large diameter, the core and mould are built up vertically in a pit as deep as the pipes are long ; and matters are so arranged that the liquid metal is poured in at one end. In cast- ing large cylinders for steam-engines and other purposes, the formation of the mould and core is a matter of much im- portance ; each being formed of brick- work built up cylindrically, and of such dimensions that the larger may inclose the former, leaving a space between them equal to the intended thickness of the metal cylinder. The outer surface of the inner cylinder, or core, and the inner surface of the outer cylinder, or mould, are wrought very smooth and regular; and both cylinders being adjusted in a pit, melted metal is poured into the va- cuity between them. Thus is the cylin- der formed. The process of boring, to which such cylinders, as well as cannon and other articles requiring a smooth in- terior, are afterwards subjected, is not, as the name seems to imply, the boring or making a hole, but a planing, scrap- ing, or cutting away of the inner surface, till it becomes regular and smooth from end to end. In all large specimens of casting, such as bed-plates for marine engines, arches for bridges, beams for roofs, plates for large cisterns aud tanks, turn-tables for railways, framework for engines and ma- chines of various kinds, and such like, the mould is made in sand on the floor of the casting-house, from moulds or patterns previously constructed in ac- cordance with the working drawings, and the liquid metal is poured into these moulds at once from the blast-furnace, or from the ponderous vessels, or from a cupola-furnace, according to the cir- cumstances of the case. FOUNT, or FONT, among printers, &c. ; a set of types, sorted for use, that incudes running letters, large and small capitals, single letters, double letters, points, commas, lines, numerals, &c. ; as a fount of English, of Pica, of Bourgeois, &c. A fount of 100,000 characters, which is a common fount, would contain 5000 types of a, 3000 of c, 11,000 of «, 6000 of i, 3000 of m, and about 30 or 40 of k, x, y, and z. But this is only to be under- stood of the lower-case types ; those of the upper-case having other proportions. A small fount may consist of fifty or one hundred pounds weight, comprising the usual proportion of the various let- ters of the alphabet ; and a large fount, of thirty or forty thousand pounds weight, or more. FOUNTAIN. By this term is desig- nated any natural or artificial apparatus by means of which water springs up. In natural fountains the ascensional effort is produced by the hydrostatic pressure of the water itself; in artificial fountains it is produced either by the same pres- sure, or by that of compressed air, or sometimes "by machinery. The theory of natural fountains is ex- tremely simple : it depends on the well- known property of fluids, which when inclosed in tubes or vessels communica- ting with each other, the fluid rises to the same level in all of the tubes : the pressure on the sides of the tube at any point being equal to the height of the vertical column above the tube. Now it is precisely on this principle that all natural fountains are explained. The rain which falls from the atmosphere is absorbed in three different ways. One part of it collects in rills on the surface of the ground ; these unite in streams or rivulets, which flowing into one another form rivers, and thus it is conveyed to the ocean. A second part is taken up in giving humidity to the soil, from which it is returned to the atmosphere by eva- poration. A third portion descends into the earth, through soils of a spongy or porous nature, or through crevices and in- terstices in the strata, until it meets, fre- quently at a very considerable depth, with strata through which it cannot penetrate, and is then" collected in subterraneous reservoirs. When confined in this man- ner it is subject to the pressure of the water which fills the channels through which it has descended ; and when this pressure is sufficient to overcome the re- sistance of the superincumbent mass of earth, the water breaks the artificial stra- ta, and gushes forth in a spring. But if the strength of the superincumbent ma- terials exceed the hydrostatic pressure, pre] CYCLOPEDIA OF THE USEFUL ARTS. 187 the water will remain stored up as it were in the subterraneous reservoir. Now if the ground above such a reser- voir, or any channel communicating with it, be perforated, the water, having free access to the opening, will rise in it till it attains the level of the highest part of the channels from which it is supplied. If this level is above the surface of the ground, the water will have a tendency to rise ; and when the ascensional force is considerable, it may by proper means be formed into a fountain. That subter- raneous reservoirs formed in this man- ner exist in great abundance, and at great depths under the surface, we have suffi- cient evidence in the facility with which water may be obtained in almost all countries from Artesian Wells. FOUNTAIN OF HERO. An ingeni- ous hydraulic machine, ascribed to Hero of Alexandria, who lived 150 years B. C. Its principle depends on the transmis- sion of the pressure sustained by a body of water in one vessel to that in another by means of the elasticity of air. The essential parts of the fountain consist of two close vessels, A and B. The one placed somewhat above the other, and connected by a frame ; and having a jet- pipe in the centre, its lower end reaching near the bottom of A. A pipe passes down from A to near the bottom of B : another pipe is connected with B nnd passes up to near the top of A. This pipe conducts air from B to A. When water is poured into A it runs down the pipe into B ; this drives the air up the pipe into the upper part of A, which presses on the surface of the water there and compels it to pass up the jet-pipe and issue out as a fountain, the height of which is equal to the difference of the levels of the water in C and B : the wa- ter will, according to the theory, spout to a height above its level in A equal to that distance. The second figure represents the foun- tain of Hero in another form. An appa- ratus of this kind is used to drain the Hungarian mines at Schemnitz. Artificial fountains are also produced by means of the elasticity of heated air, or air condensed by some other means. Two different forms are used for this purpose. The first consists of two close vessels of tin, placed one above the other; the lower one Deing of considerable size : the upper, furnished with a tube or jet, which reaches to near the bottom of the vessel. On applying the heat of a lamp to the lower vessel, the air within it expands and forcing its way through the open tube is com- pressed at the top of the vessel, and thus by its pressure forces the water in that vessel through K, L, forming a small jet at K. This apparatus being generally constructed in the form of a temple, produces a very pleasing effect. - FRANKFORT BLACK. Calcined vine ashes, and refuse lees of wine manufac- tories. FRANKLINITE is a compound of ox- ide of iron, with the oxides of mangan- ese and zinc, which is found at Frank- lin, N. J. It crystallizes in octohedrons, which occasionally by replacements be- come nearly globular. It commonly oc- curs in granular masses : it is black, brit- tle, and has much of the appearance of magnetic iron, but somewhat less me- tallic, and the streak is reddish brown. It consists of iron 66, oxide of zinc 17, and oxide of manganese 16. Its sp. gr. is 4-87. It is found accompanying the red oxide of zinc, and is often imbedded in limestone, and mixed with garnets and spinelle. FREEZING. The congelation of a li- quid. When cold is applied to any sub- stance, its particles approximate, so that they no longer have the same freedom of motion among themselves : a gas or vapor is condensed into a liquid. Dis- tillation is an ordinary example of this- If the cold be continued still further, or, what is the same thing, if heat contiuue to be abstracted, the liquid gives out heat, and ultimately becomes a solid ; the freezing of water and other liquids are ex- amples. Various degrees of cold are re- quired to bring different liquids into the solid state, and tables of freezing mix- tures have been made to accomplish this end artificially. These mixtures are com- binations of various salts, which react upon each other, and tend continually to pass from the solid to the liquid state. They hence absorb heat from every thing producing this intense cold. Dr. Ure gives the following as the best proportions for producing artificial cold. 188 CYCLOPEDIA OF THE USEFUL ARTS. [fri MIXTURES IN PARTS Thermometer sinks from. Degree of cold produced. Phosphate of soda 6 ) Nitrate of ammonia . *T 03 to —84P 34 Diluted nitric acid 4) Phosphate of soda 8 , Nitrate of ammonia . 2 h _340to— ■ 50O 16 Diluted mixed acids . 4\ Snow .... Diluted nitric acid 5 00 to -^6° 46 Snow .... 8 ) Diluted sulphuric acid 4 — 10O to — 56° 46 Diluted nitric acid 8f Snow .... Diluted sulphuric acid il _20o to — 60° •10 Snow .... Muriate of lime . S -f 2(P to -480 63 Snow .... Muriate of lime . 3 t 4 J +10O to —Mo 64 Snow .... Muriate of lime . 2 l . 3f —150 to — 6SO 63 Snow .... Cryst muriate of lime : H 00 to — 66o 66 Snow .... Cryst muriate of lime : i -400 to — 730 33 Snow .... Diluted sulphuric acid ■J\ —680 to — 91o 23 FRENCH CHALK is a variety of talc, in which the folia arc so small that it has a somewhat granular texture and a glim- mering: lustre. FRENCH POLISH. This is an alco- holic solution of shellac, some of the softer resinous gums are usually added, but too much of them renders the polish less durable. Highly rectified spirit, not less than 60 over proof, should be used. Rectified wood naptha is sometimes sub- stituted, to which the unpleasant smell is the only objection. 1st. Orange shel- lac 22 oz.', rectified spirits 4 pints, dis- solve. 2d. Shellac 3 oz., gum sandarao * oz., rectified spirit 1 pint. 3d. Shellac 4 oz., gum thus, i oz., rectified spirit 1 pint, dissolve and add almond or poppy oil, 2 oz. 4th. Shellac 5 oz., oxalic acid i oz., rectified spirit 1 pint, dissolve and add linseed oil 4 oz. 5th. Shellac 10 oz., seed-lac 6 oz., gum thus. 3 oz., sandarac 6 oz., copal varnish 6 oz., rectified nap- tha, or dissolve 8 oz. each of seed-lac, gum thus, and sandarac, separately in a pint of naptha ; and 1 lb. ot shellac in 8 pints of naptha. Then mix 6 oz. of co- pal varnish, 12 oz. of solution of seed-lac, 6 oz. of solution of frankincense, and 12 of solution sandarac, and Bf lbs. solution of shellac. Let the copal varnishes be put into a tincture of shellac, and well shaken, and the other ingredients be added. A correspondent iaiprms us that this polish cannot be excelled. 6th. Copal { oz., gum arabic $ oz., shellac 1 oz., pulverize, mix, and sift the powders, and dissolve in a pint of spirit. French polish is sometimes colored with dragon's blood, turmeric root, &c. The general directions for preparing the polish are to put the gums with the spi rit in a tin bottle, and set it on the stove or in water, so as to keep it at a gentle heat, shaking it frequently. The cork should be loosened a little before shak- ing it, taking care that there is no flame near to kindle the vapor. When the gums are dissolved let it settle for a few hours, and pour off the solution from the dregs. The method of using it is to have a roll of list, over the end of which five or six folds of linen rags are placed. The polish is applied to the linen with a sponge and a little linseed oil is dropped on the centre of it. FRICTION. In Mechanics, the resist- ance produced by the rubbing of the sur- faces of two solid bodies against each other. If the surfaces of bodies were perfectly smooth and polished, they would slide along one another without suffering any resistance from their con- tact, and all the simple relations between power and resistance determined by the- ory in respect of the different machines would hold good without any modifica- tion whatever. But this state of perfect polish never exists. The surfaces of all bodies with which we are acquainted, even when most carefully polished, re- tain a greater or less degree of asperity, FRl] CYCLOPEDIA OF THE USEFUL ARTS. 189 which prevents them from sliding over one another without impediment ; and in many cases the resistance thus created amounts to a large proportion of the whole resistance to be overcome. In or- der, therefore, to ascertain the real value of the effect of powers applied to machin- ery, it is necesaary to determine the amount of the friction, and to add this new resistance to that which is given by the theory of mechanics. The determination of the laws of fric- tion, and its amount with respect to par- ticular substances, have occupied the at- tention of many experimental philoso- phers and mathematicians, as Amontons, Euler, Desaguliers, Vince, &c. ; but the first complete set of experiments on the the subject was made by Coulomb about the year 1780. His results, though they have been partly modified by subsequent experiments, throw much light upon the subject, and are of great value to the practical engineer. There are two modes by which the na- ture and operation of friction may be as- certained. The first is very simple, and consists in merely placing a heavy body on a horizontal plane, and elevating the end of the plane till the body begins to slide. When this motion commences, it is evident that the force of gravity just begins to exceed the resistance occa- sioned by the friction ; and as the gravi- ty is known from the weight of the body, and the inclination of the plane, we have thus the means of comparing the friction with a given force. But this method is liable to some un- certainty. Most bodies, after having been in contact for some time, require a greater force to originate than to keep up progressive motion ; but it is obvious that the inclination of the plane of de- scent marks only the initial obstruction. Coulomb accordingly adopted a different mode of proceeding. His general me- thod was to draw a sort of loaded sledge along a horizontal bench, by means of weights placed in a dish attached to the sledge by a cord passing over a pulley. The sledge was mounted on sliders of the substance on which the experiments were to be made ; and the corresponding slips of the same or a different substance placed upon the sliders on the bench. This apparatus has been called a tribome- ter. The following are some of the re- sults which were obtained. Assuming the pressure as equal to 100 parts, the friction of oak against fir was 66 in the direction of the fibres, but amounted only to 16 when moved with the velocity of a foot each second: the friction of oak against oak in the direc- tion of the fibres was 43, and across them only 27, the effect being still reduced by motion to 10 ; the friction of fir against fir in the direction of the fibres was 56, which sunk to seventeen during motion ; the friction of elm against elm in the di- rection of the fibres was 46, and reduced by motion to 10. On the other hand, the friction of copper upon oak, length- wise, was 8 at the commencement of the motion, but increased to 18 when the velocity was a foot in a second ; the fric- tion of iron upon oak with the initial velocity was 11, and was increased by the motion to 18. But the mutual friction of metals appeared in general to be scarce- ly, if at all, affected by motion. In these experiments no unguents were used. Where metals rub against wood, it is necessary that the two bodies continue longer in contact, in order that the fric- tion may acquire its maximum. In the case of iron against wood at least 4 or 5 hours must elapse before the momentary increase of friction disappears ; whereas in the case of wood against wood a sin- gle minute was sufficient. But the re- sistance appears to increase by contact, though less sensibly, even for several days. The application of grease to the surfaces of wood produces a similar ef- fect, and the resistance does not attain its maximum till after a very considerable time. At the end of 5 or six days the resistance is perhaps 14 times greater than it was at the first instant, if the sur- face of contact is considerable in respect of the pressure ; but when the surface is small, the friction reaches its maximum much more quickly. An important part of the investigation was to ascertain whether the friction is increased by the velocity of the rubbing bodies. "VVith respect to the bodies of the same kind descending on inclined planes, Coulomb found that the time re- quired for passing over the first half was a little more than double that required for passing over the second. But a body put in motion by a constant accelerating force employs for passing over one space, and over two equal consecutive spaces, times that are to each other in the ratio of v'l : V2=100 : 142 ; that is to say, if 100 units of time are consumed in pass- ing over the first space, 142 will be con- sumed in passing over the first and se- cond together, and consequently 42 in passing over the second. Now this 190 CYCLOPEDIA OP THE USEFUL ARTS. [fri agrees as nearly as possible with the re- sult of the experiments ; consequently we infer that a load drawn along a smooth plane by a constant accelerating force (that of a descending weight for exam- ple) is uniformly accelerated. But this requires that the friction, at every in- stant, destroys only a proportional quan- tity of the force added by the constant action of gravity. The conclusion there- fore is, that for moderate velocities at least, the resistance due to friction is a constant quantity, and very nearly the same for every degree of velocity. Another point of great importance was to ascertain the relation the friction bears to the pressure ; for example, in what ra- tio the friction has increased by doubling or trebling the load. Coulomb found that when wood has been allowed to rest on wood for some time, without the in- tervention of any unguent, the resistance occasioned by the friction is proportional to the pressure. The resistance for a short time increases rapidly by the con- tact, but attains its maximum in a few minutes. The friction of wood sliding on wood with any velocity is still propor- tional to the pressure ; but the resistance is much less in amount than that which is required to detach the surfaces after some minutes of contact. In the case of oak, for instance, the force required to detach the surfaces after being some mi- nutes in repose is to that which is neces- sary to overcome friction alone after mo- tion has commenced in the ratio of 100 to 23. The friction of metals on metals is also proportional to the pressure ; but the intensity is the same, whether the surfaces have been any length of time in contact, at rest, or are gliding along with a uniform velocity. The friction of heterogeneous sub- stances, as woods and the metals, is en- tirely different from the above. In the case of wood against wood dry, or of me- tal against metal, the friction of the rub- bing" bodies is very little influenced by the velocity ; but in the present case the friction increases very sensibly with an augmented velocity. Coulomb in- ferred that the friction increased as the natural numbers, when the velocities are increased as the squares of those num- bers. In all cases of a hard body rub- bing against a very soft substance, the friction increases remarkably with the velocity. Since the friction is in general propor- tional to the pressure, it follows that it will not be altered by increasing or di- minishing the extent of the rubbing sur- faces. Nevertheless, this consequence fails in the extreme cases. The friction is sensibly diminished when the surfaces in action are reduced to the smallest di- mensions. Thus, while the friction of a ruler^ of brass against a similar one of iron is expressed by 26, it was found to be only 17 after the sledge had been mounted on 4 round-headed brass nails. Other causes of friction are the rough- nesses, spieulae, and angles of surfaces removeable by filling them with oil-tal- low, &c, and by diminishing the extent of surface in contact. Olive-oil reduces the friction of woods one-half. In all cases, the rubbing of large sur- faces against each other should be avoid- ed ; and hence the use of litti i wheels to turn with the axis of shafts called friction- wheels, by which the contact and rub- bing of large breadths is avoided. Differ- ent substances, too, should work against one another, the ultimate atoms of the bodies tending to combine by their simi- larity of forms. In the screw and the wedge, the fric- tion is equal to the power. The sheaves of pullies should not press against the blocks. It has been carefully determined at Baltimore, that one quart of oil is suffi- cient for 2000 miles run of a steam-car- riage weighing 3 tons. In the Winan's waggon, the friction- wheels dip into the oil ; but being in a cast-iron case, none is lost, while the renewal of oil is better than the same in long work. Purified ve- getable oils answer best. Black-lead is found to destroy friction with the best effect. Ferguson found that the quantity of friction was always proportional to the weight of the rubbing body, and not to the quantity of surface ; and that it in- creased with an increase of velocity, but was not proportional to the augmenta- tion of celerity. He found also, that the friction of smooth soft wood, moving up- on smooth soft wood, was equal to one- third of the weight ; of rough wood upon rough wood, one half of the weight; of soft wood upon hard, or hard upon soft, one-fifth of the weight ; of polished steel upon polished steel or pewter, one quar- ter of the weight ; of polished steel upon copper, one-fifth ; and of polished steel upon brass, one sixth oi the weight. Coulomb brought to light many new and striking phenomena, and coufirmed others, which were previously but par- tially established. fue] CYCLOPEDIA OF THE USEUL ARTS. 191 The obstruction which a cylinder meets with in rolling along a smooth plane is quite distinct in its character, and far in- ferior in its amountj to that which is f>roduced by the friction of the same cy- inder drawn lengthwise along a plane. For example, in the case of wood rolling on wood, the resistance is to the pressure, if the cylinder be small, as 16 or 18 to 1000 ; and if the cylinder be lame, this may be reduced to 6 to 1000. The fric- tion from sliding, in the same cases, would be to the pressure as 2 to 10, or 3 to 10, according to the nature of the wood. Hence, by causing one body to roll on another, the resistance is dimin- ished from 12 to 20 times. It is there- fore a principle in the composition of machines, that attrition should be avoid- ed as much as possible, and rolling mo- tions substituted whenever circumstances admit. On this principle depends the advan- tages resulting from the application of f notion wheels and friction rollers. The extremity of an axle, instead of resting in a cylindrical socket, is made to rest on the circumference of two wheels, to the axles of which the friction is transferred, and consequently diminished in the ra- tio of the radius of the wheel to the radi- us of the axle. This ingenious contriv- ance appears to have first been applied by Henry bully, in the year 1716. Soapstone has been used for diminish- ing motion with great profit and success. It is first thoroughly pulverized, and then mixed with oil, tallow, lard, or tar. It is used in all kinds of machinery where it is necessary to apply any unctuous sub- stance to diminish friction, and it is an excellent substitute for the usual compo- sition applied to carriage vehicles. Perkins has avoided the necessity of employing oil, grease, or any other lubri- cator to the piston of the steam engine by forming his piston of bell-metal, com- posed of the following materials : — cop- per, 20 parts ; tin, 5 parts ; zinc, 1 part. This, as well as his cast-iron cylinder, is cast under the pressure of a considerable head of metal ; by which means the den- sity and closeness of grain of both of them is very greatly increased, and in- deed, the cast-iron has as close a grain as wrought-iron itself. These two metals he finds to act so as to polish each other in use. He also uses the same dense cast- iron to form his steam-engine crank- axes, and the spindles of axes of his grindstones, &c., with ; and he runs the cylindrical necks of them upon bearings formed of his bell-metal, placed under- neath them, and made with hollow cylin- drical cavities, across their upper faces, not exceeding the sixth part of a circle in extent ; and yet, upon these very small bearings, his necks run, with a very tri- fling portion indeed of grease, as a lubri- cator. In thi3 manner, the cylindrical necks of the axis of a large grindstone, employed in grinding large articles, run ; and yet, on throwing off the band from the rigger, or band-wheel, the stone will make fifty revolutions at least before it stops. FUEL. Any combustible substance which is used for the production of heat, constitutes a species of fuel ; and in this extended sense of the term, alcohol, wax, tallow, coal gas, oil, and other inflamma- ble bodies which are occasionally used, especially in the chemical laboratory, as sources of heat as well as light, might be included under it. But the term fuel is more properly limited to coal, coke, char- coal, wood, and a few other substances, which are our common sources of heat, and as such are burned in grates, stoves, fireplaces, and furnaces of different de- scriptions. In this country, coal, In the neighbor- hood of cities, is the fuel commonly employed ; but where wood is abun- dant, or where its value is little more than that of felling it, it is used either in its original state or in the form of char- coal. But whatever substance is used, the ultimate elements of fuel are carbon and hydrogen ; and the heat which is evolv- ed by their combustion is derived from their combination at high temperatures with the oxygen of the air: the results or products of this combustion are carbonic acid and water, these escaping into the atmosphere by the flue or chimney gene- rally attached to furnaces and fireplaces. It is essential to good and profitable fuel that it should be free from moisture ; for unless it be dry, much of the heat which it generates is consumed in con- verting its moisture into vapor : hence the superior value of old, dense, and dry wood, to that which is porous and damp ; hence also the greater quantity of heat evolved during the combustion of char- coal as compared with that of wood, for even the driest wood always retains a certain quantity of water ; hence also coke gives out more heat than pit coal, partly because it is absolutely dry, and partly because during the combustion or heating of coal, tar, oil, water, and gas are evolved, all of which carry off a cer- 192 CYCLOPEDIA OF THE USEFUL ARTS. [fue tain proportion of the heat in a latent form. A pound of dry wood will, for in- stance, heat 35 pounds water from 32° to 212°, and a pound of the same wood in a moist or fresh state will not heat more than 25 pounds from the same to the same temperature ; the value, there- fore, of different woods for fuel is nearly inversely as their moisture, and this may be roughly ascertained by finding how much a given weight of their shavings loses by drying them at 212°. Charcoal is itself very hygrometric, and when exposed to air increases in weight to the amount of 10 or 12 per cent, in consequence of the absorption of humi- dity : a pound of dry charcoal is capable of raising, when properly burned, 73 pounds of water from the freezing to the boiling point. The different kinds of pit coal give out variable quantities of heat during their combustion; upon an average, one pound of coal should raise 60 pounds of water from the freezing to its boiling point. The heating power of coke as compared with coal is nearly in the ration of 75 to 69 : a pound of good coke will heat from 64 to 66 pounds of water from 32° to 212° ; its power, therefore, is about nine- tenths that of wood charcoal. The value of turf and peat as fuel is liable to much variation, and depends partly upon their density, and partly upon their freedom from earthy impuri- ties. A pound of turf will heat about 26 pounds of water from 32° to 212°, and a pound of dense peat about 30 pounds : by compressing and drying peat its value as a fuel is greatly increased. The following table, by Dr. Ure, shows the quantity of water raised from 32° to 212° by one pound weight of the dif- Combustible. Pounds of Water which a Pound can raise from 32° to 212°. <_ — a • Weight of Atinoaohfric Air at fcr* re- quired to buru one Pound. Dry wood . . . Common wood . Charcoal . . . Pit coal. . . . Coke .... Turf Coal gas . . . Oil, wax, or tallow Alcohol . . . 35-00 26-00 73-00 60-00 65-00 30-00 7600 78-00 52-00 6-36 4-72 13-27 10-90 11-81 5-45 13-81 14-18 9-56 5-96 4-47 11-46 9-26 11-46 4-60 14-58 15-00 11-60 ferent combustibles enumerated in the first column; it also shows the number of pounds of boiling water, which the same weight of fuel will evaporate, and the quantity of atmospheric air absolute- ly consumed during combustion. The quantity of air, however, as given in the last column, is much less than would be necessary in practice, where much of the air passes the fuel without coming into contact with it so as have its oxygen con- sumed. The heating power also, as re- presented by this table, can seldom bo practically attained. Fuel, Artificial. Coal, in its natural state, consists principally of bitumen, carbon, and some earthy matters. All fuel contain substances possessing bitu- minous and carbonaceous properties. Various compounds have been brought forward from time to time, some of them patented, to produce artificial fuel. All those compounds have been combina- tions of substances of a carbonaceous and bituminous nature, capable of gene- rating inflammable gas and sustaining combustion. Among the first compounds was refuse coal dust, with pitch, which was capable of producing an intense heat. A patent was taken out in London, in 1800, by a Mr. P. Davy, for an artificial fuel, to burn without smoke or sulphur- ous smell. It was composed of sea coal dust mixed with charcoal, tanners' bark, and saw-dust. The materials were mix- ed together wet, placed in a kilu and slightly cooked, care being taken not to use too high a temperature. Another artificial fuel was to place upon a shelf, above the fire, a quantity of chalk, or lime, which becoming heated from the combustion of the coal below, concen- trated the heat for a long time. Another plan was to bake bituminous and anthra- cite coal together, to produce a very last- ing coke. The proportions were one- third of the bituminous. Another plan was that of a Mr. T. Sunderland, who took out a patent for a compound of gas- tar, clay, saw-dust, tanners' bark, and refuse dye wood ; all were mixed toge- ther, formed into cakes, and dried by any artificial heat. Another compound, and patented too, was saw-dust, spent bark, coke, cinder ashes, and clay, re- duced to powder, mixed, cut and dried into cakes, and then dipped into coal tar, or grease, and afterwards dried. An- other compound was peat, clay, nitre, alum, linseed and resin, all ground in a mill and pressed into moulds, like bricks, and afterwards dried in the sun. An- other, and an ingenious plan, to harden peat, or swamp earth, was to mix it with powdered coal, or powdered brimstone, to break up the fibres and deprive the ful] CYCLOPEDIA OF THE USEFUL ARTS. 19« peat or swamp earth of its water, after- wards pressing it and making it into hard blocks. Another compound, by a Mr. Stirling, patented in England, was to mix pulverized coal with tar and clay. All were intimately mixed together, moulded into blocks and dried, and then they were excellent in shape for stowage. The great object of the producers of arti- ficial fuel has been to make it in such a shape that it would be easily stowed away for sea voyages, but the expense always exceeded the benefits. We might enumerate a great number of compounds of the above nature, varying but little from one another, but which constitute the subjects of no less than twenty-one patents, recorded in the London Reper- tory of Arts, and in the List of American Patents. Very favorable accounts are given of using the gas-tar along with spent-tan bark, in the gas-works, to heat the retorts. A patent was taken out in Washington, last year, for the compress- ing of coal dust into fuel. Another kind is made at Newton's Corners, near Al- bany, N. Y., by grinding swamp muck in a pug mill, then submitting it to a very severe pressure, and afterwards drying it. It is represented to burn well. We know of no kind of fuel, taking it for all in all, that can equal the anthra- cite. It is compact and cleanly, good qualities certainly; but it has another, viz., great and enduring calorific qualities. Bituminous coal is good fuel, but very uncleanly, for domestic use especially. One thing can make its use more agree- able, namely, to burn the smoke. This can be done by injecting fine jets of air on the top of the coals. FULLER'S EARTH is a soft, friable, coarse or fine grained mass of lithomarge clay. Its color is greenish, or yellowish f^ray ; it is dull, but assumes a fatty ustre upon pressure with the fingers, feels unctuous, does not adhere to the tongue, and has a specific gravity vary- ing from 1*82 to 2*19. It falls down readi- ly in water, into a fine powder, with ex- trication of air bubbles, and forms a non-plastic paste. It melts at a high heat into a brown slag. Its constituents are 53-0 silica; 10*0 alumina; 9-75 red oxide of iron; 1*25 magnesia; 0*5 lime; 24 water, with a trace of potash. Its cleans- ing action upon woollen stuffs depends upon its power of absorbing greasy mat- ters. It should be neither tenacious nor sandy ; for in the first case it would not diffuse itself well through water, and in the second it would abrade the cloth too much. The finely divided silica is one of its useful ingredients. After baking it is thrown into cold wa- ter, where it falls into powder, and the separation of the coarse from the fine is effectually accomplished, by a simple method used in the dry color manufac- tories, called washing over. It is done in the following manner : Three or four tubs are connected on a line by spouts from their tops ; in the first the earth is beat and stirred, and the water, which is continually running from the first to the last through intermediate ones, carries with it and deposites the fine, whilst the coarse settles m the first. The advan- tages to be derived from this operation are, that the two kinds will be much fitter for their respective purposes of cleansing coarse or fine cloth ; for with- out baking the earth they would be unfit, as before noticed, to incorporate so mi- nutely with the water in its native state ; it would neither so readily fall down, nor so easily be divided into different quali- ties, without the process of washing over". When fuel is scarce for baking the earth, it is broken into pieces of the same size, as mentioned above, and then exposed to the heat of the sun. The benefit of fuller's earth is mainly due to the alumina, which, by rubbing on the cloth unites with the grease, form* ing a soap which may either be washed^ or may serve as a mordant to fix the co- lors better on the stuffs. FULLING. The art of cleansing, scouring, and pressing stuffs, cloths, stockings, &c, to render them stronger, firmer, and closer ; it is also called mill- ing, because these cloths, &c, are in fact scoured bv a water mill. FULMINATES. Compounds of the fulminic acid with various bases, all more or less possessed of the property of ex- ploding or detonating by heat or friction. The fulminates of silver and mercury (or fulminating silver and mercury) are ob- jects of manufacturing interest ; the for- mer being used in detonating bonbons, and the latter more largely and impor- tantly as a priming for the percussion caps of gun locks. FULMINATING POWDER. A com- pound of three parts of nitre, two of purified pearlash, and one of flowers of sulphur, carefully mixed and dried be- fore the fire : about 20 grains of this powder heated upon an iron plate over a slow fire becomes brown and pasty j a blue flame then appears upon it, ana im» 194 CYCLOPEDIA OF THE USEFUL ARTS. [fur mediately after the whole explodes with a stunning' report. FUNNEL. In architecture, the upper part of a chimney. In common life, it is a trumpet-mouthed utensil, with a pipe fixed to the apex for the purpose of con- veying liquors into a vessel without spill- ing them. FUMIGATION, is the employment of fumes or vapors to purify articles of ap- parel, and goods or apartments supposed to be imbued with some infectious or contagious poison or fumes. The vapors of vinegar, the fumes of burning sulphur, explosion of gunpowder, have "been long prescribed and practised, but they have m all probability little or no efficacy. The diffusion of such powerful agents as chlorine gas, muriatic acid gas, or nitric acid vapor, should alone be trusted to for the destruction of morbific effluvia. FUNICULAR MACHINE. In mecha- nics, if a body fixed to two or more ropes is sustained by powers which act by means of those ropes, the assemblage is called the funicular ?nachine, or rope machine. If a rope is stretched horizon- tally between two points, its own weight alone will prevent it from becoming per- fectly straight, whatever force be em- ployed in stretching it ; and a very small force applied at its middle point, at right angles to its direction, will be sufficient to overcome a very great resistance at the points to which its extremities are attached. In this manner a very small force may be made to raise a very great weight to a minute height. This method of applying force is familiar to seamen, who frequently have recourse to it in bracing their sails. FUR. The coated skins of wild ani- mals, especially of those of high northern latitudes ; such as the wolf, bear, beaver, &c. The hair of fur is cleansed, and the skin is generally slightly tanned or taw- ed. The most valuable furs, such as ermine and sable, come chiefly from Russia. When unprepared, or merely dried, the fur skins go under the name of peltry. FURNACES bear various names, ac- cording to their purpose. The object of all is to procure great heat, directly ap- plicable to the purpose. Iron furnaces consist of ,a cone 20 or 30 feeVdeep, to receive the ore, the flux, and the coke or fuel, in layers, with an ash grate beneath, and blasting bellows to in- crease the supply of oxygen. They are many weeks in preparation, so as to ac- quire a high degree of heat, and then they are never suffered to cool, but constantly supplied with ore, flux, and fuel. A gas furnace is so built that the fire and flame surround the retorts full of coal, and keep them at a white heat. A chemical furnace is more various in its uses, and should be built with a table- top, and horizontal flue covered with plate iron, over which should be sand baths, and other receptacles, with hoods and covers. The air-furnace, for melting, has an ashes hole, and a lateral hole near the bottom of the grate. The fire-place is inclosed, and fuel put in at the top, so as to surround the covered crucibles or cucu- bets placed in the fire. The exit of smoke, &c, is at the side, in a horizontal flue. A reverberators furnace is one closed at the top, or with a reverberating dome with a fire beneath, and a perpendicular flue through the dome. At the side is an orifice for the neck of any retort placed in the body. There are various patent and special varieties of furnaces, but the same gene- ral forms pervade them. Charcoal, or coke, or ashes, produce the highest heat, but coals are used in glass-houses, distil- leries, and breweries. Accuni's Lamp Furnace is very conve- nient and powerful for operations in the small way. In the burning part it is Ar- gand's lamp, but, on the upright stan- dard, three or four arms slide with rings at their ends, to raise higher and lower, and fix with nuts and screws, adapted t& receive retorts, alembics, flasks, ac, for distillations, digestions, &c. In some, a second cylinder and second flame is made, by which the heat is trebled, and most processes performed in a small way, with- out a furnace. The furnace of the Royal Institution is of brick -work, 52 inches by 30. The iron plate and sand-baths, 57 by 42. It is 34 inches high. A very powerful furnace, equal to any purpose, has been made at the Royal In- stitution, by cutting the bottom off a blue pot, and fixing it tight in a larger one, 18 by 13 inches ; then, through a single hole in the bottom of the outer pot, blowing with a pair of double bellows. It melts pure iron in a quarter of an hour, renders platinum soft, and fuses rhodium. The fuel is coke, and it disappears, leaving scarcely slag ; proving the superiority of the blast furnace over all others. Faraday states, that a pint of water may be boiled in a cartridge-paper vessel, placed over a chemical lamp. >] CYCLOPEDIA OF THE USEFUL ARTS. 195 Mr. Nott haa taken out a patent for a mode of giving to furnaces a circular or semicircular form, that the fresh coals, when the fire receives a supply of them, may be, by turning the furnaces on pivots, by which it is supported, brought mto a position with reference to the coals already ignited, that the gaseous products of the fresh coals shall pass through the ignited portion, that the combustible part may be consumed ; and thus etfect a sav- ing of fuel, and the prevention of much of the nuisance arising from the escape of uneonsumed smoke. This rotating, or rather vibrating furnace, is of course to be provided with an iron casing, to sur- round the sides of the furnace not in- tended to be exposed. By Witty' s improved furnace, fresh coal is first carbonized, that is, the gas is separated from it and inflamed, leaving only coke, which, being slowly pushed forward, supplies the coke fire ; and the combusion or burning of the coke pro- duces heat enough to carbonize the coal, and air enough to inflame the gas ; con- sequently, coal, instead of being burned in its usual - crude state, is subjected to two distinct processes, viz. carbonization, and then combustion ; for, by this con- trivance, he burns the gas and the coke together. The vent of a furnace has given rise to much difference of opinion as to the size it ought to have. Some make it large, to allow a freer passage for the burnt air into the chimney ; others again, small, that the heat may not be dissipated and carried up into the chimney in waste. It is generally a single opening, but, in por- celain furnaces, the manufacturers use a number of small openings, instead of a single vent, with the view of assisting in the equal distribution of the heat through- out all parts of the chamber, and this practice should be adopted whenever this equal distribution is requisite. These artists are also careful that the sum of the areas of these holes should be exactly equal to that of the throats by which the flame and heated air enters into the cham- ber. It seems, therefore, advisable, in all cases, to make the vent or vents equal in area to that of the free space left be- tween the bars of the grate. Mr. Losh proposed to remove the vent to the front of the furnace, immediately over the feed- ing or stoking-door, and to conduct the burned air, through channels made in the masonry, into the flue of the chim- ney. A great advantage attends this construction, that, when either of the en- trances into the fire-room are opened, the indraught of air, instead of rushing over the surface of the burning fuel, and striking against the vessels and mate- rials, instantly passes up the vent, and does not enter at all into the interior of the furnace, whence this is much less cooler than in the furnaces of the usual construction. The chimney, or flue, is one of the most important parts of a furnace ; and yet, in general, the least attended unto ; being usually made much too large in its horizontal area. By making it thus large, the draught through it is much diminished, and" the soot collects and be- comes troublesome. For, when the sides of the flue contain a larger surface than can be duly heated, the necessary rarefac- tion of the air passing through it is de- stroyed. On this principle, alone, the draught of chimneys depends ; and the cavity being too large proportionably to the current of air, the force of it is so diminished that the soot, instead of being blown out, gathers and rests on the sides till it obstructs the passage, and choking up the draught deadens the fire, espe- cially at the first lighting of it, by which means the progress of the operation is sometimes greatly retarded. Instead, therefore, of the large proportion now made use of, if the chimney be intended for the use of one furnace only, an area equal to that of the free space between the bars of the grate is fully sufficient ; and this may be increased in proportion, where it is'designed for a greater num- ber. The calculations of Tredgold show that each side of a chimney having a square basis, or the narrowest side, if the basis be rectangular, should be, at the least, one foot in breadth for every 10 feet in height ; and the area of the flue ought not to exceed one-third of the area of the chimney. The wall of chimneys is usually single, but when the air which passes up the flue is very hot, it has been found pre- ferable to have the wall double, with an empty space left between the two, which are tied together from space to space, by bricks passing from one to the other. FUENACF. (Russian.) A kind of furnace adapted for burning wood, and used much in the villages and rural dis- tricts in New England. It consumes less wood than a stove, and requires but little care, preserving an agreeable and equal temperature in the room, as it presents a greater amount of heated surface than « 196 CYCLOPEDIA OF THE USEFUL ARTS. [fus stove, and does not require to be so in- tensely heated up. The annexed cut represents this furnace in a transverse sec- tion. A is the fire place, to which an iron door is fixed. C is the brick- work ; D a soap- stone cap ; 1 2 3 4 are flues in con- nexion with each other, and 1 being in connexion with A ; to 4, a fun- nel connecting the flue with the chimney is fixed, which has a damper attached. The furnace should stand out a few inches from the chimney, so as to save the heat from all sides. The fire place is filled with wood, and the dampers opened till the wood gets well on fire. The dampers are then closed perfectly tight, though not so suddenly as to make it smoke. It will want no more attention till the wood is nearly gone, when it can be replenished and im- mediately shut up if there are plenty of coals. It never need be opened more than three times a day in coldest weather, morning, noon, and night, and in more moderate weather not more than once or twice. The draught is generally good. A common form is about three feet in length, sixteen inches wide, two and a half feet high — though the size should depend upon the size of the room. They may be built upon the floor by having a sufficient thickness of brick between the floor and fire. The cost of one made all of brick, is not over four dollars, (pressed brick). A new furnace must be dry be- fore it is used. FURNACE (Salter's). Mr. Salter, of New Jersey, has taken out a patent for his improved furnace, which is adapted to ores, yielding 40 percent, and upwards of iron. * It consists of a triple chambered furnace, one above the other — the ore being pulverized and mixed with hard coal, and ground fine, is placed in the upper chamber — where the gases and impurities, such as sulphur, &c, are carried off at low temperature. From thence it is drawn through openings in the bottom, into the second or middle chamber, where the fluxing materials are added — thence it is drawn down openings to the lower or puddling chamber — the whole process occupying less than an hour and a half. Five men are required each turn to work the furnace, and the yield is about 400 lbs. per hour and a half. Two and a half tons coal are consumed in 24 hours. The cost of the iron wDl vary according to the facilities forgetting the'ore and coal, the cost of labor, &c. Former experi- ments have proved, as far as they have been made, that anthracite coal does bet- ter as the deoxidizing material than bitu- minous coal, and quite as well as char- coal, but the bituminous coal is quite as good (though no better) as either for fuel to heat the ores. It is stated that iron of the first quality can be made by it at Newark, and sold in New-York at $25 per ton. FUSEE. In watch-work, that part of the machinery about which the chain is wound, and which is immediately acted upon by the mainspring. The use of the fusee is to equalize the action of the spring. In proportion as the spring becomes un- wound, its effort con- tinually relaxes.;, so that if the first wheel were attached to the barrel, as is often the case in common watches, the in- equality of the impelling power would produce a corresponding inequality in the rate of going. In order to correct this, one end of the chain is attached to and wound round the barrel in which the main-spring is contained ; while the other end is coiled about the fusee, which has a conical shape, and is fixed on the axis of the first wheel. The principle generally adopted for determining the figure of the fusee is, that its radius, at any point to which the chain is a tangent, should be inversely as the tension of the chain in that position. Within certain limits this is true ; and if we assume with Hooke, that the force of a spring is pro- Sortional to the distance to which it is rawn from the position of rest, and also lay aside all consideration of the length of the chain wrapped about the fusee, it would be easy to show that the fusee should be the solid generated by the re- volution of the equilateral hyperbola about its asymptote. This conclusion is, however, by no means correct; but though the subject has been treated by several eminent mathematicians, very little practical advantage has been de- rived from the theoretical investigations. In fact, a moderate approximation to the gag] CYCLOPEDIA OF THE USEFUL ARTS. 197 true figure (whatever that may be) is all that can be attained in practice, and all that is necessary. FUSIBILITY. That property by which solids assume the fluid state. Some chemists have asserted that fu- sion is simply a solution in caloric ; but this opinion includes too many yet unde- cided questions, to be hastily adopted. Fusibility of Metals, as given, by M. Thenard. 1. Fusible below a red heat. CentigT. Mercury —39° Potassium -f-5S Sodium 90 Tin 210 Bismuth 256 Lead 260 Tellurium Less fusible than lead. Arsenic Undetermined. Zinc 370^ Antimony A little below a red heat Cadmium 2. Infusible below a red heat. Silver Copper Gold Cobalt Pyrometer of Wedgewood. 20 27 | A little less difficult to melt than iron. (130 (158 160 As manganese. Nearly infusible ; and to be obtained at a forge heat only in small buttons. Infusible at the forge fur- nace. Fusible at the oxy- hydrogen blowpipe. Iron Manganese Nickel Palladium Molybdenum Uranium Tungsten Chromium Titanium Cerium Osmium Iridium Khodiun Platinun. Columbium FUSIBLE METAL. See Alloy. FUSTET. The wood of the rhus eoti- nus, a fugitive yellow dye. FUSTIAN is a species of coarse thick twceled cotton, and is generally dyed of olive, leaden, or other dark color. Be- sides the common fustian, which is known by the name of pillow (probably pilaw), the cotton stuffs called corduroy, vel- verett, velveteen, thicksett, used for men's wearing apparel, belong to the same fabric. The commonest kind is mere- ly a tweed of four, or sometimes five leaves, of a very close stout texture, and very narrow, seldom exceeding 17 or 18 inches in breadth. It is cut from the loom in half pieces, or ends, as they are usually termed, about 35 yards long, and after undergoing the subsequent operations of dyeing, dressing, and folding, is ready for the market. FUSTIC. The old fustic of the English dyer, as the article fustet is their yellow fustic. It is the wood of the Morus tinc- toria. It is light, not hard, and pale yel- low with orange veins ; it contains two coloring matters, one resinous, and an- other soluble in water. The latter resem- bles weld, but it has more of an orange cast, and is not so lively. Its decoctions in water are brightened by the addition of a little glue, and more by curdled milk. This wood is rich in color, and imparts permanent dyes to woollen stuffs, when aided by proper mordants. It unites well with* the b;ue of the indigo vat, and Saxon blue, in pro- ducing green of various shades. Alum, tartar, and solution of tin, render its color more vivid ; sea salt and sulphate of iron deepen its hue. From five to six parts of old fustic are sufficient to give a lemon color to sixteen parts of cloth. The color of weld is however purer and less inclined to orange ; but that of fustic is less affected by acids than any other yel- low dye. This wood is often employed with Sulphate of iron in producing olive and brownish tints, which agree well with its dull yellow. For the same rea- son it is much used for dark greens. GADOLIN1TE or YTTEKITE, is a mineral black, brownish, or yellow color, granular or compact, vitreous and conch oi- dal in fracture; of spec. grav. 4*23. It readily scratches glass, and melts before the blow-pipe into an opaque glass, and sometimes with intumescence. It affords, with acids, a solution which gives with soda a precipitate partly soluble in car- bonate of ammonia. It contains nearly 50 per cent, of the earth yttria. Its remain- ing constituents are silica, 25*8, oxide of cerium 17-92, oxide of iron 11-43. This mineral is rare, found at Fahlun and Ytterly in Sweden, and also in the south of Ireland. Its peculiar constituent was discovered by Dr. Gadoline, hence the name. GAGE or GAUGE. In architecture, the length of a slate or tile below the lap ; also the measure to which any substance is confined. Plasterers use the word to signify the greater or less quantity of piaster of Paris used with the common plaster to accelerate its setting. Gage. In physics, an instrument or apparatus for measuring the state of a phenomenon. Gage qf"the air purryp is 198 CYCLOPEDIA OF THE USEFUL ARTS. [GAL merely a barometer communicating with the inside of the receiver, which marks, in the usual manner, the pressure of the air within the receiver by the height of the equiponderant column of mercury, and consequently shows the degree to which the air is rarefied. A short ba- rometer may be employed for this pur- pose ; but in this case it will not be aftect- ed till the rarefaction of the air has been carried so far as to correspond with the length of the tube. An instrument for the same purpose, but on a different principle, was invented by Smeaton, and trom its form called a pear-gage. It is a vessel suspended in the receiver, and ex- hausted to the same degree ; but when the rarefaction i« carried as far as intend- ed, the open orifice of the gage is let down into a vessel containing mercury, which, on the readmission of the air, is forced up into the pear, and the degree of rarefaction is judged of by the quan- tity of mercury introduced. The idea is ingenious ; but the indications given by this instrument are not correct. For wind-gage, see Anemometer ; water-gage, Bee Hydrometer. GALENA. . Sulphuret of lead, found massive and in cubic crystals. Color is blue gray, like lead, but brighter ; lustre, metallic ; breaking into cubic fragments, soft but brittle. Spec. grav. 7-22 to 7-58 ; it effervesces with nitric and hydrochloric acids, and contains from 45 to 83 per cent, of lead, and from 56 to 16 of sulphur. It also contains some silver and occasion- ally antimony, zinc, iron and bismuth. Be- fore the blow-pipe it decrepitates, and is decomposed and melted on the charcoal, yielding a button of metallic lead. Some- times as much as 100 oz. of silver will be found in a ton of ore ; it is then worked as a silver ore, and called argentiferous galena. The varieties which contain most silver are not the most lustrous, being sometimes black-gray ; occasionally ga- lena is mixed with silex and lime, and only yields 50 per cent, of lead. Sulphu- ret of lead occurs in primitive and meta- morphic beds, but more frequently in the upper secondary, especially in the compact blue limestone alternating with fossiliferous beds ; occasionally it is found in beds of coal, and bitumen is rarely found in its veins. Galena is abundant in Great Britain, and widely dispersed over this country. The mines of Missouri are very rich and extensive, and still more bo those extending through Illinois, Iowa, and Wisconsin, of which Galena is the centre. This lead region embraces about three thousand square miles in the S. E. of Iowa, extending across the Mississippi into Wisconsin and Illinois. Most of the metallic lead is obtained from galena, and contains a little silver. (See Lead.) GALL OF ANIMALS, or OX-GALL, purification of. Painters in water colors, scourers of cloth, and many others, em- ploy ox-gall or bile ; but when it is not puri- fied, it is apt to do harm from the green- ness of its own tint. It becomes therefore an important object to clarify it, and to make it limpid and transparent like wa- ter. The following process has been given for that purpose. Take the gall of newly killed oxen, and after allowing it to settle for 12 or 15 hours in a basin, pour the supernatant liquor off the sediment into an evaporating dish of stone ware, and expose it to a boiling heat in a water bath, till it is somewhat thick. Then spread it upon a dish, and place it before a fire till it becomes nearly dry. In this state it may be kept for years in jelly pots covered with paper, without undergoing any alteration. When it is to be used, a piece the size of a pea is to be dissolved in a tablespoonful ot water. Another and probably a better mode of purifying ox-gall is the following. To a pint of the gall boiled and skimmed, add an ounce of fine alum in powder, and leave the mixture on the fire till the alum be dissolved. When cool, pour into a bottle, which is to be loosely corked. Now take a like quantity of gall, also boiled and skimmed, add an ounce of common salt to it, and dissolve with heat ; f)ut it when cold into a bottle, which is ikewise to be loosely corked. Either of these preparations may be kept for several years without their emitting a bad smell. After remaining three months, at a mode- rate temperature, they deposit a thick sediment and become clearer, and fit for ordinary uses, but not for artists in water colors and miniatures, on account of their yellowish-green color. To obviate this inconvenience, each of the above liquors is to be decanted apart, after they have become perfectly settled, and the clear portion of both mixed together in equal parts. The yellow coloring matter still retained by the mixture coagulates im- mediately and precipitates, leaving the ox-gall perfectly purified and colorless. If wished to be still finer, it may be passed through filtering paper; but it becomes clearer with age, and never acquires a disagreeable smell, nor loses any of its good qualities. Clarified ox-gall combines readily with CYCLOPEDIA OF THE USEFUL ARTS. 199 coloring matters or pigments, and gives them solidity either by being mixed with or passed over them upon paper. It in- creases the brilliancy and the durability of ultramarine, carmine, green, and in general of all delicate colors, whilst it contributes to make them spread more evenly upon the paper, ivory, &c. When mixed with gum-arabic, it thickens the colors without communicating to them a disagreeable glistering appearance ; it prevents the gum from cracking, and fixes the colors so well that others may be applied over them without degradation. Along with lamp-black and gum, it forms a good imitation of China ink. When a coat of ox-gall is put upon drawings made with black lead or crayons, the lines can be no longer effaced, but may be painted over safely with a variety of colors pre- viously mixed up with the same ox- gall. Miniature painters find a great ad- vantage in employing it; by passing it over ivory it removes completely the unctuous matter from its surface ; and when ground with the colors, it makes them spread with the greatest ease, and renders them fast. It serves also for transparencies. It is first passed over the varnished or oiled paper, and is allowed to dry. The colors mixed with the gall are then applied, and cannot afterwards be removed by any means. It is adapted finally for taking out spots of grease or oil. GALL OF GLASS. The salts and other impurities which float upon the fused materials for the manufacture of glass, and which is skimmed off. It is also called sandlver. GALLON. An English measure of capacity. By act of parliament the impe- rial gallon is to contain 10 lbs. avoirdu- pois "of distilled water, weighed at the temperature of 62° of Fahrenheit, and the barometer standing at 30 inches. This is equivalent to 277 '274 cubic inches. The old English gallon, wine measure, contained 231 cubic inches ; beer mea- sure, 282 cubic inches. GALLIC ACID. (See G all-Nuts) It is composed of 7 atoms of carbon, 3 atoms of hydrogen, and 5 atoms of oxygen. GALL-NUTS. Excrescences produced by the cynips, a small insect which depo- sits its eggs in the tender shoots of the Quercus in/f ectopia, a species of oak abun- dant in Asia Minor. When the maggot is hatched it produces a morbid excres- cence of the surrounding parts, and ulti- mately eats its way out of the nidus thus formed. The best galls are imported from Aleppo and Smyrna ; their princi- ?al ingredients are tan and gallic acid, lie infusion of galls affords a dense white precipitate in solution of jolly, and a black precipitate with the persalts of iron. The latter property leads to the use of galls in the manufacture of ink and black dye ; they are also used as an as- tringent in medicine. Galls consist principally of three sub- stances ; tannin or tannic acid ; yellow extractive ; and gallic acid. Their decoc- tion has a very astringent and unpleasant bitter taste. The following are their ha- bitudes with various re-agents : — Litmus paper is powerfully reddened. Proto-chloride ot tin produces an Isa- bel-yellow precipitate. Alum ; a yellowish gray precipitate. Acetate of lead ; a thick yellowish white precipitate. Acetate of copper ; a chocolate brown precipitate. Ferric sulphate (red sulphate of iron); a blue precipitate. Sulphuric acid; a dirty yellowish pre- cipitate. Acetic acid brightens the muddy de- coction. The galls of the Q-uercus Cerris and common oak are of a brown color, prickly on the surface, and irregular in shape and size. They are used chiefly for tan- nine: in Hungary, Dalmatia, and the southern provinces of the Austrian states, where they abound. Tannin or tannic acid is prepared as follows : — Into a long narrow glass adopt- er tube, shut at its lower orifice with a cotton wick, a quantity of pounded galls are put, and slightly pressed down. The tapering end of the tube being inserted into a matrass or bottle, the vacant upper half of the tube is filled with sulphuric ether, and then closed with a ground- glass stopper. Next day there will be found in the bottle in two distinct strata, of which the more limpid occupies the upper part, and the other, of a sirupy consistence and amber color, the lower. More ether must be filtered through the galls, till the thicker liquid ceases to aug- ment. Both are now poured into a fun- nel, closed with the finger, and after the dense liquor is settled at the bottom, it is steadily run off into a capsule. This, af- ter being washed repeatedly with ether, is to be transferred into a stove chamber, or placed under the receiver of an air- pump, to be evaporated. The residuary 200 CYCLOPEDIA OF THE USEFUL ARTS. [gai matter swells up in a spongy crystalline form of considerable brilliancy, some- times colorless, but more frequently of a faintly yellowish hue. This is pure tannin, which exists in galls to the amount of from 40 to 45 per cent. It is indispensable that the ether employed in the preceding process be previously agitated with water, or that it contain some water, because by using anhydrous ether, not a particle of tannin will be obtained. Tannic acid is a white or yellowish so- lid, inodorous, extremely astringent, very soluble in water and alcohol, much less so in sulphuric ether, and uncrystalliza- ble. Its watery solution, out of contact of air, undergoes no change ; but if, in a very dilute state, it be left exposed to the atmosphere, it loses gradually its trans- parency, and lets fall a slightly grayish crystalline matter, consisting almost en- tirely of gallic acid. For procuring this acid in a perfectly pure state, it is merely necessary to treat that solution thus changed with animal charcoal, and to fil- ter it, in a boiling state, through paper previously washed with diluteinuriatic acid. The gallic acid will fall down in crystals as the liquid cools. Gallic acid is always produced when any substance containing tannic acid is exposed to the air. Tannin or tannic acid consists of car- bon 51*56; hydrogen 4*20 ; oxygen 44*24. Gallic acid does not exist ready formed in gallnuts, but that is produced by the reaction of atmospheric oxygen upon the tannin of these concretions. Gallic acid is a solid, feebly acidulous and styptic to the taste, inodorous, crys- tallizing in silky needles of the greatest whiteness ; soluble in about 100 times its weight of cold, and in a much smaller quantity of boiling water; more soluble in alcohol than in water, but little so in sulphuric ether. Gallic acid does not decompose the salts of protoxyde of iron, but it forms, with the sulphate of the peroxyde, a dark blue precipitate, much less insoluble than the tannate of iron. Gallic acid takes the oxyde from the acetate and nitrate of lead, and throws down a white gallate unchangeable in the air, when it is mixed with that acetate and nitrate. It occa- sions no precipitate in solutions of gela- tine (isinglass or glue), by which its freedom from tannin is verified. GALVANIZED IKON is the some- what fantastic name newly given to iron tinned by a peculiar patent process, whereby it resists the rusting influence of damp air, and even moisture, much longer than ordinary tin plate. The fol- lowing is the prescribed process. Clean the surface of the iron perfectly by the joint action of dilute acid and friction, plunge it into a bath of melted zinc, and stir it about till it be alloyed superficially with this metal ; then take it out, and immerse it in a bath of tin, such as is used for making tin plate. The tin forms an exterior coat of alloy. When the metal thus prepared is exposed to humidity, the zinc is said to oxydize slowly by a galvanic action, and to pro- tect the iron from rusting within it, whereby the outer tinned surface remains for a long period perfectly white, in cir- cumstances under which iron tinned in the usual way would have been superfi cially browned and corroded with rust. GALVANISM. (From Galvani, pro- fessor of anatomy at Bologna, the disco- verer of some of the phenomona copnect- ed with this form of electricity in the year 1790.) Under this term are frequently included the phenomena of Voltaic elec- tricity (which see). We shall here limit it to the apparent evolution of electricity by the contact of different metals ; this is best observed by the muscular contrac- tions which are produced in the leg of a frog recently killed, when two different metals, such as zinc and silver, tin and gold, &c, one of which touches the cru- ral nerve, and the other the muscles, are brought into contact. Every time the metals touch each other the limb be- come powerfully convulsed ; and if the experiment be made with a dead rabbit, so that one of the metals be in contact with the brain, and the other with the muscles of the extremities, the whole body of the animal is strangely agitated. Similar experiments have been made up- on the bodies of criminals shortly after execution. These results, which have till lately been considered to depend up- on the effects of electricity excited by the contact of the metals upon the nervous and muscular systems, led Volta to his celebrated researches, which terminated in the discovery of the Voltaic battery. Nearly all the cases, however, of the ap- E aren't production of electricity by contact avebeen satisfactorily traced by Faraday to chemical action. (See Voltaic Battery.) GALVANOMETER. An instrument for ascertaining the presence of a current of electricity, especially Galvanic or Vol- taic electricity, by the deviation which it occasions in' the magnetic needle. T*ie gal] CYCLOPEDIA OF THE USEFUL ARTS. 201 simplest form of a galvanometer is a mag- netic needle poised upon a point, and surrounded by one or more coils of cop- per wire covered with silk, the ends a * & and b being either left O free, or terminating in EEEIE SEzEE) tw0 8ma ^ copper cups I containing mercury, for j^ the convenience of com- munation with the source of electricity. When this needle is placed parallel to the coil, and in the magnetic meridian (as re- S resented in the margin), it immediately eviates when the electric current passes through the coil ; and the deviation is ei- ther to the east or west, according to the direction of the current. (See Electro- Magnetism:.) GAMBOGE. A gum resin, concreted in the air from the milky juice which ex- udes from several trees. The gambogia gutta, a tree which grows wild upon the coasts of Ceylon and Malabar, pro- duces the coarsest kind of gamboge; the guttaefera -vera (Stalagmites cambogio- ides) of Ceylon and Siam affords the best. It comes to us in cylindrical lumps, which are outwardly brown yellow, but reddish yellow within, as also in cakes ; it is opaque, easily reducible to powder, of specific gravity 1*207, scentless, and near- ly devoid of taste, but leaves an acrid feeling in the throat. Its powder and watery emulsion are yellow. GANGUE. A term to denote the stony matter which fills the cavities and ac- companies the ores in the veins of metals. GAS. When solid substances are ren- dered permanently aeriform by heat, the air thus produced is called a gas, to dis- tinguish it from those substances which turn to the solid or fluid states when the heat is abstracted. GAS (Coal) MANUFACTUKE OF. The separation and purification of the volatile elastic fluids from pit coal, which have the property of giving out light when burned. They are various com- pounds of carbon and hydrogen, accom- }>anied by hydrogen and carbonic oxide in arge quantity. The application of the gases produced during the destructive distillation of pit coal to the purposes of illumination is a very modern invention. But the germ of it may be traced back above 100 years ; for the first mention of the production of a permanently elastic and inflammable gas from coal occurs in the Philosophical Transactions for 1739, in which there is a paper by the Rev. Dr. Clayton, describing a method of filling bladders with what he 9* calls thespirit of coal, obtainedby distilling coal in a retort in the open fire.' He says, " I filled a good many bladders therewith, and might" have filled an inconceivable number more ; for the spirit continued to rise for several hours, and filled the blad- ders almost as fast as a man could have blown them with his mouth, and yet the quantity of coals distilled was inconsidera- ble. I kept this spirit in the bladders a considerable time, and endeavored several ways to condense it, but in vain ; and when I had a mind to divert strangers or friends, I have frequently taken one of of these bladders and pricked a hole therein with a pin, and compressing gently the bladder near the flame of a candle till it once took fire, it would then continue flaming till all the spirit was com- pressed out of the bladder ; which waa the more surprising, because no one eould discern any difference in the ap- pearance between these bladders and those which are filled with common air." Dr. Clayton seems also to have observed those curious phenomena which have lately excited so much attention under the terms exosmose and endosmose ; for he goes on to say that he found " that this spirit must be kept in good thick blad- ders, as in those of the ox or the like ; for if I filled calves' bladders therewith, it would lose its inflammability in twenty- four hours, though the bladders become not relaxed at all.'' Dr. Hales (in his Vegetable Statics) and Dr. Watson (in his Chemical Essays) have each alluded to the properties of the gas from coal ; but it was not until the end of the last century that the practicability of substituting coal gas for other inflam- mables, as a means of lighting streets and buildings, became an object of attention. The idea of applying coal gas to eco- nomical purposes seems first to have oc- curred in 1792 to Mr. William Murdoch, then residing at Kedruth, in Cornwall. His apparatus consisted of an iron retort, with tinned _ copper and iron tubes, through which the gas was conducted to a considerable distance ; and there, as well as at the intermediate points, was burned through apertures of varied forms and dimensions ; he also washed the gas with water, and used other means for its purification. In 1798 Mr. Murdoch con- structed a larger and improved apparatus for the purpose of lighting Boulton and Watt's celebrated manufactory at Soho, near Birmingham, which, on the occasion of the peace in 1802, was publicly illumi- nated by the same means. 202 CYCLOPEDIA OF THE USEFUL ARTS. [gas In all extensive and well conducted es- tablishments, the processes for the man- ufacture of gas are similar and uniform in the various stages. A great extent of ground is occupied with the retort house, Kurifying chambers, and space for the trge gasometers. The arrangements are similar in all. They are, with slight exceptions, which we need not heed here, as follows : — Each side of the retort house has a succession of arched recesses, each eight or ten feet high, six or seven wide, and about as many in depth. These recesses, when bricked or otherwise closed in front, form ovens or furnaces, in which fuel is burnt on a grate at the lower part. Five, six, eight, or more ob- long iron vessels, each holding from two to three bushels of cOals, are ranged ho- rizontally in this oven, from front to back, so that the heat, flame, and smoke from the surface may play around them, and make them red-not. * The outer end of these vessels, which are the retorts, are left opened or closed as occasion may re- quire ; an iron door, connected with a screw, being accurately fitted to each re- tort. The retorts are semi-cylindrical in shape, with the flat side placed lower- most. The average height of the retorts is perhaps about five feet from the ground ; under them is a fireplace, through which the fuel is introduced by which they are heated ; and under this again is a kind of ash-pit or shallow vessel into which the lime water is poured for the purpose of evaporation. The operation then con- sists in this : — The empty retorts are first brought to a red heat ; then a ' charge of coals' is introduced ; then the cover is screwed on the end, and made air-tight by a cement of clay and lime. Thus the retorts remain for about five hours, dur- ing which the fireplace is opened every hour for the renewal of the fuel with which the retorts are heated ; and at the end of this time all the gaseous and vaporizable matters having left the coal, and passed up from each retort by a pipe into the ' hydraulic main, 1 the ' drawing of the retorts ' commences. The retort- cover is loosened by turning a screw ; a slight explosion takes place when com- munication with the atmosphere is open- ed : the cover is removed by the sooty and almost fire-proof hands of the men, and the coke is drawn out by means of rakes eight or ten feet long. A kind of box, made entirely of iron, and placed ; upon wheels, is wheeled beneath the ! front of the retorts, and into it a portion I of ihc fiery contents of each retort 13 ! drawn. The box is wheeled away, and in a few minutes volumes of steam are ascending profusely from it, the result of a plentiful supply of water, which is thrown on it for the sake of speedy cool- ing. The remainder of the coke is then drawn out on the iron floor of the building, and, after being partially cool- ed by water, is removed out into the open air. In the upper part of every retort is an opening from which ascends a vertical pipe three or four inches in diameter. The gas, as it is formed, having no other outlet, ascends this pipe, passes thence to another pipe placed horizontally, and then enters a descending pipe, which dips into a large main fourteen or fifteen inches in diameter. This main is placed horizontally along the whole length of the retort-house, and receives all the gas from the whole range of retorts on one side, there being two mains on oppo- site sides of each retort-house. _ In these mains commences that purification of the gas which is the object of four successive processes, carried on in four distinct kinds of apparatus, viz. the hydraulic mains, the condensers, the purifiers, and the saturators. As may be readily sup- posed, the transference of the various products, such as gas, tar, ammoniacal liquor, &c, from vessel to vessel, requires a large assemblage of pipes, some of which are carried underground, and others within view. The retort-houses, such as have just been described, are four in number ; two situated in the northern quadrangle, and the other two being placed parallel and contiguous in the central building of the southern quadrangle. To these a series of smaller rooms are attached to the southern end of the retort-houses, and within view from the entrance-gates. One of these is the office of the superin- tendent of the works, and the other two contain very ingenious specimens of ap- paratus whereby he can regulate the sup- ply of gas at all hours of the day, calculate how much gas has been made within a certain period, ascertain the rate at which it is being manufactured at any particular time, and keep a check over the labors of the men. One of these rooms is called the 'valve-room,' and contains the apparatus for regulating the pressure and supply of the gas. To un- derstand the use ot such apparatus, it is necessary to recall to mind the striking change which occurs throughout a large city as evening is drawing on. The lamp- gas] CYCLOPEDIA OF THE USEFUL ARTS. 203 lighter is seen busily hastening from lamp to lamp, placing his slight ladder against the street lamp-irons, and kind- ling the flames which give to our streets no small share of their evening attrac- tions ; the shopkeeper begins to illumi- nate his wares, with one blaze if he be a humble dealer, with a dozen if his house b e a ' gin-palace,' with a score or two if he sells ' unparalleled bargains 1 in linen drapery; the theatres, the club-houses, the evening exhibition-rooms — all begin to display a blaze of light near about one time. Now it must be obvious that the sudden demand thus created is enor- mous, and it may be easily conceived that great judgment is required in ad- justing the supply. In order that the gas may be propelled through the main- pipes from the factory to the remotest point supplied from the works, it is ne- cessary to give the gas a pressure or elas- tic force greater than that of the atmos- {>here. If this pressure be too small, the ights at remote places would burn much too faintly ; if tob large, the flames would become so strong as to consume an inor- dinate quantity of gas ; if the gas flowed from the gasometers at an hour before dusk at the same rate as at an hour after dusk, the utmost confusion and ir- regularity would occur. To obviate these evils is the object of the pressure appara- tus. Around the valve-room are placed valves connected with the great main. There are several mains branching out from the factory in as many different di- rections, for the supply of different parts of the town; and as each main requires a supply of gas proportionate to the nature and extent of the district through which it passes, a pressure-apparatus is attached to it distinct from the others. Directing attention to one main only, it may be stated that after the gas leaves the gaso- meters and enters the main, it is placed in communication with a small tube lead- ing to a ' pressure-indicator,' by which the exact pressure at any time of the day or night is determined. So long as the pressure is such as is required, no changes are made ; but when it is either too great or too small, recourse is had to a valve, whose interior apparatus is in connection with the main. If the pressure is too great, the valve is drawn partly across the main, by which the sup- ply of gas is slackened : if too small, the valve is opened more than before, to ad- mit a greater volume of gas. These ad- justments are, as was before observed, made in the 'valve-room,' every main ! having its own 'pressure-indicator 1 and ! its own ' valve.' A room adjacent to the one just men- I tioned, and called the " meter-room, 1 ' ex- hibits to view a cast-iron case, about ten I feet square, and seven or eight feet high, | occupying the centre of the room. On the front are six or eight small dials, like clock-faces, and at the back are two pipes ascending through the floor, and entering the case. All the gas made at the works passes into this case or " meter 11 by one of the pipes just spoken of, and leaves it by the other. The meter will contain a certain known quantity of gas ; and while this quantity is passing through the ma- chine, an index hand "is caused, by me- chanism within the case, to revolve once round a dial-plate. Every ten revolutions of this hand causes another index to re- volve once round another dial-plate ; ten of these latter revolutions cause one revo- lution of a third index ; and so on through six successive stages, the last index re- volving only once while a million cubic feet of gas are passing through the meter. The superintendent, by looking at the in- dications in these six dial-faces, is thus able to tell, even to a single foot, how much gas has passed through the meter to the main pipes. There are two other dials on the front of the meter, one of which is a regular clock, and the other an ingenious arrangement for showing the rate at which the gas is passing through the meter at any particular time. The operations of a gas factory are in- terminable from the beginning to the end of the year. No cessation, even for a moment, occurs in the labors. One party of men are engaged at night ; an- other party relieve them after an interval of twelve hours, and are employed by day ; but the furnaces are always heated, the retorts always supplied with their fiercely burning contents, the gas always undergoing the purifying processes pre- vious to its passage into "the gasometers. The number of retorts worked varies at different seasons of the year, according to the length of time between sunset and sunrise; for the gas-manufaeturer is re- gulated, more perhaps than most other manufacturers, by the movements of the sun. But whether the number actually worked at any one time be greater or smaller, the system pursued is nearly the same. At the works we have noticed, the retorts are so divided into groups that some of them shall be ready for " draw- 204 CYCLOPEDIA OF THE USEFUL ARTS. [gas ing" every hour. If, for instance, a charge of coals remains five hours in the retort, and the retorts are divided into five parcels or sets, one set would he filled at noon, another at one o'clock, and the rest at two, three, and four respec- tively. Then, by five o'clock the first set of retorts are ready to be drawn ; at six o'clock the second set; and so on with the others. The precise arrangements need not be entered into, hut it will suf- fice to say that exactly as the clock strikes each successive hour, the men loosen and remove the covers of the retorts, draw out a portion of the coke into large iron boxes, draw out the rest upon the iron fioor of the retort-honse, throw water on the coke preparatory to its removal from the retort-house, recharge the re- torts with fresh coal, replenish the fires with a fresh supply of coke, and fit the covers — coated on their inner surface with a thick layer of lime and clay cement — firmly on the mouths of the retorts. In the intervals which elapse between the successive " drawings," the men are era- ployed in pouring the lime-water into the troughs beneath the fireplaces, in placing new layers of cement on the retort-covers to be used after the next drawing, in carrying out the coke into the open air, and afterwards into the sheds or stores, in bringing coals from the coal-stores to the retort-houses, in removing the ashes which fall into the lime-water in the ash- pit, and in various other duties sub- sidiary to the manufacture of gas. The subsequent preparation, or rather perfect- ing ot the gas, demands hut a small amount of manual labor; it is in fact performed by the steam-engine, which pumps up the water from the well, trans- fers from vessel to vessel the tar and the aramoniacal liquor abstracted from the gas, and sets in rotation the arms or fans in the purifying vessels. There is perhaps no part of the gas mechanism which requires better work- manship and more careful attention than the pipes which convey the invisible agent from the works to the places where it is consumed. However perfect may be the mode in which the gas is manu- factured, however plentiful the supply, yet if the pipes are either too small or too large, if they are laid either too hori- zontal or too much inclined, if any of the innumerable joints are imperfectly fitted, the most serious inconvenience results. The mains vary from three inches to eighteen inches in diameter, indepen- dent of the small lateral pipes which pro- ceed from the mains into the houses. The largest mains are placed nearest to the gas-works ; the next in size are ap- propriated to the leading streets and thoroughfares ; while the smaller are for the less important lanes and streets. Where the streets are wide, and the num- ber of lights required large, it is usual to lay mains on both sides of the street ; and the diameters of these mains are made to depend not only on the magni- tude and importance of the street, but on its elevation, its distance from the works, and other circumstances. There is a cir- cumstance attended to in laying down the mains which is perhaps not generally known. They are laid with a gradual in- clination, amounting perhaps to an inch in ten or twelve yards, instead of being horizontal ; and when this slope has con- tinued for one or two hundred yards, the mains begin to ascend in a similar de- gree. The line of mains thus ascends and descends alternately throughout its whole length. The reason for this ar- rangement is, that a small deposition of fluid takes place in the mains ; and this fluid, by flowing down the inclined pipes, accumulates at the lower points, where two descending lines meet ; here a reser- voir is formed, into which the liquid flows, and by the occasional use of a small pump from above the inconvenience is removed. When gas is made from coal, the selec- tion of the coal becomes an object The most bituminous is most desirable, and what is termed Cannel coal is usually preferred. The Philadelphia Gas Com- pany use Virginia (Richmond) coal, while the two New York companies use two parts of Cannel coal and one part of New- castle. The compositions of these two varieties are given, by Richardson — Newcastle. Cannel. Carbon 84-846 67"597 Hydrogen .... 5-048 5405 SSmi- *» :::::: »*» When these coals are heated to redness in closed vessels, the following process results : — A coaly residue (coke) remains, and certain volatile products escape, which partly condense on cooling into tar and an aqueous fluid, while the rest is a mixture of gases, but contains also no inconsiderable portion of the volatile va- pors of different compounds, which re- main dissolved in the coal gases without being condensed into liquids. These are oily products, mostly hydro-carbons, with a large proportion of carbon ; to these gas] CYCLOPEDIA OF THE USEFUL ARTS. 205 belong kyanol, leucol, pyrole, rosolic and carbonic acids and napthaline; most of these contain 90 per cent, of carbon, nap- thaline as much as 94 per cent., and in burning they deposit it in greater quan- tity than olefiant gas. These, therefore, enhance very much the illuminating power of the gas. Illuminating gas is not a definite compound of one or two gases, as carburetted hydrogen or olefi- antT gas, but a mechanical mixture of very various bodies, some of which are only slightly luminous, some absolutely prejudicial for illumination, whilst others are exceedingly luminous, as olefiant gas and the carbo-hydrogens, possessing similar properties, and to which the mix- ture owes its illuminating properties. By distilling coal, we have left behind the solid coke in the retort, and then are given off, as volatile matters, a number of gases, vapors, and liquids which separate in their passage, and are received in the tar-cistern and condenser. The liquids consist of, first, coal tar, which, on redistilling, yields pitch, coal oil (nap- tha), containing the hydro-carbons noticed above ; and, second, of ammoniaml li- quor, containing water, hydro-sulphate, carbonate, muriate, acetate, hydrocyauate, sulphite, and gallate of ammonia. The gases and vapors may be divided into three classes. First, those separated by the lime purifier, viz. carbonic, hydro- sulphuric, and hydrocyanic acids and am- monia. Second, those separated by water or in the alum, or green vitriol puri- fier, viz. ammonia (and nydrocyanic acid by green vitriol). Third, those which pass on to the gasometer, viz. trace of naptha vapor, trace of vapor of sulphuret carbon, nitrogen, hydrogen, carbonic oxide, light carburetted hydrogen, and olefiant gas. These numerous substances are not af- forded in the same relative proportions, at the same periods of the distillation. On the first application of the heat to coal, steam, along, with the air of the retort, comes off ; as the heat approaches red- ness, tar is disengaged, but only a small proportion of gas below a red heat ; and such gas has a feeble illuminating power ; when the retort is heated bright red, the evolution of gas is at its maximum, but tar is still produced, though slowly. At a white heat, carried on for two hours, the tar is small in proportion, that of the gas is still large, biit decreasing. At length, the gas ceases to be given off. Mr. Peck- ston's table, showing the relative amount of gas given off from one chaldron of Newcastle coal at different periods of the process, illustrates this — In 1st hour 2000 cubic feet " 2d. " 1495 " " 3d. " 138T " " " 4th. " 1279 " " 5th. " 11S9 " "6th. " 991 " " 7th. " 884 " " ■ 8th. " 775 ■ " Total in 8 hours 10,000 cubic feet. The composition and illuminating power of gas produced at different periods of the process, vary considerably. The gas evolved before the retort is red hot, con- tains a great deal of carbonic oxide, hence its feeble illuminating power ; that pro- duced at a bright red heat contains a larger portion of olefiant gas and vapors of hydro-carbons, than what is formed at a higher or lower temperature. As dis- tillation advances the temperature in- creases ; the proportion of illuminating gas decreases, while that of carbonic oxide and hydrogen increases in proportion. The density of the gas is also in some de- gree in proportion to its illuminating power, but decreases as the heat ad- vances. Dr. Henry's table, here annex- ed, shows the nature of the gas evolved from Cannel coal, at different periods of the process : — Olefiant gas and vapors of hydro- carbons Light carburetted hydrogen Carbonic oxide.. Hydrogen Nitrogen gas 13 82-5 32 12. 72- 1-9 8-8 5-3 '100.0 12. 7' 58- 56- 12-3 11- 16- 21-8 1-7 4-7 100-0 100-0 No. 1, 2, and 3 were produced during the first hour, 4 at the commencement of the 6th hour, and No. 5 10 hours from be- ginning. After those various liquid and gase- ous substances are obtained, they have to be separated so as to isolate the illu- minating gases : the first step is to pass the whole of the volatile matters through the condenser. The warm gases which issue [have a tendency to condense and stop up the tubes] are conducted to the coolers or condensers, which are of various construction. Ordinarily it con- sists of an iron chest filled with water, and having a false bottom ; a series of tubes connected by saddle joints are in 206 CYCLOPEDIA OF THE USEFUL ARTS. [gas the box. The lower part of this is di- vided into cells in which the fluids col- lect until they reach the level of a draw- ing-off tube, and they are thus separated — other condensers consist of a high per- pendicular tank, with a system of zig-zag gas tubes, over which an uninterrupted shower of water rains from above. On leaving the condenser the whole of the gases are still retained ; several of those are useless, as carbonic oxide and hydro- gen, which burn with a very slight evo- lution of light, and only tend to dilute the gas : others, on the contrary, are det- rimental, as ammonia, combined with carbonic, muriatic, and sulphuric and sulphurous acids and sulphuretted hydro- gen. The purification of the gas only removes the latter class, not the former. The lime purifier consists of a cham- ber containing milk of lime, stirred up with water, and agitated with a stirrer : the gas is passed through it in a very fine stream of bubbles. This removes the carbonic acid and sulphuretted hydro- gen, but appears to diminish the illumi- nating power of the gases. To separate the ammonia a solution of alum is some- times used. Protosulphate of iron has been used for the same purpose. Dilute sulphuric acid removes the ammonia much more rapidly, forming a sulphate of ammonia, which is produced in gas works in large quantity, and is sold either to farmers as manure, or to manufacturers for the formation of other salts of am- monia. Washing the gas with water, will by itself separate the ammonia. Mallet proposes to transmit the gas through two purifiers, one a solution of green vitriol or sulphate of manganese, and the other one ot milk of lime. This is the most profitable and least laborious plan. When gas has been thus prepared and purified, it has a composition variable as the coal used, and the heat and time of the operation. The composition marked No. 1 in Henry's table, is a very pure gas. During the present year, while public attention in New Yorkwas turned toward the cost and purity of gas, the two gas companies of that city (the Manhattan Co. and the New York Co.) jointly re- quested Drs. Torrey, Ellet, and Chilton, to undertake a thorough investigation and analysis of the gases of both com- panies, as well as that of the Philadel- phia City Gas Co., and the report of these chemists appeared on the 22d May. The plan of their investigation and character of the experiments were those most likely to insure accuracy and involve means of detection not previously used in Europe. The following is an ab- stract from their report : — "The following we believe represents the true constitution of the Philadelphia gas, as delivered to the consumers from April 15th to April 24th, and of the Man- hattan and New York Companies' gases from April 24th to May 22d. by Chlorine, [ HJ^^ LightCarbureited Hydrogen Carbonic Oxide Hydrogen Nitrogen •£ — • ■§. iSjf-f =. J " 3 Sal £ zero 2.30 5.65 4.20 6.85 37.75 © 10 7-50 8.40 45.38 33.20 2.87 3.80 100.00 lOO.OOl 1-^ m 5.60 6.40 48.00 7.50 30-20 2.30 L00.00 "All of the gases are effectually cleansed from carbonic acid and from sulphuret- ted hydrogen, not the slightest traces of either of them being discernible by the most delicate re-agents. The lime puri- fiers seem to perform their office tho- roughly, and the gases have a less offen- sive odor than was formerlv the case. Ammonia has been detected in all of them, but the quantity is very minute, and has not yet been estimated". " It will be seen from the above results that the New York gases resemble each other very closely, (as might have been anticipated,) since their manufacture is conducted as nearly as possible in the same way, and the materials employed in their production are the same, viz., two-thirds of Cannel coal, and one-third of Newcastle coal. They have both an advantage over the Philadelphia iras in the greater relative quantity ot their two> most valuable constituents, viz., olefiant gas, and hydro-carbon vapors. "Photometrical processes are obviously the most reliable for determining the relative illuminating value of different fases, and they accordingly have not een neglected by us. The comparisons have been made by means of a standard candle of Judd's manufacture, which itself has been compared with a standard candle used in the English gas works, and which had been employed within a few months in determining: the relative value of their products. We have thus been enabled to compare the illuminating values of the American gases on which we have experimented, not only with gel] CYCLOPEDIA OF THE USEFUL ARTS. 207 each other, but also with those of Great Britain. It results from our experiments that no appreciable difference in this respect exists in the New York gases, the slight excess of defiant gas and hy- dro-carbon vapors in the one, being com- pensated by the greater quantity of light carburetted hydrogen in the other. " The quality of these gases we believe to be better than that of most of those manufactured in the principal cities of Great Britain, and if excelled by any of them, it is only by those which are de- rived from pure Cannel coal. " We find that the New York gases are of decidedly superior value to that manu- factured in Philadelphia, and that to obtain a certain definite quantity of light, we must employ them in quantities represented by the following numbers — of Manhattan Gas, 100 cubic feet, New York Company's Gas. ... 100 " " Philadelphia Gas, 152.3 " " " Hie values of these gases as sources of light are of course inversely as these num- bers. " We do not attach much importance to specific gravity as exhibiting the worth of an illuminating gas. Carbonic oxide, and nitrogen, (the one of very little value, and the other absolutely worthless,) are always present in these gases, and are both identical in specific gravity with olefiant gas, which is one of. their most valuable constituents; a circumstance which renders the test an unreliable one, except in connection with other charac- ters. We have, however, made many trials on these gases, and have found that the specific gravity of the Philadelphia fas is below 450, while that of both the lanhattan and New York Companies' gases is on the average 550, atmospheric air being 1000. Good gas furnished at moderate prices is still a desideratum, and has led to the use of camphene and water gas manufactured on a small scale. The cost of coal gas might be diminished by the sale of the waste substances produced as Coke, Sul- phate of Ammonia, Gas Lime, and Tar. (See Oir, Gas, Resin Gas, and Water Gas.) GAUGE-POINT, is a term used in gauging to denote the diameter of a cy- linder whose altitude is one inch, and its contents equal to that of a unit of a given measure. For example, the old wine gallon contained 321 cubic inches. The diameter of a cylinder of the same capa- city, and whose altitude is one inch, is 17*15 inches ; which, therefore, is the gauge-point for this measure. GAUGING, in mensuration, is the measuring of the capacities of vessels, chiefly casks, barrels, vats, &c, and de- termining the contents of the substances contained in them. The principles of gauging are those which geometry fur- nishes for the measurement of solids in general ; but as the contents of vessels of the kind now mentioned are so frequent- ly required to be known, at least approxi- mately, for the purposes of commerce and the collection of the revenue, a set of technical rules and appropriate instru- ments have been contrived, by the help of which the art can be, and generally is, practised mechanically by those who are utterly ignorant of the principles on which it depends. The instrument ge- nerally used for the purpose is the gaug- ing-rod, or diagonal-rod, by which the contents of a cask are inferred from its diagonal length, measured from the bung to the extremity of the opposite stave at the head. On one face of a square rule, generally about four feet long, is a scale of inches for taking the measure of the diagonal ; and on the opposite face is a scale expressing the corresponding con- tents of the cask in gallons. It is obvi- ous that this method of proceeding can only give approximate results, on the supposition that all casks are similar soiias. GELATINE is an animal product which is never found in the humors, but it may be obtained by boiling with water the soft and solid parts ; as the muscles, the skin, the cartilages, bones, ligaments, tendons, and membranes. Isinglass con- sists almost entirely of gelatine. This substance is very soluble in boiling wa- ter* the solution forms a tremulous mass of icily when it cools. Cold water has little action upon gelatine. Alcohol and tannin (tannic acid, see Gall-nuts) pre- cipitate gelatine from its solution ; the former by abstracting the water, the lat- ter by combining with the substance itself into an insoluble compound, of the nature of leather. No othei acid, except the tannic, and no alkali possesses the property of precipitating gelatine. But chlorine and certain salts render its solu- tion more or less turbid ; as the nitrate and bi-chloride of mercury, the proto- chloride of tin, and a few others. Sul- phuric acid converts a solution of gelatine at a boiling heat into sugar. (See Ligne- ous Fibre.) Gelatine consists of carbon, 47-88 ; hydrogen, 7*91 ; oxygen, 27*21 (See Glue.) Gelatine brut fin, is from the skulls, 208 CYCLOPEDIA OF THE USEFUL ARTS. [GEN blade-bones, and shank-bones of sheep, the ends cut off, the bones cut down the middle to remove the fat, steeped in mu- riatic acid, then in boiling water a few minutes, wiped carefully, dried, shaken together in a bag to remove the internal pellicle, cut across, or into dice, to dis- guise them, and finally dipped in a hot solution of gelatine to varnish them. It is used to make soup, keeps better than the cakes of portable soup ; and, less carefully prepared, makes carpenters' glue for fine work. Very recently, a very beautiful spark- ling gelatine has been prepared under a patent granted to Messrs. J. & G. Cox, of Edinburgh. By their process the sub- stance is rendered perfectly pure, while it possesses a gelatinizing force superior even to isinglass. It makes a splendid calves' feet jelly and a milk-white blanc- mange. The patentees also prepare a semi-solid gelatine, resembling jujubes, which readily dissolves in warm water, as also in the mouth, and may be employed to make an extemporaneous jelly. The gelatine of bones may be extracted best by the combined action of steam and a current of water trickling over their crushed fragments in a properly constructed apparatus. When the gela- tine is to be used as an alimentary arti- cle, the bones ought to be quite fresh, well preserved in'brine, or to be dried strongly by a stove. Bones are best crushed by passing them between grooved iron rolls. The cast-iron cylinders in which they are to be steamed, should be three times greater in length than in diameter. To obtain 1,000 rations of gelatinous soup daily, a charge of four cylinders is required ; each being 3* feet long, by 14 inches wide, capable of hold- ing 70 lbs. of bones. These will yield each hour about 20 gallons of a strong jelly, and will require nearly 1 gallon of water in the form of steam, and 5 gal- lons of water to be passed through them in the liquid state. The 5 quarts of jelly produced hourly by each cylinder, pro- ceeds from the 1 quart of steam-water and 4 quarts of percolating water. GEMS are precious stones, which, by their color, limpidity, lustre, brilliant polish, purity, and rarity, are sought after as objects of dress and decoration. They form the principal part of the crown jewels of Kings, not only from their beauty, but because they are sup- posed to comprise the greatest value in the smallest bulk; for a diamond, no larger than a nut or an acorn, n ay be the representative sign of the territorial value of a whole country, the equivalent in commercial exchange of a hundred for- tunes, acquired by severe toils and pri- vations. Among these beautiful minerals man- kind have agreed in forming a secret class, to which the title of gems or jewels has been appropriated; while the term precious stones is more particularly given to substances which often occur under a more considerable volume than fine stones ever do. Diamonds, sapphires, emeralds, rubies, topazes, hyacinths, and chrysoberyls, are reckoned the most valuable gems. Crystalline quartz, pellucid, opalescent, or ot various hues, amethyst, lapis lazuli, malachite, jasper, agate, &c, are ranked in the much more numerous and inferior class of ornamental stones. These dis- tinctions are not founded upon any strict philosophical principle, but are regulated by a conventional agreement, not very well denned ; for it is impossible to sub- ject these creatures of fashion and taste to the rigid subdivisions of science. We have only to consider the value currently attached to them, and take care not to confound two stones of the same color, but which may be very differently prized by the virtuoso. Gems, Artificial. These are made of a very fusible, transparent, and dense glass, or paste, as it is called, containing a large proportion of oxide of lead, and generally some borax : the colors are given by metallic oxides. Much of their perfection depends upon the skill with which the exact tint of the real stone is imitated, and upon the care with which they are cut and polished. Mr. Ebelman, Director of the National Porcelain Manufactory of Sevres, has dis- solved in boric acid, alum, zinc, magne- sia, oxides of iron and chrome, and then subjecting the solution to evaporation during three days, he has obtained crys- tals equalling in hardness, clearness, and beauty the natural stones. With chrome he has made most brilliant rubies, from two to three millimetres in length, and as thick as a grain of corn. He has also made artificially, diaphonous quartz, hy- drophane, and chalcedony. GENEVA, or Hollands gin, is made by mashing 120 lbs. of malt with 240 lbs. of rye flour, in 480 gallons of water at 162°. Yeast is added at 80° : and in two days the fermentation raises it to 90°. The whole, grains and all, is then subjected ger] CYCLOPEDIA OP THE USEFUL ARTS. 209 to three distillations, and before the last, juniper berries and hops are infused. GEODES. Kound masses or no- dules of iron-stone, hollowed in the cen- tre. Eounded pebbles having an internal cavity, lined with crystals, are also so called. GEODESY. A word occasionally used, which literally signifies the division of the earth, in which sense it is synonvmous with land surveying ; but it is usually em- ployed in a more general sense to denote that part of practical geometry which has for its object the determination of the magnitude and figure either of the whole earth, or of any given portion of its sur- face. In this sense it comprehends all the geometrical or trigonometrical opera- tions that are necessary for constructing a map of a country, measuring the lengths of degrees, &c. In order to con- struct an accurate map, or determine the form and dimensions of a country, it is necessary, in the first place, to determine the absolute distances oetween the seve- ral stations or points; secondly, to de- termine the azimuths of the lines thus measured, that is, their situation with respect to the meridian ; and thirdly, the differences of latitude and longitude of the stations. The operations necessary for determining the absolute distances, comprehending the measurement of a base, the observation of angles, the com- putation of the sides of the triangles, and their reduction to the same level, are called the geodesical or geodetical opera- tions ; while those which are required for determining the azimuths and lati- tudes are called the astronomical opera- tions. The determination of the figure and dimensions of the earth is a problem of very great importance to astronomy and geography, and has accordingly at all times been a subject of much interest to mathematicians ; but it is only since towards the middle of the last century that operations on an adequate scale for its solution have been undertaken in dif- ferent parts of the world. Further de- tails do not come within the scope of this volume. See Theodolite. GERMAN SILVER. See close of the article Copper. GERMINATION, or Budding. The process by which a plant is produced from a seed. The phenomena of germi- nation are best observed in dicotyledo- nous seeds ; such, for instance, as the bean, pea, lupin, &c. These seeds con- sist of two lobes or cotyledons, enveloped in a common membrane; when this is removed a small projecting body is seen, which is that part ot the germ which af- terwards becomes the root, and is termed the radicle : the other portion of the germ is seen on carefully separating the cotyledons, and is termed the plumula ; it afterwards forms the stem and leaves. When the ripe seed is removed from the parent plant it gradually dries, and may be kept often for an indefinite period without undergoing any change ; out if placed under circumstances favorable to its germination, it soon begins to grow : these requisite circumstances are a duo temperature, moisture, and the presence of air. The most favorable temperature is between 60° and 80° ; at the freezing point none of the more perfect seeds vegetate ; and at temperatures above 100°, the young germ is usually injured. No seed will grow without moisture : water is at first absorbed by the pores of the external covering, and decomposed ; the seed gradually swells, its memnranes burst, and the germ expands. The root is at first most rapidly doveloped, the materials for its growth being derived from the cotyledons ; and when it shoots out its fibres or rootlets, these absorb nourishment from the soil, and the plu- mula is developed, rising upwards m a contrary direction to the root, and ex- panding into stem and leaves. For this growth the presence of air is requisite ; if it be carefully excluded, though there be heat and moisture, yet the seed will not vegetate. Hence it is that seeds buried very deep in the earth, or in a stiff clay, remain inert ; but, on admis- sion of air by turning up the soil, begin to shoot forth. From experiments which have been made upon the germination of seeds in confined atmospheres, it ap- pears that the oxygen set free by the de- composition of water combines with a portion of the carbon of the seed, and carries it off in the form of carbonic acid, and that the consequence of this is the conversion of part of the albumen and starch of the cotyledons into gum and sugar ; so that most seeds, as we see in the conversion of barley into malt, be- come sweet during germination. Light is injurious to the growth of a seed. It is, therefore, obvious that the different requisites for germination are attained by placing a seed under the surface of the soil warmed by the sun's rays, when it is moistened by its humidity and by occasional showers : excluded from light, but within reach of the access of air. When the young plant is perfected, 210 CYCLOPEDIA OF THE USEFUL ARTS. [< the cotyledons, if not coverted into leaves, rot away, and the process of nu- trition is carried on by the root and leaves : the principal nourishment is taken up from- the soil by the root, and chiefly by its small and extreme fibres ; so that when these are injured or torn, as by careless transplantation, the plant or tree generally dies. The matters ab- sorbed, consisting of water holding small portions of saline substances, and of or- ganic matter in solution, become the sap of the plant ; and this is propelled up- wards in the vessels of the stem, or of the outer layer of wood, into the leaves ; here it is exposed to the agency of air, or of light : it transpires moisture, and oc- casionally carbonic acid. But the leaves also at times absorb moisture, and ding- ing the influence of light they decom- pose the carbonic acid, and, retaining the carbon, evolve oxygen ; the sap thus becomes modified in its composition, and the characteristic proximate principles of the vegetable are formed. These return in appropriate vessels from the leaves, chiefly to the inner bark, where we ac- cordingly find the accumulation of the peculiar products of the plant : they also enable it annually to form a new layer of wood. Hence it is that the transverse section of the wood exhibits as many dis- tinct zones as the tree is years old. We are ignorant of the causes of this circula- tion of the sap ; but that it does follow the cause which has been stated is proved by the operation which gardeners call ringing, and which they sometimes re- sort to, to make a barren branch bear flowers and fruit : it consists in cutting out and removing a circular ring of bark, so as to prevent the return of the sap by the descending vessels, which at first ooze copiously, but afterwards the wound heals, and the juices are accumulated in all parts above the extirpated riner, pro- ducing tumefaction in the limb, and often inducing a crop of flowers and fruit, or causing those to appear earlier than on the uncut branches. If a tree be wound- ed so as to cut into the central portions of the wood, or the outer layer of new wood, the flow of ascending sap is then seen to take place upon the lower sec- tion, where the vessels are that carry it up to the leaves ; and the flow of de- scending sap is principally confined to the upper section of the inner bark, from which, after a time, new bark is pro- duced, and the parts again united. GIG. A well-known kind of light carriage drawn by one horse. Gigs, or gig machines, are rotatory cylinders co- vered with wire-teeth, for teazling wool- len cloth. GILDING. The application of a su- perficial coat of gold on wood, metal, and other materials. The beauty and dura- bility of gold render it the most valuable of all ornamental substances ; but, on ac- count of its weight and high price, its use in these respects would be exceed- ingly limited, were it not the most ex- tensible and divisible form of matter, so that it may be made to cover a larger surface than an equal quantity of any other body. Metals are usually covered with gold by the process of water gilding. It consists in perfectly cleaning their surface, and then, in the case of silver, for instance, rubbing it over with a solu- tion of gold in mercury, called amalgam of gold : the vessel is then heated over a clear charcoal fire, by which the mercury is driven off, and the gold left adhering to the silver surface, upon which it is afterwards burnished. The surface of copper or brass is usually prepared by cleaning and rubbing it over with a so- lution of nitrate of mercury, which amal- gamates the surface, and enables the gold amalgam, when subsequently ap- plied, to adhere ; heating and burnish- ing are then resorted to as before. Brass and copper buttons are gilt in this way ; and the requisite quantity of gold is so small that twelve dozen buttons of one inch diameter may be completely gilt upon both surfaces by five grains of gold. Other kinds of gilding are per- formed by gold leaf, which, if intended for out-door work, is laid on by the help of gold size, which is drying oil mixed with calcined red ochre ; or, if for pic- ture and looking-glass frames, they are prepared by a size made by boiling parch- ment clippings to a stiff jelly, and mixed with fine Paris-plaster or yellow ochre. The leaves of books are gilt upon the edges by brushing them over, while in the binder's press, with a composition of four parts of Arminian bole and one of powdered sugar candy mixed up with white of egg ; this coating, when nearly dry, is smoothed by the burnisher, then slightly moistened, and the gold-leaf ap- plied and burnished. To impress gilt figures on book covers, the leather is dusted over with finely-powdered mastic: the iron tool by which the figure is made is then moderately heated and pressed upon a piece of leaf-gold, which slightly adheres to it. In gilding wood, the operator should gil] CYCLOPEDIA OF THE USEFUL ARTS. 211 be provided with a cushion, made of a board about 10 inches square, covered with leather, and lightly stuffed with cotton, and a thumb-piece at the back : also, with a tip-brush, a pallet-knife, and a dabber, or silk bag filled with cotton. The pattern to be gilt is then exactly washed with jappanner's gold size, (lin- seed-oil and gum animi, thinned with oil of turpentine,) and the gold leaves being cut on the cushion with the pallet- knife, are transferred by the tip-brush to the sized surface and tapped with the silk bag, and left to dry. In covering surfaces with gold, the size is made of 3 boiled oil, 1 japanner's gold size, with yellow ochre ground in boiled oil. Two separate washes of this must be applied to the pattern, and be- fore quite hard, the gold-leaf laid "on. Other size is made by grinding red lead with thick drying-oil, and diluting with turpentine ; and, in other cases, with mere glue. Iron and steel are gilt by simply dip- Eing. The solution in aqua-regia is to e evaporated till it crystallizes, and then, if dissolved in water and alcohol, the iron may be dipped. But, if sulphuric ether be added, polished steel will be gilt by simple immersion. Silver is gilt by a solution of the gold in a menstruum of nitric acid, sal ammo- niac, and corrosive sublimate. It black- ens the silver, but a red heat restores the gold color. The mercurial amalgam can be applied to copper, or brass, or silver, by wasliing the surface with a solution of dilute sui- phuric acid and mercury. The amalgam is then evenly applied with a wet brush of brass wire. The heat of a furnace evaporates the mercury, and leaves the gold. Rub with gilders' wax, and bur- nish with sted. Iron is gilt by heating it blue, and laying on the gold-leaf, burnishing, and heating. Repeat till perfect. Copper buttons are gilt by putting them in nitric acid, and then burnishing on hard stone. Then stir them in nitric solution of mercury till white. The amalgam of gold is then mixed with nitric acid, and the buttons being well stirred the gold attaches. By heating, the mercury is made to run, when, after trituration in a hairy bag, farther heat evaporates it, and the buttons are bur- nished. Gilding in cornices, &c, is effected by priming with boiled linseed-oil, and car- bonate of lead. The surface is then co- vered with gold size, on which slips of gold-leaf are pressed with cotton. The edges are then brushed off. Burnished gilding requires priming with gum 2 and bole must be mixed with the gold size. Gilding in oil. — 1. The first operation is to give a priming coat of color, formed by grinding white lead in oil, rendered drying by boiling with litharge, and tem- pered afterwards with linseed-oil, adding a little fat oil, and a very small portion of spirits of turpentine. 2. Grind cal- cined white lead very fine in fat oil ; this must immediately be tempered with oil of turpentine, as it is subject to become thick very quickly. Three or four thin coats of this are to be given very evenly in the ornaments, and in nil parts in- tended to be gilt. Care must be taken in applying the color to the deeper parts of the work, that it may be even and perfect. — This is the teinte dure, or hard ground. 3. The gold color or size, pre- viously strained through fine linen, is then to be laid on, very thin and even, with a soft brush which has been used for oil colors. A smaller brush must be used for the deeper parts of the sculp- tured or other ornaments, carefully od- serving to remove any hairs which may be detached from the brush. 4. Where the size is so far dried as to become tacky, the gold leaf is to be spread upon the cushion, and divided with the knife ; the gold is placed on with a small block of wood, faced with cloth, called a pa- lette, and lightly pressed with cotton, repairing where necessary with pieces of f;old cut small, applied by a badger's mir-pencil. 5. If the articles gilt are to be exposed to the weather, as balconies, gratings, statues, &c, they ought not to be varnished, as gilding in oil is more durable without than with varnish. The heat of the sun will, after a heavy rain, cause gilding covered with varnish to craze or crack over its whole surface. Gilding in the interior of a building, as on the rails of staircases, &c, should have a coat of spirit of wine varnish, drying it by means of a chafing-dish, and then ap- plying a coat of oil varnish. The beauty of oil-gilding depends greatly upon the manner of varnishing it. For gilding metal buttons. — To 4 oz. of yellow melted bees'-wax add, in fine powder, H oz. of red ochre, li oz. of verdigris, calcined till it yields no fumes, and i oz. of calcined borax, and mix them well. It is necessary to calcine the ver- digris. To exalt the color of green gold. — Take 212 CYCLOPEDIA OF THE USEFUL ARTS. [oil saltpetre 1 oz. 10 dwts., sal-ammoniac 1 oz. 4 dwts., and verdigris 18 dwts., and dissolve a portion of the mixture in water, as occasion requires. To exalt the color of yellow gold. — Take saltpetre 6 oz., green copperas'2 oz., white vitriol and alum, of each 1 oz. If the color be wanted redder, a small portion of blue vitriol must be added. To be dissolved in water, as wanted. These two last compositions must be applied to the surfaces of the gilt works, either with a pencil, or by dipping them ; a proper degree of heat must then be used to cause them to assume a black color, when they must be quenched, or ccoled, either in vinegar or water. Gilding japan- work is performed with japanner's gold size J and for dead gold it should be used with turpentine only, but for lustre with fat oil only. Gilding earthenware and porcelain. — Take 2 drs. or 5 dwts. of pure gold and triturate in a porcelain mortar carefully, until very fine ; add, at distinct times, 1, 2, and 3 dwts. of pure mercury, and mix well together ; then add 10 grs. of white oxide of lead. Or, exclude the lead, and 1 dwt. of the mercury, when a strong body of gold is required. On a glass plate, long, and very care- fully grind for use. When the gold (as on some occasions) contains an alloy of silver, less mercury must be taken, and lead wholly ex- cluded. In executing the superior specimens of this art, men are employed ; and in many of the porcelain manufactories may be seen specimens of the high excellence of which it is susceptible, in flowers, landscapes, and portraits. Other less delicate patterns are the work of young women ; of whom, great numbers pro- vide for their comforts by these employ- ments. When the gilded ware has been through the muffle, and is cool, the gold is bur- nished with agate or bloodstone ; the ware is then wrapped in tissue paper, and carefully packed for home, or foreign markets. On some of the least valuable porce- lain, leaf-gold is fixed by being placed on a warm size, formed of these compo- nents. Boil together half a pint of pure linseed-oil, i oz. of gum arable, gum ben- zoin, and acetate of lead severally ; and after being well boiled, cool ; lay evenly on the ware, heat the whole a little, add the strips of leaf-gold, and carefully place for sale. To gild with burnished gold. — Give five or six coats of size and whiting. First with varnish of Armenian bole, wax and size. Wet with water, and lay on the gold, and in a few hours burnish with agate. To gild the edges of boohs. — Wash them, in the press, with Armenian bole, sugar candy, and white of eggs. Wet with water and lay on the gold leaf, and burnish with a dog's tooth, or steel tooth. Golden articles of jewelry. — The two best mixtures for the purpose of giving a good gold color to articles of jewelry, are as follows : — PARTS. Muriatic acid at 22° 10 Oil of vitriol 4 Crystall ized boracic acid 2 Water 150 Or, Acid muriate of alumine (liquid) 13 Crystallized sulphate of soda 4 Crystallized boracic acid 3 Water 150 Either of these mixtures, with 20 grs. of neutral muriate of gold, constitutes the bath, which is to be used in the fol- lowing manner : — A large glass mattrass, carefully luted at the bottom, is placed over a circular furnace, so as to have heat readily applied to it ; the solution is to be be put into it, and when at the boiling point, the pieces of jewelry, previously cleaned and picked, are to be introducecf, suspended upon golden wires. After a few minutes, a copper wire is to be im- mersed, and left until the gold has ac- quired a deep color; it is then to be withdrawn, but the articles still left in until they have acquired the color neces- sary. They are then to be put into warm water, acidulated by sulphuric or acetic acid, to remove particles of oxide of cop- §er, washed in clean warm water, and ried near a fire. Generally, a single operation is not enough ; for, as a long immersion produces harm from the oxide of copper, it is better to shorten it, and repeat the operation. Gold size. — Mix 16 oz. of linseed-oil, 8 oz. of turpentine, 2oz. of asphaltum, and 1 oz. each of brown umber and of red lead. 6>r, melt together 1 oz. each gum asphaltum and anime ; i oz. each of li- tharge, red lead, and brown umber ; 4 oz. of linseed-oil and 8 oz. of drying oil ; strain. Gilders' 1 wax is 4 lbs. of bees'-wax, a } of verdigris, and also of sulphate of copper, kept in a red heat until the wax has evaporated. gla] CYCLOPEDIA OF THE USEFUL ARTS. 218 Shdl gold may be obtained by amalga- mating the metal with 8 parts of mercury in a crucible, and then evaporating the mercury. Or, gold leaf may be tritu- rated with gum- water, and the gum dis- solved and poured off. GIMBALS, or GIMBOLS. A piece of mechanism consisting of two brass hoops or rings, which move within one another, each perpendicularly to its plane, about two axes placed at right angles to each other. GLANCE COAL. Anthracite : it is subdived into two classes — 1st, the slaty ; and 2d, the conchoidal. GLASS is a transparent solid formed by the fusion of siheious and alkaline matter. It was known to the Phcnicians, and constituted for a long time an exclu- sive manufacture of that people, in con- sequence of its ingredients, natron, sand, ana fuel, abounding upon their coasts. It is probable that the more ancient Egyptians were unacquainted with glass, for we find no mention of it in the writ- ings of Moses. But according to Pliny and Strabo, the glass works of Sidon and Alexandria were famous in their times, and produced beautiful articles ; which were cut, engraved, gilt, and stained of the most brilliant colors, in imitation of precious stones. The Ko- mans employed glass for various pur- poses ; and have left specimens in Her- culaneum of window-glass, which must have been blown by methods analogous to the modern. The Phenician processes seem to have been learned by the Cru- saders, and transferred to Venice in the 13th century, where they were long held secret, and formed a lucrative commer- cial monopoly. Soon after the middle of the 17th century, Colbert enriched France with the blown mirror glass manufac- ture. Chance undoubtedly had a principal share in the invention of this curious fabrication, but there were circumstances in the most ancient arts likely to lead to it ; such as the fusing and vitrifying heats required for the formation of pot- tery, and for the extraction of metals from their ores. Pliny ascribes the origin of glass to the following accident. A merchant-ship laden with natron being driven upon the coast at the mouth of ! the river Belus, in tempestuous weather, the crew were compelled to cook their i victuals ashore ; and having placed lumps ! of the natron upon the sand, as supports to the kettles, found to their surprise ! masses of transparent stone among the ! cinders. The sand of this small stream of Galilee, which runs from the foot of Mount Carmel, was in consequence sup- posed to possess a peculiar virtue for making glass, and continued for ages to be sought after and exported to distant countries for this purpose. The researches of Berzelius having re- moved all doubts concerning the acid character of silica, the general composi- tion of glass presents now no difficulty of conception. This substance consists of one or more salts, which are silicates with bases of potash, soda, lime, oxide of iron, alumina, or oxide of lead ; in any of which compounds we can substi- tute one of these bases for another, pro- vided that one alkaline base be left. Silica in its turn may be replaced by the boracic acid, without causing the glass to lose its principal characters. Under the title glass are therefore com- prehended various substances fusible at a high temperature, solid at ordinary temperatures, brilliant, generally more or less transparent, and always brittle. The following chemical distribution of glasses has been proposed. 1. Soluble glass ; a simple silicate of {>otash or soda ; or of both these alka- ies. 2. Bohemian or crown glass ; silicate of potash and lime. 3. Common window and mirror glass ; silicate of soda and lime ; sometimes also of potash. 4. Bottle glass ; silicate of soda, lime, alumina, and iron. 5. Ordinary crystal glass ; silicate of potash and lead. 6. Flint glass ; silicate of potash and lead ; richer in lead than the preceding. 7. Strass ; silicate of potash and lead ; still richer in lead. 8. Enamel ; silicate and stannate or antimoniate of potash or soda and lead. The glasses wnich contain several bases are liable to suffer different changes when they are melted or cooled slowly. The silica is divided among these bases, forming new compounds in definite pro- portions, which by crystallizing, separate from each other, so that the general mix- ture of the ingredients which constituted glass is destroyed. It becomes then very ard, fibrous, opaque, much less fusible, a better conductor of electricity and of heat ; forming what Keaumur styled de- nitrified glass, and what is called after him, Reaumur's porcelain. GLASS-MAKING, General Princi- ples of. Glass may be defined in tech- 214 CYCLOPEDIA OF THE USEFUL ARTS. [gla nical phraseology, to be a transparent homogeneous compound formed by the fusion of silica with oxides of the alka- line, earthy, or common metals. It is usually colorless, and then resembles rock crystal, but is occasionally stained by accident or design with colored me- tallic oxides. At common temperatures it is hard and brittle, in thick pieces ; in thin plates or threads, flexible and elas- tic ; sonorous when struck • fracture conchoidal, and of that peculiar lustre called vitreous ; at a red heat, becoming soft, ductile, and plastic. Besides glass Eroperly so called, other bodies are capa- le of entering into vitreous fusion, as phosphoric acid, boracic acid, arsenic acid; as also certain metallic oxides, as of lead and antimony, and several chlo- rides, some of which are denominated glasses. Impure and opaque vitriform masses are called slags ; such are the productions of blast iron furnaces and manv metallurgic operations. Silica, formerly styled the earth of flints, which constitutes the basis of all commercial glass, is infusible by itself in the strongest fire of our furnaces ; but its vitreous fusion is easily effected by a competent addition of potash or soda, either alone or mixed with lime or li- tharge. The silica, which may be re- garded as belonging to the class of acids, combines at the heat of fusion with these bases into saline compounds ; and hence glass may be viewed as a silicate of cer- tain oxides, in which the acid and the bases exist in equivalent proportions. Were these proportions, or the quantities of the bases which silica requires for its saturation at the melting point, exactly ascertained, we might readily determine beforehand the best proportions of ma- terials for the glass manufacture. Glass-houses are commonly large coni- cal buildings, from 60 to 100 feet high, and from 50 to 80 feet in diameter. The furnace is in the middle, over a large vault, which is connected with it by means of an opening. This opening is" covered with an iron grate, upon which the fire is made, and it'is kept up by the draught of air from the vault. The most important part, however, of the apparatus of the glass-house is the crucible, made from clay, found at Stour- bridge. This is first pounded fine, then sifted, moistened, and worked into a thick dough. Sometimes old crucibles are used, which are broken into powder, and then mixed with a red clay. Some pots, for bottle and flint glass, are made 40 inches deep and wide. They are from 2 to 4 inches in thickness. They remain several days at a white heat, before they are placed in the furnace. The basis of glass is silica. When flints or quartz are used, they are first reduced to powder by being heated red hot, and then plunged into cold water. This causes them to whiten and fall to pieces, after which they are ground and sifted. The second ingredient is potash or soda. The alkali used is more or less pure, according to the fineness of the glass to be made. Lime is often em- ployed in small quantities ; also borax. Of the metallic oxides added in dif- ferent cases, the deutoxide of lead is the most common. It renders flint glass more fusible, heavy, and tough, more easy to be ground and cut, and increases its bril- liancy and refractive power. A small quantity of black oxide of man- ganese renders the glass more transpa- rent ; too much gives a purple tinge, which, however, may be destroyed by a little charcoal or wood. Arsenious acid (white arsenic), in small quantities, promotes the clearness of glass ; too much of it gives the glass a milky whiteness. Its use in drinkiug- vessels is not free from danger, if the glass contains so much alkali that any part is soluble in acids. The various materials are carefully washed, and, after the extraction of all the impurities, are conveyed to the fur- nace in pots made of tobacco-pipe clay. The produce of this process is called the frit, which is again melted in large pots 'or crucibles, till the whole mass becomes beautifully clear, and the dross rises to the top. Blmoing is the next process, which, in round glass, as phials, drinking-glasses, &c, is thus performed ; — The workmen dip the end of long iron pipes, red hot, into the liquid glass, then roll it on a polished iron plate to give it an external even surface ; they next blow down the iron pipe, till it enlarges the metal like a bladder, and, if necessary, roll it again on the iron plate, and proceed to form it into a globular form, or any other one required. The glass is then transferred from the blowing-pipe, by dipping the end of another iron rod into the liquid glass, which adheres to the heated rod, and with which the workman sticks it to the bottom of the vessel ; then, with a pair of pincers, wetted with water, he touches the neck, which immediately cracks, and, on being slightly struck, a la] CYCLOPEDIA OF THE USEFUL ARTS. 215 separates at the end of the blowing-pipe, and becomes attached to the iron rod. ; The vessel is next carried up to the mouth of the furnace, to be heated and softened, that the operator may finish it. If the vessel require a handle, the opera- tor forms it separately, and unites it while melting hot, forming it with pincers to the requisite shape and pattern. Annealing is the removing of the glass, after it has been blown or cast, into a furnace, whose heat is not sufficiently intense to melt it ; and gradually with- drawing the article from the hottest to a cooler part of the annealing chamber, till it is cold enough to be taken out for use. If cooled too suddenly, it is extremely brittle. Coloring. — The different colored glasses owe their tints to the different metallic oxides mixed with the materials while in a state of fusion. In this manner are made those elegant pastes, which so faith- fully imitate, and not unfrequently excel, . in brilliancy, their originals, the gems of antiquity. The glass, however, for this purpose is preserved in a peculiar man- ner, and requires great nicety. It com- bines purity and durability. Opaque glass is made by the addition of the oxide of tin, and produces that beautiful imitation of enamel which is so much admired. Dials for watches and clocks are thus made. Bottle-glass is made of soap-boilers' waste and river sand, or sand and lime with clay and salt, mixed, evaporated, and fritted. Common window-glass, of 2 soap waste, 1 kelp, and 1 sand. Super window-glass, 25 sand, 12 sulphate of soda, or Glauber's salt, 4 carbonate of lime, or lime unburnt, and 1 of charcoal ; or 2 purified sand, 3 strong kelp. Plate, or sodaic glass, is sand 100, sub-carbonate of soda 55, unslaked lime 9, nitre 4, and powdered glass 60. The product is three- fourths. Flint, or litharge glass, is 10 fine sand, 6 red lead, 3 pearlash, a half part oxide of manganese. Grinding and polishing give plate-glass a fine lustre. The grinder takes it rough out of the hands of the caster, and, lay- ing it upon a stone table, to which it is fixed with stucco, he lays another rough glass, half the size of the former, upon it. To the smaller glass a plank is fast- ened, by means of stucco, and to the whole a wheel, made of hard, light wood, about six inches in diameter, by the pul- ling of which from side to side, and from end to end, of the glass, a constant at- trition is kept up ; and, by allowing water and fine Band to pass between the plates, the whole is very finely polished ; but, to give the finishing polish, powder of smalt is used. As the upper glass grows smoother, it is taken away, and a rougher one substituted in its stead ; and so on till the work is done. Except in the very largest plates, the workmen Eolish their glass by means of a plank, aving four wooden handles to move it ; and to this plank a plate of glass is ce- mented, as above. Various ornamental fo?'ms are given to the surface of glass vessels by metallic moulds. The mould is usually of cop- per, with the figure cut on its inside, and opens with hinges to permit the glass to be taken out. The mould is filled by a workman, who blows fluid glass into its top. The chilling of the glass, when it comes in contact with the mould, im- pairs its ductility, and prevents the im- Sression of the figure from being sharp, ome moulds, however, are made in parts, which can be suddenly brought together on the inside and outside of the glass vessel, and produce specimens nearly equal to cut glass. Cut glass, so called, is produced by grinding the surface with small wheels of stone, metal, or wood. The glass is held to the surface of the wheels. The first cutting is with wheels of stone ; then with iron, covered with sharp sand or emery ; and, finally, with brush wheels, covered with putty. A small stream of water is kept continually running on the glass, to prevent the friction from excit- ing too much heat. Glass may be ground on any coarse grained stone, with sand, or emery and water. Flat pieces of glass may be di- vided in any shape, by making a notch with a file, and carrying a piece of hot charcoal before the line in which it is in- tended the fracture should proceed. The charcoal must be kept aiive with the breath, and the progress humored by experience. Tubes, &c, are cut with a file all round, and then broken. GLASS COLOKING. Mr. G. Bon- temps has shown that all the colors of the prismatic spectrum might be given to glass by the use of the oxide of iron in varying proportions and by the agency of different degrees of heat ; and that all the colors are produced in their natural disposition in proportion as you increase the temperature. Similar phenomena were observed with the oxide of manga- nese. Manganese is employed to give a pink or purple tint to glass, and also to 216 CYCLOPEDIA OF THE USEFUL ARTS. [gla neutralize the slight green given by iron and carbon to glass in its manufacture. If the glass colored by manganese re- mains too long in the melting-pot or the annealing-kiln, the purple tint turns first to a light brownish red, then to a yellow, and afterwards to green. White glass in which a small proportion of manga- nese has been used is liable to become light yellow by exposure to luminous power. This oxide is also in certain window-glass disposed to turn pink or purple under the action of the sun's rays. M. Bontemps has found that similar changes take place in the annealing oven. He has determined, by experiments made by him on polygonal lenses for M. Fres- nel, that light is the agent producing the change mentioned • and the author ex- presses a doubt whether any change in the oxidization of the metal will explain the photogenic effect. A series of chro- matic changes of a similar character were observed with the oxides of cop- per ; the colors being in like manner regulated by the heat to which glass was exposed. It was found that silver, al- though with less intensity, exhibited the same phenomena; and gold, although usually employed for the purpose of im- parting varieties of red, was found by varying degrees of heating at a high temperature and recasting several times to give a great many tints, varying from blue to pink, red, opaque yellow, and green. Charcoal in excess in a mixture of silico alkaline glass gives a yellow color, which is not so bright as the yel- low from silver, and this yellow color may be turned to a dark red by a second fire. Mr. B. is disposed to refer these chromatic changes to some modifications of the composing particles rather than to any chemical changes in the materials employed. GLAZIER'S PUTTY. Whiting and linseed drying oil, beaten together some time. GLAZING EARTHENWARE AND PORCELAIN. In the bisquet state, earthenware and porcelain will adhere to the tongue, and imbibe moisture. The tendency of the earths to absorb water is the cause; and the ware in this state would not retain water and many other liquids. Hence, there is necessity for an artificial vitrified covering, whose com- ponents are so adapted to those of the body as to be equally affected with them by change of temperature, and preserve equality of expansion or contraction. We have not yet discovered a body and glaze that will be complete ware by once baking. The components of the present bodies do not sufficiently eon- glomerate to remain unaffected by the moisture of the glaze, but the articles become soft, and either shrink, or alter their figure. The only probable sugges- tion towards this is: — Grind very well some of the flesh-colored feldspar from Montgomeryshire, precipitate whatever iron may be in the mineral, then add 8 per cent, of ground native carbonate of barytes, and 1 per cent, of cobalt blue calx ; mix in water for dip and glaze, and fire only once. Feldspar is the glaze of Nankin porcelain. The manufacturers have their particu- lar glazes, for certain bodies. The several components are carefully proportioned, then ground to a pulpy state, almost im- palpable between the thumb and finger ; this is mixed with a certain quantity of water, and kept agitated to preserve uni- form suspension. The dipper places nigh him a board covered with bisquet ware, and another with a number of small pegs or nails. He immerses (or dips) each article, with a suitable motion to cover the whole, then places it on the pegs to drain. The water is imbibed by the pores of the ware, and, to the thick- ness of writing paper, the components form a covering, which is vitrified by baking. From the pegs the vessel is placed in a sagger, and at a lower heat of the oven the whole glaze is fused. The following are excellent glazes : Fob Porcelain. — Pulverize well, and carefully fuse together, flint 20 parts, cullet 7, Cornish-stone 20, red lead 20, borax 20, subcarbonate of soda 7, nitrate of potash 3, oxide of tin 24-, cobalt calx 1. Or, Fuse together, flint glass 66 parts, red lead 15, arsenic 7, muriate of soda 5, ni- trate of potash 6, cobalt calx 1. When well ground, mix with Cornish-stone 40 parts, frit (as above) 18 parts, flint 12 parts, and white lead 30: grind in the glaze mill, and use carefully. Fuse together Cornish-stone 80 parts, soda 20; pulverize, and grind together, for use. The fritt 40 parts, flint 16, Cor- nish stone 24, and white lead 20. Fuse together, cullet 85 parts, flint 10, white lead 2, arsenic 1, nitrate of potash 2; then grind together, fritt 30 parts, Cornish - stone 40, flint 25, boracio acid 5. The feldspar glazes are subjoined for general purposes of utility. They are GLU] CYCLOPEDIA OF THE USEUL ARTS. 21V most secretly preserved by their first em- ployers, but it is well they be exten- sively known. Fuse together, feldspar 66 parts, borate of soda 34 ; then grind, and mix with flint 95, nitrate of potash 5, ground for use. Or, feldspar 60, borax 40, fused, and mixed with flint 50, potash 2. Or, feldspar 90, carb. barytes 7, lime 2, magnesia 1 ; and mixed with flint 67, borax 30, and potash 3. Or, feldspar 60, borax 24, nitre 6, salt 4, and potash 6, mixed with flint 60. Raw glazes. — White lead 45, Cornish- stone 22, cullet 22, flint 8, borax 2, salt 1. Or, white lead 51, Cornish-stone 25, cullet 11, flint 12, carb. potash 1. Or, white lead 49, Cornish-stone 24, cullet 10, flint 14, borax 3. Or, white lead 42, Cornish-stone 27, cullet 14, flint 11, bor. acid 6. GLAZING IRON VESSELS. The iron vessels are cleaned perfectly in weak sulphuric acid, then washed well in soft cold water, and. dipped into a thin paste made with quartz melted with borax, feldspar, and clay free from iron, reduced into an impalpable powder with sufficient water to make it into a thin paste. After the vessels are dipped in this paste, or the said paste laid on with a brush, they are powdered in the inside with a linen bag containing a very finely pulverized mixture of feldspar, carbonate of soda, borax, and a little oxide of tin. They are then left to dry for some time in a clean place, and then heated in an enam- elling furnace. This coating is very white, and resists the action of heat, acids, and alkalies. The great defect in coating iron vessels, for cooking, or to be used and exposed to great changes of heat and cold, is the expansion and con- traction of the metal, which soon scales off the glazial coverings. GLASS PAINTING. In Painting, the method of staining glass in such a manner as to produce the effect of repre- senting all the subjects whereof the art is susceptible. A French painter of Mar- seilles is said to have been the first who instructed the Italians in this art, during the pontificate of Julius II. It was, how- ever, practised to a considerable extent by Lucas of Leyden, and Albert Durer. The different colors are prepared as follows : Black is composed of two-thirds of iron scales or flakes, and the other third of small glass beads, or a substance called roccaqlla by the Italians. White is pre- pared from sand, or small white pebbles, 10 calcined, pounded, and then grouud finely ; one fourth part of saltpetre is ad- ded, and the mixture is then again cal- cined and pulverized : when dyed, a lit- tle gypsum or plaster of Paris is added. Yetuno is formed from leaf silver ground and mixed in a crucible with saltpetre or sulphur ; then ground on a porphyry stone; and, lastly, ground over again with nine times the quantity of red ochre. Red, one of the most difficult of the colors to make, is prepared of li- tharge of silver and iron scales, gum Ara- bic, ferretta, glass beads, and bloodstone, in nearly equal quantities. Experience alone will command success in making this color. Green is formed from ces ustum one ounce, the same quantity of black lead, and four ounces of white lead, incorporated by the action of fire. When calcined a fourth part of saltpetre is ad- ded, and after a second calcination a sixth part more ; after which a third coction is made before using it. Azure, purple, and violet are prepared in a similar man- ner to green, omitting the ass ustum, and in its stead using sulphur for azure, perigneux for purple, and both these drugs for violet. Carnations are com- pounded colors, are calcined, and mostly mixed with water, and must be finished part by part, and each with great dis- patch, before the plaster dries, and there is little opportunity for blending. The lights cannot be heightened; but the shadows may, when they begin to dry, be a little strengthened. Promptitude and facility in execution are the great requisites for this method of painting. GLAUBEE'S SALT. Sulphate o? so- da, originally made by Glauber, in his process for obtaining muriatic acid, by distilling a mixture of common salt and sulphuric acid. GLAUCOLITE. (Gr. yUvKos, blue.) A mineral of a bluish green color, found near the lake Baikal, in Siberia ; it is a silicate of alumina and lime. GLUCINA. One of the primitive earths, originally discovered by Vauque- lin, in the beryl and emerald. It may be extracted from either of these minerals, by treating their powder successively with potash, with water, and with muri- atic acid. The solution by the latter, being evaporated to d^-ness, is to be di- gested with water, and filtered. On pouring carbonate of ammonia in excess into the liquid, we form soluble muriate of ammonia, with insoluble carbonates of lime, chrome, and iron, as also carbon- ate of glucina, which may be dissolved. 218 CYCLOPEDIA OF THE USEFUL ARTS. b out from the rest by an excess of carbon- ate of ammonia. When the liquid is fil- tered anew, the glucina passes through, and may be precipitated in the state of a carbonate by boiling the liquid, which expels the excess of ammonia. By wash- ing, drying, and calcining the carbonate, pure glucina is obtained. It is a white insipid powder, infusible in the heat of a smith's forge, insoluble in water, but soluble in caustic potash and soda ; as al- so, especially when it is a hydrate, in carbonate of ammonia. It has a metallic base called glueinum, of which 100 parts combine with 45-252 of oxygen to form the earth. It is too -rare to be susceptible of application in manufactures. GLUE is the chemical substance gela- tine in a dry state. The preparation and preservation of the skin and other animal matters employed in the manufacture of glue, constitute a peculiar branch of in- dustry. Those who exercise it should study to prevent the fermentation of the substances, and to diminish the cost of carriage by depriving them of as much water as can conveniently be done. They may then be put in preparation by mace- rating them in mine of lime, renewed three or four times in the course of a fortnight or three weeks. This process is performed in large tanks of masonry. They are next taken out with all the ad- hering lime, and laid in a layer, 2 or 8 inches thick, to drain and dry, upon a sloping pavement, where they are turned over by pronsrs two or three times a day. The action of the lime dissolves the blood and certain soft parts, attacks the epider- mis, and disposes the gelatinous matter to dissolve more readily. When the cleansed matters are drieel, they may be packed in sacks or hogsheads, and trans- Sorted to the glue manufactory at any istance. The principal substances of which slue is made are the parings of ox and other thick hides, which form the strongest article ; the refuse of the lea- ther-dresser ; both afford from 45 to 55 per cent, of glue. The tendons, and many other offals of slauorhter-houses, also afford materials, though of an inferi- or quality, for the purpose. The refuse of tanneries, such as the ears of oxen, calves, sheep, &c, are better articles ; but parings of parchment; old gloves, and, m fact, animal skin, in every form, uncombined with tannin, may be made into glue. These various matters aTc first rinsed, then drained, and afterwards boiled in large shallow copper vessels for some hours, during which they are well stir- red. The solution must be drawn off in suc- cessive portions ; a method which frac- tions the products, or subdivides them into articles of various value, gradually decreasing from the first portion drawn off to the last. It has been ascertained by careful experiments that gelatine gets altered over the fire very soon after it is dissolved, and it ought therefore to be drawn off whenever it is sufficiently fluid and strong for forming a clear gelatinous mass on cooling, capable of being cut in- to moderately firm slices by the wire. This point is commonly determined by filling half an egg-shell with the liquor, and exposing it to the air to cool. The jelly ought to get very consistent in the course of a few minutes ; if not so, the boiling must be persisted in a little long- er. When this term is attained, the fire is smothered up, and the contents of the boiler are left to settle for a quarter of an hour. The stop-cock being partially turned, all the thin gelatinous liquor is run off into a deep boiler, immersed in a warm water bath, so that it may continue hot and fluid for several hours. At the end of this time, the supernatant clear liquid is to be drawn off into con- gealing boxes, in which the solution as it "cools into a jelly takes the shape of the space. It is then exposed to the air, or a stove heat, to dry, and receives a gloss by being dipped in water and brushed. It is finally dried, and rendered fit for pack- ing. GLUTEN was first extracted by Bec- caria from wheat flour, and was long re- garded as a proximate principle of plants, till Einhof, Taddei, and Berzelius, suc- ceeded in showing that it may be re- solved by means of alcohol "into three different substances, one of which re- sembles closely animal albumine, and has been called Zymome, or vegetable albu- mine ; another has been called Gliadine; and a third, Murine. The mode of sepa- rating gluten from the other constituents of wheat flour has boen described to- wards the end of the article Brkad. Gluten, when dried in the air or a stove, diminishes greatly in size, becomes hard, brittle, glistening, and of a deep yellow color. It is insoluble in ether, in fat, and essential oils, and nearly so in water. Alcohol and acetic acid cause gluten to swell and make a sort of milky solution. Dilute acids and alkaline leys dissolve gluten. Its ultimate constitu- ents are not determined, but azote is one gol] CYCLOPEDIA OF THE USEFUL ARTS. 219 of them, and accordingly when moist glu- ten is left to ferment, it exhales the smell of old cheese. GLYCERINE is a sweet substance which may be extracted from fatty sub- stances. If we take equal parts of olive oil and finely-ground litharge, put them into a basin with a little water, set this on a sand bath moderately heated, and stir the mixture constantly, with the oc- casional addition of hot water to replace what is lost by evaporation, we shall ob- tain in a short time a soap or plaster of lead. After having added more water to this, we remove the vessel from the fire, decant the liquor, filter it, pass sulphur- eted hydrogen through it to separate the lead, then filter afresh, and concentrate the liquor as much as is possible without burning upon the sand bath. What re- mains must be finally evaporated within the receiver of the air-pump. Glycerine thus prepared is a transparent liquid, without color and smell, and of a sirupy consistence. It has a very sweet taste. Its specific gravity is 1*27 at the tempera- ture of 60°. When thrown upon burn- ing coals, it takes fire and burns like an oil. Water combines with it in almost all proportions ; alcohol dissolves it readily ; nitric acid converts it into oxalic acid ; and according to Vogel, sulphuric acid transforms it into sugar, in the same way as it does starch. Ferment or yeast does not affect it in any degree. Its constituents are, carbon, 40 ; hydro- gen, 9 ; oxygen, 51 ; in 100. GNEISS is the name of one of the great mountain formations, being reck- oned the oldest of the stratified rocks. It is composed of the same substances as franite, viz. : quartz, mica, and feldspar. n gneiss, however, they arc not in gran- ular crystals, but in scales, so as to give the mass a slaty structure. It abounds in metallic treasures. GOLD. This metal is distinguished by its splendid yellow color; its great density = 19*3, compared to water 1*0 ; its fusibility at the 32d degree of Wedge- wood's pyrometer ; its pre-eminent duc- tility and malleability, whence it can be beat into leaves only one 282,000th of an inch thick ; and its insolubility in any acid menstruum, except the mixture of muriatic and nitric acids, styled by the alchymists aqua regria, because gold was deemed by them to be the king of me- tals. Gold is found only in the metallic state, sometimes crystallized in the cube, and its derivative forms. It occurs also in threads of various size, twisted and in- terlaced into a chain of minute octahedral crystals ; as also in spangles or roundish grains, which, when of a certain magni- tude, are called pepitas. The small grains are not fragments broken from a greater mass ; but they show by their flattened ovoid shape, and their rounded outline, that this is their original state. The spec. grav. of native gold varies from 13-3 to 17*7. Humboldt states that the larg- est peplta known was one found in Peru, weighing about 12 kilogrammes (26£ lbs. avoird.) ; but masses have been quoted in the province of Quito which weighed nearly four times as much. It is scattered over the whole globe in primary geological districts ; in the moun- tains of Wicklow in Ireland; in Lead- hills, Scotland, and parts of Wales. In France, in the Valley of Oyseens, there is a vein of gold in quartz. Its aurife- rous rivers are numerous. The Rhone, near Geneva, the Rhine, near Strasbourg, the Salat, Garonne, and the Herrault. The gold mines of Piedmont are still worked. It is worked at Salzbourg, in Germany, and also in Hungary and Transylvania. The Asiatic Ural chain contains many gold mines ; Africa pos- sesses large auriferous deposits, chiefly alluvial. In South America, Brazil, Chi- li, Peru, and Colombia, furnish produc- tive quantities of gold. It is found in Canada, Maine, Virginia, North and South Carolina, and California, in this continent. Along the Sierra Nevada, in this latter state,^ are found the chief sites of the gold diffused through the quartz mass. Along the Yuba, Trinity, San Jo- achim, Sacramento, and San Francisco rivers, numerous rich placers have been found in the beds of the streams. There seems to be no limit to the extent of the quantity of gold diffused through the granitic rocks of this district, from which by attrition the streams have derived their gold. At Trinity Bluffs, the gold scales are found mixed with Basaltic sand, which so envelops and protects the gold that it is difficult to separate and purify the metal. Auriferous sands require little treat- ment to separate the gold. The sands are washed on a rocking table, and after- wards in wooden bowls by hand. Amal- gamation is employed to carry off from the sand the lighter particles of gold: much of the California gold is obtained in this way. In some places the sand is so heavy as not to allow the particles of gold to be separated, nor can acids bo 220 CYCLOPEDIA OF THE USEFUL ARTS. [goi used, as lime and iron are present ; solu- tion of chlorine from chloride of lime has been found to separate the gold ef- fectually. In South Carolina the plan adopted is this : — The ore is crushed by huge rotating iron rollers, during which a gentle fall of water carries the metal, as fast as it is pulverized, through a small aperture into a narrow trough, across which, at intervals, is a deposit of mer- cury. The trough is slightly inclined, by rhich means the sand passes out freely ndiile the gold adheres to the quicksilver. A.t the close of the day this mercury, «rith the gold attached, is all taken out, ind by a simple process called " pan- ning," the metals are neatly separated. The mercury is bottled for re-use, and the gold is burned to eradicate the few particles of mercury which still adhere to it. The other ores are metallic sulphurets. as those of copper, silver, arsenic, ana iron. The following is an outline of the treatment of these : — The stony ores are first ground in the stamping mill, and then washed in hand-basins, or on wood- en tables. The auriferous sulphurets are much more common, but much poorer than the former ores ; some contain only one 200,000th part of gold, and yet they may be worked with advantage, when treated with skill and economy. The gold of these ores is separated by two different processes; namely, by fu- sion and amalgamation. The auriferous metallic sulphurets are first roasted ; then melted into mattes, which are roasted anew ; next fused with lead, whence an auriferous lead is obtained, which may be refined by the process of cupellation. When the gold ores are very rich, they are melted directly with lead, without preliminary calcination or fusion. These processes are, however, little practised, because they are less economical and cer- tain than amalgamation, especially when the gold ores are very poor. If these ores consist of copper pyrites, and if their treatment has been pushed to the point of obtaining auriferous rose copper, or even black copper including gold, the precious metal cannot be sepa- rated by the process of liquation, becauso the gold, having more affinity for copper than for lead, can be but partially run off by the latter metal. For these reasons the process of amalgamation is far prefera- able. This process being the same for silver, its description is reserved for that me- tal. The rich ores in which the na- tive gold is apparent, and merely dissem- inated in a stony gangue, are directly tri- turated with quicksilver, without any preparatory operation. As to the poor ores, in which the gold seems lost amid a great mass of iron, sulphuret of copper, &c, they are subjected to a roasting be- fore being amalgamated. This process seems requisite to lay bare the gold en- veloped in the sulphurets. The quick- silver with which the ore is now ground, seizes the whole of its gold, in however small quantity this metal may be present. The gold procured by the refining pro- cess with lead, is free from copper and lead, but it may contain iron, tin, or sil- ver. It cannot be separated from iron and tin without great difficulty and expense, if the proportion of gold be too small to admit of the employment of muriatic acid. By cupellation with lead, gold may be deprived of any antimony united with it. Tin gives gold a remarkable hardness and brittleness, ; a piece of gold, exposed for some time over a bath of red-hot tin, becomes brittle. The same thing hap- pens more readily over antimony, from the volatility of this metal. A 2,000th part of antimony, bismuth, or lead, de- stroys the ductility of gold. The tin may be got rid of by throwing some cor- rosive sublimate or nitre into a crucible containing the melted alloy. By the first agent, perchloride of tin is volatalized ; by the second, stannate of potash forms, which is carried off in the resulting al- kaline scoriae. Gold treated by the process of amalga- mation, contains commonly nothing but a little silver. This silver is dissolved out by nitric acid, which leaves the gold untouched ; but to make this parting with success and economy on the great scale, several precautions must be ob- served. If the gold do not contain fully two- thirds of its weight of silver, this metal, being thoroughly enveloped by the gold, is partially screened from the action of the acid. "Whenever, therefore, it is known by a trial on a small scale, that the silver is much below this proportion, we must bring the alloy of gold and silver to that standard by adding the requisite quanti- ty of the latter metal. This process is called quartation. Tins alloy is then granulated or lami- nated; and from twice to thrice its weight of sulphuric or nitric acid is to bo gol] CYCLOPEDIA OF THE USEFUL ARTS. 221 boiled upon it ; and when it is i that the solution has been pushed as~far as possible by this first acid, it is decant- ed, and new acid is poured on. Lastly, after having washed the gold, some sul- phuric acid is to be boiled over it, which carries off a two or three thousandth part of silver, which nitric acid alone could not dissolve. Thus perfectly pure gold is ob- tained. The alloys of gold have been examined in detail by Mr. Hatchett. Of these the most important is that used for the gold coin of England, commonly called stand- ard gold, which consists of eleven parts of pure gold and one of copper ; it is ex- tremely ductile and malleable, but harder than pure gold, and, therefore, better calculated to resist the wear and tear of circulation. The specific gravity of this alloy is 17-157: 20 lbs. troy of it are coined into 934 sovereigns and one half sove- reign ; 1 lb. troy, therefore, produces 46 29-40 sovereigns ; the same weight was formerly coined into 44 £ guineas. The color of this alloy is deeper yellow than that of pure gold, and verges upon orange : it frequently happens that a part of the alloy of gold coin is silver, hence the pale color of some sovereigns as com- pared with others. The United States ^old contains an alloy of one-tenth of pop- per. Among the metals which destroy the color and malleability of gold, none is so remarkable as lead. It appears from Mr. Hatchett's experiments, that when lead forms about one 2000th part of the alloy, it is too brittle for rolling, and that the fumes of lead destroy the good quali- ties of gold. The chemical equivalent of gold is probably about 200, and that of the protoxide 208, and of the protochlo- ride 236. The peroxide is a compound of one proportional of gold and three of oxy- gen, and the perchloride contains three proportionals of chlorine. When ether is agitated with solution of chloride of gold, it takes up the metal, and forms a yellow ethereal solution of gold; when polished steel instruments are dipped into this so- lution, and immediately washed in water, and wiped with a piece of soft leather, they become beautifully gilt with a very thin film of gold. See Gilding. For the separation of gold in a spongy form, Dr. C. Jackson, of Boston, adopts an economical plan. After separating the gold and silver by aqua regia, the so- lution containing gold and copper is eva- porated to a small bulk, and the excess of nitric acid driven of. A little oxalic acid is then added, and a solution of car- bonate of potass sufficient to take up nearly all the gold as aurite of potass, is gradually added. Then an excess of ox- alic acid is added, and the whole boiled. The gold is immediately precipitated in the form of sponge : this is a suitable form for the jeweller and dentist. Gold, Artificial: The following ia Hemsdorf's proportions for imitation gold, which not only resembles gold in color, but also in specific gravity and ductility ; it consists of 16 parts of plati- tinum, 7 parts of copper and 1 of zinc, put in a crucible, covered with charcoal powder, and melted into a mass. Gold, Amalgam : Place a gold leaf in the palm of the hand, and pour upon it a globule of mercury. The latter will be seen to absorb, or combine with the gold ; forming a more or less fluid and yellow amalgam, according to the proportion oi the two metals. This amalgam is used in water gilding. The affinity of mercu- ry for gold and silver is so strong, that those who are foolish enough to clean their watch cases with mercury, or one of its salts, will find them irretrievably spoiled ; the same holds good with plated articles cleaned by a vile composition, sold about the streets for this purpose, made of the nitrate of mercury, ground up with whitening. Water gilders adopt the following plan to make amalgam : They put 2 drachms of mercury into a crucible, and heat it until vapor is seen to issue from it ; now throw into the crucible 1 drachm of gold or silver, and stir them with an iron rod. When the gold or silver is found to be fused, or incorporated with the mercury, the amalgam is poured into cold water ; when cold, pour off the water, and col- lect the amalgnm, which will be of about the consistence of soft butter. This af- ter having been bruised in a mortar, or shaken in a strong phial, with repeated portions of salt and water, till the water ceases to bo fouled by it, is fit for use, and may be kept for any length of time without injury in a stopped phial. It is essential in this manufacture, that the mercury should be extremely pure, as the least admixture of lead, tin, or metal would materially injure the gilding for which it is used. GOLD-BEATING. The malleability and extreme divisibility of gold are the foundation of the art oi gold-beating. In consequence of the wonderful extension which the gold-beater is enabled to give to this precious metal, it is employed for ornamental purposes to an extent which, 222 CYCLOPEDIA OF THE USEFUL ARTS. [gol from its comparative scarcity, would oth- erwise be impossible. Thus, it is esti- mated that an equestrian statue, of the natural size, may be gilded with a piece of gold not exceeding in value $3. The gilding of the dome of the Hotel des Inva- lids at Paris cost but £3500. And in In- dia, where it is common to gild towers, bridges, gate3, and colossal idols, it is known to be attended with still less ex- pense. In gold-beatvng. the gold used is as pure as possible, antl the operation is commenced with masses weighing about two oz. These are beaten into plates six or eight inches long, by three quarters of an inch wide. They are then passed be- tween steel rollers," till they become as thin as paper. Each one of these is now cut into 150 pieces, and forged on an an- vil till it is about an inch square, after which they are well annealed. Each of the squares in this state weighs 6'4 grs., and in thickness is equal to l-766th of an inch. The 150 plates of gold, thus pro- duced from one mass, are interlaid with pieces of very fine vellum, about four inches square, and about 20 vellum leaves are placed on the outside; the whole is then put into a case of parch- ment, over which is drawn another simi- lar case, so that the packet is kept close and tight on all sides. It is now laid on a smooth block of marble, and the work- man begins the beating with a round- faced hammer, of 16 lbs ; the packet is turned, occasionally, upside down, and beaten with strong strokes, till the gold is extended nearly to an equality with the vellum leaves. The packet is then taken to pieces, and each leaf of gold is divided into four with a steel knife. The 600 pieces, thus produced, are interlaid with pieces of animal membrane, from the in- testines of the ox^of the same dimension, and in the same manner as the vellum. The beating is continued, but with a lighter hammer, about 12 lbs., till the gold is brought to the same dimensions as the interposed membrane. It is now again divided into four, by means of a piece of cane, cut to an edge. The 2400 leaves hence resulting are parted into three packets, with interposed membrane as before, and beaten with the finishing, or gold hammer. The packets are now taken to pieces, and the gold leaves, by means of a cane instrument and the breath, are laid flat on a cushion of lea- ther, and cut, one by one, to an even square, by a cane frame ; they are lastly la> } in books of 25 leaves each, the paper o/ arhich is previously smoothed, and rubbed with red bole, to prevent them j from adhering. Gold Wibe is, in fact, only silver wire gilt, and is prepared in the following manner : A solid cylinder of fine silver, weighing about 20 lbs., is covered with thick leaves of gold, which are made to adhere inseparably to it, by means of the burnisher: successive laminae are thus applied, till the quantity of gold amounts to 100^ grs. for every lb. troy of silver. This gilt silver rod is then drawn succes- sively through holes made in a strong steel plate, till it is reduced to the size of a thick quill, care being taken to anneal it accurately after each operation. The succeeding process is similar to the for- mer, except that a mixed metal, somewhat softer than steel, is employed for the drawing-plates, in order to "prevent the gilding from being stripped off; and no further annealing is requisite after, if it is brought to be as slender as a crow- quill. When the wire is spun as thin as is necessary, it is wound on a hollow cop- per bobbin, and carefully annealed by a very gentle heat; finally, it is passed through a flatting mill, and the process is complete. Gold Thread. — The gold thread com- monly used in embroidery consists of threads of yellow silk, covered by flat- tened gilt wire, closely wound upon them by machinery. Crystallization of Gold. A small glass-stoppered vial, containing a solu- tion of gold in a mixture of nitric and muriatic acids, had stood neglected for a considerable time (perhaps four or five years) in a cupboard. Upon accidentally examining it, it was found a portion of the acid had escaped, and the gold crystalliz- ed. This effect had probably been pro- moted by a flaw in the vial, which extend- ed through the neck, and a little way down its length. The stopper in conse- quence must have been slightly loosened, and thus allowed more space for the for- mation of a thin dendritic crystallization of the gold. This was further continued down the -inner surface of the vial, and was there sufficiently thick to admit the impression of minute, but distinct crys- tallization facets. A small crystallized lump of gold lay at the bottom of the vial ; but supposed to have been originally at- tached to the rest, and merely by its weight, as has since observed to be the case in another portion. Around the stopper, and along the flaw, there was a saline concretion, which tasted like sal- ammoniac, and as ammonia was kept in GOV] CYCLOPEDIA OF THE USEFUL ARTS. the same cupboard, it had probably uni- ted with the muriatic acid as it exuded. On examining some other metallic so- lutions, it was found that a similar separation of the metal had taken place in a vial containing a solution of pla- tina, and in another, containing a so- lution of palladium. In both these cases, a thin, interrupted, and dentritic lamina of metal might be seen between the stopper and the neck ; but the crys- tallization had proceeded no further. On unstopping the vial containing the pla- tina, the lamina (as might have been expected) immediately disappeared in the form of a slight muddy film. These facts, if multiplied, may, per- haps, serve to throw some light upon the mode in which the dentritic laminae of native gold, silver, &c, are formed in rocks. Gold (Chloride of). Great difficulty has hitherto occurred in preparing the chloride of gold, of the yellow and red colors, perfectly soluble in water, and without suffering reduction. The follow- ing processes are recommended for this purpose : — 1st. In order to prepare the yellow salt of gold, take aqua regia prepared with three parts of hydro-chloric acid, one part of nitric acid, and one of distilled water. Then put one part of pure gold into a porcelain capsule with a plate of glass, and heat it in a salt water bath, the heat being eontinued till red vapors cease ; the cover is then to be removed, and if the gold is not entirely dissolved, some aqua regia is to be added to it, the cap- sule being again covered, the heat is to be continued till vapor ceases to appear ; the glass plate must then be removed ana replaced by folds of blotting paper, the heat being continued in the bath, until a glass rod, upon being immersed in the capsule, becomes covered with yellow solid chloride of gold. The capsule is then to be removed from the salt water bath and the chloride of gold soon crystallizes in small prismatic crystals, of a fine yellow color, with an orange tint. The chloride thus obtained is perfectly soluble in water without re- duction ; it is successfully employed in Daguerreotype and other operations. The red chloride of gold (ter-chloride) is prepared in the same manner, except that the aqua regia employed is prepared with two parts of hydro-chloric, and one part of nitric acid. The operation is commenced by acting upon gold with excess of aqua regia on a sand bath, the salt water bath not being used until the gold is entirely dissolved ; the remainder of the operation is conducted in the same manner as that for the vellow chloride. GOVEENOK. A contrivance for re- gulating the speed of machinery, which has long been in use in mill- work, but has of late years attracted more attention by its adaptation to the steam-engine. It consists of two heavy balls B B, attached to the extremi- ties of two rods B F, B F, which play upon a joint at E, passing through a mor- tise in the verti- cal shaft D D. These are united by joints at F to the short rods F II, which again are connect- ed by joints at II to a ring, which slides on the shaft DD. A horizontal wheel, W, is attached to ~D D, having a groove to receive a rope or strap on its rim, by means of which the motion is communi cated to D I) from a corresponding wheel on some shaft of the machinery to be re- gulated. It is evident, from the disposi- tion of the rods, that if the balls B B are by any means raised or drawn asunder, the extremities F F of the rods turning on the pivot E will also be separated, and their distance from the axes increased. This will draw the rods F II in the same direction, and cause the ring or collar II to descend. This ring is connected with the end I of a lever, whose fulcrum is at G, and whose other extremity K is con- nected by some means with the part of the machine which supplies the power. Suppose now the velocity from any cause to undergo a sudden increase ; by reason of the increased centrifugal force arising from the whirling motion, the balls B B will recede from the shaft D D, and raise the extremity K of the lever. On the other hand, if the velocity is diminished, the centrifugal force of the balls will be diminished, and they will fall by their own weight nearer the axes, and cause the end K of the lever to descend. When the governor is applied to a steam-en- gine, the rod K 1 communicates with a flat circular valve V, placed in the princi- pal steam-pipe, and so arranged that when K is elevated as far as the divergence of the balls will allow, the opening of the pipe will be closed by the valve V, and the passage of steam entirely stopped. On the other hand, when the balls sub- side to their lowest position, the valve will be entirely open. Thus, when the 224 CYCLOPEDIA OF THE USEFUL ARTS. [< Velocity is increased, the supply of steam is checked ; and when it is diminished, the supply of steam is immediately in- creased; by which means a uniform proper velocity of the machinery is maintained. . When the governor is applied to a water wheel, the lever is made to act on the shuttle through which the water flows, and thereby controls its quantity. "When applied to ft windmill, it regulates the sailcloth so as to diminish the efficacy of the power upon the arms as the force of the wind increases, or vice versa. GRAFTING. The operation of affix- ing one portion of a plant to another, in such a manner as that vital union may take place between them. A graft con- sists of two parts ; the stock or stem, which is a rooted plant, fixed in the ground, and the scion, a detached por- tion of another plant, to be affixed to it. The operation ot grafting can only be per- formed within certain limits. In general, all the species of one genus may be grafted on^one another recipro- cally ; but this is not universally the case, because the apple cannot be grafted on the pear, at least not for any useful pur- pose. In general, it may be presumed that all the species of a natural order, or at least of a tribe, may be grafted on one another ; but this does not "hold good uni- versally. The reverse of this doctrine, however, that the species belonging to different natural orders cannot be grafted on one another holds almost universally true ; and therefore a safe practical con- clusion is, that in choosing a stock, the nearer in affinity the species to which that stock belongs is to the scion, the more certain will be the success. Grafting is one of the most important operations in horticulture, as affording the most eligible means of multiplying and perpetuating all our best varieties of fruit-trees, and many kinds of trees and shrubs not so conveniently propagated by other means. Varieties of fruits are ori- ginally procured by selection from plants raised from seed, but they can only be perpetuated by some mode which con- tinues the individual ; and though this may be done by cuttings and layers, yet by far the most eligible mode is by graft- ing, as it produces stronger plants in a shorter time than any other methods. Grafting is performed in a great many different ways, but the most eligible for ordinary" purposes is what is com- monly called spliced grafting or whip grafting. In executing this mode, both the scion and the stock are pared down in a slanting direction ; afterward applied together, and made fast with strands of bast matting, in the same manner as two pieces of rod are spliced together to form a whip handle. To in- sure success, it is essentially necessary that the alburnum or inner bark of the scion should coincide accurately with the inner bark of the stock, because the vital union is effected by the sap of the stock rising up through" the soft wood of the scion. After the scion is tied to the stock, the graft is said to be made ; and it only remains to cover the part tied with a mass of tempered clay, or any convenient composition that will exclude the air. The season for performing the operation is, for all deciduous trees and shrubs, the spring, immediately before the movement of the sap. The spring is also the most favorable season for ever- greens ; but the sap in this class of plants being more in motion during winter than that of deciduous plants, grafting, if thought necessary, might be" performed at that season. Grafting by approach, or inarching, is a mode of grafting, in which, to make sure of success, the scion is not separated from the parent plant till it has become united with the stock. For this pur- pose, the stock and the plant containing the scion must be growing close together ; and the scion being drawn to one side, and made to approach the stock, is spliced to it by cutting off a portion of its bark and wood, and a similar portion of the bark and wood of the stock, applying the one to the other so that their alburnums may join, and then making both fast by matting, and excluding the air by clay, grafting wax, or moss. When the scion has effected a vital union with the stock, its lower extremity is cut through, so as to separate it from the parent plant, and it now becomes an independent graft. In this way trees of difficult propagation may be propagated with certainty ; while if any of the other modes of propagation, whether by cuttings or grafting, were adopted, a proportion of the cuttings or scions would , in all probability, be lost. Grafting herbaceous plants differs in no- thing from grafting such as are of a woody nature, excepting that the opera- tion is performed when both stock and scion are in a state of vigorous growth. Grafting herbaceous plants is but little practised in England, and on the Conti- nent chiefly as a matter of amusement. The only useful purpose to which it lias hitherto been applied, is that of grafting CYCLOPEDIA OF THE USEFUL ARTS. 225 the finer kinds of dahlias on tubers of the more common and vigorous growing sorts. In the Paris gardens the tomato is some- times grafted on the potato, the cauli- flower on the borecole, and one gourd on another, as matter of curiosity. Grafting the herbaceous shoots of woody plants — the greffe herbace of the French — is scarcely known among English gar- deners ; but it has been extensively em- ployed by French nurserymen, and even in some of the royal forests of France. The scions are formed of the points of growing shoots ; and the stocks are also the points of growing shoots cut or broken over an inch or two below the point, where the shoot is as brittle as as- paragus. The operation is performed in the cleft, manner : that is, by cutting the lower end of the scion in the form of a wedge, and inserting it in a cleft or slit made down the middle of the stock. The finer kinds of azalias, pines, and firs are propagated in this way in the French nurseries, and thousands of Pinus lari- cio have been so grafted on Pinus sylves- tres in the forest of Fontainebleau. At Hopetouii House, near Edinburgh, this mode of grafting has been successfully practised with Abies Smithiana, the stock being the common spruce fir. GRANITE is considered as the foun- dation rock of the globe, or that upon which all secondary rocks repose. From its great relative depth, it is not often met with, except in Alpine situations, where it presents the appearance of hav- ing broken through the more superficial strata of the earth, the beds of other rocks in the vicinity rising towards it at increasing angles of elevation as they ap- proach it. It is composed of three mi- nerals, viz., quartz, feldspar, and mica, which are more or less perfectly crystal- lized and closely united together. The three constituents of granite are as under, taking their mean : Feldspar. Quartz. Mica. Silica 64 96 47 Alumina 19 2 22 Lime 2 2 Potash 13 o 14-5 Iron, (oxide) 1 15 Mang. (do.) . 1'75 Granite has been divided into several sub-species, or varieties ; of these, the following are the most important : — Common granite, in which the three ordinary constituents above-mentioned occur in nearly equal proportions ; the feldspar may be white, red. or gray. Porphyritic granite, in which large crys- 10* VU1IOWUO K7L X^XVX0^7t*l «1 WAV penetrated perpendicularly imperfect crystals of quartz, \ tals of feldspar are disseminated through a common granite, whose ingredients are fine grained. Graphic granite, which consists of feldspar in broad laminae, with long whose trans- verse angular sections bear some resem- blance to certain letters, especially to those of Oriental languages. Sienite or sienitic granite, in which hornblende, either wholly or in part, supplies the place of mica. Talcky or chloruic granite (the protogine of the French), in which talc or chlorite takes the place of the mica. FeHspathic granite, in which feld- spar is the principal ingredient. The aspect of granitic mountains is extremely diverse, depending, in part, upon the nature of its stratification, and the degree of disintegration it has under- gone. Where the beds are nearly hori- zontal, or where the granite, from the preponderance of feldspar, is soft and disintegrating, the summits are rounded and heavy. Where hard and soft granite are intermixed in the same mountain, the softer granite is disintegrated, and falls away, leaving the harder blocks and masses piled in confusion upon each other, like an immense mass of ruins. Where it is hard, and the beds are nearly vertical, it forms lofty pyramidal peaks or aiguilles, like the Aiguille de Due and others, in the neighborhood of Mont Blanc. Granite forms some of the most lofty of the mountain-chains of the eastern continent. In Europe, the central part of the principal mountain-ranges is of this rock — as in Scandinavia, the Alps, the Pyrenees, and the Carpathian moun- tains. In Asia, granite forms a consi- derable part of the Uralian and Altaic ranges of mountains ; and it appears, also, to compose the principal mountains that have oeen examined in Africa ; whereas, in the western hemisphere, it has never been observed rising to such great elevations, or composing such ex- tensive chains. It is, nevertheless, very abundantly distributed over the northern Earts of the American continent, as in .abrador, the Canadas, and the t New England States. In New Hampshire, it is the predominating rock of the White Mountains, in which it attains the eleva- tion of more than 6000 feet. In the Andes, it has been observed at the height of 11,000, but is here generally covered by an immense mass of matter, ejected by ancient and recent eruptions. Granite very frequently forms veins 226 CYCLOPEDIA OF THE USEFUL ARTS. [gra shooting up into the superincumbent rocks, which seems to indicate that it has existed below in a state of fusion, the heat of which has softened and parted the tipper rocks, and forced up the granite, in a melted state, into these fissures. Granite abounds in crystallized earthy- minerals ; and these occur, for the most part, in those masses of it existing in veins. Of these minerals, beryl, garnet., and tourmaline, are the most abundant. It is not*rich in metallic ores, though it contains the principal mines of tin, as well as small quantities of copper, iron, tungsten, bismuth, silver, columbiurn, and molybdenum. Granite supplies durable materials for architecture and for decoration. It va- ries much in hardness, as well as in co- lor ; accordingly, there is room for much care and taste in its selection. GRANULATION ; the method of di- viding metallic substances into grains or small particles. This is done either by pouring the melted metal into water, or by agitating it in a box until the moment of coagulation, at which instant it be- comes converted into a powder. GRAPES. The method of training vines at Fontainebleau, where the famous f rapes are produced that supply the 'ans markets, consists in allowing the plants very little room to grow either with their branches or their roots, and in keeping the latter very near the sur- face of the ground ; each vine is only allowed to occupy a space of about six feet, so that the walls are supplied by a multitude of plants. The error in growing grapes in Britain consists in training them into elevations. They ripen best when trained near the ground, in open air. The heat of hot- ouses is an exception. Vineyards, in France, resemble plantations of goose- berry-bushes, with the bunches close to the soil, the heat of which ripens them. Grape Wine. Take water 4J galls., grapes 5 galls., crushed and soaked in the water 7 days, sugar 17£ lbs. The cask in which it was made held exactly 6f galls., and produced 34 bottles of wine clear. A bottle kept 10 years proved very good. To preserve Grapes. Take a well-bound cask, from which the head is to be re- moved, and place at the bottom a good layer of bran. On this place a layer of grapes, then bran and grapes alternately until the cask is full. Put on the head, which is to be cemented, and the grapes >will keep for a year. When used, in order to restore their freshness, fresh cut the stalk of each bunch, and place it in wine, as flowers are placed in water. GRAPE-SHOT. In artillery, a quan- tity of small shot put into a canvas bag, and corded together in the form of a cylinder, the diameter of which is adapt- ed to the piece of ordnance from which it is intended to be discharged. It is now superseded by canister-shot. GRAPHOMETER. A mathematical in- strument used in land surveying ; other- wise called a semicircle. GRAPHITE. The substance impro- perly called black lead, of which pencils are made. It is a peculiar form of mi- neral carbon with a trace of iron. The finest is found only at Borrodale in Cum- berland. Coarse varieties are not un- common. It occurs very abundantly throughout the United States. GRAPNEL. A small anchor for a boat. GRAPPLING IRONS. Small grapnels with four flukes for securing ships toge- ther in action. GRASS, is the union, in spring, of 11 species of natural grasses in one pasture ; in summer of 11 other species, and in autumn of 3 others, florin, yarrow, and couch. Certain weeds and flowers, also, mingle in small quantities, as butter- cups, burnet, sorrel, dock, &c. Some species prevail in particular soils, but the most general in all, is cocksfoot, meadow- fescue, crested dog's-tail, hand-fescue, sweet-scented vernal, rye, (grasses,) and upright brome. The meadow fox-tail and oat-grasses occasionally abound. GRAY DYE. The gray dyes, in their numerous shades, are merely various tints of black, in a more or less diluted state, from the deepest to the lightest hue. The dyeing materials are essentially the tannic and gallic acid of galls or other astringents, along with the sulphate or acetate of iron, and occasionally wine- stone. Ash-gray is given for 30 pounds of woollen stuff, by one pound of gall- nuts, i pound of wine-stone (crude tar- tar), ana 2i pounds of suiphate of iron. The galls and the wine-stone being boiled with from 70 to 80 pounds of water, the stuff is to be turned through the decoc- tion at a boiling heat for half an hour, then taken out, when the bath being re- freshed with cold water, the copperas is to be added, and, as soon as it is dissolved, the stuff is to be put in and fully dyed. Pearl-gray is produced by passing the stuff first through a decoction of sumach and logwood (two pounds of the former oua] CYCLOPEDIA OF THE USEFUL ARTS. 227 to one of the latter), afterwards through a dilute solution of sulphate or aceiatc of iron ; and finishing it in a weak bath oT weld containing a little alum. Mouse- gray is obtained, when with the same proportions as for ash-gray, a small quan- tity of alum is introduced. For several other shades, as tawny- gray, iron-gray, and sla^e-gray, the stuff must receive a previous blue ground by dipping it in the indigo vat ; then it is passed first through a boiling bath of sumach with galls, and lastly through the same bath at a lower temperature after it has received the proper quantity of solution of iron. For dyeing silk gray, fustet, logwood, sumach, and elder-tree bark, are employ- ed instead of galls. Archil and annotto are frequently used to soften and beau- tify the tint. GRAVITY. (See Specific Gkavity.) GREASE. Anti-attrition for axles : 1st. One part of fine black lead, ground gerfectly smooth, with four parts lard, ome recipes add a little campnor. 2d. Booth's Axle Gkease, (expired pa- tent.) Dissolve £ lb. of common soda in 1 gallon of water; add 3 lbs. of tallow, and 6 lbs. palm oil (or 10 lbs. palm oil only), heat them together to 200 or 210° Fahr. ; mix and keep the mixture con- stantly stirred till the composition is cooled down to 60 or 70°. A thinner composition is made with i lb. of soda, a gallon of water, a gallon of rape oil, and \ lb. of tallow or palm oil. GREEN PAINTS. Green, which is so common a color in the vegetable kingdom, is very rare in the mineral. There is only one metal, copper, which affords in its combinations uiq various shades of green in general use. The other metals capable of producing this color are, chromium in its protoxycfe, nickel in its hydrated ox- yde, as well as its salts, the seleniate, ar- seniate, and sulphate ; and titanium in its prussiate. Green pigments are prepared also by the mixture of yellows and blues ; as, for example, the green of Rinman and of Gellert, obtained by the mixture of cobalt hlue, and flowers of zinc; that of Earth, made with yellow lake, Prussian blue, and clay ; but these paints seldom appear in the market, because the greens are ge- nerally extemporaneous preparations of the artists. Mountain green consists of the hydrate, cxyde, or carbonate of copper, either fac- titious, or as found in nature. Bremen or Brunswick green is a mixture of carbonate of copper with chalk or lime, and sometimes a little magnesia or am- monia. It is improved by an admixture of white lead. It may be prepared by adding ammonia to a mixed solution of sulphate of copper and alum. Frise green is prepared with sulphate of copper and sal ammoniac. Mittis green is an arseniate of copper ; made by mixing a solution of acetate or sulphate of copper with arsenite of potash. It is in fact Scheel's green. JSap green is the inspissated juice of buckthorn berries. These are allowed to ferment for 8 days in a tub, then put in a press, adding a little alum to the juice, and concentrated by gentle evaporation. It is lastly put up in pigs' bladders, where it becomes dry and hard. Schweinfurt green ; see Schweinfcrt. Verona' green is merely a variety of the mineral called green earth. GREEN VITRIOL is sulphate of iron in green crystals. GREEN, PRUSSIAN, is the sediment of the two first processes for making Prussian blue, before the muriatic acid is added ; or it may be made by pouring oxymuriatic acid upon fresh precipitated Prussian blue. GREYWACKE, a German word of three syllables, which imports a forma- tion of distinct pieces of quartz, hard slate, and feldspar, combined in a bed of clay slate. But when the pieces are gran- ulated in the clay state, it is then called grey wacko slate. It contains early shells though a transition rock ; also transition limestone and trap, with many ores and veins. Since its formation there must have been at least 12 revolutions of the perihelion. GUANO or HUANO. A substance first noticed by Humboldt andsentby him from Peru to France, where it was ex- amined by Vauquelin. It is the excre- ment of sea-birds inhabiting the coast of South Seas. Besides excrement, it is made up of the remains of penguins, albatrosses, and gannetts, booby birds and seals. It is found at Chincha and Payta, in Peru, and in Chili. It also abounds in Ichaboe and a few smaller islands off the West coast of Africa. Peruvian guano is found on the islands of the Pacific, near the coast of Peru, and some of the head- lands on the adjacent shores between lat. 13° and 21° South. It is here deposited to the depth of 50 and 60 feet. Within this district rain seldom falls, and there is little waste either of the substance or quality of these accumulations from the 228 CYCLOPEDIA OF THE USEFUL ARTS. [qua lapse of time or the action of elements. The water fowl, which resort to this coast and the vicinal island, subsist principally on lish, and their faeces are, of course, richer in nitrogen than any species of the feathered tribes, excepting such as are exclusively carnivorous. The Chmcha islands, which afford the best Peruvian guano, are three in num- ber, and lie in one line from north to south, about half a mile apart. Each is- land is from five to six miles in circum- ference, and consists of granite covered with guano in some places to a height of 200 feet, in successive horizontal strata, each stratum being from 3 to 10 inches thick, and varying in color from light to dark brown. No earthly matter whatever is mixed with this vast mass of excre- ment. At Mr. Bland's visit to these is- lands in 1842, he observed a perpendicu- lar surface of upward of 100 feet of per- fectly uniform aspect from top to bottom. In some parts of these islands, however, the deposit does not exceed 3 or 4 feet in thickness. In several places, where the surface of the guano is 100 feet or more above the level of the sea, it is strewed here and there with masses of granite, like those from the Alpine mountains, which are met with on the slopes of the Jura chain. These seem to indicate an ancient formation for the guano, and ter- raqueous convulsions since that period. No such granite masses are found imbed- ded within the guano, but only skeletons of birds. The good preservation of the Chincha guano is to be ascribed to the absence of rain ; which rarely, if ever, falls between the latitude of 14° south, where these is- lands lie, about 10 miles from the main land, and the latitude of Paquica, on the island of Bolivia, in 21° S. L. By far the soundest cargoes of guano which have been analyzed have come from Chincha and Bolivia. Beyond these limits of latitude, where rain falls in greater or less abun- dance, the guano is of less value — and what has been imported from Chili lias been found very far advanced in decay — most of the ammonia and azotized ani- mal substances having been decomposed by moisture, and dissipated in the air (by the eremacausis of Licbig), leaving phos- phate of lime largely to predominate along with effete organic matter. The range of the American coast from which the giiano is taken must therefore be well consider- ed ; and should not extend much beyond the Chincha islands as the northern limit, and Paquica, in Bolivia, as the southern. Peruvian guano is of a light brown co- lor, resembling yellow loam, and is the best guano yet discovered, or than any other manure yet known ; besides nitro- gen, which it contains so abundantly, it contains a large amount of phosphoric acid united with lime and magnesia, and as both of these substances are so neces- sary to the cultivated crops, it is the rea- son why this substance is the manure. i The following remarks of Dr. Ure ex- plain this point more fully : — The admirable researches of Professor Liebig have demonstrated that Azote, the indispensable element of the nourish- ment of plants, and especially of wheat | and others abounding in gluten (an azo- tized product), must be presented to them : in the state of ammonia, yet not altoge- ther ammonia in the pure or saline form, i for, as such, it is too readily evaporated | or washed away ; but in the dormant, or | as one may say, in the potential condition \ in contradistinction from the actual. ; Genuine Peruvian and Bolivian guanos, | like those which have been minutely ana- j lyzed, surpass very far all other species of manure, whether natural or artificial, in : the quantity of potential ammonia, and, ; therefore, in the permanency of their ac- : tion upon the roots of plants, while, in : consequence of the ample store of actual ' ammonia which they contain ready form- ed, they are qualified to give immediate vigor to vegetation. Urate of ammonia constitutes a considerable portion of the ! azotized organic matter in well-preserved 1 guano; it is nearly insoluble in water, not at all volatile, and is capable of yield- ing to the soil, by its slow decomposition, nearly one-third of its weight of ammonia. No other manure can rival this animal sa- line compound. One of the said samples of guano afforded me no less than 17 per cent, of potential ammonia, besides 4i per cent, of the actual or ready formed ; others from 7 to 8 per cent, of ammonia in each of these states respectively. These guanos which were examined are the mere excrement of birds, and are quite free from the sand, earth, clay, and common salt, reported in the analyses of some guanos, and one of which (sand) to the amount of 30 per cent, has been found in a sample of guano from Chile. The Peruvian guano, moreover, con- tains from 10 to 25 per cent, of phosphate of lime, the same substance as bone-earth, but elaborated by the birds into a pulpy consistence, which, while it continues in- soluble in water, has been thereby ren- i dered more readily absorbable and diges- gdd] CYCLOPEDIA OF THE USEFUL ARTS. 229 tible (so to speak) by the roots of plants. There is therefore no doubt, that by the judicious application of these genuine gu- anos, mixed with twice or thrice their weight of a marly or calcareous soil, to convert their phosphate of ammonia into phosphate of lime and carbonate of am- monia, as also to dilute all their ammoni- acal compounds — such crops will be pro- duced, even on sterile lands, as the far- mer has never raised upon the most im- proved soil by the best ordinary manure. To the West India planter, guano will prove the greatest boon, since it conden- ses in a portable and inoffensive shape the means of restoring fertility to his ex- hausted cane-fields, a benefit it has long conferred on the poorest districts of Peru. Messrs. A. Gibbs, of London and Li- verpool, have a monopoly of the sale of Peruvian guano. This, perhaps, is not to be regretted, as what comes direct from them is genuine, and otherwise it is im- possible to procure an unadulterated ar- ticle, so great is the temptation and exten- sive the use of the article. A sample lately imported into New-York by Messrs. A. B. Allen, Watcr-st., N. Y., and ana- lyzed by the editor, afforded by chemical examination in 100 parts, Water T 83 Organic matter and salts of ammonia as urate oxalate and sulphate 69*79 Phosphates of lime and magnesia and ammonia phosphate of magnesia. . .17"60 Lime -60 Sulphuric acid 3' Alkaline salts, chloride of sodium, and traces of potass -48 Sand 1-20 100-00 This guano was capable of yielding 12& percent, of ammonia. The following analysis of a good sample of Peruvian guano made by the late Mr. Fownes, Englandj affords a good idea of what is the constitution of a superior ar- ticle in 100 parts : Azotized animal matter, including urate of ammonia and other ammo- niacal salts, together, capahle of af- fording from 8 to 16 per cent of ammonia by slow decomposition in the soil 50* Water 11- Phosphate of lime 25* " of ammonia, oxalate of am- monia, phosphate of magnesia, toge- ther, yielding from 5 to 9 parts of ammonia 13* Silica I- 100' From the foregoing analysis its valu- able character is evident. This is sus- tained by the astonishing and generally profitable results which follow its appli- cation, and has rendered it, though of re- cent introduction, one of the most popular manures in this country and Europe. It has been known and appreciated by the Peruvians, from time immemorial ; and by its liberal use, combined witn irrigation, they have for ages produced the most abundant crops of maize and wheat. It was not used agriculturally in Europe until 1840 ; in England at present 400,000 tons per year are used. African or Ichaboe and Patagonian guano have been brought into this coun- try to a limited extent. They have been used with advantage, but are by no means equal to the Peruvian variety. Those guanos have been accumulated in damp climates, and have hence under- gone decomposition, so that most, if not all, the urate of ammonia is broken up into oxalate of ammonia — a salt far less valuable in agriculture : even this is dis- sipated and washed away by the rains, so that the proportion of "ammoniacal salts falls often in this variety below 20 per cent., leaving the phosphates in a corresponding excess, so that it more re- sembles bones in composition. Guano was first introduced into the States in 1825, when it was used in gar- dens, and forgotten : after its use in England it was again re-imported. Its application here was but slow in in- crease, yet it has advanced, and the de- mand for this year will probably be 25,000 tons. Its value cannot be over-esti- mated, as it is suitable for almost all crops and soils, but is perhaps best adapted for sandy loams. From 2 to 5 cwt. is a proper dressing. It is better to compost it with five times its bulk of loam, vegetable mould, or with char- coal or gypsum. Lime or ashes must be avoided carefully, as the ammonia is thus driven off. It snould be kept dry and under cover, as that which smells strong- est is losing its ammonia. It is usually spread broadcast on meadows and grain, or placed with the seeds in the hill : it develops both leaf and ear wonderfully, and hence is as suitable for grain as for green crops ; it ought to be used only in autumn or in spring in the south. The sun's heat is too great for summer application, the loss of ammonia being very great. GUDGEONS are the ends of axles, on which they work and rest. In water- 230 CYCLOPEDIA OF THE USEFUL ARTS. [gur ■wheels they ought to be strong enough, but not so large as to increase friction un- necessarily. The proportions of wrought iron and cast iron are as 3 inches to 3i or 8 to 9J. To determine their diameter, extract the cube-root of the weight of the wa- ter-wheel, in hundred weights, and the root is the inches for the diameter in cast-iron ; but if wrought-iron, it may be as 14 to 9 less. If it is a wooden axle, multiply the diameter in feet by the width in feet, and add half the square of the diameter : then the cube-root of this sum is the diameter of the fit gud- geon in inches. A gudgeon contains in cwts. the cube of its diameter in inches. GUM. A vegetable product, distin- guished by solubility in water, and in- solubility in alcohol : it is tasteless and inodorous. Gum-arabic, which is the produce of the Acacia vera, may be taken as a sample of the purest form of gum. It is imported from Barbary and Morocco. Its specific gravity is 1-45. Its solution is viscid, and is termed mucilage. Gum is used as a demulcent in medicine, and for giving a gloss to linens, silks, &c. It consists of carbon 41*4, oxygen 52*09, hydrogen 6-51 ; or, in other terms, of 41-4 charcoal and 58-6 water. Guerin has analyzed several varieties of gum. Arabia, which constitutes the greater portion of gum-arabic, is com- posed of Carbon 43 81 Oxygen 4985 Hydrogen 6 20 Azote 14 100-00 Gum-arabic is found to consist of Arabin 7940 Water 1760 Ashes 3 00 100 00 Messrs. Gay-Lussac and Thenard found its composition to be : Arabin 8416 Water 1343 Ashes 2 41 10000 The difference of water found depended upon the different methods of analysis. The dried root of the blue-bell contains mucilage, very similar to gum-arabic. Gum Senegal is less soluble than gum- arabic, and deeper in color. GUM-RESIN. An exudation from many trees, composed of a mixture of gum and resin, or of a substance inter- mediate between the two. GUN. Under this general term most of the species of fire-arms are included, the pistol and mortar being almost the only exceptions. Great guns, or cannon, began to be used as military engines about the middle of the 14th century ; but small guns, or muskets, appear to have been introduced nearly two centuries later, namely, 1521. They were first used by the Spanish infantry at the siege of K'hege. Muskets were at first of a very clumsy construction, being so heavy that they could not be levelled and fired from the shoulder ; accordingly the soldier was provided with a rest, which it was ne- cessary to carry along with him and plant in the ground in order to support the weapon before it could be used. The gun was generally fired with a match ; sometimes by means of sparks gene- rated by the revolution of a notched wheel of steel, placed directly above the pan containing the priming. Muskets with rests were employed so lately as the civil wars in the time of Charles I. ; afterwards a lighter matchlock musket came into use : and about the beginning of the last century the troops through- out Europe were armed with firelocks. Small guns were invented by Swartz, a German, about 1378 ; brought into use by the Venetians, 1382. Cannon were first used at the battle of Cressy, 1346 ; first used in England at the siege of Ber- wick, 1405 ; first cast in England, 1544 ; used in shipping by the Venetians, 1539 ; before they were only used to batter walls. Mohammed, at the siege of Con- stantinople, employed some of the larg- est guns ever made use of before or since. One of his cannon was of such enormous size as to require 70 yoke of oxen to draw it, and 2000 men to man it. It discharged a ball of the weight of 300 lbs. The report waB heard to a great distance, and the country shaken to the distance of 40 furlongs. The barrel forms the essential part of the gun ; and the first requisite to a good barrel is toughness in the material of which it is made, for safety iu using it depends mainly on this quality. The best iron for the formation of musket barrels is that which has been much worn, and toughened by the loss of its fiery particles ; and, accordingly, old horse stub-nails are much in request for this Eurpose, and sold at a high price to the arrel-forgers. Formerly the best gun- barrels were made in Spain ; and their gun] CYCLOPEDIA OF THE USEFUL ARTS. 231 superiority was attributed to the excel- lency of the iron made use of, which consisted almost exclusively of stub-nails, and the old shoes of horses and mules : but the barrels now made in this coun- try are not inferior to those of any coun- try in the world. The method of mak- ing the barrel is this : the iron is first formed into a thin flexible bar, some- thing like a cooper's hoop, and when heated is plied or twisted round a man- dril, much in the same manner as a rib- bon of leather is turned round the handle of a whip. For the best barrels the breadth of the bar does not exceed half an inch ; and it is turned round the man- dril in such a manner that the edges are brought close together, but do not over- lap. In this position it is wedded by horizontal strokes with the hammer. But in common guns a broader bar is em- ployed ; and its edges, which are placed so as to overlap considerably, are welded down on each other. The Damascus barrels, prized for their beauty, though inferior in strength, are composed of iron and steel in certain proportions laid crossways, and hammered together the whole length of the barrel. After the barrel has been forged, the inside is ren- dered smooth and perfectly cylindrical by boring it with a bit, or rather bits of different sizes used in succession. In ri- fles a certain number of parallel grooves, either straight or slightly twisted, are cut in the inside of the barrel, of equal depth and fineness, and through its whole length. The exterior is smoothed by turning it on a lathe. Mr. Aaron Eose, of Worcester, Eng- land, has just enrolled his description of a new method of manufacturing twisted gun barrels, which is thus described : — An iron or steel rod, or a mixture of both, of sufficient length and thickness to form a gun or pistol barrel, is wound into a compact coil, and then placed in an anvil having a semi-circular groove, where it is submitted to the action of the tilt hammer. The coil is then submitted to a welding heat in an air furnace, then hammered and rolled, a stream of water being used in both cases to wash away the scale. The tilt hammer has a groove on its face corresponding with the anvil to act upon the coil, before the welding. Mr. Vandenberg, a Flemish gentleman, has invented a new gun which can make six and eight charges per minute, carry- ing the distance of 2000 feet ; the ball weighs about one ounce and a quarter, and the powder is one-twelfth the weight of the ball. An ordinary gun requires three times more powder, the ball does not weigh half an ounce. The new gun is loaded from the breech. The shape of the ball is round. At Utica, N. Y., the new rifle of Mr. Milo M. Cass dis- charged 24 balls in two minutes and 30 seconds ; then loading with 26 cartridges in 4 minutes, and discharged 24 in 2 mi- nutes and 30 seconds, — thus loading once and firing 48 shots in 9 minutes, The shooting was very accurate, considering the rapidity, and the performance of the gun gave great satisfaction to those pre- sent." The barrel of the gun was so little heated after the first 24 discharges, that it was immediately loaded and again fired the same number of times. _ The Air-Gun is a machine in which highly-compressed air is substituted for gunpowder to expel the ball, which will be projected forward with greater or less velocity, according to the state of conden- sation and the weight of the body pro- jected. The effect will, therefore, be similar to that of a gun charged with gunpowder, for inflamed gunpowder is nothing more than air very greatly con- densed, so that the two forces are exactly similar. There is this important con- sideration to be attended to, namely, that the velocities with which balls are im- pelled are directly proportional to the square root of the forces ; so that if the air in an air-gun be condensed only ten times, the velocity will be equal to one- tenth of that arising from gunpowder ; if condensed twenty times, the velocity would be one-seventh that of gunpow- der, and so on. Air-guns, however, pro- ject their balls with a much greater ve- locity than that assigned above ; and for this reason, as the reservoir or magazine of condensed air is commonly very large in proportion to the tube which contains the ball, its density is very little altered by passing through that narrow tube, and consequently the ball is urged all the way by nearly the same force as at the first instant ; whereas the elastic fluid arising from inflamed gunpowder is but very small indeed in proportion to the tube or barrel of the gun, and therefore, by dilating into a comparatively large space, as it urges the ball along the bar- rel, its force is proportionally weakened, and it always acts less and less on the ball in the tube. An air-gun recently invented by Mr. Shaw, of Glassop, England, is one of much simplicity of construct >n. It has 232 CYCLOPEDIA OF THE USEFUL ARTS. not the effective force of gunpowder, but it will enable a sportsman to amuse him- self at but little expense, and will do execution, too, at considerable distance from the mark. The air that projects the bullet is condensed by a piston, which draws out a strong India rubber spring, which, when it is set free, suddenly draws up the piston, condensing the air in the air chamber, and impelling it against the bullet to discharge it with considerable velocity and power. GUNPOWDER is explosive nitre brought into intimate contact with in- flammable sulphur and charcoal. 75 of the nitre, 16 of charcoal, and 9 of sul- phur, pounded as paste with wooden mortars, fixed in a wheel for 12 hours. It is granulated by being forced through a sieve, and glazed by agitation in a cask. The gas formed by an explosion is 2 volumes of nitrogen to 1 carbonic acid. Dr. Ure has analysed various samples of gunpowder, "and the following are the results of his investigations : — Waltham Abbey, nitre 74*5, charcoal 14-4, sulphur 10*0, water 1*1. Hall, Dartford, nitre 76-2, charcoal 14-0, sulphur 9*0, water 0-5. Pigou and Wilks, nitre 77*4, charcoal 13-5, sulphur 8*5, water 0*6. Curtis and Harvey, nitre 76*7, charcoal 12*5, sulphur 9*0, water 1*1. Battle gunpowder, nitre 77*0, charcoal 13-5, sulphur 8-0, water 0-8. Charcoal, sulphur, and nitre, being ready for manufacturing into gunpowder. 1st. They are separately ground to a fine powder, which is passed through proper silk sieves or bolting machines. 2d. They are mixed together in the proper proportions. 3d. The composition is then sent to the gunpowder mill, which consists of two edge-stones of a calca- reous kind, turning by means of a hori- zontal shaft on a bed-stone of the same nature ; incapable of affording sparks by collision with steel. On this bed-stone the composition is spread, and moistened with as small a quantity of water as will, in conjunction with the weight of the re- volving stones, bring it into a proper body of cake, but by no means to a pasty utate. The line of contact of the rolling edge-stone is constantly preceded by a hard copper scraper, which goes round with the wheel, regularly collecting the caking-mass, and bringing it into the track of the stone. The materials for gunpowder are ground by a wheel revolving in a trough. They are then moistened and put into boxes with holes in the bottoms. The boxes are placed in a circular frame suspended by cords, and briskly agitated by a crank, when the paste passes through the holes as corns ot powder. These are afterwards polished by being revolved in a barrel, dried by vessels of steam, and packed for sale. Gunpowder to be good should ba quick, strong, free from impurity, and not liable to absorb moisture. The gene- ral method of trying the purity is by burning it on clean white paper : two or three small heaps are made near each other, and one of them is fired ; if the smoke rises perpendicularly, and there be no feculent matter left on the paper, nor the other heaps fired, it is considered that the ingredients were of a good qual- ity, and well compounded. If the other heaps are fired, the paper burnt, or a dirty residuum left, it may be supposed that the nitre was impure, or that the charcoal was not completely pulverized. M. Angendre, Assayer at the Mint of Constantinople, has addressed a commu- nication to the Academy of Sciences at Paris, describing the discovery of a new explosive powder, having for its base the prussiate of potash. The composition is (by weight) crystallized dry yellow prus- siate of potash one part, dry white sugar one part, chlorate of potash one part. These three substances are reduced se- parately in a mortar to fine powder, and then intimately mixed by hand. In ope- rating on any quantity, the mixture is moistened with a very little water, and beaten in a bronze mortar with a wooden pestle. It is not necessary that the mix- ture should be as intimate as in the case of ordinary gunpowder, — a quarter of an hour will suffice to mix it. It is then grained in the ordinary manner, and dried in the air. The discoverer, M: An- gendre, considers that this powder is equal in strength to three times its weight of the common kind. It is easily made, and the substances of which it is composed have a fixed and determined composition. It is not injured either in dry or damp air, but it is not suitable for small fire-arms, only for those of cast- iron, and it will answer a good purpose in blasting. The reason why it is not good for any fire-arms of steel is owing to the chlorate of potash, which oxidizes steel with great rapidity. Some of our civil engineers may find this powder in- valuable for blasting, as they can make it themselves, it being equally as effec- gun] CYCLOPEDIA OF THE USEFUL ARTS. 233 tive when in a state of powder as when grained. No other powder must he al- lowed to mix with it, for in ramming the hore for a hlast, the friction of the parti- cles of the old powder will be ready to ignite the new kind. GUNTER'S CHAIN, so called from its reputed inventor, is the chain com- monly used for measuring land. It is 66 feet or 4 poles in length, and is divided into 100 links, each of which is joined to the adjacent one by three rings ; and the length of each link, including the connecting rings, is 7-92 inches. The advantage of this measure consists in the facility which it affords to numerical cal- culation. The English acre contains 4840 square yards ; and Gunter's chain being 22 yards in length, the square ot which is 484, it follows that a square chain is exactly the tenth part of an acre. A square chain again contains 10,000 square linics, so that 100,000 square links are equal to an acre ; consequently, the contents of a field being cast up in square links, it is only necessary to di- vide by 100,000, or to cut off the last five figures, to obtain the contents expressed in acres. GUNTEE'S LINE. A logarithmic line engraved on scales, sectors, &c, serving to perform the multiplication and division of numhers instrumentally, as a table of logarithms does arithmeti- cally. The numbers are usually drawn on two separate rulers sliding against each other. In rough calculation this line affords considerable facilities. GUNTER'S QUADRANT. A quad- rant of a peculiar kind adapted to the problems of finding the hour of the day, the sun's azimuth, and other common problems of the sphere. GUN COTTON was first announced by Professor Schonbein, and shown by him to the Natural History Society of Basle in 1846. Shortly after this Bcelt- zer, Otto, and Morel, discovered similar explosive compounds, all of which may fairly be traced to Pelouse and Brac- caurd's discovery of Xyloidine. It has been looked on as identical with the lat- ter, but n^t correctly, for gun cotton dis- solves in acetic acid, while xyloidine does not. Schonbein made it originally by dipping cotton in nitric acid, sp. gr. 1*49, which after immersion for ten mi- nutes it was rinsed in a large quantity of cold Avater, to free it from any adher- ing acid ; and then carefully dried. Dr. Ellet, Professor of Chemistry in Univer- nity of South Carolina, adopted as an im- provement the use of sulphuric acid, with the view of keeping the nitric acid concentrated. Dr. Taylor, of London, adopted a similar plan ; nitre was after- wards added to the mixed acids. In order to obtain a good gun cotton it is necessary 1st. To steep purified cotton in a mix- ture of equal parts of nitric and sul- phuric acids. 2d. The duration of immersion is not important : the best samples have been ten minutes steeped. 3d. A mixture may be used in which cotton has been previously immersed, re- viving it if necessary. 4th. The cotton must not be above the level of the liquid. 5th. It must be dried slowly, and not exposed, especially when damp, to a tem- perature exceeding 100°. 6th. By washing in water saturated with nitre or chlorate of potass its power is a little increased, but it is not worth the additional expense. Burned on the hand it causes no sen- sible pain, leaves no stain, and produces no smoke ; dipped in water and pressed, and afterwards dried between two leaves of blotting paper, it preserves its fulmi- nating properties. It explodes on being heated to 350°, or on bringing a red hot body in contact with it : a dry piece of the cotton laid upon gunpowder may be exploded without igniting the powder. This is due to the rapidity of the explo- sion. Mr. E, F. Teschemacher and Mr. R. Forrett have found gun cotton to con- sist uniformly of nitric acid and liquin, in the proportion of 60 of the former to 40 of the latter. Properly exploded in a narrow glass tube so as to collect the gaseous product, 52-33 grains of the cot ton were found to give 100 c. i. of gas, of which the composition was remark- able, consisting of Carbonic acid 14-286, or 2 vols. Cyanogen 7143, or 1 vol. Nitric oxide 35-715, or 5 vols. Carbonic oxide 35915, or 5 vols. Nitrogen 7-143, or 1 vol. Besides which a sublimate of oxalic acid and a quantity of water was formed in the combustion. Exposed to a dry heat, between 200° and 300°, it became brown, and lost its explosive property. Steaming it, seems to increase its power. Examined under the microscope, there is no difference visible betAveen cotton so prepared and that unacted on by acid. Under the action of polarized light there CYCLOPEDIA OF THE USEFUL ARTS. [gut is, however, a marked difference. The fibres of ordinary cotton are then bril- liantly illuminated on a dark colored ground, while the gun cotton is dark and colorless, and invisible at every half turn of the prism. In practice, it has not fulfilled all that was originally predicted of it; it is unfit for gunnery and fire-arms of any kind, but is admirably adapted for mining and blasting. The advantages of its use are: its cleanliness, the rapid combustion, and non residuum ; the absence of any bad smell ; its lightness : the possibility of handling it without danger at a distance from the fire ; the absence of dust, and its indisputable force, which is triple that of gunpowder of equal weight. The disadvantages are : bulk, increased in- flammability, the disadvantage of evolv- ing vapor during its explosion ; it wets the guns and cannon just as gunpowder /outs them. Gun cotton dissolved in ether forms a good varnish for covering wounds, or giving a thin film to cover any surface, and is a powerful deoxidizer, reducing salts of silver and a few other metals very rapid , y. GIjTTA PERCH A, or Gutta Tvban. The Malay name for the concrete juice of a large forest tree : one of the Sapoteae — a native of Borneo, Malacca, and the neighboring countries. It is chiefly brought from Singapore : it was used by the natives as a substitute for horn and wood, to make handles for knives and choppers. The juice is obtained by cut- ting down the tree, and allowing the juice to exude from the cut end. This is a most wasteful proceeding, as the number of trees must shortly be so limited as to destroy the supply of the article. Mr. Brooke, of Borneo, says the tree is often six feet in diameter at Sara- wak, and is believed to be plentiful all over Borneo, and probably at the thou- sand islands that cluster to the south of the Straits of Singapore. Its frequency is proved by the circumstance that seve- ral hundred tons of the Gutta Percha have been annually exported from Singa- pore since 1842, when the substance first came into notice. There is reason, how- ever, to fear that the supply must shortly decrease, and the price he raised, from the wasteful mode in which the natives collect it, often sacrificing a noble tree, of from fifty to one hundred years growth, for the sake of twenty or thirty pounds of gum, which is the largest quantity any one trunk ever affords. The juice might, in all likelihood, be obtained from the Percha, as from other trees, by tap- ping, and thus procuring a smaller por- tion for several successive years; but this process is too slow for the Malayans, and is also less likely to be adnpted be- cause the forests are common property. The people fell the tree, strip off its bark, and collect its milky juice in a trough formed of the hollow stem of the plantain leaf, when, being exposed to the air, it soon coagulates. As it comes to market, it is a dirty white, pinkish, solid, opaque, having but little smell, and insoluble in water ; it has a silky, fibrous texture, especially when drawn out. It feels smooth and greasy between the fingers. Below 50° it is hard, tough, and partially flexible, when thin like horn ; between 50° and 70°, it is elastic, and more flexible, yet still tough and stiff 2 between 140° and 160°, .it becomes quite soft and plastic, and loses its tenacity. In this stato pieces of it may be joined, all that is ne- cessary being to press them together, when they form a perfect joint. By cut- ting it up in fragments, and boiling in hot water, most of the impurities may be removed. When thus purified by cooling, it passes into a solid mass ; when softened by either hot water or simple dry heat, it may be molded into any shape, or pressed into a pattern : as it cools, it gradually recovers its tough- ness and rigidity. In consequence of this it forms perfect casts of coins, me- dals, &c, which, if carefully made, have all the sharpness of sulphur without its brittleness. When hot, it is easily cut with the knife or saw, but when cold it is difficult to cut it, without wetting the tool with cold water. It is lighter than water, and floats on it : the spec, gravity being when pure -9791. In its chemical relations it closely resembles caoutchouc, and is isomeric with it : it differs, how- ever, in some physical properties. By destructive distillation it yields similar products, affording a clear limpid oil of a mixed composition between 360° and 390°. It is insoluble in alcohol and water, dissolves partially in oil of tur- pentine, ether, and perfectly in cold naphtha, benzole, sulphuret of carbon, and caoutehicine. Or these the benzole is the fittest; when dissolved in it by the aid of gentle heat, and then poured out on a glass plate to evaporate the benzole, the gutta percha is left behind in the form of a white film or skin. In gut] CYCLOPEDIA OF THE USEFUL ARTS. 235 this way very thin sheets of this sub- stance is obtained. Souberain has made an ultimate analysis of it, which yielded to him carbon 87-8, hydrogen 12-2. Mr. Crane believes the crude article to be composed Of two substances: 1st, the pure white gntta ; and 2d, a brown color- ing material. Benzole separates them. Dr. Montgomerie suggests, among the less immediately obvious uses to which gntta percha is applicable, that of mak- ing raised type for the blind, and em- bossed maps for the same unfortunate beings : it takes a clear, sharp impres- sion, and is also tough and durable ; he thinks it would likewise be found ser- viceable in stopping decayed teeth. G. Hancock, Esq., has taken out a pa- tent for improving the manufacture of gntta percha. He suggests several me- thods of purifying the substance, which generally comes here much mixed with extraneous matter. It may be dissolved by heat and strained, or passed through a screw press, or melted by the addition of rectified oil of turpentine ; and, after filtering through flannel or felt, the sol- vent may be evaporated. In every case the gutta percha should form a residuum of the consistency of dough or putty — this plastic state being gained by the maintenance of a suitable temperature during the above process. Mr. Hancock would combine gutta percha with caoutchouc, and a substance called gintawan (we have no clue to what this gintawan may be), in order to form an elastic material impervious to water ; varying the proportions according to the greater or less degree of hardness or elasticity required for making elastic bands — a compound is used where 50 parts of gutta percha are combined with 24 of gintawan, 20 of caoutchouc, and 6 of orpiment. From a mixture of these, Mr. Hancock also prepares a light, po- rous, and spongy material, suited for stuffing or forming the seats of chairs, cushions, mattresses, saddles, &c. ; like- wise, springs of clocks, clasps, belts, garters, and strings. Wherever the re- quisite is flexibility and elasticity, then the quantity of gutta percha should be diminished, and increased where firm- ness is wanted. By prolonging the pro- cess much hardness may be acquired, and moulds and balls of gutta percha will bear turning in the lathe, like wood or ivory. The material is also applica- ble to useful and ornamental purposes, as picture frames, door handles, walking sticks, chessmen, handles of swords, and knives, buttons, combs, flutes, &c, &c. By the admixture of sulphuric acid, or of a tenth or larger part of vegetable wax or tallow, any degree of solubility, pli- ancy, and softness, may be acquired ; or the composition may be used as varnish to cover other materials, concealing any odor, and imparting a surface impervious to water. In printing silks and cottons it is useful, as it amalgamates readily with colors. The applications of gutta percha are endless : it makes good tubes lor conveying water or gases ; speaking tubes, and hose ; drinking vessels, pitch- ers, basins, and other domestic articles. An extensive use' is as soles for shoes, which are fastened to the clean and rasped leather sole by a fluid varnish made of the gutta dissolved in coal tar. A solution of it forms a good varnish for wires or cordage, or any substance which it may be desirable to protect or insulate. It is sulphurized occasionally, and some- times combined with caoutchouc. At the American Gutta Percha Company, having their factory in Brooklyn, !N. Y., the various modifications and articles of which this substance is susceptible of being applied to, is interestingly demon- strated. Gutta percha is of the most powerful negative electrics, and may be used for insulating positive surfaces, or for de- veloping quantities in place of the glass cylinder. A thin sheet of this substance wrapped round a bottle or wooden cylin- der, and turned by hand, gives a copious supply of the fluid for experiment. Previous to 1844, the very name of gutta percha was unknown to European commerce. In that year two cwt. of it was shipped, experimentally, from Sing- apore. In the first four and a half years of the trade, 21,598 pieuls of gutta percha valued at $274,190, were_ shipped at, Singapore, the whole of which were sent to England, with the exception of 15 pieuls to Mauritius, 470 to the Continent of Europe, and 922 to the United States. But this rapid growth of the new trade conveys only a faint idea of the commo- tion it created among the native inhabi- tants of the Indian Archipelago. The jungles of Johore were the scenes of the earliest gatherings, and they were soon ransacked, in every direction, by parties of Malays and Chinese, while the indi- genous population gave themselves up to the search with a unanimity and zeal only to be equalled by that which made railway jobbers of every man, woman, and ciiifd in ' England, about the same CYCLOPEDIA OF THE USEFUL ARTS. f< time. The knowledge of the article stir- ring the avidity of gatherers, gradually spread from Singapore northward as far as Penang, southward along the east coast of Sumatra to Java, eastward to Borneo, where it was found at Brune, Sarawak and Pontianak on the west coast at Keti, and Passe on the east. GYPSUM. Sulphate of lime, alabaster ; plaster of Paris. Plaster. This sub- stance is found in three geological situa- tions in the crust of the earth : 1st, among the early secondary rocks ; 2d, in the new red sandstone formations, and above the chalk in the tertiary beds. The gypsum of England is' found in the new red sandstone, that of France in the ter- tiary beds, and that of this country is chiefly in the secondary formation. In the State of New- York are the best de- veloped beds of gypsum as yet explored in this country, where they are found in the beds known to correspond with the tipper Silurian strata of English geolo- gists. It extends over the central and western portions of the State in a belt extending from east to west, where it thickens as it advances until it reaches Ontario county, where its greatest purity and development appears to exist. It is quarried extensively in Cayuga, Yates, and Ontario county. The purest varie- ties consist of the elements of the crys- tallized selenite or alabaster, viz. : Sulphuric acid 40 Lime 28 Water 18 In 86 parts. But the rock gypsum is never so pure ; it contains aluminous or argillaceous clay, and variable quantities ot carbonate of lime and magnesia, soluble salts, and silica. The Editor of this work having occasion to examine the soils and mine- rals of Seneca county, N. Y., found the composition of the rock gypsum to be as follows in 100 parts. Water 660 Carbonate oflime 17-40 Carbonate of magnesia 9-80 Insoluble silicates and sand 39 60 Salis of alkalies soluble in water. '40 Sulphate of lime 2620 10000 The gypsum of Ontario county is pur- er, and is fit for application in the arts, which the above is not. These beds of gypsum occur chiefly in isolated masses, appearing as if they had crystallized out of a plastic moist clay, and are generally surrounded by a gypseous marl made up of the carbonates of lime and magnesia and sulphate of lime. These marls, as well as the above impure gypsum, are admirably adapted for agricultural use as amending manures, and are not used at all to the extent which their value would justify. The most interesting gypsums in a general point of view are certainly the tertiary, or those of the plains, or hills of comparatively modern formation. They are characterized by the presence of fos- sil bones of extinct animals, both mam- mifera and birds, by shells, and a large proportion of carbonate of lime, which gives them the property of effervescing with acids, and the title of limestone gypsums. Such are the gypsums of the environs of Paris, as at the heights of Montmartre, which contain crystallized sulphate of lime in many forms, but most commonly the lenticular and lance- shaped. Sulphate of lime occurs either as a dense compound without water, and is called anhydrite from that circumstance, or with combined water, which is its most ordinary state. Of the latter there are six sub-species ; sparry gypsum or selenite in a variety of crystalline forms ; the foliated granular ; the compact : the fibrous ; the scaly foliated ; the earthy. < The prevailing color is white, with va- rious shades of gray, blue, red, and yel- low. More or less translucent. Soft, sectile, yielding to the nail. Specific gravity 2-2. Water dissolves about one five-hundredth part of its weight of gyp- sum, when it acquires the quality of hard- ness, with the characteristic selenitic taste. When exposed on red hot coals, it decrepitates, becomes white, and splits into a great many brittle plates. At the heat of a baker's oven, or about 400° Fahr., the combined water of gypsum escapes with a species of ebullition. At a higher temperature the particles get indurated. When rightly calcined and pulverized, gypsum is mixed with water to the consistence of cream, and poured into moulds by the manufacturers of stucco ornaments and statues. A spe- cies of rapid crystallization ensues, and the thin paste soon acquires a solid con- sistence, which is increased by drying the figure in proper stoves. During the consolidation of the plaster, its volume expands into the finest lines of the mould, so as to give a sharp and faithful impression. The plaster stone of the Paris basin UAl] CYCLOPEDIA OF THE USEFUL ARTS. 23' contains about 12 per cent, of carbonate , of lime. This body, ground and mixed j with water, forms an adhesive mortar i much used in building, as it fixes very speedily. Works executed with pure gypsum never become so hard as those made with the calcareous kind; and hence it might be proper to add a certain portion of white slaked lime to our cal- cined gypsum, in order to give the stuc- eo this valuable property. Colored stuc- cos of great solidity are made by adding to a clear solution of glue any desired coloring tincture, and mixing in the pro- per quantity of the calcined calcareous gypsum. The compact, fine-grained, gypseous alabaster is often cut into various orna- mental figures, such as vases, statuary groups, urest plasters arc those which harden east, and that the addition of lime is of no use toward promoting their solidity, nor can the heat proper for boiling gyp- N»nm ever expel the carbonic acid gas from the calcareous carbonate present in the gypsum of Montmartre. He con- ceives that a hard plaster-stone having lost its water, will resume more solidity in returning to its first state than a plas- ter-stone naturally tender or soft ; and that it is the primitive molecular ar- rangement which is regenerated. Franklin was the first to call public at- tention to the use of gypsum as a ma- nure, and by the experiment of sowing it in the form of letters on a field, which when the grass grew could be read by its superior growth and verdure, tested fully its value. It is now justly considered indispensable to good farm- ing, but it exerts its chief value only on dry or drained soils. Sands and loams feel its influence at once. Two pecks on sandy soils and fifteen bushels on clays have been applied : the farmers of Western New- York look uponjtwo bush- els per acre as sufficient. It is chiefly valuable to leguminous plan's, as pease, beans, clover, saintfoin, and lucerne. It should be sown broadcast in spring when the young leaves are started ; it then throws turnips on to grow so quick that they escape the ravages of the fly. On account of dissolving so sparingly in water, it is best sown in wet weather. Calcined gypsum after being moistened with a solution of alum, and again burn- ed, acquires much greater hardness and solidity. A Mr. Kreating lias recom- mended for the same purpose a solution of 1 lb borax in 9 lbs. of water, which is poured over the calcined fragments of gypsum. They are then kept at a strong red heat for six hours, ground to a pow- der, and worked. The effect is better if a lb. of tartar and twice the quantity of water were added to the solution. HAIR. The characteristic covering ot the mammiferous class of animals. It consists of slender, more or less elon- gated, horny filaments, secreted by a matrix, consisting of a conical gland or bulb, and a capsule, which is situated in the mesh-work of the corium, or true skin. The hairs pass out through ca- nals in the corium, which are lined by a thin layer of cuticle adherent to the base of the hair : the straightness or curl of the hair depends on the form of the ca- nal through which it passes. Spines, bristles, fur, and wool, are all modifica- tions of hair, having the same chemical composition, mode of formation, and general structure. In the spines of the porcupine, the bulb secretes a fluted pith, and the cap- sule invests it with a horny sheath, the transparency of which allows the ridges of the central part to be seen. In the spines of the hedgehog, the spine-like whiskers of the walrus, and the bristles of the hog, the twofold structure of the hair is very conspicuous : but in the finer kind of hair, as in the human head and beard, the central pith can only be de- monstrated in fine transverse sections viewed with the microscope. Some kinds of hair, as of the human head, the mane and tail of the horse, are perennial, and grow continuously by a persistent ac- tivity of the formative capsule and pulp ; other kinds, as the ordinary hair of the horse, cow, and deer, are annual, and the coat is shed at particular seasons. In the deer the horns are shed contempora- neously with the deciduous hair. Many quadrupeds, especially those^ of cold climates, have two kinds of hair : a long and coarse kind, forming their visible external covering ; and a shorter, finer, and more abundant kind, which 238 CYCLOPEDIA OF THE USEFUL ARTS. [hai lies close to the skin, and called " fur." It is one of the processes in the arts to remove the close hairs, and leave the fur attached to the dried skin, as in the pre- paration of seal-skin, &c. The peculiar characteristic of wool, and that on which its valuable qualities chiefly depend, is the serrated character of its surface, aris- ing from its structure, which consists of a series or succession of inverted cones, the base of each being directed from the root of the woolly fibre, and receiving the apex of the succeeding cone. It re- sults from this structure that the pres- sure to which the workman subjects the wool in moving it backwards and for- wards brings the fibres together, and multiplies their points of contact. The agitation gives to each hair a progressive motion towards the root, and the serra- tions of one hair fix themselves on those of another hair which happens to have its root turned in the opposite direction, and the mass at length assumes the compact form which is termed "felted" woof. The microscope has likewise de- monstrated various other remarkable modification in the form of the hair in different quadrupeds. In the mole, each hair is alternately constricted and ex- panded from its root to its apex, where- by it readily assumes any position, and lies flat and smooth, either towards the head when the little burrower is retro- grading in his subterranean galleries, or in the contrary direction when moving forwards. The organization of the hair is such as to allow of its undergoing certain changes when once formed, ac- cording to the state of health and gene- ral condition of the rest of the frame, and even to be affected by loss of color in consequence of violent mental emo- tions in the human subject. Some of the lower animals, as the Alpine hare, are subject to periodical change of color of their fur, by which it is made to harmonize with the prevailing hue of the ground which they habitually tra- verse. The chemical properties of hair were first pointed out by Mr. Hatchett. It chiefly consists of an indurated albu- men, and when boiled with water, it yields a portion of gelatine. Soft flexi- ble hair, which easily loses its curl, is that which is most gelatinous. Vauquelin discovered two kinds of oil in .hair : the one colorless, and in all hair ; the other colored, and imparting according to its color the peculiar tint of hair in the indi- vidual. HAIR PENCILS or BRUSHES for painting. Two sorts are made; those with coarse hair, as that of the swine, the wild boar, the dog, &c, which are attached usually to short wooden rods as handles ; those are commonly called brushes; and hair pencils, properly so called, which are composed of very fine hairs, as of the minever, the marten, the badger, the polecat, &c. These are mounted in a quill when they are small or of moderate size, but when larger than a quill, they are mounted in white iron-tubes. The most essential quality of a good pencil is to form a fine point, so that all the hairs without exception may be united when they are moistend by laying them upon the tongue, or drawing them through the lips. When hairs present the form of an elongated cone in a pencil, their point only can be used. The whole difficulty consists after the hairs are cleansed, in arranging them together so that all their points may lie in the same horizontal plane. We must wash the tails of the animals whose hairs are to be used, bv scouring them in a solution of alum till they be quite free from grease, and then steeping them for 24 hours in lukewarm water. We next squeeze out the water by pressing them strongly from the root to the tip, in order to lay the hairs as smooth as possible. They are to be dried with pressure in linen cloths, combed in the longitudinal direc- tion with a very fine-toothed comb, final- ly wrapped up in fine linen, and dried. When perfectly dry, the hairs are seized with pincers, cut across close to the skin, and arranged in separate heaps, accord- ing to their respective lengths. Each of these little heaps is placed se- parately, one after the other, in small tin pans with flat bottoms, with the tip of the hair upwards. On striking the bot- tom of the pan slightly upon a table, the hairs get arranged parallel to each other, and their delicate points rise more or less according to their lengths. The longer ones are to be picked out and made into so many parcels, whereby each parcel may be composed of equally long hairs. The perfection of the pencil depends upon this equality; the tapering point being produced simply by the attenua- tion of the tips. A pinch or one of these parcels is then taken, of a thickness corresponding to the intended size of the pencil ; it is set in a little tin pan, with its tips undor- most, and is shaken by striking the pan har] CYCLOPEDIA OF THE USEFUL ARTS. 239 on the table as before. The root end of the hairs being tied by the fisherman's or seaman's knot with a fine thread, it is taken out of the pan, and then hooped with stronger thread or twine ; the knot being drawn very tight by means of two little sticks. The distance from the tips at which these ligatures are placed is of course relative to the nature of the hair, and the desired length of the pencil. The base of the pencil must be trimmed flat with a pair of scissors. Nothing now remains to be done but to mount the pencils in quill or tin-plate tubes, as above described. The quills are those of swans, geese, ducks, lap- wings, pigeons, or larks, according to the size ol the pencil. They are steeped during 24 hours in water, to swell and soften them, and to prevent the chance of their splitting when the hair-brush is pressed into them. The brush of hair is introduced by its tips into the larger end of the cut quill, having previously drawn them to a point with the lips, when it is Sushed forwards with a wire of the same iameter, till it comes out at the other and narrower end of the quill. HANDSPIKE. A wooden lever used on shipboard for working the windlass and capstan, one end of which is squared to fit the holes of the capstan-head and in the barrel of the windlass. HANK, in spinning, the name given to two or more skeins of yarn, silk, or cotton, when tied together. HAKBOE, has been defined to be a piece of water communicating with the sea, or with a navigable river or lake, having depth sufficient to floats ships of considerable burden, where there is con- venient anchorage, and where ships may lie, load, and unload, screened from the winds and beyond the reach of the tide. HAED BODIES, in Natural Philoso- phy, are such as resist any pressure or percussion whatever, in opposition to soft bodies, the parts of which readily yield to pressure, and do not recover them- selves ; and to elastic bodies, the parts of which also yield to pressure or impact, but presently recover themselves when the disturbing force ceases to act. HARDNESS. In physics, that quality of bodies in virtue of which their parti- cles resist the action of any external force tending to alter their relative positions, or to impart to them any motion in re- spect of each other. Newton supposes the primary particles of all bodies to be perfectly hard, and not capable of being broken or divided by any power in na- ture ; but we are still too little acquaint- ed with the constitution of matter to de- termine with any certainty the conditions of the elementary particles which render bodies hard, brittle, and elastic. Hardness. In Mineralogy. Minerals may occasionally be distinguished and identified by their relative degrees of hardness ; to specify which various scales have been suggested, among which that of Mohs is perhaps the most simple. According to it the relative degrees of hardness are expressed in numbers, re- ferring to the following standard sub- stances, which are easily obtained in a state of purity, or crystallized ; namely, 1. Talc. 6. Adularia (Feldspar). 2. Rook-salt. 7. Rock-crystai. 3. Calc-spar. 8. Topaz. 4. Fluor-spar. 9. Corundum. 5. Apatite. 10. Diamond. Any mineral, which neither scratches nor is scratched by any one of the above substances, is said to possess the hardness expressed by the attached number. Thus if a mineral neither scratches nor is scratched by calcareous spar, its hardness is represented by 3 ; if it scratches feld- spar and not rocK-crystal, its hardness is stated to be between 6 and 7. HABDW ABE, is used to signify every kind of goods manufactured from metals, comprising iron, brass, steel, and copper articles of all descriptions. The hard- ware manufacture is one of the most im- portant carried on in Great Britain. Its Erincipal seats are Birmingham and Shef- eld, which furnish immense quantities of knives, razors, scissors, gilt and plated ware, fire-arms, &c, both for home con- sumption and exportation. HAEEOW. In agriculture, a rectan- gular frame with a number of spikes in- serted in it on one side. This frame when dragged over ploughed land, breaks; the furrow slices into small pieces, for the purpose of preparing the land for seed in some cases, and for covering the seed in others. The most common' form of the frame of the harrow is rectangular, and the usual material employed is wood, with the spikes of iron ; but in some cases both the frame and the spikes are of wood, and in others both are of iron. Occasionally the frame is a circle of iron, and the spikes are inserted in it, at such distances that when the frame is drawn along in a straight line, the spikes, or tines as they are technically termed, pass through every part of the soil traversed by the frame "or harrow. In the common kinds of harrows the spikes are inserted 240 CYCLOPEDIA OF THE USEFUL ARTS. I? at right angles to the frame : but in the improved forms they are inserted at an oblique angle, or pointing forwards, by which means the harrow is drawn much more easily through the soil. The best implement of this description at present in use is Finlayson's harrow. This im- Element, by means of a long lever, can e regulated to such a nicety as to stir the soil to the depth of only one or two inches, for the purpose of covering grass or clover seeds ; or it can be pressed into it of such a depth as to serve, in the case of stubble lands, instead of ploughing. Wilkie's harrow and Kirkwood's harrow can be used for similar purposes. They differ nothing from Finlayson's in prin- ciple ; but being on a smaller scale can be worked with fewer horses than Finlay- son's, which commonly requires four or six. HARROWING. The process of draw- ing a harrow through the soil for the pur- pose of reducing it to a level, of covering seed, or of turning up weeds in ploughed ground, or moss in grass lands. In agri- culture the harrow is drawn by horses or oxen ; and in market-gardening, where a light harrow is sometimes employed, by men. In either case the more rapid the motion of the harrow, up to a certain point, the more efficient will be its opera- tion. For meadow lands, the object of harrowing is to disperse the little heaps of earth raised during winter and early spring by moles and worms ; and for this purpose the harrows in some parts of the country are turned upside down ; while in others, less advanced, thorn branches are tucked into a frame resem- bling a harrow, and dragged over the surface for the purpose of effecting the same object. This is called a bush har- row. HARTSHORN, SPIRIT OF. An im- pure solution of carbonate of ammonia, obtained by the destructive distillation of hartshorn or any kind of bone. It is now never made by this process, but by a direct solution of the pure carbonate of ammonia. HAT MANUFACTURE. The mate- rials used for making hats are, besides silk, the fur of hares and rabbits chosen from the long hair ; together with wool and beaver and nutria. The two latter are reserved for the finer hats. The body of a beaver hat is made of fine wool and coarse fur mixed and felted together, then stiffened and shaped ; the covering consists of a coat of beaver-fur felted upon the body. Cheap hats have their bodies made of coarse wool, and their co- verings of coarse fur or fine wool. The body'br foundation of a good beaver hat, is at present made of 8 parts of rabbit's fur, 3 parts of Saxony wool, and 1 part of lama, vicunia, or red wool. About two ounces and a half of the above mixture are sufficient for one hat, and these are placed in the hands of the bower ; his tool is a bow or bent ashen staff, from 5 to 7 feet long, having a strong catgut string stretched over a bridge at each end, and suspended at its middle by a cord to the ceiling, so as to hang nearly level with the work bench, and a small space above it. The wool and coarser fur are laid in their somewhat matted state upon this bench, when the bower, grasping the bent rod with his left hand, and oy means of a small wooden catch plucking the string with his right, makes it vibrate smartly against the fibrous substances, so as to disentan- gle them, toss them up in the air, and curiously arrange themselves in a pretty uniform layer or fleece. A skilful bower is a valuable workman. The bowed ma- terials of one hat are spread out and di- vided into two portions, each of which is compressed, first with a light wicker frame, and next under a piece of oil cloth or leather, called a hardening skin, till by pressing the hands backward and for- ward all over the skin, the filaments are linked together by their serrations into a somewhat coherent fleece of a triangular shape. The two halves or " bats " are then formed into a cap ; one of them is covered in its middle with a 8-eornered piece of paper, smaller than itself, so that its edges may be folded over the paper, and by overlapping each other a little, form a complete envelope to the paper ; the junctions are then partially felted to- gether by rubbing them hard, care being taken to* keep the base of the triangle open by means of the paper ; the second bat being made to enclose the first by a similar process of folding and friction. This double cap, with its enclosed sheet of paper, is next rolled up in a damp cloth and kneaded with the hands in " every direction, during which it is un- folded and creased up again in different forms, whereby the two layers get tho- roughly incorporated into one body ; thus, on withdrawing the paper, a hollow cone is obtained. This cap is next taken and dipped occasionally into a weak acid solution made of vitriol and water and is j also wrought by hands or with the roller ! on the sloping planks. This constitutes j falling or thickening and is continued 4 iiatJ CYCLOPEDIA OF THE USEFUL ARTS. 241 or 5 hours ; knots are picked out and fresh felt added by a wet brush. The beaver is applied at the end of this ope- ration on oeaver hats. The foundation of men's hats, upon the outside of which the beaver, down, or other fine fur is laid, to produce a nap, is usually made of wool felted together by hand and form- ed first, into conical caps, which are af- terwards stretched and moulded to the desired shape. Hemp and felt are also used as foundations. Stopping, or thickening the thin spots, seen by looking through the body, is per- formed by daubing on additional stuff with successive applications of the hot acidulous liquor from a brush dipped into the kettle, until the body be sufficiently shrunk and made uniform. After dry- ing, it is stiffened with varnish composi- tion rubbed in with a brush ; the inside surface being more copiously imbued with it than the outer ; while the brim is peculiarly charged with the stiffening. When once more dried, the body is ready to be covered, which is done at the battery. The first cover of beaver or nap- ping, which has been previously lowed, is strewed equally over the body, and patted on with a brush moistened with the hot liquor, until it gets incorporated ; the cut ends towards the root, being the points which spontaneously intrude. The body is now put into a coarse hair cloth, then dipped and rolled in the hot liquor, until the root ends of the beaver are thoroughly worked in. This is tech- nically called rolling off, or roughing. A strip for the brim, round the edge of the inside, is treated in the same way ; where- by every thing is ready for the second cover (of beaver), which is incorporated in like manner; the rolling, &c, being continued, till a uniform, close, and well- felted hood is formed. The hat is now ready to receive its pro- per shape. For this purpose the work- man turns up the edge or brim to the depth of about \\ inch, and then returns the point of the cone back again through the axis of the cap, so as to produce ano- ther inner fold of the same depth. A third fold is produced by returning the point of the cone, and so on till the point resembles a flat circular piece having a number of concentric folds. In this state it is laid upon the plank, and wetted with the liquor. The workman pulls out the Joint with his fingers, and presses it own with his hand, turning it at the same time round on its centre upon the plank, till a fiat portion, equal to the 11 crown of the hat, is rubbed out. This flat crown is now placed upon a block, and, by pressing a .string called a commander, down the sides of the block, he forces the parts adjacent to the crown, to assume a cylindrical figure. The brim now appears like a puckered appendage round the cy- lindrical cone ; but the proper figure is next given to it, by working and rubbing it. The body is rendered waterproof and stiff by being imbued with a varnish composed of shellac, sandarach, mastic, and other resins dissolved in alcohol or naptha. The hat being dried, its nap is raised or loosened with a wire brush or card, and sometimes it is previously pounced or rubbed with pumice, to take off the coarser parts, and afterwards rubbed over with seal-skin. The hat is now tied with pack-thread upon its block, and is afterwards dyed. See Hat-dyeing. The dyed hats are now removed to the stiffening shop. Beer grounds are next applied on the inside of the crown, for the purpose of preventing the glue from coming througli ; and when the beer grounds are dried, glue (gum Senegal is sometimes used) a little thinner than that used by carpenters, is laid with a brush on the inside of the crown, and the lower surface of the brim. The hat is then softened by exposure to steam, on the steaming basin, and is brushed and ironed till it receives the proper gloss. It is lastly cut round at the brim by a knife fixed at the end of a gauge, which rests against the crown. The brim, however, is not cut entirely through, but is torn off so as to leave au edging of beaver round the external rim of the hat. The crown being tied up in a gauze paper, which is neatly ironed down, is then ready for the last opera- tions of lining and binding. The furs and wools of which hats are manufactured contain, in their early stage of preparation, hemps and hairs, which must be removed in order to produce a material for the better description of hats. This separation is effected by a sort of winnowing machine, which wafts away the finer and lighter parts of the furs and wools from the coarser. Silk hats, for several years after they were manufactured, were liable to two objections ; first, the body or shell over which the silk covering is laid, was, from its hardness, apt to hurt the head ; se- cond, the edge of the crown being much exposed to blows, the silk nap soon got abraded, so as to lay bare the cotton foun- 242 CYCLOPEDIA OF THE USEFUL ARTS. [hea dation, which is not capable of taking so fine a black dye as the silk ; whence the hat assumed* a shabby appearance, j Messrs. Mayhew and White, of London, hat-manufacturers, remedied these de- j fects, by making the hat body of stuff or | wool, and relieving the stiffness of the in- j ner part round the brim, by attaching a ' coating of beaver upon the under side of j the brim, so as to render the hat pliable. Eound the edge of the tip or crown, a j quantity of what is called stop wool is to ' be attached by the ordinary operation of bowing, which will render the edge soft and elastic. The hat is to be afterwards dyed of a good black color, both outside and inside ; and being then properly stiffened and blocked, is ready for the co- vering of silk. The plush employed for covering silk hats, is a raised nap or pile woven usu- ally upon a cotton foundation ; and the cotton, being incapable of receiving the same brilliant black dye as the silk, ren- ders the hat apt to turn brown whenever the silk nap is partially worn off. The way to counteract this evil is by making the foundation of the plush entirely of silk. To these two improvements, now pretty generally introduced, the present excellence of the silk hats may be, in a good measure, ascribed. In a great hat factory women are em- ployed, at respectable wages, in plucking the beaver skins, cropping off the fur, sorting various qualities of wool, pluck- ing and cutting rabbit's fur, shearing the nap of the blocked hat, picking out un- seemly filaments of fur, and in trimming the hats; that is, lining and binding them. With regard to the stiffening of hats, Dr. Ure gives the following receipts as furnished by a skilful operator with the following valuable information : — All the solutions of gums which I have hitherto seen prepared by hatters, have not been perfect, out, in a certain degree, a mixture, more or less, of the gums, which are merely suspended, owing to the consistency of the composition. When this is thinned by the addition of spirit, and allowed to stand, it lets fall a curdy looking sediment, and to this cir- cumstance may be ascribed the frequent breaking of hats. My method of pro- ceeding is, first, to dissolve the gums by agitation in twice the due quantity of spirits, whether of wood or wine, and then, after complete solution, draw off one half the spirits in a still, so as to bring the stiffening to a proper consisten- cy. No sediment subsequently appears on diluting this solution, however much it may be done. Both the spirit and alkali stiffenings for hats made by the following two re- ceipts, have been tried by some of the first houses in the trade, and have been much approved of: — Spirit Stiffening, 7 pounds of fine orange shellac. 2 pounds of gum sandarac. 4 ounces of gum mastic. Half a pound of amber resin. 1 pint of solution of copal. 1 gallon of spirit of wine or wood naptha. The shellac, sandarac, mastic, and re- sin, are dissolved in the spirit, and tho solution of copal is added last. Alkali Stiffening. 7 pounds of common black shellac 1 pound of amber resin. 4 ounces of gum rhus. 6 ounces of borax. Half a pint of solution of copal. Hat-dyking. The ordinary bath for dyeinsf hats, employed by the London manufacturers, consists, for 12 dozen, of— 144 pounds of logwood. 12 pounds of green sulphate of iron, or cop- peras. 1)4 pounds of verdigris. The copper is usually made of a semi- cylindrical shape, and should be sur- rounded with an iron jacket or case, into which steam may be admitted, so as to raise the temperature of the interior bath to 190° F., but no higher, otherwise the heat is apt to affect the stiffening varnish, called the gum, with which the body of the hat has been imbued. The logwood having been introduced and digested for some time, the copperas and verdigris are added in successive quantities, and in the above proportions, along with every suc- cessive two *r three dozens of hats, sus- pended upon the dipping machine. Each set of hats, after being exposed to the bath with occasional airings during 40 minutes, is taken off the pegs, and laid out upon the ground to be more com- pletely blackened by the peroxydizement of the iron with the atmospheric oxvgen. In 3 or 4 hours the dyeing is completed. When fully dyed, the hats are well wash- ed in ranning water. HEART WHEEL. The name given to a well-known mechanical contrivance for converting a circular motion into an al- ternating rectilinear one, common in cot- ton mills. It is an ellipse turned either hem] CYCLOPEDIA OF THE USEFUL ARTS. on an axle, or by means of a winch and handle on one of its foci, or its centre, on whose edge a movable point or circle presses ; the latter receives an alternating motion from the circumference of the el- lipse, which in its revolution presses it to different distances from the centre of motion. The practical disadvantages of this contrivance are the inequality of pressure and of moving force which will be required at different parts of the rota- tion of the ellipse, and the consequent wearing of some parts of it faster than others. HEAVY SPAR. Native sulphate of baryta. This is a common mineral in many raining districts. It occurs in several crystalline forms, of which the cleavage is a right rhomboidal prism ; it also occurs fibrous, radiated, and stalac- titic. Some beautiful specimens of the latter variety have been found in Derby- shire of a brown color. The crystals are usually white, or nearly colorless. The specific gravity of sulphate of baryta is 4*1 to 4-6. It consists of 77 baryta, 40 sul- phuric acid, its equivalent being 117. It enters into the composition of some kinds of pottery, but its chief consumption is in the adulteration of white lead. It is a mineral common in the States of New- York and New Jersey. HECKLE is an implement for dissev- ering the filaments of flax, and laying them in parallel stricks or tresses. See Flax. HELIOCHROMATYPE. Under the article Daguerreotype, notice has been taken of the attempts of Becquerel and Hill, to produce naturally colored impres- sions on the silver plate. In March of this year (1851), M. Niepce de St. Victor communicated to the Paris Academy of Sciences, a memoir showing the manner of taking the natural colors. Having formed the idea that there might be some relation between the color that a sub- stance communicates to flame, and the color that light produces on a plate of silver chloridized with the substance that colors the flame, he undertook the expe- riments which led to his success. He found it necessary to expose the plate to chlorine, and then coat it with the chlo- ride of the particular metal he was inves- tigating; no other salts acted similarly to the chlorides. Dry chlorine does not produce any effect, but when the plate is immersed in the liquid chlorine, or ex- posed to the aqueous vapor, the colors are all reproduced. The mode of operat- ing is thus : The bath is made of chlo- j en rine 1 part, and 3 parts of water. When hydrochloric acid, with a salt of copper, is used, it is diluted with 1-10 of water. The liquid chlorine should not be con- centrated, as good yellows are not then obtained. Clear solutions and stoppered bottles should be used. The purest sil- ver plate is preferable for these experi- ments j this is cleaned with ammonia and tnpoli, then plunged into the bath, and left there for some minutes in order to receive a sufficiently heavy coating, the plate is then removed, rinsed with water, and dried by a spirit-lamp. In the bath it takes on a dark color, almost black, and though it will take the colors. yet the ground will be black. In order to have a cleai'er ground and a quicker operation, the plate is changed by heat to a cherry red, when the dark plate is heated by a lamp placed below it. It asses through the following tints, ownish red, cherry red, bright red, reddish white, whitish. In the last stage it has lost the power of producing images. The plate should only be brought to the cherry red condition. It is then to be exposed in the camera. To obtain a picture it requires two hours. This must be owing to Niepce's not using any accelerator ; he mentions fluoride of soda, chl6ric acid, and the chlorates as worthy of trial for this purpose. These images disappear very quickly, and Niepce has not been successful in fixing them ; exposing the plate to the flame of alcohol containing chloride of sodium or muriate of ammonia, partially succeeds. The chlorides which, when employed alone, act upon the silver plate, so as to make it take all the several colors of the model, arc the chlorides of copper, of iron, of nickel, uf potassium, and the hy- pochlorites of soda and lime, as well as liquid chlorine. It is evident from the foregoing, that Heliochromatype is yet but in its infancy, and cannot be practically applied as yet. HELIOTROPE is a variety of jasper, mixed with chlorite, green earth, and diallage ; occasionally marked with blood- red points ; whence its vulgar name of blood-stone. HEMATINE is the name given by its discoverer, Chevreul, to a crystalline sub- stance, of a pale pink color, and brilliant lustre when viewed in a lens, which he extracted from logwood, the hcematoxylon Canvpeehiawum of botanists. It is, in fact, the characteristic principle of this dye- wood. To procure hematine, digest, dur- ing a few hours, ground logwood in 244 CYCLOPEDIA OF THE USEFUL ARTS. [hem ■water heated to a temperature of about 130° F. ; filter the liquor, evaporate it to dryness by a steam bath, and put the ex- tract in alcohol of 0-835 for a day. Then filter anew, and after having inspissated the alcohol solution by evaporation, pour it into a little water, evaporate gently again, and then leave it to itself in a cool place. In this way a considerable quan- tity of crystals of hematine will be ob- tained, which may be readily purified by washing with alcohol and drying. When subjected to dry distillation in a retort, hematine affords all the usual products of vegetable bodies, along with a little ammonia : which proves the pre- sence of azote. Boiling water dissolves it abundantly, and assumes an orange- red color, which passes into yellow by cooling, but becomes red again with heat. Sulphurous acid destroys the color of solution of hematine. Potash and am- monia convert into a dark purple-red tint, the pale solution of hematine ; when these alkalis are added in large quantity, they make the color violet blue, then brown- red, and lastly brown-yellow. By this time, the hematine has become decom- posed, and cannot be restored to its pris- tine state by neutralizing the alkalies with acids. The waters of baryta, strontia, and lime exercise an analogous power of decompo- sition ; but they eventually precipitate the changed coloring matter. A red solution of hematine subjected to a current of sulphureted hydrogen be- comes yellow ; but it resumes its original hue when the sulphureted hydrogen is removed by a little potash. The protoxyde of lead, the protoxyde of tin, the hydrate of peroxyde of iron, the hydrate "of oxydes of "copper and nickel, oxyde of bismuth, combine with hematine, and color it blue with more or less of a violet cast. Hematine precipitates glue from its so- lution in reddish flocks. This substance has not hitherto been employed in its pure state ; but as it constitutes the ac- tive principle of logwood, it enters as an ingredient into all the colors made with that dye-stuff. These colors are principally violet and black. Chevreul has proposed hematine as an excellent test of acidity. HEMATITE is a native reddish-brown peroxyde of iron, consisting of oxygen 80-66 ; iron 60-34. It is the kidney ore of Cumberland, which is smelted at Ulver- stono with charcoal, into excellent steel iron. It is one of the most abundant and valuable of the iron ores in the United States. See Ikon. HEMP. The fibres of the cannabis sativa ; a plant grown extensively in this country, but mostly in Kentucky and Missouri. It is a native of India and Persia, and was thence introduced into Europe. Though much grown here, yet more is imported from Russia. It grows wild in many waste places. It grows well on strong soils, and hence on newly cleared lands. Soon after flowering, the male plants are pulled, and the female plants let to remain some weeks longer to mature the seed. These do not preserve their vitality longer than a year, owingr to the large quantity of oil in them. The males should be tied immediately in bun- dles, the roots cut off while fresh, the upper leaves also beaten off, and it is the most eligible practice to immerse them in water without delaying for rotting. The females, which are three times more numerous than males, should be pulled very carefully, without shaking or inclin- ing the summits, and the flail should not be used, as it bruises the seed. This, when separated, should be spread out and turned at intervals, and exposed to a current of air; otherwise they ferment. The process of rotting consists in the decomposition of the substance which envelopes and unites the fibres, and takes place much more rapidly in stagnant f)Ools than in running water or extensive akes, in warm weather than the re- verse. The time requisite varies from five to fifteen days, even in stagnant water. The water in which hemp has been rotted has a disagreeable odor and taste, proving fatal to fishes, and should be distant from any inhabited place, lest it engender pestilential diseases. When water is not at hand, hemp is rotted in the open air, by spreading it at night upon the green-sward, and heaping it together in the morning, before the sun's rays have much power. In wet weather it may be left on the ground during the whole day ; and should, the nights be very dry, it is'better to water it. This process is called dew-rotting, and is very tedious, requiring three, six, or even eight weeks. Another method again, is by placing it in a pit, and covering it over* with about one foot of earth, after having watered it abundantly a single time ; but even this method requires double the time of water. After being rotted and rapidly dried, it is ready for canting, beating, &c, but these subsequent manipulations are found by experience to be very un- hem] CYCLOPEDIA OF THE USEFUL ARTS. 245 healthy, probably from the fine dust created and flying about. J. T. Crook & Co., Maysville, Ohio, have sent into the markets cordage manu- factured by them, of rotted hemp, so ky- anized by the use of antiseptic substances as to render it indestructible when ex- posed to the weather. Cordage, pre- pared like this, has been buried in a fun- gous heap, filled with decaying vegetable matter, tor five years, without showing j the least sign of decay. In respect to j the preparing of this cordage in this coun- j try, they were compelled to use the un- \ rotted hemp, since it is an established fact ! that antiseptics will not prevent the de- j cay of vegetable matter, when decay has \ actually commenced, as is the case of dew ; and water-rotted hemp. The Russia hemp, in not being carried to the fer- menting point in rotting, is not, like our water-rotted hemp, affected by decay, and is capable of being kyanized like the un- rotted hemp, as has been successfully done in England, by the use of suitable antiseptics. The comparative value of different Borts of hemp, as it regards durability, is easily and speedly tested by any one, since nearly all kinds are very short- lived when exposed to causes favorable to decay. The Manilla will last some four or five months as used in the sum- mer season upon our steamboats — the Sisal, which is often sold in the west as manilla, will not last much more than half as long — the Eussian hemp, when kept moist and warm, will lose its strength in about three weeks — the American water-rotted in two weeks, and the dew- rotted in from five to ten days. The un- rotted hemp, without being kyanized, will not last longer than the dew-rotted, j end will even show more signs of putre- ' faction before losing its strength. The color and appearance of this cord- age is similar to the Russia or water-rot- ted hemp. The strength is greater than either, while it is not " frayed down" like Manilla, by friction. Dr. Leavitt has devised a method of Ereparing hemp, which consists of a hemp- rake of ingenious construction and great strength, propelled by a steam engine, breaking hemp at the rate of two pounds per minute, 1200 pounds in ten iiours ; and delivering the hemp in such condi- tion as to be more easily and speedily heckled upon the common hand-heckle, than the dew-rotted hemp of the com- mon hand-brake, and with quite as little, if not less waste. The cleaning appara- tus is also thought to be likely to prove equally effective when furnished, as its simplicity and adaptation seem to war- rant this conclusion. More than the whole of the fuel necessary for one steam engine, will be furnished, it is said, from the hemp itself, by three brakes, and is supplied to the furnace without neces sity of a fireman. The hemp-brakes stand in a line over a strong grating, beneath which is a trough, whose sides, inclined inward, re- ceive and deposit upon an endless band, running in the direction of the furnace, all the woody matter falling from the brakes and carrying it to a funnel, through which it is thrown into the furnace and scattered in its bed, igniting instantly, and keeping up an intensely hot fire. A man and two boys are sufficient to at- tend each brake with ease, and a third one can bear off the hemp from the three brakes, delivered in bands or endless roving to be passed through the various subsequent machinery, a portion of which is designed to supersede the waste- ful heckling now in use, avoiding the manufacture of tow entirely. Connected with it is also to be an apparatus for sup- plying the powerful antiseptic substances now in use in the manufactories of ship cordage and canvas in England, the effi- cacy of which has been so severely tested in the Niger expedition, and. on the west- ern coast of South America, so celebrated for its production in the cordage and sails of shipping exposed to that climate. The material to be used will be made at the factory, and will not cost over $5 for each ton of hemp. Dr. Leavitt's efforts will prove of great value to our commercial interests, as weL as probably greatly encourage the agri- culturists whose attention is devoted to the cultivation of hemp, and the amount of this product will doubtless be much increased at the west. By a recent trial it appears that the strength of a rope of this unrotted hemp, was much greater than those of American water-rotted Russia or steam hemp. HEMP-BRAKE. Mr. Colver, of Mis- souri, has invented a hemp-brake, which with four men and two boys, will break 2,240 lbs. in a day. This machine is pre- cisely on the principle of the hand-brake, the swords moving with great rapidity. On each machine there are two 'places for breaking, and two for cleaning the hemp, the ends of the swords serving admirably for the latter purpose. The 246 CYCLOPEDIA OF THE USEFUL ARTS. [hon machine is as simple as the hand-brake, as easily kept in repair, and it can readi- ly be moved about in the field. The loss by tow, &c, is only about from 12 to 20 per cent. HOE. In agriculture and gardening, an instrument for stirring the surface of the soil, cutting annual weeds up by the roots, and earthing up plants. The hand hoc is a thin plate of iron, six or eight inches broad, and sharpened on the edge, fixed at right angles on the extremity of a pole or rod, which serves as a handle. This is called a draw hoe, because in the operation of hoeing the instrument is drawn or pulled towards the operator. Another description of garden hoe has the blade or iron plate fixed on the extre- mity of the handle, and in continuation of it ; and this is called a thrust hoe, be- cause in hoeing the operator always pushes the hoe forward. This kind "is also called a Dutch hoe, most probably from having been first introduced from Holland. In agriculture there are hoes of the thrust kind drawn by beasts of la- bor, and commonly called horse hoes. In general form they resemble a plough ; but~instead of the share they have one or more iron blades, or plates with sharp edges, fixed to perpendicular iron rods at their lower extremities. These sharp- ened plates being drawn through the soil, cut through the roots of weeds an inch or two beneath the surface. Agri- cultural or field hoes are only used in the case of those field crops which are sown or planted in rows. There are a great many kinds of field or horse hoes ; but it is worthy of remark, that they differ very little in mechanical merit. The im- plement, indeed, does not seem suscepti- ble of the same degree of improvement as the plough and the harrow. HOEING. The operation of stirring the surface, cutting off weeds, or earth- ing up plants with the hoe. In the case of any of these operations dry weather must be chosen, otherwise the result will either be useless or injurious. Plants rooted up by the hoe in wet weather will produce fresh roots and grow again, while plants earthed up under similar circumstances will have the leaves which are covered by the soil decayed by it. In either case, also, the ground will be hardened by the treading of the feet of men or horses, so as to obstruct the pro- gress of the roots, and to exclude air and water from penetrating through it to them- Hoeing is sometimes performed on surfaces which are without weeds, for the purpose of stirring the soil; but in such cases pronged hoes, or hoes having three or more long spikes or teeth, are more effective than noes with broad plates or blades. HOGSHEAD. An ancient measure of capacity, containing 63 old wine gal- lons. HOLD. The inside of the bottom of the ship. It is divided into compart- ments by bulkheads across ; and contains the ballast, water, coal and wood, pro- visions, and cargo. HOMBERG'S PHOSPHORUS. The combination of lime and muriatic acid, which remains after distilling the volatile alkali from sal ammoniac, has usually an over-proportion of lime. If it be urged by a violent heat it fuses ; and when cold it has the property of emitting a phosphoric light, when struck with any hard body. HONEY, is the product of flowers, chiefly of the base of the pistil, where it serves to entangle the pollen. It may, by alcohol, be separated into two parts, yellow and fluid, and white and solid. It is separated from the combs by heat- ing and stirring them in water, and then squeezing the honey through a cloth. Candia and the Levant produce the best, in rocks and hollow trees. And it is sometimes made from ripe grapes, by evaporating must to a 3yrup ; or collect- ed from trees, as left by other insects. The whole economy of bees bespeaks design, purpose, and intelligence in the insects, under habits adapted to their powers and form. Honey differs much in color and in consistence ; it contains much saccharine matter, and, probably, some mucilage, from which it derives its softness and viscosity. Honey very readily enters into the vinous fermentation, and yields a strong liquor, called mead. There are two species of honey ; the one is yellow, transparent, and of the consistence of turpentine ; the other white, and capable of assuming a solid form, and of concret- ing into regular spheres. These two species are often united; they may be separated by means of alcohol, which dissolves the liquid honey much more readily than the solid. Honey lias never been accurately analyzed, but some late experiments go to prove it to be com- posed of sugar, mucilage, and an acid. The honey made in mountainous coun- tries is more highly flavored than that of low grounds. The honey made in the spring is more esteemed than that ga- hop] CYCLOPEDIA OF THE USEFUL ARTS. 247 thered in the summer ; that of the sum- mer more than that of the autumn. There is also a preference given to that of young swarms. Yellow honey is ob- tained, by pressure, from all sorts of honey-combs, old as well as new, and even from those whence the virgin-honey has been extracted. The combs are broken, and heated, with a little water, in basins or pots, being kept constantly stirred ; they are then put into bags of thin linen cloth, and these in a press, to squeeze out the honey. The wax stays behind in the bag, excepting some par- ticles, which pass through with the honey. Honey is supposed to undergo no alte- ration in the body of the bee, as it retains the odor, and not unfrequently the qual- ities, of the plants it was gathered from, so that it is sometimes deleterious, where poisonous shrubs abound. Honey, purification of. M. Veling recommends the white of an egg to be beaten up with 5 lbs. of honey until it froths, and water is then added till i t reach- I es a thin consistence, then boiled till the I albumen can be removed with the froth, i It is then poured into an upright vessel j having a cork at its lower part. It is well covered, and set aside in a cellar for six to eight weeks. The impurities be- come coagulated, collect on the surface, and the honey can be drawn off clear below. HONEY STONE. A yellow mineral found in octohedral crystals at Artern in i Thuringia. It is extremely rare. It con- ; sists of a peculiar acid (the melitic acid) j combined with alumina and water. HOP. The Hamulus lupvlus of Lin- ' nseus, the female flowers of which are used for imparting a bitter flavor to malt liquors for the purpose of preserving them from fermentation. The hop plant is a perennial indigenous to Britain and different parts of Europe ; but, to pro- duce abundance of hops, it requires to be very carefully cultivated in good soil, and even then is one of the most preca- rious of crops. The fields in which hops are grown are commonly called hop gar- dens : a loamy soil on a dry subsoil is chosen, and the plants are placed in hills, stools, or groups of three or four in a group, the hills being in rows five or six j feet apart, and at about the same dis- I tance in the row. A full crop is not produced till the fourth or fifth year after j planting. Every year the ground is dug i in winter, and kept clear of weeds during j summer ; and the hills have poles, gene- i rally three or four to a hill, for the plants to twine on : the purchase of these poles, the fixing them in the soil every spring, and taking them down and stacking them every autumn, and their removal every five, six, eight, or ten years, ac- cording to the kind of wood used, con- stitute a considerable part of the expense of hop culture. The hops, when mature, are picked by hand, and as they are picked they are carried to a drying kiln, dried, and packed into bags or pockets ; and this is also an expensive process. The hop plant is particularly liable to be injured by insects, by cold and continued rains, and by thunder storms ; in conse- quence of which, it is estimated that a full crop is not obtained oftener than above once in five years. Hence it is easy to conceive that the price of hops must vary greatly in different years, and that the grower who has a command of capital may profit largely by keeping them back from market when the prices are low, and only exposing them when they are high. In order to keep hops for two or three years, they require to be powerfully compressed, and put into much closer canvas bags than when they are to be sent immediately to mar- ket ; they also require to be kept in dry airy lofts, neither too warm nor too cold.. Hops are a necessary ingredient of malt liquor, as they contain a rich bitter, and an aroma, which modifies the bitter, while its astringent ingredient destroys the fermentation. Quassia, used as a substitute, contains only the bitter, and not the aroma, or the "astringent, and therefore fails, except when attempts are made to supply the other qualities of hops by other drugs. Ives has separated the aroma and tannin in a yellow pow- der, one-sixth the weight of the hops, in a substance called lupuline. The strobiles, or female flowers, are dried in charcoal kilns, till five pounds of the green flowers are reduced to one pound, and they are then laid in heaps and bags. Their bitter aromatic arises from a substance called li/puUn, forming a sixth part, which may be obtained by merely sifting with a fine sieve. They yield also an aromatic oil. A pillow of them is said to promote sleep, and a fo- mentation is useful in tumors. Hops contain several elements of activ- ity, not in its substitutes. _ Its bitter principle is tonic, its aromatic is warm and stimulant, and its astringent quality precipitates the mucilage, and thus re- moves the cause of fermentation. Thest 248 CYCLOPEDIA OF THE USEFUL ARTS. [hor several properties render it superior to quassia, gentian, etc. HOKDEIN. A modification of starch, containing 55 per cent, of barley meal. HORN. The hollow horns of the ox, goat, &c, the hoof, the horny claw and hail, and the scale of certain'insects, as the shell of the tortoise, resemble each other in chemical characters ; but they differ very widely from stag's horn, ivo- ry, &c. Horn is distinguished from bone, in being softened very completely by heat, either applied immediately, or through the medium of water, so as to be readily bent to any shape, and to adhere to other pieces of horn m the same state. It contains but a small portion of gela- tine, and in this it differs from bone, which contains a great deal. Horn con- sists chiefly of condensed albumen, com- bined with a small and varying portion of gelatine, with a small part of phosphate of lime. The fixed alkalies readily dis- solve horn into a yellow saponaceous liquor. Horn, Manufacture of articles In. Horn, particularly of oxen, cows, goats, and sheep, is a substance soft, semi-trans- parent, and susceptible of being cut and pressed into a variety of forms ;'it is this property that distinguishes it from bone. These valuable properties being known render horn susceptible of being em- ployed in a variety of works fit for the turner, comb, and snuff-box maker. The kind of horn most to be preferred, is that of goats and sheep, from its being whiter and more transparent than the horn of any other animal. When horn is wanted in sheets or plates, it must be steeped in water, to be able to separate the pith from the kernel, for about fifteen days in summer, and a month in winter ; and when it is soaked it must be taken oiit by one end and well shaken and rubbed, in order to get out the pith ; af- ter which it must be put for hall an hour in boiling water, and then taken out, and the surface sawed even, lengthwise ; it must again be put into the boiling water to soften it, so as to render it capable of separating ; then with the help of a small iron chisel it can be divided into sheets or leaves. The thick pieces will form three leaves, those which are thin will form only two, whilst young horn, which is only one quarter of an inch thick, will form only one. These plates or leaves must again be put into the boiling water, and when they are sufficiently soft, they must be well worked with a sharp cutting instrument, to render those parts that are thick even and uniform ; it must be put once more into the boiling water, and then carried to the press. Mr. J. James has contrived a method of opening up the horns of cattle, by which he avoids the risk of scorching or frizzing, which is apt to happen in heating them over an open fire. He takes a solid block of iron pierced with a conical hole, which is fitted with a conical iron plug, heats them in a stove to the temperature of melting lead, and having previously cut up the horn lengthwise on one side with a saw, he inserts its narrow end into the hole, and drives the plug into it with a mallet. By the heat of the irons, the horn gets so softened in the course of about a minute, as to bear flatting out in the usual way. At the bottom of the press employed, there must be a strong block, in which is formed a cavity of nine inches square, and of a proportionate depth ; the sheets of horn are to be laid within this cavity, in the following manner : at the bottom, first a sheet of hot iron, upon this a sheet of horn, then again a sheet of hot iron, and so on, taking care to place at the top a plate of iron even with the last, and the press must then be screwed down tight. There is a more expeditious process, at least in part, for reducing the horn into sheets, when it is wanted very even. Af- ter having sawed it with a very fine and sharp saw, the pieces must be put into a boiler used for the purpose, and then boiled until sufficiently soft, so as to be able to be split with pincers ; then bring quickly the sheets of horn to the press, where they are to be placed in a strong vice, the clasps of which are iron, and larger than the sheets of horn, and screw the vice as quick and tight as possible ; let it then cool in the press or vice, or it is as well to plunge the whole into cold water. The last mode is preferable, be- cause the horn does not dry up in cool- ing. Now draw out the leaves of horn, and introduce other horn to undergo the same process. The horn so enlarged in pressing is to be submitted to the action of the saw, which ought to be set in an iron frame, if the horn is wanted to be cut with advantage, in sheets of any de- sired thickness, which cannot he done without adopting this mode. The thin sheets thus produced, must be kept con- stantly very warm between the plates of hot iron to preserve their softness. Every leaf must be loaded with a weight heavy enough to prevent its warping. To join »] CYCLOPEDIA OF THE USEFUL ARTS. 249 the edges of these pieces of horn to- gether, it is necessary to provide strong iron moulds suited to the snape of the ar- ticle that is wanted, and to place the pieces in contact with copper plates, or with polished metal surfaces against them ; when this is done, the whole should be put into a vice and screwed up tight, then plunged into boiling water, and after some time it is to be removed from thence, and immersed in cold water, which will cause the edges of the horn to cement together, and become perfectly united. To complete the polish of the bora, the surface must be rubbed with sub-nitrate of bismouth, by the palm of the hand. The process is short and has this advan- tage — that it makes the horn dry prompt- ly. When it is wished to spot the horn in imitation of tortoise shell, metallic so- lution must be employed as follows : To spot it red, a solution of gold in aqua regia must be employed ; to spot it black, a solution of silver in nitric acid must be used ; and for brown, a hot solution of mercury in nitric acid. The right side of the horn must be impregnated with those solutions, and they wili assume the color intended. The brown spots can be produced on the horn by means of a paste made of red lead, with a solution of pot- ash, which must be put in pieces on the horn, and subjected some time to the ac- tion of heat. 'The deepness of the brown shade depends upon the quantity of pot- ash used in the paste, and the length of time the mixture lies on the horn. A decoction of Brazil wood, a solution of indigo with sulphuric acid, a decoction of saffron, and Barbary tree wood is used. After having employed these materials, the horn may be left for half a day in a strong solution of vinegar and alum. HORNBLENDE. A mineral of a dark green or black color, abounding in oxide of iron, and entering into the composi- tion of several of the trap rocks. It is the amphibole of Hauy. It often inclines to brown with every intermediate shade ; nearly transparent in some varieties ; in others opaque ; brittle ; hardness about the same with feldspar ; specific gravity, 3-00. Three varieties, analyzed by Bons- dorf, gave the following results : White Green Black Silex 60-31 46-26 45-69 Magnesia 24-23 19-03 18 79 Lime 13*66 13-96 13-85 Almnine 0-26 11-48 1218 Protoxide of iron.. 0-15 3-43 7*32 Do. of masnanese. 0*00 9-26 0'22 Fluoric acid 0-94 1-60 1-50 Water, &c 010 1*04 0-00 Of those varieties of the present spe- cies which have obtained distinct names, aid which, in some systems of mineralo- gy, have ever been regarded as forming separate species, the following are the most remarkable, viz : hornblende, tremo- lite, actynotite, and certain kinds of as- bestos. HORNBLENDE SCHIST. A slaty va- riety of hornblende, generally including feldspar and grains of quartz : it is of a da^k green or black color. Where clay slate is in contact with granite, it some- times passes into hornblende slate. HORSE POWER. It is well known among engineers that a horse is capable of raising a weight of about 150 lb. 220 feet high in a minute, and to continue exertions enabling him to do that for 8 hours a-day. < Multiply the number of pounds by the height to which thev are raised in a min- ute, 150 X 220 gives 33,000 lb., and the power of a horse is generally expressed by a sum varying from 30,000 lb., to 36,000 lb., raised 1 foot high in a minute. Bolton and Watt express it by 32,000lb.; Woolf, by 36,0001b.; Tredgold, Palmer, and others, by 33,333 lb. One horse can draw horizontally as much as seven men. In trains of machinery from \ to £ is allowed for friction in calculating its equivalent of horse power. HORSE. Table of Power and Speed. Let us suppose 15 to represent the great- est unloaded speed, ana the square of 15, or 225, to represent the greatest load which can be sustained without moving ; the following table gives for each degree of speed, from 1 to 15, the corresponding load and useful effect : — Load Effect 12 3 4 5 6 7 8 9 10 11 12 13 14 15 25 196 169 144 121 100 81 64 49 36 25 16 9 4 1 196 338 432 484 500 486 484 392 324 250 176 108 52 14 Thus, if the greatest unloaded speed of a horse be 15 miles an hour, and the greatest weight he is capable of sustain- ing, without moving, be divided into two hundred and twenty-five equal parts, his labor will be most advantageously em- 11* ployed if he be loaded with 100 of those parts, and travel at the rate of five miles an hour. If he be thus employed it will be found that he will carry a greater weight through a distance, in a given time, than under any circumstances. 250 CYCLOPEDIA OF THE USEFUL ARTS. [ho? A horse, upon a well-constructed rail- road, can draw 10 tons at the rate of 2 miles per hour, or 5 tons 4 miles per hour. The absolute force of the horse draw- ing horizontally is, on average, 770 lb. From various calculations it would appear when the period of continuance is made an element in the calculation, that the Sower of a horse working eight hours a ay is on an average not more than an equivalent to that of five men working 10 hours ; the most useful mode of ap- plying a horse's power is in draught, and the worst is in carrying a load; it has been found that three men carrying each 100 lb., will ascend a hill with greater ra- pidity than one horse carrying 300 lb. The best disposition of the traces in draught is when they are perpendicular to the collar. When a horse is employed in moving a machine in a circular path, the diame- ter of this path should not be less than 25 or 30 feet ; 40 feet would be better than either. HUMAN STRENGTH. An active man, working to the best advantage, can raise 10 lb. 10 feet in a second for 10 hours in the day, 100 lb. one foot in a second. Absolute force of pressure with the hands was found by the dynamometer of Regnier to be on an average equal to 100 lb. Absolute force of a man lifting with both hands, 286 lb. The greatest ave- rage load which a man can support on his shoulders, for some seconds, is esti- mated at 330 lb. ; and it is supposed that he can exert the same force in drawing vertically downwards. The mean absolute force of a man, in drawing or pulling horizontally is found by the dynamometer to be 110 lb. ; the force of the pull in the strongest man was found to be only 20 lb. more than the average. The greatest effect of man's strength in raising a weight will be when the weight of the man is to that of his load as 1 : — -T- V 3, or nearlv as 4 : 3. HOSIERY. The stocking frame, which is the great implement of this business, though it appears at first sight to be a complicated machine, consists merely of a repetition of parts easily understood, with a moderate degree of attention, provided an accurate conception is first formed of the nature of the hosiery fa- bric. This texture is totally different from the rectangular decussation which constitutes cloth, as the slightest inspec- tion of a stocking will show ; for this, instead of having two distinct systems of thread, like the warp and the weft, which are woven together, by crossing each other at right angles, the whole piece is composed of a single thread united or looped together in a peculiar manner, which is called stocking- stitch, and sometimes chain-work. A single thread is formed into a num- ber of loops or waves, by arranging it over a number of parallel needles ; these are retained or kept in the form of loops or waves, by being drawn or looped through similar loops or waves formed by the thread of the preceding course of the work. The fabric thus formed by the union of a number of loops is easily unravelled, because the stability of the whole piece depends upon the ultimate fastening of the first end of the thread : and if this is undone, the loops formed by that end will open, and release the subsequent loops, one at a time, until the whole is unravelled, and drawn out into the single thread from which it was made. In the same manner, if a thread in a stocking-piece fails, or breaks at any part, or drops a stitch, as it is called, it immediately produces a hole, and the extension of the rest can only be pre- vented by fastening the end. It should be observed that there are many differ- ent fabrics of stocking-stitch for various kinds of ornamental hosiery, and as each requires a different kind of frame or machine to produce it, we should greatly exceed our limits to enter into a detailed, description of them all. The species we have described is the common stocking- stitch used for plain hosiery, and is form- ed by the machine called the common stocking-frame, which is the ground- work of all the others. The operation consists in drawing the loop of a thread successively through a series of other loops, so long as the work is continued. There is a great variety of different frames in use for producing various or- namental kinds of hosiery. Rib stocking-frame. This frame, which, next to the common frame, is most ex- tensively in use, is employed for work- ing those striped or ribbed 3tockings, which are very common in all the dif- ferent materials of which hosiery is formed. In principle it docs not differ from the common frame, and not greatly in construction. The preceding general description will nearly apply to this ma- chine with equal propriety as to the for- hyd] CYCLOPEDIA OF THE USEFUL ARTS. 251 mer; that part, however, by which the ribs or stripes are formed, is entirely an addition. This frame has been already referred to for the illustration of those parts of the machinery which are common to both, and those parts therefore require no recapitulation. The principle of weav- \ ing ribbed hosiery possesses considera- j ble affinity to that which subsists in the I weaving of that kind of cloth which is j distinguished by the name of tweeling, j for the formation of stripes, with some variation arising merely from the dif- : ferent nature of the fabric. In cloth | weaving, two different kinds of yarn, in- tersecting each other at right angles, are employed ; in hosiery only one is used. In the tweeling of cloth, striped as dimi- ty, in the cotton or kerseymere, and in the woollen manufacture, the stripes are }>roduced by reversing these yarns. In losiery, where only one kind of yarn is used, a similar effect is produced by re- versing the loops. To effect this revers- ing of the loops, a second set of needles is placed upon a vertical frame, so that the bends of the hooks may be nearly under those of the common needles. These needles are cast into tin moulds, pretty similar to the former, but more oblique or bevelled towards the point, so as to prevent obstructions in working them. They are also screwed to a bar of iron, generally lighter than the other, and se- cured by means of plates : this bar is not fixed, but has a pivot in each end, by means of which the bar may have a kind of os- cillatory motion on these pivots. The two frames of iron support this bar; that in which it oscillates being nearly vertical, but inclin- ed a little towards the other needles. This figure, which is a profile elevation, will serve to illustrate the relative position of each bar to the other. The vertical frame at a is attached to the horizontal frame d, by two centre screws, which serve as joints for it to move in. On the top of this frame is the rib-needle bar at/, and one needle is represented at/". At g is a small presser. to shut the barbs or* the rib-needles, in the same manner as the large one does those of the frame. At h is one of the frame-needles, to show the relative position of the one set to the other. The whole of the rib-bar is not fitted with needles like the other ; for here needles are only placed where ribs or stripes are to be formed, the intervals being filled up with blank leads, that is to say, with sockets of the same shape as the others, but without needles; being merely designed to fill the bar and pre- serve the intervals. Two small handles depend from the needle-bar, by which the oscillatory motion upon the upper centres is given. The rising and sinking motion is communicated to this machine by chains which are attached to iron sliders below, and which are wrought by the hosier's heel when necessary. The pressure takes place partly by the action of the small presser, and partly by the motion of the needles in descending. A small iron slider is placed behind the rib-needles, which rises as they descend, and serves to free the loops perfectly from each other. In the weaving of ribbed hosiery, the plain and rib courses are wrought alter- nately. When the plain are finished, the rib-needles are raised between the others, but no additional stuff is sup- plied. The rib-needles, intersecting the plain ones, merely lay hold of the last thread, and, by again bringing it through that which was on the rib-needle before, give it an additional looping, which re- verses the line of chaining, and raises the rib above the plain intervals, which have only received a single knitting. HYALITE, Manufacture of. This name is given to a black glass first made in Bohemia, in 1820, by M. de Buquoi. To prepare it, it is necessary to add to the materials for white glass, a quantity of iron forge cinder powder, charcoal dust in excess, and calcined bone powder. The forge cinder may be replaced by ba- salt, or lava. If sufficient charcoal is not present, the glass takes a green color. A red hyalite may be obtained with cal- cined bone powder, oxide of copper, car- bon, &c, and all these varieties present a marbled structure upon cutting. These glasses are very beautiful: they are fit to take the place of porcelain m many cases, possess far more lustre, and can receive a more perfect polish. HYDRARG^LLITE. A name given to the native phosphate of alumina, under the erroneous idea that it consisted of alumina and water. HYDRATES. Compounds containing water as one of their proximate elements, and in definite proportion. Caustic pot- ash is a hydrate of jootaasa^ composed of 252 CYCLOPEDIA OF THE USEFUL ARTS. [hyd 1 equivalent ot potassa = 48, and 1 of water = 9. Slaked lime, which is an ap- parently dry white powder, is a hydrate of lime. HYDKAULIC RAM, or WATER RAM. An ingenious hydraulic machine for raising water by means of its own impulse. The principle of its action and the mechanism of its construction may be described as follows : The water arriving at A from the re- servoir with the velocity due to the hei.ght of the fall, passes aloner the pipe A B, which should have an inclination of at least an inch for every two yards, escapes through an orifice C, which may be shut at pleasure by means of a valve. A reservoir, F, filled with air, is attached by means of a cylinder, abed, to the pipe A B D; in the middle of the bottom of the reservoir F is a circular orifice, to which there is adapted a short cylindri- cal tube, of which the extremity E is also furnished with a valve. Another valve, S, serves to supply the air to the space comprised between the cylinder abed and the tube E. G I H is an as- censional tube rising from the reservoir F. The water which escapes at C is car- ried off by the waste pipe K L. The form of this apparatus (or perhaps its mode of action) suggested the name it has received. The pipe A B C is called the body of the ram ; and the extremity, where the valves and the reservoir F are placed, is called its head. Both valves D and E are formed of hollow balls sup- ported on muzzles, and of such a thick- ness of metal that they weigh about twice as much as the quantity "of water they displace. We may now consider the effects of the engine when in action. The water, flowing through the orifice G, acquires the velocity due to the height of the fall, and raises the ball D from its support till it comes to the orifice C ; the extremity of this orifice is covered with leather, or with cloth filled with pitch, so that when the ball is applied to it, the passage of the water is effectually prevented. As soon as this orifice is closed, the water raises the ball E which had shut the ori- fice of the reservoir F, and a portion of it introduces itself into this reservoir, and into the pipe G I H. It thus loses the velocity which it had when the ori- fice C was shut, and the balls D and E fall down in consequence, the one on its support, and the other on the orifice at E. When this takes place, every thing is in the same state in which it was at first. The water begins again to flow through the orifice C; the valve D is again shut ; and the same effects are re- peated in an interval of time, which, for the same ram, undergoes little variation. Every time the impulse is renewed, a quantity of water is forced up into the reservoir F and the tube H ; and as it is prevented from returning by the action of the valve, it must necessarily be deli- vered at the extremity of H. The use of the air-vessel F is to keep up a continu- ous motion of the ascending column of water. The communication with the ex- ternal atmosphere being cut off, the air within F is compressed by a force pro- portional to the height of the surface of the water in II above its surface in F ; and this compressed air, acting by its elasticity on the water, maintains a con- tinuous flow through H. The air-vessel, however, though it assists the action of the ram, is not an essential part of it ; the continuity of the discharge of water may be effected by means of two or more rams, of which the ascensional pipes G I H all terminate in a single branch. On this principle works have been erected at Marly, in France, which raise water in a continuous jet to the height of 57 metres, or 187 English feet. As the ascending column of water com- municates with the air in the reservoir F, this would soon be exhausted if a fresh portion of air were not introduced at each stroke of the ram. The little tube S, which is stopped by a valve opening inwards, serves for this purpose. At the instant when the orifice C is closed a re- coil takes place, by which the water is thrown back from the head of the ram to- wards the cistern ; and a partial vacuum being thus produced within the cylinder abed, the pressure of the external at- mosphere forces open the valve in the canal S, and a portion of air enters the cylinder, whence it is driven into the re- servoir, excepting the small part of it which lodges in the space between the cylinder abed and the tube E. The invention of the hydraulic ram, >] CYCLOPEDIA OF THE USEFUL ARTS. 253 at least in the improved form here de- scribed, belongs to Montgolfier, of Mont- pelier. A machine, however, on the same principle had previously been sug- ?ested, and even erected at Chester (Eng.), y Mr. Whitehurst, but much less perfect in its mode of action ; for the orifice C, instead of being opened and shut by the action of the water itself, required to be opened and shut by the hand by means of a stop-cock. Owing to this circum- stance, Whitehurst's machine was of lit- tle utility, and appears to have soon been entirely forgotten. HYDKAULIC PRESSURE EN- GINES. A Mr. Glynn brought under the notice of the British Association in 1849 the means of employing high falls ofwater to produce reciprocating motion, by means of a pressure engine ; this latter acted on by the power of a descending column of water upon the piston of a cylinder to give motion to pumps for raising water to a different level, or to produce a re- ciprocating motion for other purposes. The pressure engine was calculated to give great mechanical effect in cases where water-falls exist of much too great a height and too small a volume to be practically used efficiently on water wheels within the ordinary limits of di- ameter. One of these engines is at pres- ent worked at the Allport Mines, Derby- shire. The cylinder is 50 inches di- ameter, and the stroke 10 feet, worked by a column of water 132 feet high, so that the proportion of power to act on it was the area of a piston to that of the plunger, namely, 1,963 to 1,385, or fully 70 per cent. The engine lever cost 60 dollars a year since its erection in 1841. Its usual speed is 5 strokes per minute, but can work 7 without any concussion in the descending column. The duty ac- tually done being equal to 163 horse power. Area of plunge 9-621 feet X 10 ~ 7 strokes == 673-41. 673-41 X 62-5 H- 182 == 5 5 5 5^^ 2 — 163 horse power. In this engine as in others, when water acts by its gravity or pressure, these ma- chines do the best work when the water enters the machine without shock or im- pulse, and leaves it without velocity, obtaining thus all the available power that the water can yield with the least loss of effect. This result is best accom- plished by making the pipes and passages of sufficient size to prevent acceleration of the hydrostatic column. The pressure of a small column of wa- ter, as that of a common hydrant pipe, has been made to turn a coffee-mill, which it works economically and efficiently. There arc many small machines which might readily be turned by the Croton water in New York, and also in other large cities by the mere descending force of the small hydrant or hose pipe. It would be in cities one of the simplest and le.ist expensive powers. HYDRIOD1C ACID. ^ A gaseous com- Eound of hydrogen and iodine, obtained y the mutual decomposition of iodide of phosphorus and water. It is com- posed of 126 iodine + 1 hydrogen ; and its equivalent, therefore, is 127. The specific gravity of this gas is 4-4. One hundred cubic inches weigh 136 grains. It is rapidly absorbed by water, furnish- ing a sour, colorless, and dense liquid, winch soon becomes brown by exposure to air, in consequence of the evolution of a little free iodine. It is instantly de- composed by chlorine, which abstracts the hydrogen to form hydrochloric (mu- riatic) acid, and sets the iodine free. HYDEOBROMIC ACID. A gaseous acid composed of 78 bromine + 1 hydro- gen. It is obtained by the mutual de- composition of bromide of phosphorus and water. HYDROCARBON. A term applied by chemists to compounds of hydrogen and carbon. These elements unite in several proportions, and form a variety of curious definite combinations, which are commonly called hydrocarburets. IIYDROCARBURETS. Compounds of hydrogen and carbon. These appear to be several definite combinations of these elements ; among them the follow- ing deserve especial notice : 1. Light car- buretted hydrogen gas, which is the fire- damp of coal mines and of marshes : 100 cubic inches weigh about 17-4 grains. It consists of two atoms of hydrogen = 2, and 1 of carbon = 6 ; its equivalent is 8. It burns with a pale blue flame. 2. Olefiant gas, which is formed during the distilla- tion of equal measures of alcohol and sul- phuric acid : 100 cubic inches weigh 30-5 grains. It is composed of 2 atoms of hydrogen = 2, and 2 of carbon = 12 ; and its equivalent, therefore, is 14. It burns with a bright white flame. Coal gas con- sists of a mixture of these two hydrocar- bons. The term olejiunt gas is derived from the action of chlorine upon it, which, when mixed with the gas over water, gradually condenses it into a liquid looking like oil, which is a hydrochloride of carbon. 3. Quadricarburetted hydro- gen, which is produced during the de- structive distillation of oil (Faraday, An,' 254 CYCLOPEDIA OF THE USEFUL ARTS. [hyg rials of Philosophy, xxvii,, 44), and which is a vapor condensable at 0°, of which 100 cubic inches weigh 61-2 grains. It con- sists of 4 atoms of hydrogen = 4, and 4 of carbon = 24 ; and its equivalent is 28. It burns with a dense and very smoky flame. This compound has also been called etherine, 1 volume of the vapor of of ether being constituted of 1 volume of quadrihydrocarbon and 1 of water vap>jr. 4. Bicarburet of hydrogen, obtained, like the last, from the volatile products formed during the destructive distillation of whale oil. When the quadrihydrocarbon has been distilled off from the more vola- tile portion, that which remains yields a Eroduct which congeals at 0°. It is a rittle white solid at that temperature : 100 cubic inches of its vapor weigh 85*3 grains, and it consists of 3 atoms of hy- drogen = 3, and 6 of carbon = 36 ; its equivalent, therefore, is 39. These are the principal forms of hydrocarbon which have been satisfactorily identified : they all afford carbonic acid and water when burned in a sufficiency of oxygen ; and the proportions in which these are formed, together with the specific gravities of their respective vapors, furnish the data upon which their composition is estima- ted. See Naptha and Napthalin. HYDROMETER. An instrument for de- termining the specific gravities of liquids, and thence the strengths of spirituous liquors ; these being inversely as their specific gravities. Various instruments of different forms have been proposed for ascertaining readily the specific gravi- ties of fluids ; but as Sikes's hydrometer is directed by act of parlia- ment to be used in collect- ing the revenue of Great ©Britain, it may be consider- B ed as more deserving of de- scription than any of the oth- ers. This instrument is rep- resented in the annexed fig- ure. A B is a flat stem, divi- ded on both sides into eleven equal parts, each of which is again subdivided into two. The stem carries a hollow brass ball B C, in which is fixed a conical stalk C D, ter- minating in a pear-shaped bulb D. Eight different weights of a circular form, nnd marked with the nmmbers 10, 20, 30, 40, 50, 60, 70, and 80, are cut in the man- ner represented at W, so that they can be placed on the stalk C D. When the strength of spirits is to be measured, one of the circular weights is placed on C D, which is found by trial to be capable of sinking the ball so far that the surface of the liquid cuts the stem at one of the divisions between A and B. The num- ber of this division is then observed, and also the temperature of the liquid ; and the corresponding strength per cent, of the spirits is then found in a table which accompanies the instrument. Another easy method of determining the destinies of different liquids, fre- quently practised, is by means of a set of glass beads previously adjusted and numbered. Thrown into any liquid, the heavier balls sink and the lighter float at the surface ; but one of them approach- ing the density of the liquid will be in a state of indifference as to buoyancy, or will float under the surface. The number on this ball indicates, in thousandth parts, the specific densitv of the liquid. HYDROSTATIC PRESS, also called the Hydraulic Press, and sometimes from the name of the engineer who gave it the form under which it is now constructed, and brought it into general use, BramaKs Press, is a machine by means of which an enormous force of pressure is obtained through the medium of water. The principle is the same as that of the hy- drostatic bellows ; from which, indeed, it only differs by the substitution of a strong forcing pump for the long tube, and a barrel and ^ 7 piston for the leather and boards. It consists of a short and very strong pump-bar- rel A B, with a solid piston C of proportionate strength, which is pushed upwards against the thing to be compressed, by water driven iuto the barrel beneath it at F from the small forcing pump E. If the small pump have only one thousandth of the area of the large barrel, and if a man, by means of its lever handle D, press its piston down with a force of five hundred pounds, the piston of the great barrel, in virtue of the hydrostatic principle of equal pres- sure in all directions, will riso with a force of a thousand times five hundred pounds, or more than 200 tons. The hydrostatic press is applied to a great variety of useful purposes ; for compressing bales of goods, as paper, cotton, wool, tobacco, &c, for expressing oils from seeds, raising weights, uprooting trees, &c. HYGROMETER, or Dew-Measurer, is an instrument for measuring the de- HYDROSTATIC 1'RESS. p 26,1. hyg] CYCLOPEMA OF THE USEFUL ARTS. 255 grecs of moisture or dryness of the at- mosphere. Variations in the state of the atmos- phere with respect to moisture and dry- ness are manifested by a great variety of phenomena ; and, accordingly, numerous contrivances have been proposed for as- certaining the amounts or those variations by referring them to some conventional scale. All such contrivances are called hygrometers ; but though the variety of form that may be given to them, or of substances that may be employed, is end- less, they may all be referred to two classes ; namely, 1st, those which act on the principle of absorption ; and, 2d, those which act on the principle of condensation. 1. Hygrometers on trie Principle of Ab- sorption. — Many substances in each of the three kingdoms of nature absorb moist- ure from the atmosphere with greater or less avidity, and thereby suiter some change in their dimensions, or weight, or some of their physical properties. An- imal fibre is sottened and relaxed, and consequently elongated, by the absorp- tion of moisture. Cords composed of twisted vegetable substances are swollen, and thereby shortened, when penetrated by humidity ; and the alternate expan- sion and shrinking of most kinds of wood, especially when used in cabinet-work, and after the natural sap has been evapo- rated, is a phenomenon with which every one is familiar. Many mineral substan- ces absorb moisture rapidly, and thereby obtain an increase of weight. Now it is evident that any of these changes, either of dimension or of weight, may be re- garded as the measure of the quantity of moisture absorbed, from which the quan- tity of water existing in the atmosphere in the state of vapor is inferred; but many, indeed the far greater part of them, are so small in amount, or take place so slowly, that they afford no certain indica- tion of the actual state of the atmosphere at any particular moment. Of the different kinds of hygrometers whose construction depends on change of dimensions, arising foom the absorp- tion of moisture, there are two deserving of notice on account of their historical celebrity, though they are now seldom, if at all, used where accurate meteorolo- gical observations are attempted. One is the hair hygrometer of Saussure ; the other the whalebone hygrometer of DeLuc. Saussure's hygrometer consists of a human hair prepared by boiling it in a caustic ley. One extremity of the hair is fastened to a hook, or held by pincers ; the other has a small weight attached to it, by which it is kept stretched. The hair is passed over a grooved wheel or pulley, the axis of which carries an index which moves over a graduated arch. Such is the essential part of the instru- ment, and it is easy to conceive how it acts. When the surrounding air becomes more humid, the hair absorbs an addi- tional quantity of moisture, and is elon- the counterpoise consequently de- scends, and turns the pulley, whereby the index is moved towards the one hand or the other. On the contrary, when the air becomes drier, the hair loses a part of its humidity, and is shortened. The counterpoise is consequently drawn up, and the index moves in the opposite di- rection. The accuracy of the indications of this instrument depends on the as- sumed principle that the expansion and contraction of the hair are due to moisture alone, and are not affected by tempera- ture or other changes in the condition of the atmosphere. Experiment shows that the influence of temperature is not very great ; but, after all precautions have been taken in preparing the instrument, it is found to be exceedingly irregular in its movements, and subject to great un- certainties. Besides, the substance is soon deteriorated, and will scarcely main- tain its properties unimpaired during a single year. The hygrometer of De Luc consists of a very thin slip of whalebone cut trans- versely or across the fibres, and stretched by means of a spring between two points. One end is fixed to a bar, while the other acts on the shorter arm of the index of a graduated scale. When the whalebone absorbs moisture it swells, and its length is increased ; as it becomes dry it con- tracts ; and the space over which the in- dex moves by the one or the other of these effects gives the measure of the ex- pansion or contraction, and the corre- sponding change in the hygometric state of the atmosphere. The action of this hygrometer appears to be more uncertain than that of Saussure. The hygrometers which have been pro- posed on the principle of a change of weight arising from the absorption of moisture, are liable to still greater ob- jections. Changes of weight may indeed be measured with greater accuracy by the common or torsion balance : but in the present case they are so small, that the Sarticies of dust which are at all times oating in the atmosphere may produce a great alteration in the results. A great 256 CYCLOPEDIA OF THE USEFUL ARTS. [hyo variety of substances which attract moist- ure have been employed, such as sponge, cotton, bibulous paper, caustic potash, the deliquescent salts, sulphuric acid, &c. • but the indications which they give are deserving of very little credit. Chan- ges of property indicated by the torsion of cords formed of gut, hemp, cotton, &c, and the torsion of certain vegetable fibres, are still more fallacious. 2. Hygrometers on the Principle of Con- densation. — The instruments of this class are of a far more refined nature than those which we have been describing. In order to give an idea of the general principle on which they depend, let us conceive a glass jar, having its sides per- fectly clean and transparent, to be filled with water, and placed on a table in a room where the temperature is, for exam- ple, 60°, the temperature of the water being the same as that of the room. Let us next suppose pieces of ice, or a freez- ing mixture, to be thrown into the water, whereby the water is gradually cooled down to 55, 50, 45, &c, degrees. As the process of cooling goes on, there is a cer- tain instant at which the jar loses its transparency, or becomes cum ; and, on attentively examining the phenomenon, it is found to be caused by a very fine dew or deposition of aqueous vapor on the external surface of the vessel. The precise temperature of the water, and, consequently, of the vessel, at the instant when this deposition begins to be form- ed, is called the dew point, and is capable of being noted with great precision. Now this temperature is evidently that to which, if the air were cooled down, under the same pressure, it would be complete- ly saturated with moisture, and ready to deposit dew on any body in the least de- gree colder than itself. The difference, therefore, between the temperature of the air, and the temperature of the water in the vessel when the dew begins to be formed, will afford an indication of the dryness of the air, or of its remoteness from the state of complete saturation. But the observation which has now been described is capable of affording far more interesting and precise results than a mere indication of the comparative dry- ness or moisture of the atmosphere. With the help of tables of the eh^tic force of aqueous vapor at different im- peratures, it gives the means of deter- mining the absolute weight of the aque- ous vapor diffused through any given volume of air, the proportion of vapor existing in that volume to the quantity that would be required to saturate it, and of measuring the force and amount of evaporation. The elastic force of aqueous vapor at the boiling point of water is evidently equal to the pressure of the atmosphere. This may be assumed as corresponding to a column of mercury 30 inches in height. Mr. Dalton, in the fifth volume of the Manchester Memoirs, has given the details of a most valuable and beautiful set of experiments, by which he ascer- tained the elastic force of vapor from water at every degree between its freez- ing and boiling points in terms of the column of mercury which it is capable of supporting. As the same experiments have since been frequently repeated, and the different results present all the ac- cordance which can be expected in so delicate an investigation, the tension of vapor at the different temperatures may be regarded as sufficiently well determin- ed. Supposing, then, we have a table exhibiting the elasticity or tension corre- sponding to every degree of the thermo- meter, the weight of a given volume of vapor, for example a cubic foot, may be determined as follows : Steam at 212°, and under a pressure of 30 inches of mercury, is 1700 times light- er than an equal bulk of water at its greatest density, or a temperature of about 40°, and a cubic foot of water at that temperature weighs 437272 grains ; the weight, therefore, of a cubic foot of steam at that temperature and pressure is 437272-5-1700=257-218 grains. Hence we may find the weight of an equal bulk of vapor of the same temperature under any other given pressure, suppose 0-56 of an inch ; for the density being directly as the pressure, we have 30 in. : 0*56 in. : : 257-218 grs. : 4-801 grs., which is the weight required. Having tound the weight of a cubic foot of vapor under a pressure of 0-56 of an inch, and at the temperature 212°, we may find its weight under the same pres- sure at any other temperature, suppose 60°. It is ascertained by experiment that all aeriform bodies, whether vapors or gases, expand the l-480th part of their volume for every accession of tempera- ture equivalent to one degree of Fahren- heit's scale ; therefore, reckoning a vol- ume of gas at 32° as unity, its vol- ume at 60° is to its volume at 212° as 1 + ffi is to 1 + £f <> ; or as 1-058 : 1-375 ; and the density and weight being in- versely as the volume, we have 1-058 : 1-375 : : 4-801 grs. 6-222 grs. hyg] CYCLOPEDIA OF THE USEFUL ARTS. 251 for the weight of a cubic foot of vapor at temperature 60°, and under a pres- sure of 0-56 of an inch of the mercurial column. The following table, abridged from DanieWs Meteorological Essays, shows the force of tension, weight, and expa#ion of aqueous vapor, at different tempera- tures, on Fahrenheit's scale. Temp. Force. Weight of a cubic foot. Expansion. •068 •S56 •9334 5 •0S3 1-034 •9438 10 •09S 1-208 •9542 15 •119 1-451 •9646 20 •140 1-688 •9750 25 •170 2-028 •9S55 30 •200 2-361 •9959 85 •240 2.805 1-0063 40 •280 3-239 1-0167 45 •340 3-S93 1-0271 50 •400 4535 1-0375 55 •476 5-342 1-0479 60 •560 6-222 1-0583 65 •657 7-230 1-0687 70 •770 8-392 1-0791 75 •906 9780 1-0895 80 1-060 11-333 1-0999 85 1-235 13-081 1-1003 90 1430 15-005 1-1107 95 1-636 17-009 1-1211 212 30-000 257-218 20-6005 Having thus explained the principle of the common hygrometer, we will now de- scribe one or two of the forms under which it has been most frequently con- structed. Daniell's hygrometer consists of two thin glass balls orl4 inch diameter, connected together by a tube having a bore about Jth of an inch. The tube is bent at right angles over the two balls, and the arm contains a small thermometer whose bulb, which should be of a length- ened form, descends into the ball. This ball, having been about two thirds filled with ether, is heated over a lamp till the fluid boils, and the vapor issues from the capillary tube which terminates the ball. The vapor having expelled the air from both balls, the capillary tube is hermeti- cally closed by the flame of a lamp. The other baJl is to be covered with a piece of muslin. The stand is of brass, and the transverse socket is made to hold the glass tube in the manner of a spring, al- lowing it to turn and be taken out with little difficulty. A small thermometer is inserted into "the pillar of the stand. The manner of using the instrument is this : after having driven out all the ether into the ball by the heat of the hand, it is to be placed at an cpen window, or out of doors, with the ball so situated that the surface of the liquid may be on a level with the eye of the observer. A little ether is then to be dropped on the cov- ered ball. Evaporation immediately takes place, which producing cold upon the covered ball causes a rapid continuous condensation of the ethereal vapor in the interior of the instrument. The con- sequent evaporation from the included ether produces a depression of tempera- ture in the ball, the degree of which is measured by the thermometer. This ac- tion is almost instantaneous, and the thermometer begins to fall in two seconds after the ether has been dropped. A de- pression of 30 to 40 degrees is easily pro- duced, and the ether is sometimes ob- served to boil and the thermometer to be driven "below zero of Fahrenheit's scale. The artificial cold thus produced causes a condensation of the atmospheric vapor up- on the uncovered ball, which first makes, its appearance in a thin ring of dew co- incident with the surface of the ether. The degree at which this takes place must be carefully noted. In very damp or windy weather the ether should be very slowly dropped upon the ball, oth- erwise the descent of the thermometer will be so rapid as to render it extremely difficult to be certain of the degree. In dry weather, on the contrary, the ball re- quires to be well wetted more than once, to produce the requisite degree of cold. The instrument which has now been described is extremely beautiful in prin- ciple ; but it may be doubted whether, even when the greatest caution is ob- served, the temperature which it indi- cates is precisely that at which the depo- sition of dew takes place. The deposi- tion first occurs in a narrow ring on a level with the surface of the etherln tha ball h, thereby indicating that the ethei is colder at tlie surface than a little undei it. But if the temperature is not uniform throughout the ball, it is evident that only a small part of the bulb of the ther- mometer can be placed in the point where the greatest cold exists : consequently the temperature indicated by the ther- mometer will be greater than is necessarj for producing the deposition of moisture ' in other words the dew point will be given too high. Various attempts have been made tc obviate the defects of Daniell's hygrome- ter, but hitherto without much success. The apparatus proposed by Pouillet may be described as follows : A small cup C 258 CYCLOPEDIA OF THE USEFUL ARTS. [iNO C, formed of gold, and extremely thin, is fixed to a little collar of ivory B B, sup- ported on a stand. The stem of an in- verted thermometer T T de- scends through a perforation in the bottom of the cup, and is fitted closely into it and sealed, the ball of the thermometer being placed at the centre of the cup. In order to prevent the mercury from separating, a small portion of the air is left in the stem. When an ob- servation is to be made, sul- phuric ether is poured into the cup ; and in consequence of the rapid evaporation which takes place, a considerable de- gree of cold is produced, and i deposition takes place on the outside of the cup. The degree of the thermometer at the instant the bright- ness of the metal begins to be dimmed gives the dew point. The correctness of the indication depends on the identity of temperature of the ether, the metal of ttvB cup, and the thermometer. Bright fcOid is* found to answer the purpose bet- ter than any other metal. As the hygrometer is one of the prin- cipal instruments in meteorological re- searches, its theory and the best form of its construction have been the subject of frequent discussion in the various scien- tific journals. HYGROMETRIC. This term is com- monly applied to substances which readi- lv become moist and dry with correspon- ding changes in the state of the atmos- phere, or which readily absorb and retain moisture. Sea-weed, several saline sub- stances, porous clays, potash and its car- bonate, chloride of calcium, sulphuric acid, are in this sense of the term said to be hygrometric. HYGROMETRIC REGISTER. Atone of Lord Rosse's recent scientific soirees, in London, Mr. Appold exhibited his cu- rious Register Hygrometer for keeping the atmosphere of the house at one regu- lar moisture. The instrument with a va- riation at one degree in the moisture of the atmosphere opens a valve capable of supplying ten quarts of water per hour ; delivering it to pipes covered with blot- ting paper heated by a gas stove, by which the water is evaporated until the atmosphere is sufficiently saturated and the valve thereby closed. A lead pencil is attached to register the distance the hygrometer travels ; and thus a sheet of paper moved by clock-work shows the difference between the wet and dry bulbs of the thermometer at any period of time. HYPOSULPHITE OF SODA. This salt, so extensively used in the practice of Vaquerrotyging, may be easily pre- pared in quantities by the following pro- cess—Mix one pound of finely pulverized ignited carbonate of soda with ten ounces of flowers of sulphur, and heat the mix- ture slowly in a porcelain dish till the sulphur melts. Stir the fused mass, so as to expose all its parts freely to the atmosphere, whereby it passes from the state of a sulphuret, by the absorption of atmospherical oxygen, into that of a sul- phite, with the phenomenon of very slight incandescence. Dissolve in water, filter the solution, and boil it immediate- ly along with flowers of sulphur. The filtered concentrated saline liquid will afford, on cooling, a large quantity of pure and beautiful crystals of hyposul- phite of soda. IMPERMEABLE, is the epithet given to any kind of textile fabric, rendered water-proof by one or other of the follow- ing substances : — 1. Linseed oil to which a drying quali- ty has been communicated by boiling with litharge or sugar of lead, &c. 2. The same oil holding in solution a little caoutchouc. 3. A varnish made by dissolving caout- chouc in rectified petroleum or naptha, applied between two surfaces of cloth, as described under Mackintosh's patent. See Caoutchouc. 4. Vegetable or mineral pitch, applied hot with a brush, as in making tarpawl- ing for covering goods in ships. 5. A solution of soap worked into cloth, and decomposed in it by the action of a solution of alum; whence results a mixture of acid fats and alumina, which insinuates itself among all the woolly fila- ments, fills their interstices, and prevents the passage of water. 6. A solution of glue or isinglass, in- troduced into a stuff, and then acted upon by a solution of galls or tannin wlien an insoluble leather is deposited in the stuff. INCOMBUSTIBLE CLOTH is'a tissue of the fibrous mineral called amianthus or asbestos. This is too rare to form the object of any considerable manufacture. Cotton and linen cloth may be best ren- dered incapable of taking fire, or burning with flame, by being imbued with a solu- tion of sal ammoniac or phosphate of magnesia. INCUBATION, ARTIFICIAL. The INC] CYCLOPEDIA OF THE USEFUL ARTS. 259 Egyptians have from time immemorial been accustomed to hatch eggs by artifi- cial warmth, without the aid of hens, in peculiar stoves, called Mammals. The inhabitants of the village Berme still travel through the most distant pro- vinces of Egypt at certain seasons of the year, with a portable furnace, heated by a lamp, and either hatch chickens for sale, or undertake to hatch the eggs be- longing to the natives at a certain rate per dozen. M. de Reaumur published in France, about a century ago, some inge- nious observations upon this subject ; but M. Bonnemain was the first person who studied with due attention all the circumstances of artificial incubation, and mounted the process successfully upon the commercial scale. So far back as 1777 he communicated to the Academy of Sciences an interesting fact, which he had noticed, upon the mechanism em- ployed by chicks to break their shells; and for some time prior to the French revolution he furnished the Parisian mar- ket with excellent poultry at a period of the year when farmers had ceased to supply it. His establishment was ruined at that disastrous era, and no other has ever since been constructed or conducted with similar care. There can be no doubt however of the practicability and profit- ableness of the scheme, when judiciously managed. Some imitations of his plans have been made in England, but how far they have succeeded, in an economical point of view, it is difficult to determine. His apparatus derives peculiar interest from the fact that it was founded upon the principle of the circulation of hot water, by the intestine motions of its particles, in a returning series of con- nected pipes ; a subject afterwards illus- trated in the experimental researches of Count Rumford. It has of late years been introduced as a novelty, and applied to warm the apartments of many public and private buildings. They were then publicly exhibited at his residence in Paris, and were afterwards communicated to the world at large in the interesting article of the Dictionnaire Technologique, entitled Incubation Artificielle. The apparatus of M. Bonnemain con- sisted, 1. of a boiler and pipes for the circulation of water ; 2. of a regulator calculated to maintain an equable temper- ature; 3. of a stove-apartment, heated constantly to the degree best fitted for incubation, which he called the hatcli- ing pitch. He attached to one side a po'msimere or chick-room, for cherishing the chickens during a few days after in cubation. The boiler is represented in vertical section. It is composed of a double cyl- inder of copper or cast-iron, 1 1, having a grate, I (see plan), an ashpit at d. The water occupies the shaded J , I < p5 1 D space, c, c. A, — I "J— X\ g, g, e, e, are five vertical flues, for con- ducting the burnt air and smoke, which first rise in the two exterior flues, which have an affinity for oxygen superior to its own, such as certain metals and metallic oxydes, or by mixing it with fer- menting matters, or, finally, by dissolving it in a strong acid, such as the sulphuric. The second of the above methods is called the warm hue, or pastel vat ; and being the most intricate, we shall begin with it. Before the substance indigo was known in Europe, woad having been used for dyeing blue, gave the name of woad vats to the apparatus. The vats are sometimes made of copper, at other times of iron or wood, the last alone being well adapted for the employment of steam. The di- mensions are very variable ; but the fol- lowing may be considered as the average size : depth, 7£ feet ; width below, 4 feet ; above, 5 feet. The vats are built in such a way that the fire does not affect their bottom, but merely their sides half way up ; and they are sunk so much under the floor of the dyehouse, that their upper half only is above it, and is surrounded with a mass of masonry to prevent the dissipation of the heat. About 3 or 3s feet under the top edge an iron ring is fixed, called the champagne by the French, to which a net is attached in order to suspend the stuffs out of contact of the sediment near the bottom. In mounting the vat the following arti- cles are required: 1. woad prepared by fermentation, or woad merely dried, which is better, because it may be made to ferment in the vat, without the risk of becoming putrid, as the former is apt to do ; 2. indigo, previously ground in a proper mill ; 3. madder ; 4. potash ; 5. slaked quicklime; 6. bran. In France, weld is commonly used instead of potash. The vat being filled with clear river water, the fire is to be kindled, the in- gredients introduced, and if fermented woad be employed, less lime is needed than with the merely dried plant. Mean- while the water is to be heated to the temperature of 160° Fahr., and main- tained at this pitch till the deoxidize- ment and solution of the indigo begin to show themselves, which, according to the state of the constituents, may happen in 12 hours, or not till after several days. The first characters of incipient solution are blue bubbles, called the flowers, which rise upon the surface, and remain like a head of soap-suds for a consider- able time before they fall; then blue coppery shining veins appear with a like colored froth. The hue of the liquor now passes from blue to green, and an ammoniacal odor begins to be exhaled. Whenever the indigo is completely dis- solved, an acetic smelling acid may be recognised in the vat, which neutralizes all the alkali, and may occasion even an acid excess, which should be saturated with quicklime. The time for doing this cannot be in general very exactly defined. When quicklime has been added at the beginning in sufficient quantity, the liquor appears of a pale wine-yellow color, but if not, it acquires this tint on the subsequent introduction of the lime. Experience has not hitherto decided in favor of the one practice or the other. As soon as this yellow color is formed in the liquor, and its surface becomes blue, the vat is ready for the dyer, and the more lime it takes up without being alkaline, the better is its condition. The dyeing power of the vat may be kept up during six months, or more, according to the fermentable property of the woad. From time to time, madder and bran must be added to it, to revive the fer- mentation of the sediment, along with some indigo and potash, to replace what mav have been abstracted in the progress of dyeing. The quantity of indigo must be proportional, of course, to the depth or lightness of the tints required. Cold vats. — The copperas or common blue vat is so named because the indigo is re- duced by means of the protoxide of iron. This salt should therefore be as free as possible from the red oxide, and espe- cially from any sulphate of copper, which would re-oxidize the indigo. The neces- sary ingredients are : copperas (green sulphate of iron), newly slaked quick- lime, finely ground indigo, and water; to which sometimes a little potash or soda is added, with a proportional diminution of the lime. The operation is conducted in the following way: the indigo, well triturated with water or an alkaline ley, must be mixed with hot water in the preparation, vat, then the requisite quan- tity of lime is added, after which the so- lution of copperas must be poured in with stirring. Of this preparation vat, such a portion as may be wanted is laded into the dyeing vat. For one pound of indigo three pounds of copperas are ta- ken," and four pounds of lime (or 1 of indigo, 2i of copperas, and 3 of lime). If the copperas be partially peroxidized, somewhat more of it must be used. A vat cowtaining a considerable excess of lime is called a s?ia?-p vat, and is not well adapted for dyeing. A soft vat, on the contrary, is that which contains too ind] CYCLOPEDIA OF THE USEFUL ARTS. 2G3 much copperas. In this case the preci- pitate is apt to rise, and to prevent uni- formity of tint in the dyed goods. The sediment of the copperas vat consists of sulphate of lime, oxide of iron, lime with indigo brown, and lime with indigo blue, when too much quicklime has been em- ployed. The clear, dark wine yellow fluid contains indigo blue in a reduced state, and indigo red, both combined with lime and with the gluten of indigo dissolved. After using it for some time the vat should be refreshed or fed with copperas and lime, upon which occasion the sediment must first be stirred up, and then allowed time to settle again and become clear. For obtaining a series of blue tints, a series of vats of different strengths is required. Linen and cotton yarn, before being dyed, should be boiled with a weak alka- line ley, then put upon frames or tied up in hanks, and after removing the froth from the vat, plunged into and moved gently through it. For pale-blues, an old, nearly exhausted vat is used ; but for deep ones, a fresh, nearly saturated vat. Cloth is stretched upon a proper square dipping-frame made of wood, or preferably of iron, furnished with sharp nooks or points of attachment. These frames are suspended by cords over a pulley, and thus immersed and lifted out alternately at proper intervals. In the course of 8 or 10 minutes, the cloth is sufficiently saturated with the solution of indigo, after which it is raised and suspended so as to drain into the vat. The number of dippings determines the depth of the shade ; after the last, the goods are allowed to dry, taken off the frame, plunged into a sour bath of very dilute sulphuric or muriatic acid, to re- move the adhering lime, and then well rinsed in running water. The mode of making the China blue- dye has been described under Calico Printing. A blue dye may likewise be given by a solution of indigo in sulphuric acid. This process was discovered by Barth, at Grossenhayn, in Saxony, about the year 1740, and is hence called the Saxon blue- dye. The chemical nature of this pro- cess has been already fully explained. If the smoking sulphuric acid be employed, from 4 to 5 parts are sufficient for 1 of indigo ; but if oil of vitriol, from 7 to 8 parts. The acid is to be poured into an earthenware pan, which in summer must be placed in a tub of cold water, to pre- vent it getting hot, and the indigo, in fine power, is to be added, with careful stirring, in small successive portions. If it becomes heated, a part of the indigo is decomposed, with the disengagement of sulphurous acid gas, and indigo-green is produced. Whenever all the indigo has been dissolved, the vessel must be cover- ed up, allowed to stand for 48 hours, and then diluted with twice its weight of clear river water. The acidulated mass has a black color, is opaque, thick, attracts water from the air, ana is called indigo composition, or chemic-blue. It must be prepared before- hand, and kept in store. In this solu- tion, besides the cerulin, there are also indigo-red, indigo-brown, and gluten, by which admixture the pure blue of the dye is rendered foul, assuming a brown or a green cast. To remove these con- taminations, wool is had recourse to. This is plunged into the indigo previ- ously diffused through a considerable body of water, brought to a boiling heat in a copper kettle, and then allowed to macerate as it cools for 24 hours. The wool takes a dark-blue dye by absorbing the indigo-blue sulphate and hyposul- phite, while at the same time the liquor becomes greenish-blue ; and if the wool be left longer immersed, it becomes of a dirty-yellow. It must therefore be taken out, drained, washed in running water till this runs off colorless, and without an acid taste. It must next be put into a copper full of water, containing one or two per cent, of carbonate of potash, soda, or ammonia (to about one-third the weight of the indigo), and subjected to a boiling heat for a quarter of an hour. The blue salts forsake the wool, leaving it of a dirty red-brown, and dye the wa- ter blue. The wool is in fact dyed with the incligo-rcd, which is hardly soluble in alkali. The blue liquor may now be employed as a fine dye, possessed of su- perior tone and lustre. It is called dis- tilled blue and soluble blue. Sulphuric acid throws down from it the small quan- tity of indigo-red which had been held in solution by the alkali. When wool is to be dyed with this sulphate of indigo-blue, it must be first boiled in alum, then treated with blue liquor, and thus several times alternate- ly, in order to produce a uniform blue color. Too long continuance of boiling is injurious to the beauty of the dye. In this operation the woollen fibres get im- pregnated with the indigo-blue sulphate of alumina. With sulphate of indigo, not only blues 264 CYCLOPEDIA OF THE USEFUL ARTS. INK of every shade are dyed, but also green, olive, gray, as also a' fast ground to log- wood-blues ; for the latter purpose the preparatory boil is given with alum, tar- tar, sulphates of copper and iron, and the blue solution ; after which the goods are dyed up with a logwood bath con- taining a little potash. INK. The colored liquid used for writing, is made usually by the action of the tannin of vegetable' substances upon salts of iron. In the case of black ink, nut-galls, sulphate of iron, and gum, are the only substances necessary : others being added to modify the shade, or diminish the cost. Those which contain most gallic acid or tannin acid are most valuable, and the reverse. To make 12 gallons of ink, Dr. Ure directs to take 12 lbs. of Nut-galls. 5 lbs. of Green Sulphate Iron, 5 lbs. of Gum Senegal, 12 gallons of Water. The nut-galls and water are put into a copper and well boiled, replacing the water lost : it is then poured into a tub, let to settle, and strained. The gum is then dissolved, strained, and added to the gall liquor. The copperas is also dis- solved and added, when the whole be- comes gradually black. It should be bottled before it attains its full black- ness. A few bruised cloves added in, prevents mouldiness. Sumach, logwood, and oak-bark, are often used instead of galls, or in addition to it, to diminish the cost of manufacture ; but the ink is deteriorated by their use. Logwood requires less copperas than galls. The foregoing ink is much stronger than that commonly sold, and it may be diluted with an equal quantity of water to form an ink of similar strength to that usually sold. A good black ink should write pale and become black afterwards in the paper : that which writes black at once and shines on the surface of the paper, easily rubs off and is not as permanent Japan ink, as such is called, is not lasting. Inks are of almost every shade, and generally are solutions of chemical salts. Red ink. Take a strong decoction of Brazil wood and a little gum-water, and add some alum with a few drops of the chloride of tin. A still better red ink is a decoction of cochineal, to which a little water of am- monia has been added : or an extempo- raneous red ink may be made by rubbing up carmine in strong water of ammonia, diluting the solution down to the desired shade, and adding mucilage. Green ink. Dissolve distilled verdi- gris is strong vinegar, and make into a proper consistency for writing with a so- lution of gum arabic : or boil 2 parts of verdigris, 8 parts of water, and 1 part of cream of tartar together down to one half, let settle, strain, and bottle. Yellow ink. A little alum added to saffron and water, makes a very good yellow ink — thicken with gum : or boil 3 parts of alum, 100 parts of water, and 25 parts of Persian berries together, strain, and add mucilage ; or dissolve gamboge in water. The different dye-stuffs and solutions, afford inks of any desired shade. Mr. I. Deck has recommended a new mode of making black ink, which affords a good color and is remarkably cheap. The process is this : boil 1 part of log- wood in 100 parts of water until the liquor is pretty strong, and to one quart of it put in one quarter of an ounce of chromate of potash, and set it apart, shaking it frequently, for about three weeks. At first the appearance of the ink will be a little greenish, but after it is exposed to the sun and air for some time, it gets beautiful, is very fast, and does not injure steel pens. Ink powder. Blue galls, 2 ounces ; gum arabic, £ an ounce; sulphate of iron, 3 ounces — all powdered and well mixed together. IndelUtle inks. These used to have for a basis nitrate of silver, which, in a strong solution, thickened with gum and color- ed, was laid with a pen on the cloth pre- viously soaked with carbonate of soda — which" reduced the oxide of silver in the tissue of the stuff. More recently, the nitrate of silver has been dissolved in water of ammonia and laid on the cloth without any further treatment : this ink is not now indelible, its stain is removed by chlorine and water of ammonia, and of course it does not resist the bleaching- powder used in laundries. Fine gold- powder, rubbed up with genuine China ink, resists the action of chlorine, oxalic acid, and washing off with water. Char- coal, rubbed up with acetic acid and thickened, furnishes a very permanent ink. The following indestructible ink has been tried and recommended : shell lac, 2 ounces ; borax, 1 ounce ; distilled or rain water, 18 ounces — boil the whole in a closely-covered tin vessel, stirring it occasionally with a glass rod or a small iod] CYCLOPEDIA OF THE USEFUL ARTS. 265 stick, until the mixture has become ho- mogeneous ; filter, when cold, through a single sheet of blotting paper ; mix the filtered solution, which will be about 19 fluid ounces, with 1 ounce of mucilage of gum arabic, prepared by dissolving 1 ounce of water, and add pulverized in- digo and lamp-black, ad libitum. Boil the whole again in a covered vessel, and stir the fluid well to effect the complete solution and admixture of the gum ara- bic ; stir it occasionally while it is cool- ing; and after it has remained undis- turbed for two or three hours, that the excess of indigo and lamp-black may subside, bottle it for use. The above ink, for documentary purposes, is in- valuable, being, under all ordinary cir- cumstances, indestructible : it is also par- ticularly well adapted for the use of the laboratory. Five drops of kreosote added to a pint of ordinary ink will effectually prevent its becoming mouldy. Vanadate of ammonia treated with galls affords a good and permanent black which flows freely from the pen, it re- sists the action of chlorine and is not ob- literated by acids or alkalies. Whenever the metal vanadium will be found more plentiful this combination will form the best ink. Perhaps the Lake Superior copper may have its vanadium turned to advantage' in this way. Ink for Lithographers. — White soap 25 parts, white wax 25 parts, mutton suet 6 parts, lamp black 6 parts, shellac 10 parts, mastic 10 parts ; mix with heat and pro- ceed as for lithographic ink. Sympathetic Ink. — The best is a solution of muriate of cobalt. Copying Ink. — Gum arabic 240 grains, Spanish liquorice 20 grains, water 720 grains, dissolve ; then add the solution gradually in a mortar to 60 grains of lampblack previously moistened with a teaspoonful of sherry ; when well mixed strain through coarse muslin. Saxon Blue Ink, is a solution of sul- phate of indigo, used by dyers, weakened down to proper tint. A better kind of blue ink is made by rubbing together £ oz. of best Prussian blue, (th at recently made is best), oxalic acid 2 drachms, and'l pint of water ; filter, when well mixed. This has a beautiful tint. Printer's Ink. See under that head. INULINE, is a substance first extract- ed from the root of the Inula- Hellenium, or Elecampane. It is white and pulveru- lent like starch ; and differs from this substance chiefly because its solution, 12 when it cools, lets fall the inuline un- changed in powder, whereas starch re- mains dissolved in the cold, as a jelly or paste. Inuline is obtained by boiling the root sliced in 3 or 4 times its weight of water, and setting the strained decoction aside till it cools, when the pulverulent inuline precipitates. It exists also in the roots of colchicum and pellitory. IODINE, is one of the simple chemical bodies which was discovered accidentally in 1812, by M. Courtois, a manufacturer of saltpetre, in the mother-waters of that salt. Its affinities for other substances are so powerful as to prevent it from ex- isting in an insulated state. It occurs combined with potassium and sodium in many mineral waters, such as the brine spring of Ashby-de-la-Zouche, and other strongly saline springs. This combina- tion exists sparingly hi sea-water, abun- dantly in many species of fucus or sea- weed, and in the kelp made from them ; in sponges ; in several marine molluscce, such as the doris, the venus, oysters, &c. ; in several polyparies and sea-plants, as the gorgonia," the zostera marina, &c. ; particularly in the mother-waters of the salt-works upon the Mediterranean sea; and it has been found in combination with silver, in some ores brought from the neighborhood of Mexico. It is an ingredient in the salt licks, sa- line, and brine springs of this country, especially of those in the Valley of the Mississippi, and it has been found to be a constituent of coal. It seems to be be- neficial to marine plants, and they have the power of abstracting it from sea-wa- ter. It is from these plants that almost all the iodine of commerce is derived. Kelp, or the half vitrified ashes of sea- weeds, prepared by the inhabitants of the Western Islands and the northern shores of Scotland and Ireland, is treated with water, and the solution filtered. The li- quid is then concentrated by evaporation until it is reduced to a very small volume, the chloride of sodium, carbonate of soda, chloride of potassium, and other salts, being removed as they successively crys- tallize. The dark brown mother-liquor left, contains very nearly the whole of the iodide ; this is mixed with sulphuric acid and peroxide of manganese, and gently heated in a leaden retort, when the io- dine distils over and condenses in the re- ceiver. The theory of the operation is exactly analogous to that of the prepara- tion of chlorine ; it requires in practice, 266 CYCLOPEDIA OF THE USEFUL ARTS. [mo however, careful management, otherwise the impurities present in the solution in- terfere with the general result. The manganese is not really essential ; the iodide of potassium or sodium, heated with an excess of sulphuric acid evolves iodine. It is probable that this effect is due to a secondary action between the hydriodic acid first produced and the re- sidue of the sulphuric acid, in which both suffer decomposition, yielding iodine, water, and sulphurous acid. Iodine crystallizes in plates or scales of a bluish black color and imperfect metal- lic lustre, resembling that of plumbago ; the crystals are sometimes very large and brilliant. Its density is 4-948. At 225° it fuses, and at 347° boils, the vapor hav- ing an exceedingly beautiful violet color. It is slowly volatile, however, at common temperature, and exhales an odor much resembling that of chlorine. The density of the vapor is 8-716. Iodine requires for solution about 7000 parts of water, which nevertheless acquires a brown co- lor : in alcohol it is much more freely so- luble. Solutions of hydriodic acid and the iodides of the alkaline metals also dis- solve a large quantity; these solutions are not decomposed by water, which is the case with the alcoholic tincture. This substance stains the skin, but not permanently ; it has a very energetic ac- tion upon the animal system, and is much used in medicine. One of the most characteristic proper- ties of iodine is the production of a splendid blue color by contact with the organic principle starch. The iodine for this purpose must be free or uncombined. It is easy, however, to make the test available for the purpose of recognising the presence of the element in question when a soluble iodide is suspected ; it is only necessary to add a very small quan- tity of chlorine-water, when the iodine, being displaced from combination, be- comes capable of acting upon the starch. Iodine is now extensively used by the Daguerreotypist to coat the silver 'plate with so as to form a surface sensitive to light ; generally the pure iodine is used in the coating, occasionally the chloride of iodine is preferred. Iodine is also used by the French to produce a blue color adapted for dyeing cotton with. Iodine, Chloride of, is a preparation used in daguerreotyping. It is made by passing chlorine gas through iodine until the whole becomes liquid. Iodine readily absorbs chlorine forming when the chlo- rine is in excess a solid yellow compound, and when the iodine prepondeiates a brown liquid ; the solid iodide is decom- posed by water. The liquid is not, and is that which is used in the arts. It is a yellow, oily liquid, of a suffocating smell and astringent taste, soluble in water and alcohol. It consists of 1 equivalent ol chlorine united with 1 equiv. of iodine. IKIDIUM is a metal discovered by ' Descotils, in 1803, as also by Tenant, in 1804 ; and is so called because its differ- ent solutions exhibit all the colors of the rainbow. It occurs only in the ore of platinum, being found there in two states ; 1. united to that metal, and 2. as alloy of osmium and iridium, in the form of small, insulated, hard grains. Iridium is the most refractory of all the metals ; and ap- pears as a gray metallic powder. It is not fused by the flame of the hydro-oxy- gen lamp. IKON. Every person knows the man- ifold uses of this truly precious metal ; it is capable of being cast in moulds of any form ; of being drawn out into wires of any desired strength or fineness ; of be- ing extended into plates or sheets ; of be- ing bent in every direction ; of being sharpened, hardened, and softened at pleasure. Iron accommodates itself to all our wants, our desires, and even our caprices ; it is equally serviceable to the arts, the sciences, to agriculture, and war ; the same ore furnishes the sword, the ploughshare, the scythe, the pruning nook, the needle, the graver, the spring of a watch or of a carriage, the chisel, the chain, the anchor, the compass, the can- non, and the bomb. It is a medicine of much virtue, and the only metal friendly to the human frame. The ores of iron are scattered over the crust of the globe with a beneficent pro- fusion, proportioned to the utility of the metal ; they are found under every lati- tude, and every country which possesses a range of primary rocks is sure to have beds of iron ore. When pure it is a me- tal of a bluish-gray color, and a dull fi- brous fracture, but it is capable of ac- quiring a brilliant surface by polishing. Its specific gravity is 7-78. It is the most tenacious of metals, and the hardest of all those which are malleable and ductile. It is singularly susceptible of the magne- | tic virtue, but in its pure state soon loses | it. When rubbed it has a slight smell, i and it imparts to the tongue a peculiar ! astringent taste, called chalybeate. In a ' moist atmosphere, iron speedily oxydizes, and becomes covered with a brown coat- ; ing, called rust. IRO] CYCLOPEDIA OF THE USEFUL ARTS. 267 There are no less than 19 ores of iron : I, native iron of three kinds, pure, metal- liferous, and steely ; 2, arsenical iron ; 3, yellow sulphuret of iron ; 4, white sul- phuret of iron ; 5, magnetic sulphuret ; 6, black oxide, either the loadstone, the magnetic, or titaniferous ; 7, Fer oligigiste, either specular or scaly; 8, haematite, yielding red powder; 9, yellow haematite, a hydrated oxide ; 10, pitchy iron ore ; II, silico calcareous iron or zenite ; 12, sparry carbonate and clay iron stone ' } 13, phosphate of iron ; 14, sulphate of iron, native copperas ; 15, chromate of iron ; 16, arseniate of iron ; 17, chloride of iron ; 18, oxalate of iron; 19, titanate of iron. Of these ores 10 are worked by the mi- ner of the native iron, the magnetic oxide, the carbonate, or clay iron stone. The hannatite and the brown iron stone are the most important. The native iron occurs in veins gener- ally and is almost pure iron. The mete- oric iron contains nickel, and the mass is magnetic. The magnetic oxide or magnetic iron ore is a mixture of protoxide and perox- ide, and contains, according to Berzelius, in 100 parts : Iron 7174 Oxygen 28-26 It is of an intense black color crystalliz- ed in regular octohedra, sometimes in gra- nular or compact masses; its sp. gr. 5-094. This variety is found in Warwick, Orange Co., New-York. The magnetic iron exists in the primary rocks of New England, and crosses New-York and New Jersey into Pa. It occurs at Winchester and Franconia, N. H., at Cumberland, K. I., at Hawles and Bernardstown, Mass. Near Ringwood, along the Highlands, beds of ore 10 feet thick exist; in Morris county, New York, its average thickness is from 5 to 12 feet, and it yields 65 per cent, of pure iron. In the primary hills W. of Lake Champlain, there are numer- ous veins and beds of it 25 feet thick in some places and nearlv pure. It is work- ed at Peru and Crown Point. This ore, be- sides being so rich in iron, yields it of the greatest purity ; hence that of Dannemo- ra, in Sweden, has been so highly prized. Chromate of iron, or chrome iron ore, is found massive and crystallized in octo- hedra, imperfect lustre, color brown black, sp. gr. 4-49 It consists of— Oxide of chrome 5550 Protoxide of Iron 83- Alumina 6* Silica 2- docs not fuse before the blowpipe ; it is magnetic after exposure to the reducing flame ; it forms a green bead with borax. In the United States it exists abundantly in Maryland, near Baltimore, also in small quantities near New Haven, Conn., in limestone with serpentine. It is used for extracting chrome salts. (See Chrome.) The quantity of chromate of lead annu- ally made in Baltimore exceeds 80,000 lbs. Specular iron ore and red iron ore occurs in many crystalline forms derived from the acute rhomboid, lustre metallic, color dark steel gray iron black ; streak cher- ry red sp. gr. 5-25, has full action on the magnet. The micaceous iron ore and the haematite, analyzed by Bucholz, have yielded in 100 parts, Peroxide of iron 90-00 94-00 Oxide of manganese a trace a trace Silica 2-00 200 Lime a trace 1*00 Water 2-00 3-00 It yields ordinarily 60 per cent, of metal. The island of Elba is the most celebrated locality which has afforded iron for sixteen centuries. It has been worked at Hawley, Mass. It is however found but sparingly in the United States. It occurs at Ticonderoga, New-York, where it is ground to powder, and em- ployed as a polishing substance. It affords excellent iron, and often as much as 60 per cent. It occurs also at Mari- etta, Ohio. The brown iron ore, or hydrated oxide, does not occur crystalline, but in botry- oidal masses, or in stalactitic lumps; sometimes in pieces earthy and friable ; its spec. grav. is 3-922. Its composition is— proxide of iron, 84*00 ; water, 11-00; oxide of manganese, 2-00; silica, 2-00. Its most remarkable deposit in the United States is at Salisbury, Conn., where it has been wrought for nearly 100 years. This is the most extensive mine in the country, yielding 3000 tons per annum. Other localities of brown haematite exist in Litchfield, Conn., i\e well as in the vicinal county of Duchess, New-York, and Berkshire Mass. The iron which this variety affords is supe- rior in malleability to that yielded by the red ore of iron ? and is much esteemed also. This ore is abundant in Pa., yield- ing from 45 to 55 per cent, of metal. Hannatite is abundant in Wisconsin. Iron was first found in this country in Virginia, in 1715. In many parts o/ Missouri the iron is so pure as not to re- quire the preliminary roasting, and the iron mountain of that state lias a circuit 268 CYCLOPEDIA OF THE USEFUL ARTS. Tiro of two miles, and an elevation of 350 feet. It consists of specular iron, yield- ing: 70 per cent, of metal, and contains only a few crystals of felspar. The general principles which regulate the treatment of ores, will be found given under the article, Metallurgy. Some general notions of the particular treat- ment of iron ores are given here. After raising the ore it has to be picked, to separate valuable from worthless ore, or mere stone. They are next roasted in large heaps in the open air to drive off the sulphur and arsenic which they usually contain, and also render them more fri- able and easier to be powdered. In Eng- land the roasting is conducted with bitu- minous coal, but in this country alto- gether with charcoal. Trunks of trees and brushwood are laid down and over- laid with charcoal, and ignited. Upon the top of this the ore is heaped several feet high. After being roasted the ore is transferred to the crushing mill, where it undergoes another powdering, when it is transferred to the smelting furnace to be converted into iron. Here it passes through two distinct operations : 1. The reduction of the oxide to the state of pure metal ; 2. The separation of the earthy matters as scoria?. These processes consist in exposing the ore, generally mixed with fluxes, to the action of carbon at a high temperature in furnaces, urged by bellows, hence called blast furnaces, or sometimes high fur- naces. The height of the blast furnace is very variable; some being only 36 feet high including the chimney, while others have an elevation of 60 feet. These extreme limits are very rare : so that the greater {mrt of the furnaces are from 45 to 50 feet ligh. They are all terminated, by a cyl- indrical chimney of from 8 to 12 feet long; being about one fifth of the total height of the furnace. The inside diame- ter of this chimney is the same as that of the throat or mouth ; and varies from 4 to 6 feet. The chimney is frequently formed of a single course of bricks, and acquires solidity from its hoops of iron, so thickly placed that one half of the sur- face is often covered with them. At its lower end, the mouth presents one or two rectangular openings, through which the charge is given. It is built on a base- ment circle of cast-iron, which forms the circumference of the throat ; and a slop- ing plate of cast-iron is so placed as to make the materials slide over into the furnace, as shown in the figure. The inside of the blast furnaces of Staf- fordshire is most frequently of a circular form, except the hearth and working area. The inner space is divided into four portions, different in their forms, and the functions which they fulfil in the smelting of the ore. The undermost, called the hearth, or crucible, in which the cast-iron collects, is a right rectangular prism, elongated in a line perpendicular to the axes of the tuyeres. The sides of the hearth consist in general of refractory sandstone (fire- stone), obtained mostly from the bed of the coal basin, called millstons grit • and the bottom of the hearth is formed of a large block of the same nature, laid on a cast-iron plate. In this country it is chiefly a mica slate, or gneiss rock, con- taining a large mixture of quartz. The second portion is also made of the same refractory grit stone. It has the form of a quadrangular pyramidal, ap- proaching considerably to a prism, from the smalfness of the angle included be- tween the sides and the axis. The third portion, or lower body of the furnace, is conical, but hei'e the interior space suddenly expands ; the slope out- wards at this part seems to have a great influence on the quality of the cast-iron obtained from the furnace. When No. 2 of the blackest kind is wanted for cast- ings, the inclination of this cavity of the furnace is in general less considerable than when No. 2 cast-iron for conversion into bar-iron is required. The inclina- tion of this conical chamber, called the boshes, varies from 55 to 60 degrees with the horizon. The diameter of this part is equal to that of the belly, and is from 11 to 13 feet. The boshes are built ot masonry, as shown in the following fig- ure. The fourth part, which constitutes about two thirds of the height of the fur- nace from the base of the hearth up to the throat, presents the figure of a sur- face of revolution, generated by a curve whose concavity is turned towards the axis of the furnace, and whose last tan- gent towards the bottom is almost verti- cal. This surface is sloped off with that of the boshes, so that no sharp angle may exist at the belly. In some furnaces of considerable dimensions, as in that with three tuyeres, this portion of the furnace is cylindrical for a certain height. The conical orifice called the tuyere, in which the tapered pipes are placed, for imparting the blast, is seen near the bot- tom of the furnace, fig. 59, at a. Noso IRO] CYCLOPEDIA OF THE USEFUL ARTS. 269 tubes of various sizes, from 2 to 4 inches in diameter, are applied to the extremity of the main blast-pipe. Under a is the bottom of the hearth, which, in large fur- naces, may be two feet square, b is the top of the hearth, about two feet six in- ches square, a b is the height of the hearth, about six feet six inches, b shows the round bottom of the conical or funnel part, called in this country the boshes, standing upon the square' area of the hearth, c is the top of the boshes, which may be about 12 feet in diameter, and 8 feet in perpendicular height, d is the furnace top or mouth, (gueulard in French,) at which the materials are charged. It may be 4i feet in diameter. The line between c, d, is the height of the internal cavity of the furnace, from the top of the boshes upwards, supposed to be 30 feet, a, d, is the total height of the interior of the furnace, reckoned at 44i feet, e e is the lining, which is built in the nicest manner with the best fire- bricks, from 12 to 14 inches long, 3 inches thick, and curved to suit the circle of the cone. A vacancy of 3 inches wide is left all round the outside of the first lining by the builder; which is sometimes filled with coke dust, but more generally with sand firmly rammed. This void space in the brick-work is for the purpose of allowing for any expansion which might occur, either by an increase in the bulk of the building, or by the pressure and weight of the materials when descending to the bottom of the furnace. Exterior to e e is a second lining of fire-bricks simi- lar to the first. At f, on either side, is a cast-iron lintel, 8s feet long, by 10 inches square, upon which the bottom of the arches is supported, r, o, is the rise of the tuyere arch, which may be 14 feet high upon the outside, and 18 feet wide. The extreme size of the bottom or sole of the hearth, upon each side of a, may be 10 feet square. This part and the bosh- ing stones are preferably made from a coarse sandstone grit, containing large rounded grains of quartz, united by a siliceo-argillaceous cement. The blowing machines employed in Staffordshire are generally cast-iron cyl- inders, in which a metallic piston is ex- actly fitted as for a steam engine, and made in the same way. Towards the top and bottom of the blowing cylinders, ori- fices are left covered with valves, which open inside when the vacuum is made with the cylinders, and afterwards shut by their own weight. Adjutages conduct into the iron globe or chest, the air ex- pelled by the "piston, both in its ascent and descent; because these blowing machines have always a double stroke. As soon as the blast furnace gets into a regular heat, which happens about 15 days or three weeks after fires have been put in it, the working consists simply in charging it, at the opening in the throat, whenever there is a sufficient empty space; the only rule being to keep the furnace always full. The coke is measur- ed in a basket, thirteen of which go to the ton. The ore and the flux (limestone) are brought forwards in wheel-barrows of sheet iron. In 24 hours, there are thrown into a furnace the following: 14£ tons of coke, 16 tons of roasted ore, and 6| tons of limestone; from which about 7 tons of pig iron are procured. This is run off every 12 hours ; in some works the blast is suspended during the discharge. The metal intended to be converted into bar iron, or to be cast again into moulds, is run into small pigs 3feet long, and 4 inches diameter ; weigh- ing each about two hundred weight and a half. The disorders to which blast furnaces are liable have a tendency always to pro- duce white cast-iron. The color of the slag or scoria? is the surest test of these derangements, as it indicates the quality of the products. If the furnace is yield- ing an iron proper for casting into moulds, the slag has a uniform vitrification, and is slightly translucid. "When the dose of ore is increased in order to obtain a gray 270 CYCLOPEDIA OF THE USEFUL ARTS. [iRO pig iron, fit for fabrication into bars, the slag is opaque, dull, and of a greenish- yellow tint, with blue enamelled zones. Lastly, when the furnace is producing a white metal, the slags are black, glassy, full of bubbles, and emit an odor of sul- phureted hydrogen. The scoriae from a coke are much more loaded with lime than those from a charcoal blast furnace. This excess of lime appears adapted to absorb and carry off the sulphur, whicn would otherwise injure the quality of the iron. The slags, when breathed on, emit an argillaceous odor. A blast furnace of 50 or 60 feet in height gives commonly from 60 to 70 tons of cast-iron per week ; one from 50 to 55 feet high, gives 60 tons ; two united of 45 feet produce together 100 tons ; and one of 36 feet furnishes from 30 to 40. A blast furnace should go for four or five years without needing restoration. From 3i to 4 tons of coal, inclusive of the coal of calcination, are required in Stafford- shire to obtain one ton of cast-iron ; and the expense in workmen's wages is about 15 shillings British on that quantity. Heated air is applied in some iron- works. Where this method of working the ore has been introduced, the air is blown by cylinder-bellows in the usual manner, but before entering the smelt- ing-furnace it passes through pipes of cast-iron, heated to redness, which are altogether about thirty feet in length and three feet in diameter. They are usually made in three or four pieces, joined together by apertures considerably less than three feet in diameter, and placed horizontally, or in whatever manner the local arrangements about the furnace may render most convenient. A brick arch is then thrown round the pipes, leaving a free space of about eight inches, and upwards, between it and them, and two or more furnaces constructed, so as to heat the pipes in the archway, the flues playing into it, and terminating in a com- mon vent at the farther extremity. They may be considered, therefore, as placed on the floor of a long and narrow rever- beratory furnace, about six feet high, and nearly of the same breadth, being at the same time protected by fire-bricks, when they might be injured by the direct flame of the furnaces. The iron ore is smelted, according to this plan, with little more than half the coaf necessary when the furnaces are worked with air'in the usual manner ; the small coal, which is sold at an inferior price, is found quite sufficient for heating the pipes. The number of charges in English fur- naces, given in 12 hours, is different, in different furnaces, being 20, 25, and even up to 40 ; 30 is an average. Each charge is composed of from 5 to 6 cwts. of coke (or now of 3 to 4 cwts. of coal with the hot blast) ; 3, 4, and sometimes 6 cwts. of the roasted mine, according to its richness and the quality of cast iron wanted ; the limestone flux is usually one third of the weight of the roasted iron stone. There are 2 casts in 24 hours ; one at 6 in the morning, and another at 6 in the evening. According to M. Berthier's analysis, the slag or cinder of Dowlais furnace consists of silica, 40'4; lime, 38 - 4; magnesia, 5*2; alumina, 11*2 ; protoxyde of' iron, 3-8 ; and a trace of sulphur. He says that the silica contains as much oxygen as all the other bases united ; or is equivalent to them in saturating power; and to the excess of lime he ascribes the freedom from sulphur, and the good quality of the iron produced. The specimen ex- amined was from a furnace at Merthyr- Tydvil. Other slabs from the same fur- nace, and one from Dudley, furnished upwards of 2 per cent of manganese. Those which he analyzed from Saint Etienne, in France, afforded about 1 per cent, of sulphur. As the ignition in the blast furnace proceeds, and the blast let on, the metal in the ore parts with its oxygen, and sub- sides to the bottom of the furnace, cov- ered with a melted slag. This last is oc- casionally allowed to flow off, by opening some of the side holes which were stop- ped with clay, and when the bottom of the furnace becomes charged with metal, which it does after five or six hours, the iron itself is discharged, by one of these openings, into a pit of sand mixed with clay. As soon as the iron is poured out, the hole is closed, and the furnace is still kept at work, and eroes on reducing iron for six months. The flux employed to assist the fusion of the ore, by vitrifying the earths aforesaid with iron, is lime^- stone of the best quality ; very lately, it has been proposed to use caustic lime, or that which has been burned, instead of the crude limestone. It is said to pro- duce an economy of fuel. The iron which has run out from the furnace, is cast iron, or iron with carbon intermingled with it, sometimes to the extent of 5 per cent. It has a coarse grain, and is very brittle. The mould in "which the metal flows, is of a longish shape, having projecting offsets on each IRO] CYCLOPEDIA OF THE USEFUL ARTS. 271 side, which, from some fancied resem- blance to a sow and her litter, has been called pig iron. To convert this pig or crude iron into bar iron, it has to be refined. This con- sists in placing it in a furnace, like a smith's forge, or hearth, with a sloping cavity sunk a foot below the blast pipe. In the finery process, the hearth or crucible of the furnace is filled with coke ; then six pigs of cast iron are laid hori- zontally on the hearth, namely, four of them parallel to the four sides, and two in the middle above ; and the whole is covered up in a dome-form, with a henp of coke. The fire is now lighted, and in a quarter of an hour the blast is applied. The. cast iron flows down gradually, and collects in the crucible ; more coke being added as the first quantity burns away. The operation proceeds by itself; the melted metal is not stirred about, as in some modes of refinery, and the temper- ature is always kept high enough to pre- serve the metal liquid. During this stage the coals are observed continually heaving up, a movement due, in part, to the action of the blast, and in part to an expansion caused in the metal by the discharge of gaseous oxyde of carbon. When all the pig iron is collected at the bottom of the hearth, which happens commonly at the end of two hours, or two and a half, the tap-hole is opened, and the fine- metal flows out with the slag, into the loam-coated pit, on a plate 10 feet long, and 3 broad, and from 2 inches to 2s thick. A portion of the slag forms a small crust on the surface of the metal ; but most part of it collects in a basin scooped out at the bottom of the pit, into which the fine metal is run. A large quantity of water is thrown on the metal, with the view of rendering it brittle, and perhaps of partially oxydiz- ing it. This metal, suddenly cooled, is very white, and possesses in general a fibrous radiated texture ; or sometimes a cellular, including a considerable number of small spherical cavities, like a decom- posed amygdaloid rock. If the cast iron be of bad quality, a little limestone is oc- casionally used in the above operation. Three samples of cinder, analyzed by Berthier, gave : 1. Silica, 0-276 ; protox. of iron, 0-612 ; alumina, 0*040 ; phosp. acid, 0*072, Dud- ley. 2. Silica, 0*368 ; protox. of iron, 0*610 ; alumina, 0*01 5 ; puddling of Dowlais. 3. Silica, 0*424; protox. of iron, 0*520; alumina, 0*033 ; puddling of Dowlais. The remarkable fact of the presence of phosphoric acid, shows how important this operation is to the purification of the iron. The charge varies from a ton and a quarter to a ton and a half of pigs ; and the loss by the process varies from 12 to 17 per cent. The fine metal thus obtained is broken in pieces, and sent to the puddling fur- nace. This is a reverberatory furnace, which is charged by shovelling in the fine metal, and laying it all round the sides of the earth, raising the heap to the roof; the middle of the hearth is left clear. The fuel is then placed in the grate, and the doors closed* in 20 minutes the metal becomes white, melts, and falls in drops to the sole of the furnace ; the fire is then gradually checked, and the pieces separated so that the whole may not be- come too fluid, but remain as a pasty mass ; as the heat is continued and stir- red, %ae mass gets drier, and carbonic ox- ide, which at first was freely given, now gradually lessens, and ultimately ceases. The workman, with his paddle, now works the mass into lumps or balls of 70 lbs. weight. The balls are lifted out, and are fit for being hammered. The whole object of the puddling has been to remove the carbon out of the iron, to which its fluidity was due ; as the carbon escapes, the fusibility of the mass di- minishes. The puddled balls have now to under- go the next process, which is that cf ham- mering or condensing the fibres, of weld- ing them, and giving the mass the form of a bar. In England there are employed for the forging and drawing out of the iron, cast- iron hammers of great weight, and cylin- ders of different dimensions, for beating out the balls, or extending the iron bars, as also powerful shears. These several mechanisms are moved either by a steam engine, as in Staffordshire, and in almost all the other counties of England, or by water-wheels when the localities are fa- vorable, as in many establishments in South Wales. We shall here offer some details concerning these machines. The main driving shaft usually carries at cither end a large toothed wheel, which communicates motion to the different machines through smaller toothed wheels. Of these, there are commonly six, four of which drive four different systems of cylinders, and the two others work the hammer and the shears. The different cylinders of an iron work should never be placed on the same arbor, because 272 CYCLOPEDIA OF THE USEFUL ARTS. [iRO they are not to move together, and they must have different velocities, according to their diameter. In order to economize time and facilitate labor, care is taken to associate on one side of the motive ma- chine the hammer, the shears, and the reducing cylinders; and, on the other side to place the several systems of cylin- ders for drawing out the iron into bars. For the same reason the puddling fur- naces ought to be grouped on the side of the hammer ; and the reheating furnaces on the other side of the works. The hammers are made entirely of cast- iron ; they are nearly 10 feet long, and consist usually of two parts, the helve and the head or pane. The latter enters with friction into the former, and is re- tained in its place by wedges of iron or wood. The head consists of several faces or planes receding from each other ; for the purpose of giving different forms to the ball lumps. A ring of cast-iron call- ed the cam-ring bag, bearing movable cams, drives the hammer, by lifting it up round its fulcrum, and then letting it fall alternately. In one iron work, this ring was found to be 3 feet in diameter, 18 inches thick, and to weigh 4 tons. The weight of the helve (handle) of the cor- responding hammer was 3 tons and a half, and that of the head of the hammer, 8 hundred weight. The anvil consists also of two parts ; the one called the pane of the anvil, is the counterpart of the pane of the ham- mer ; it likewise weighs eight hundred weight. The second, named' the stock of the anvil, weighs 4 tons. Its form is a parallelopiped, with the edges rounded. The bloom or rough ball, from the puddle furnace, is laid and turned about upon it, by means of a rod of iron welded to each of them, called a porter. Since the weight of these pieces is very great, and the shocks very considerable, the utmost precautions should be taken in setting the hammer and its anvil upon a sub- stantial mass of masonry, as shown in the figure, over which is laid a double, or even quadruple flooring of wood, formed of beams placed in transverse layers close to each other. Such beams possess an elastic force, and thereby partially destroy the injurious reaction of the shock. In some works, a six-feet cube of cast iron is placed as a pedestal to the anvil. Forge hammers are very frequently mounted as levers of the first kind, with the centre of motion about one third or one fourth the length of the helve from the cam wheel. When well hammered by these trip i hammers, the mass is made to pass be- tween grooved cylinders, which press it into the bar shape ; as it emerges from the cylinders it is cut with a shears into shorter lengths. Such is a rough outline of the mode of obtaining bar or wrought iron, as prac- tised in England. In France, and the south of Europe, as woll as in many places in this country, it is differently conducted. Malleable iron is frequently obtained direct from the ores by one fusion, when the metallic oxide is not too much conta- minated with foreign substances ; this mode, which is allowed to be much more economical than the one described, as it saves time and combustibles, has for a long period been employed in Catalonia, in the Pyrenees, from which circum- stances it is called the method of the Catalan forge. Those ores, best adapted to its treatment, are the pure black ox- ide, red and brown oxide, and carbonate of iron ; to extract the metal from which, it is sufficient to expose them to a high temperature in contact with charcoal or carbonaceous gases. The furnace em- ployed is similar to the refining forge previously described. The crucible is a semicircular or oblong basin, 18 inches diameter, and 8 or 10 deep, excavated in an area or small elevation of masonry 8 or 10 feet long, by 6 broad, and covered in with a chimney. The tuyeres stand 5 or 6 inches above the basin, and have a slight inclination downwards, and the blast is given by a water blowing machine. The first step consists in expelling the water combined with oxide, as well as the sulphur and arsenic. When those combinations are present, this is done as usually by roasting in the air. The roast- ed ore is crushed to a fine powder, and thrown by the shovel at intervals on the charcoal fire of the hearth ; the side sand bottom of the basin being previously lined with two or three brasgues (coats of pounded charcoal). It gradually softens and unites into lumps, more or less co- herent, which finally melt and accumu- late in the bottom of the crucible or basin, and a thin slag is occasionally let off from the upper surface of the melted iron by the holes, which can be opened at discre- tion. The melted iron preserves a pasty condition, owing to the heat communi- cated from above, and when a mass suffi- ciently large is accumulated, it is remov- ed, put under the hammer, and forged at once. A lump or bloom of malleable IRO] CYCLOPEDIA OF THE USEFUL ARTS. 213 iron is thus produced in three or four hours. The iron is generally soft, very malleable, and a little steely. Four work- men are employed at one forge, and by a relief every six hours, they can make 86 cwt. of iron per week. 100 pounds of iron are obtained, in this forge, from 300 lbs. of ore. This process, generally called blooming, is one now increasing in this country. Mr. W. Lyman first put into successful operation at Pottsville, Pa., in 1830, a furnace for smelting iron by anthracite with the hot blast. In 1840, Messrs. Biddle, Chambers & Co. did the same at Dansville, Pa., and others followed. Anthracite coal is now always used with hot air in smelting, and the pud- dling is performed by Detmold's patent, with ignited gas. In Maryland bitumin- ous coal is used, in New York charcoal. Blooming or making the bar iron by one operation, without the use of the blast furnace is common in Connecticut, New York, and Vermont. In 1845, Clinton and Essex Co., N. Y\, produced 13,000 tons of iron. The whole produce in the States same year was esti- mated at 919,100 tons = $41,734,610. In New- York, the mines of Dutchess and Columbia Co. yield 20,000 tons annually ; Essex Co. 1,500 tons, Clinton 3,000, Franklin 600 : St. Lawrence 2,000, amounting in all to a value of more than $500,000. In Ohio 1200 square miles are underlaid with iron, and calculated to contain 1,080,000,000 tons. In Tennessee 100,000 tons are manufactured yearly. The following is the process recently adopted by Mr. Alexander Dickson, of Newark. " The fire is placed at the end, under a horizontal bed of fire-brick some twelve or fifteen feet in length — the fire passing through to the ether extremity. In the cen- tre, and over the bed, is erected a double cylinder, which is filled with crushed ore and pulverized anthracite coal. The in- tense flame surrounds the cylinder, and also passes through the inner cylinder, which removes the oxygen and all other impurities with the presence of atmos- pheric air. Being thus prepared, the ore gradually melts and descends to the hearth, where it first comes in contact with the fire, which destroys the remain- der of the pulverized coal by frequent stirring, and the iron is thus partially formed. From this hearth it is thrown to another about eight inches lower than the first, where it is worked into balls of about one hundred pounds amid the same 12* sheet of fire, and in a few minutes the ball is withdrawn and put under the hammer to put it in shape, which con- cludes the process. Mr. Wall, of England, has patented a process for removing the phosphorus out of iron. The process consists of two parts ; first, in adding certain substances to the metal, while in a state of fusion: 2nd, in applying electricity to the metal while in a state of fusion, and during its cooling. In carrying out the first part, two compounds are made use of, termed A and B. The compound A is formed by mix- ing two parts of iron filings or turnings with five parts of black resin, by melting the resin and stirring in the iron filings. When the mass has sufficiently cooled it is made into balls of about five pounds weight each ; and in using them these balls are thrown in the melting-furnace on the surface of the fused metal, in the proportion of one of the balls to every 5 cwt. of metal. The compound B is formed by thoroughly mixing two parts of common salt and five parts of resin, turpentine, or other carbonaceous matter, and making this also into balls of about five pounds each, and throwing these on to the surface of the melted metal, in the proportion of one pound to each cwt. of the metal, after the compound A has been employed. In carrying out the sec- ond part, a battery is employed, consist- ing of platinum and zinc plates, contain- ing eight pairs, 6 inches by 4 of active surface, in separate cells of dilute sul- phuric and strong nitric acid, arranged in the manner commonly known as Grove's battery, or 32 pairs of same sized plates, arranged in the manner commonly known as Smec's battery, which give suf- ficent electricity for all general purposes. In applying the electric current a rod of iron is inserted into each extremity of the mould, into which the metal is to bo cast, if the casting be horizontal ; or into the bottom and top of the mould, if the casting is vertical. These two rods of iron are connected with the two poles of the battery respectively ; and when the melted metal is poured into the mould, it serves to complete the circuit, and elec- tricity will continue to traverse it as long as the connection with the poles of the battery remains unbroken. The current should be kept up for a considerable time even after the metal has solidified ; but if continued for too long a time, the metal would be decarbonated and convert- ed into wrought iron. The patentee 274 CYCLOPEDIA OF THE USEFUL ARTS. [iRO also passes an electric current through the fused metal while in the furnace, by inserting a rod of iron in the lower part of the furnace so as to be in contact with the metal, which rod is attached to one pole of the battery, while another rod in connection with the opposite pole is moved by the operator in constant con- tact with the melted mass, over every part of the surface, thus directing the current through every portion of it. Overman, in his work, says, " Hydra- ted Oxide of Iron, Brown" Oxide, He- matite Bog Ore, should all be roasted, not for the purpose of oxidation, but to drive off the acids, and destroy the sul- phurets and phosphurets — all ores of this class contain more or less injurious mat- ter. Sulphates of iron should be care- fully roasted, so should phosphates, with a liberal access of air." The more carbon that is present, the greater difficulty there is to drive off the phosphorus, for carbon is necessary in every case to produce a combination of phosphorus with the metal — the process of Wall, therefore, in expelling the car- bon, would lead to infer that it would be most suitable for the removal of phos- phorus, and sulphur also. Mr. Thompson, of Newcastle-on-Tyne, England, has patented an improved fur- nace. The nature of the invention con- sists of two parts. First, the construc- tion and working of the furnace. Sec- ond, the application of the gases genera- ted in the furnace to subsequent useful purposes. The body of the furuace, is constructed somewhat in the ordinary manner ; the top of it is of a dome shape, and sur- mounted by a throat, the upper end of which can be closed by iron plate, which is intended to fit as air-tight as practicable, and when removed, it is through this aperture that the furnace is charged. Above the dome, and around the throat, is the circular tunnel or chamber ; it com- municates by the apertures or short flues, with the body of the furnace in the upper part of the dome ; from this tunnel, upon opposite sides of the furnace, proceed vertical pipes ; these are intended to carry off the gases ; two steam pipes at their lower ends communicate with a steam boiler behind the furnace, from which the steam is supplied : the steam pipes pass upwards into the centre of the ver- tical pipes, and their ends terminate in a number of steam jets, arranged so as to produce the best effects of exhaustion ; the tuyers are arranged in the usual manner and intended to supply air to the furnace by draught, either in a cold or hot state. The exhaust pipes are about eighteen inches in diameter, and the diameter of the steam pipes is about four inches. The steam jets being in action, they cause an exhausting action in the pipes, thereby drawing the gases generated in the furnace through the short flues and tunnel, and ef- fecting the necessary working of the fur- naee. The lid is lifted from its seat oc- casionally, for the purpose of charging the furnace, but this is to be done as sel- dom as possible, as at these times the ex- hausting action of the steam jets is to be stopped, and the consequent working of the furnace suspended. This method, therefore, is to do away with the blower, and use exhaust by steam as a substitute. The second improvement is, the em- ploying the gases generated in the fur- nace, in the above described operation, to subsequent useful purposes, as heating the refinery and other furnaces, or genera- ting steam in steam boilers ; to effect this, the vertical pipes are dispensed with, and the gasos generated are carried by a pipe from the tunnel to the furnace where they are to be employed. The steam jets or other exhausting means are then em- ployed in the exit or chimney from this furnace, instead of the smelting furnace, as above. The following is the comparative power of a few different metals, to sustain weights by suspension, according to Mr. Kennie's experiments, in bars one quar- ter of an inch square : lbs. A cast-iron bar, hor. sustained 1166 A ditto, vertical 1218 A cast 6teel bar previously tilted 8391 A blister-steel bar, reduced by hammering 8322 A shear-steel bar, ditto 7977 A Swedish iron ditto, ditto 4504 An English iron ditto, ditto 3492 A hard gun-metal bar 2273 A wrought-copper bar 2112 A cast-copper ditto 1192 A fine yellow brass bar 1123 A cast-tin bar 296 A cast-lead bar 114 Pennsylvania is the largest iron manu- facturing State ; it does not manufacture of late years as much as previously, owing to the low price of imported iron. The following statistics are taken from the Scientific American : — It appears that out of 62 counties which the State embraced at the date of the last report, 45 contain iron works, and 9 of the remaining 17 contain abundance of iron and coal — though, owing to the ab- IKO] CYCLOPEDIA OF THE USEFUL ARTS. 275 sence of any cheap road to market, they yet remain untouched — leaving only 8 counties in the State not adapted to the manufacture of iron. There are 304 blast furnaces and bloom- eries in the State, with an invested capi- tal of $12,921,576 ; their present capacity is for the making of 550,959 tons per an- num ; in 1847, they made 389,350 tons ; in 1849, 253,370 tons; in 1850, their pro- bable make is estimated at 198,813 tons. Of the above furnaces 57 use anthracite coal; have a capital of $3,221,000, and a present capacity for making 221,400 tons ; in 1847, they made 151,881 tons; in 1849, 109,168 tons, and the estimated product of 1850 is 81,351 tons. The furnaces using bituminous coal are 7 in number, with a capital of $223,000, and a present capacity tor making 12,600 tons. In 1847, they made 7,800 tons ; in 1849, 4,900 tons ; in 1850, the make will probably be 3,900 tons. Four furnaces use coke, have a capital of $800,000, and a present ca- pacity for making 12,600 tons, per an- num; in 1847, they made 10,000 tons. Eighty-five are charcoal hot blast furna- ces, with an investment of capital of $6,- 478,500, and a capacity for making 130,- 705 tons per annum. The make of 1847 was 94,519; 1849, 58,302; in 1850, it will be 42,555. The charcoal cold blast fur- naces number 145, with a capital of $5,- 170,376, and a capacity for making 173,- 654 tons per annum. The make of 1847, was 125,155; 1849, 80,655; in 1850, it will be 70,727. There are 6 bloomeries, with a capital of $28,700, and a capacity for producing 600 tons per annum. The product for 1847 was 545; 1848, 335; probable product of 1850, 280. The esti- mate for 1850, is obtained by deducting from the product of 1849 the amount made by such furnaces as are now idle. Of the 298 furnaces in the State, 149 or exactly one-half are in blast this year, and of these about one-third are making no preparations to blow during the next yaar. The estimate for 1850 shows a de- crease of 190,537 since 1847, or 49 per cent, in three years. Should there be no change in the aspect of affairs, the make of 1851 will not exceed 100,000 tons. The number of forges and rolling mills in the State is 200, with a capital of $7,- 580,500, with 402 forge fires, and 43.6 puddling furnaces, and a capacity to make 224,650 tons per annum. Their ac- tual make for 1847 was 202,727 tons, and 1S49, 136,853 tons. Of the above there are 121 charcoal forges, with an invest- ment of capital amounting to $2,026,300. These forges have 402 fires, with a capa- city of 125 tons per fire, per annum, or a total of 50,250 tons. In 1847, they made 39,997 tons, and in 1849, 28,495 tons. The rolling mills number 79, with a capi- tal of $5,554,200. They contain 436 pud- dling furnaces, which, at 400 tons per furnace, gives a total capacity of 174,400 tons per annum. Their make in 1847, was 163,760 tons; and in 1849, 108,358 tons. There are 606 nail machines in the State, the annual product of which is 606,000 kegs, or 30,300 tons ; being an average of 1,000 kegs, of 100 lbs. each, to a single machine. There are 13 works engaged in the conversion of iron into steel, making annually 6,078 tons. Five of these works are in Philadelphia, six in Pittsburg, one in Lancaster, and one in York. The whole number of iron works in the State is 504, with a capital of $20,502,076 invested in lands and ma- chinery, employing immediately 30,103 men, and 13,562 horses, besides 11,513 laborers not in the pay of the iron mas- ters, but directly dependent on the iron works for support ; making a total of 41,- 616 men. Allowing five persons to each laborer, and we have as the population dependent on the iron work, 208,080, or about one-tenth of the population of the State. In 1847, the consumption of fuel in all the iron works of the State was 483,000 tons of anthracite coal, at an average value of $3 per ton, making $1,448,000 ; 9,007,000 bushels of bituminous coal, at 5 cents per bushel, making $450,380; and 1,490,252 cords of wood, at $2 per cord, $2,980,504. Thus giving the total cost of fuel $4,879,884. To show how cheaply iron is obtained, and how the mechanical skill and labor expended upon it totally overshadow the original price, a number of the British Quarterly Keview, of 1847, gave the fol- lowing curious and instructive calcula- tion :— Bar iron worth £1 sterling is worth when worked into £ «. Horse-shoes 2 10 Table knives 86 Needles 71 Penknife blades 657 Polished buttons and buckles 897 Balance springs of watches 50,000 Cast iron worth £1 sterling is worth when converted into £ Ordinary machinery 4 Larger ornamental work 45 276 CYCLOPEDIA OF THE USEFUL ARTS. [iBO Buckles and Berlin work £600 Neck chains 1,386 Shirt buttons 5,896 Thirty one pounds of iron have been made into wire upwards of 111 miles in length, and so fine was the fabric, that a part was converted, in lieu of horse hair, into a barrister's wig. The process fol- lowed to effect this extraordinary tenui- ty consists of heating the iron and pass- ing it through rollers of 8 inches diame- ter going at the rate of 400 revolutions per minute down to No. 4 on the wire gauge. It is afterwards drawn cold, at Birmingham, down to 38 on the same gauge, and so on till it attains the above length in miles. Of the quantity of iron manufactured in Great Britain, in 1843, South Wales produced 279i thousand tons ; Stafford- shire, 219! ; Shropshire, 8H : Scotland, 37i ; Yorkshire, 33 ; Derbyshire, 22i ; and North Wales, 25. It is well known that it is most difficult to keep iron from oxidating or rusting on the surface ; various plans have been adopted to accomplish the object of pro- tecting the surface even in a slight de- gree. Some of these modes consisted in coating the surface ; in others, it extend- ed to an alloying of the melted mass. One method consists in the addition of pig iron, when in a state of fusion, of from 2 to 10 per cent, of copper, tin, nickel, or antimony, by which addition, the iron is rendered more malleable and less subject to oxidation. A second me- thod consists in the giving to the iron a coating of steel, or rather a species of iron containing less carbon and of course approaching to steel. This is effected by the addition of one part of blister steel to four parts of molten cast iron, and then adding scrap iron to the mass, until an iron rod is no longer rendered brittle by being dipped in the mixture. With this compound, common iron is coated in the same manner as pursued in the case of covering iron with brass ; but various methods are pursued, according to the size and nature of the article to be coated ; where it is at the end of a bar of iron, such as an axle, and is to be of a particular form, this form may be given to the cru- cible, thereby making It a mould, and when in a state of perfect fusion, the iron, either previously heated or cold, is to be immersed in the melted mass, and when it is perceived that the mass is per- fectly fluid, then the fire may be with- drawn, or the crucible be allowed to cool by any available means ; but when the iron to be coated is immersed cold, the melted mass is immediately congealed, but it must be permitted to remain in the crucible till it again becomes fluid, and then it should be allowed to cool. If the whole is allowed to cool slowly, it is then soft, and may be turned in the lathe, and afterwards hardened by heating it and cooling it suddenly in the usual manner ; but in this case care must be taken, as the coating and the iron have different powers of contracting. If the coated parts were suddenly immersed in water, it would certainly crack, the uncoated part must therefore be immersed up to the coated part, when the conducting power of the iron will cool the coating sufficiently quick to insure a proper hard- ness. A third method of preventing oxida- tion, is case-hardening the metal, by the use of ferrocyanide of sodium, calcium or barium. In order to apply the ferrocyanide, an alkaline bath, formed with carbonate of soda, or other alkali is used. This bath may be a crucible or large basin built in the brickwork of the furnace, which should be a reverberatory furnace, and previous to being used, should be raised to a white heat ; the iron to be case-har- dened requires to be previously heated to nearly a red-heat, and then immersed in the bath, and there raised to a heat sufficiently high, after which it must be immediately immersed in the ferrocya- nide previously fused in another vessel ; but it the quantity of iron to be case-har- dened is small, it would not be advisable to fuse the ferrocyanide (as it is very soon decomposed), but immediately on taking it out of the bath it must be sprinkled with the ferrocyanide ; should ferrocyanide of potassium be used, it is found that the alkaline bath prevents ef- fectively the corroding of the iron. A fourth scheme consists of a method of coating copper, or the alloys of copper or iron, with platinum. Platinum is dis- solved in aqua rcgia, and the iridium which remains undissolved as a black powder, separated by filtration, then eva- porated to dryness, and when cold a quantity of caustic potass, equal in weight to the metallic platinum employed is to be dissolved in water, and poured on the chloride of platinum. This will precipi- tate the platinum of an impure yellow co- lor ; a quantity of solution of oxalic acid equal to the weight of the metallic plati- num, is now to be added without pouring off the solution which remains on the ivo] CYCLOPEDIA OF THE USEFUL ARTS. 277 precipitate ; the solution is then to be boiled till the precipitate is entirely dis- solved j a small quantity of iridium will still remain, which, together with any other impurities, must be separated by nitration ; caustic potass equal to twice the weight of the metallic platinum is to be dissolved in water and added to the above. The solution is now ready for platinizing the copper or iron article which is to be coated with platinum. The article to be coated is to be put in a vessel. Iron in its pure state is malleable, and it is a combination of carbon with iron which produces cast-iron. In addition to carbon, the cast-iron in this country con- tains silica, lime, magnesia, alumina, oc- casionally some of the phosphates and other admixtures ; but iron made from magnetic ores is much purer. The strength of cast-iron depends upon its freedom from impurities, and upon the proportion of carbon it contains. The strongest cast-iron contains about three per cent, of carbon, or, according to Mr. Charles May, when the carbon is in the smallest proportion that produces fluidi- ty ; a larger proportion tends to make the iron soft and weak, and a smaller hard and brittle. Mr. Glynn, in his evidence before the Strength of Iron Committee, in London, states, that the strongest iron generally shows a clear gray, or slightly mottled fracture, and he considers that the color indicates the combination of carbon with iron which produces the greatest strength. Mr. Stirling states, that while color is admissible as a test of strength, it is not so of chemical consti- tution, for though dark colored iron is usually brittle, yet black iron when chil- led becomes white, although it must be supposed to contain the same quantity of carbon ; hence, as a general rule, he con- cludes that color indicates the treatment to which iron has been subjected, and in some cases only the quantity of carbon. Mr. May coincides in considering the question of strength to be very much re- ducible to the quantity of carbon con- tained in the iron, as some of the tender- est iron skilfully treated will produce some of the strongest eastings. Messrs. Stephenson and Stirling mention that the fluidity of Berlin iron is due to the pre- sence of arsenic, and the latter has ob- served that manganese mixed artificially with cast-iron, closes the grain, and is an improvement both to cast-iron and steel. On wrought iron the effect of manganese is stated to be to give it the hot-short property, while cold-short is produced by the presence of a small quantity of phos- phorus ; and the admixture of arsenic renders wrought iron hard and brittle. Iron GuNsi Pig-iron of gray color should be melted in an air-furnace with an intense and rapid fire, for iron guns ; but an alloy of copper and. tin is used for brass guns. The first are used on ship- board and the latter for field artillery, with a bush of copper, as less fusible by firing, for the touch-hole. The solid casting is then bored by the revolution of the gun, with an apparatus and steam power. A 24-pounder of iron is 10 ft. long, and weighs 52 cwt. with a bore of 5-824 inches, a ball of 5-547 inches and 8 lbs. of powder. A 24-brasa pounder weighs 50 cwt. An iron 6-poun der weighs 24 cwt. and is 9 ft. long. IVORY, is the tusk or tooth of defence of the male elephant. It is an interme- diate substance, between bone and horn, not capable of being softened by fire, nor so hard and brittle as bone. Sometimes it is an enormous size, weighing nearly 200 lbs. It is of a yellowish, brownish, and sometimes a dark brown color on the outside, internally white, hollow towards the root, and so far as was inserted into the jaw, of a blackish brown color. It is used for making ornamental uten- sils, mathematical instruments, cases, boxes, balls, combs, knife-handles, dice, and to vs. Guillot obtained from 100 parts of ivory, 24 gelatine, 64 phosphate of lime, and 0-1 carbonate of lime. Ivory is restored in color, by covering it with quick-lime and pouring vinegar on this. After 24 hours rub it with alum- powder. The best ivory comes from Ceylon. Ivory is very apt to take a yellow- brown tint by exposure to air. It may be whitened or bleached, by rubbing it first with pounded pumice stone and water, then placing it moist under a glass shade luted to the sole at the bottorii, and ex- posing it to sunshine. The sunbeams without the shade would be apt to occa- sion fissures in the ivory. The moist rubbing and exposure may be repeated several times. For etching ivory, a ground made by the following recipe is to be applied to the polished surface : — Take of pure white wax, and transparent tears of mastic, each one ounce ; asphalt, half an ounce. The mastic and asphalt having been separately reduced to fine powder, and the wax 'being melted in an earthenware 278 CYCLOPEDIA OF THE USEFUL ARTS. [rvo vessel over the fire, the mastic is to be first slowly strewed in and dissolved by stirring; and then the asphalt in like manner. This compound is to be poured out into lukewarm water, well kneaded, as it cools, by the hand, into rolls or balls about one inch in diameter. These should be kept wrapped round with taffety. If white resin be substituted for the mastic, a cheaper composition will be obtained, which answers nearly as well ; 2 oz. asphalt, 1 oz. resin, k oz. white wax, being good proportions. Callot's etch- ing ground for copper plates, is made by dissolving with heat 4 oz. of mastic in 4 oz. of very fine linseed oil ; filtering the varnish through a rag, and bottling it for use. Either of the two first grounds being applied to the ivory, the figured design is to be traced through it in the usual way, a ledge of wax is to be applied, and the surface is to be then covered with strong sulphuric acid. The effect comes better out with the aid of a little heat ; and by replacing the acid, as it becomes dilute by absorption of moisture, with concentrated oil of vitriol. Simple wax may be employed instead of the copper- plate engraver's ground; and strong muriatic acid instead of sulphuric. If an acid solution of silver or gold be used for etching, the design will become purple or black, on exposure to sunshine. The wax may be washed away with oil of tur- pentine. Acid nitrate of silver affords the easiest means of tracing permanent black lines upon ivory. Ivory may be dyed by using the follow- ing prescriptions : — 1. Black dye. — If the ivory be laid for several hours in a dilute solution of neutral nitrate of pure silver, with access of light, it will assume a black color, hav- ing a slightly green cast. A still finer and deeper black may be obtained by boiling the ivory for some time in a strained decoction of logwood, and then steeping it in a solution of red sulphate or red acetate of iron. 2. Blue dye. — When ivory is kept im- mersed for a longer or shorter time in a dilute solution of sulphate of indigo (part- ly saturated with potash), it assumes a blue tint of greater or less intensity. 3. Green. dye. — This is given by dipping blued ivory for alittle while in solution of nitro-muriate of tin, and then in a hot decoction of fustic. 4. TeUowdye is given by impregnating the ivory first with the above tin mor- dant, and then digesting it with heat in a strained decoction of fustic. The color E asses into orange, if some Brazil wood as been mixed with the fustic. A very fine unchangeable yellow may be com- municated to ivory by steeping it 18 or 24 hours in a strong solution of the neutral chromate of potash, and then plunging it for some time in a boiling hot solution of acetate of lead. 5. Bed dye may be given by imbuing the ivory first with the tin mordant, then plunging it in a bath of Brazil wood, cochineal, or a mixture of the two. Lac dye may be used with still more advan- tage, to produce a scarlet tint. It* the scarlet ivory be plunged for a little in a solution of potash, it will become cherry red. 6. Violet dye is given in the logwood bath to ivory previously mordanted for a short time with solution of tin. When the bath becomes exhausted, it imparts a lilach hue. Violet ivory is changed to purple-red by steeping it a little while in water containing a few drops of nitro- muriatic acid. With regard to dyeing ivory, it may in general be observed, that the colors pene- trate better before the surface is polished than afterwards. Should any dark spots appear, they may be cleared up by rub- bing them with chalk ; after which the ivory should be dyed once more to pro- duce perfect uniformity of shade. On taking it out of the boiling hot dye bath, it ought to be immediately plunged into cold water, to prevent the chance of fis- sures being caused by the heat. Madame Bouvier (of Paris) adopts the following process (patented) for working in plastic ivory. Take the waste turnings of ivory, bone, horn, &c, and steep them in a waste acid solution. Nearly all the acids will serve for this purpose, but the following are preferable : muriatic, nitric, tartaric, acetic, citric, and oxalic, also phosphate of lime. The solution is placed in a water bath at a temperatue of 35° to 40° C, (95° to 105° Fahr.,) in order to obtain complete liquefaction. It is then passed through fine muslin, and about one fourth the quantity of ivory gelatine is next added to absorb the sol- vent. When the paste is well prepared, the excess of liquid, and any foreign gases, are removed by means of the air pump : it thus become homogeneous, menibranous, and very close. In this state it would be difficult to run it for use ; for which purpose it must be dis- solved in copal or lac varnish, and in this state it may be run into moulds. When jar] CYCLOPEDIA OF THE USEFUL ARTS. 270 the paste is in the moulds, it may be made to undergo pressure, to expel the air, and prevent the formation of air bubbles in the interior. Coloring matters may be added to the paste. M. Charriere of Paris renders the ivory which he works into shapes, flexible by steeping it in hydrochloric acid. Either strong or diluted with water, the ivory becomes flexible, elastic, and yellow. As it dries it becomes hard again. The flexibility is however restored by wetting the ivory with a piece of linen. loory Black is made by exposing ivory and bone-shavings in an iron cylinder, at a red heat, allowing the effluvia to rise through a pipe. It does not differ from bone black, being carbon in a very fine state. JACK, is the name of a very powerful machine for raising great weights. Its ordinary power is 5 tons, or 200 times the force of man applied to the handle. The better sort are supplied with a ratchet, to prevent their running back. Jack is also the name of a kitchen- machine for cooking, and the moving power is either a weight or the smoke and rarefied air of a chimney. It has a worm, or endless screw, with a main- wheel of 60 teeth, a worm-wheel of 30, and a pinion- wheel of 15. This smoke jack is used for the same purpose as the common jack, and is so called because it appears to be moved by the smoke of the fire. It is in fact moved by the ascending current of rarefied air, which acts on a fan properly placed in the chimney. The motion may be ob- tained as above, or sometimes spiral flyers coiled about a vertical axis are employed, but more frequently a vertical wheel with oblique leaves like the sails of a wind- mill. JACQUAED. (St$ Addenda.) JADE, the true lapis nephriticits, be- longs to the siliceous order of minerals, as it gives fire with steel, and is semi- pellucid, like flint; it does not harden in fire, but melts, in the focus of a burning lens, into a transparent green glass, with some bubbles. It contains -47 silex, -38 carbonate of magnesia, -04 alumine, *02 carbonate of lime, and '09 iron. Its spec, gravity is from 2-950 to 3-389. The semitransparency, hardness, and specific gravity, are the characters by which the lapis nephriticvs may be dis- tinguished from other stones. JAMBS. In architecture, the side or vertical pieces of any opening in a wall which bear the piece that discharges the superincumbent weight of such wall. JAMESONITE. A mineral named after Professor Jameson. It occurs crystallized and massive : it consists of sulphur, lead, and antimonv. JAPANNING. The art of covering paper, wood, or metal with a thick coat of a hard brilliant varnish : it originated in Japan, whence articles so prepared were first brought to Europe. The mate- rial, if of wood or papier-machee, is first sized, polished, and varnished ; it is then colored or painted in various devices, and afterwards covered with a highly transparent varnish or lacquer, which is ultimately dried at a high temperature, and carefullv polished. JAPANNED TEA- TEA YS, were made by Clay, by uniting sheets of paper with wheaten flour and glue boiled to- gether. They were then rubbed with towels, from the centre to the edges, and dried in a stove before another sheet was laid on. JAPAN, for Tin Ware.— In 6 oz. of oil of lavender dissolve 2 oz. of copal and 1 dr. of camphor, and mix with 8 oz. of oil of turpentine. JAPAN PAINTING, is effected by colors prepared in varnish. It is finished with a coating of seed-lac varnish, made of 3 oz. of clean seed-lac, dissolved in a pint of rectified spirits of wine. This is laid on by single coats, with the brush, and each separately dried to the number of five or six coats. It is subsequently polished with a rag dipped in powdered rotten-stone, and finished with oil. In white grounds, fine putty or whiting should be used. JAPAN WAX. Under this name dif- ferent kinds of white wax are met with, the origin of which are a Japan plant, Rhus Succedanea. It is softer, more brittle, and fatty, than beeswax, easily kneaded, and melts between 40° and 42" C. It contains twice as much oxygen as beeswax, and has a different composition, consisting of palmitic acid, united with oxide of glyceryle. It is easily bleached with nitric acid'. JAEGON. A hard gem brought from the East Indies, in the form of thin plates, which appear to be split from pebbles. They are of different colors, white, black, yellow, and brown, about as hard as sapphire ; and as they have a great resemblance to the diamond, they are substituted instead of it in jeweller's work. In this stone, Klaproth discovered the earth called zircon. 280 CYCLOPEDIA OF THE USEFUL ARTS. KAL JASPER, an opaque flint, which re- j sembles dry clay. It is capable of a fine polish, and its color is generally reddish, ! or green, or striped ; but it is also found [ blue, gray, or whitish. Its specific gravi- ty is from 2-58 to 2*778. It is infusible alone with the blow- pipe ; but it melts with borax or micro- \ cosmic salt, without any effervescence, j Fire increases its hardness. It is composed of siliceous earth, united to al umine very full of iron. Daubenton mentions 15 varieties. JELLY, VEGETABLE, of ripe cur- rants and other berries, is a compound of i mucilage and acid, which loses its power j of gelatinizing by prolonged ebullition. JELLY, ANIMAL. {See Gelatine, Glue, and Isinglass.) JET, a species of pitch-coal or glance- coal, which, being found abundantly in a beautiful compact form, in the valley of Hers, arrondissement of Pamiers, depart- ment of the Arriege, has been worked up extensely there from time immemorial, into a multitude of ornamental articles. "With this black lignite, buttons, crosses, rosaries, necklaces, ear-drops, bracelets, waist-buckles, &c, are made, which were at one time much worn by ladies for mourning dresses. The greater number of these ornaments are fashioned upon grindstones which turn in a horizontal direction, and are kept continually wet • others are turned at the lathe, or shaped by files. In England, about 40 years ago, this manufacture employed from 1000 to 1200 operatives; at present it gives bread to only 60. This falling off may be ascribed to the successful imitation of the jet articles by those of black glass, which are equally beautiful, and not nearly so apt to lose their polish by use. JET D'EAU. A fountain which throws up water to some height in the air. Ac- cording to the theory of hydrostatics, the velocity with which "water issues from an orifice is equal to that which would be acquired by a heavy body in falling through a height equal to the difference between the levels of the orifice and the fountain head ; whence, if the resistance of the air and other impediments were removed, the height of the jet would be equal to that of the surface of the reser- voir. Among the causes which prevent the jet from obtaining the height which theory assigns to it, the following are the principal : 1. The resistance of the air, which is proportional nearly to the square of the velocity. 2. The friction against the sides of the pipe and the orifL-s through which the water issues. 3. The velocity of the particles diminishing at every instant as they ascend, the lower particles of the ascending column press against those next above them ; and the pressure being by the nature of fluids communicated in all directions, the consequence is, that the column is enlarged and proportion- ally shortened. 4. The water at the top of the jet does not fall off instantaneously when its velocity is destroyed ; it rests for a moment at" the top of the column, where its weight opposes an obstacle to the particles next succeeding, which re- tards their velocity, and this retardation is communicated to the whole column. This last obstacle may be avoided by slightly inclining the jet from the verti- cal ; and it is found by experience that a jet so inclined plays higher than one quite upright, though the effect is thereby rendered less pleasing. It is necessary that the diameter of the adjutage or ori- fice be considerably less than that of the pipe. (See Demgutier's Experimental Phi- losophy • Mariotte, Mouvement des Eaux.) JOGGLE JOINTS. The joints of stones or other masses indented in such a way that the adjacent stones fitting into the indentations are prevented from be- ing pushed away from each other by any force perpendicular to the pressures by which they are thus held together. JOGGLE PICA. In architecture a truss-post whose shoulders and sockets receive the lower end of the struts. JUJUBE. The fruit of the Ehamnus zizyphus : it resembles a small plum, and is occasionally used as s a sweetmeat. What is sold under the name of jujube paste professes to be the dried jelly of this fruit, but is, in fact, a mixture of gum arabic and sugar slightly colored. JUNIPER BERRIES. The fruit of the Juniperus communis. They are used in medicine as a diuretic ; but their prin- cipal consumption is in flavoring gin. When distilled with water they yield an essential oil, upon which their peculiar flavor depends. The resin of this tree is called juniper gum or sandarach, and is occasionally used in varnishes. "When powdered it is used under the name of pounce, to prevent ink sinking into paper from which writing has been erased. KALI, a maritime plant, from the ashes of which a considerable quantity of soda is obtained by lixiviation. By boil- ing the plant in water, and evaporating the decoction, a considerable quantity cf sea-salt may be obtained. kee] CYCLOPEDIA OF THE USEFUL ARTS. 281 The word Kali, and Alkali originally, had a similar meaning. The latter term is now applied to a class of bodies having peculiar properties, while the term kali is mostly confined to potash, the most active of the class of alkalies. The metal pot- assium is sometimes called kalium, and the symbol is always written with the in- itial letter K. KAOLIN, porcelain earth, is an earthy, pure white, grayish or milk white sub- stance, easily pulverized, and mixed with particles of quartz and feldspar. It is the most important material for making por- celain. Beds of pretty pure Kaolin have been found in the neighborhood of Lake Champlain, and scattered through the New-England states and that of New- York, in the valleys of the primary dis- tricts. It is clay in its pure and most original form, and is the prototype of all other clays. Kaolin is produced by the action of the atmosphere upon certain minerals belonging to the feldspar class, as spodumene and porcelain spar. Be- sides the silicate of alumina (pure clay) of the feldspar, porcelain also contains un- decomposed debris of rocks, silicates of magnesia and lime, and free silicic acid. These impurities are sometimes as much as 1 6 per cent. Out of 31 analyses made by Brogniart and Malaguti, 18 consisted of alumina and silica in equivalent propor- tions, the remainder containing an excess of silica. In 100 parts various samples contained the following ingredients : — Knolin from — According tu — St. Yrieiuc. Berthier. Pmmui. Fnclis. Halle. Bley. Silica 47-09 36-41 1-56 2-94 12*66 43-65 35-93 0-88 1-00 1S-50 3962 45-00 Magnesia 3-32 0-07 '6 : 19 10- Oxide of Iron Oxide of Manganese.. The decomposition of the feldspar out of granite affords a very good Kaolin or China Clay. KEEL. The principal piece of timber of a ship, usually first laid on the blocks in building. If we compare the body of a ship to the human skeleton, the keel seems to resemble the backbone, and the timbers the ribs. It is generally com- posed of several thick pieces of wood placed lengthways, which, after being scarfed together, are bolted and clenched upon the upper side. Keelage signifies I the duty paid by a ship on coming into port. The keel is generally elm, except the after-piece, which, on account of its being often wet and dry, is sometimes oak, especially when the ship is expected to be a great while in building. The num- ber of pieces in the keel is not very ma- terial, so that it gives good shift to the keelson and the mainmast. The keel is scarfed with a hook in the middle, which should lay very close, it being designed on purpose to bear the strain of calking the butts, that the bolt in the scarf may not be strained. The keel should not be tapered much, either forward or aft at the upper part, and from thence it is to be bearded away at the lower edge ; for, when the dead-wood is trimmed, espe- cially abaft, being frequently very thin, it is with much difficulty that the dead- wood can be securely bolted. The speed of a vessel does not depend so much upon the form of the bow as it does on the depth to which it is im- mersed in the water. In the case of a frigate drawing 17 feet water, and ano- ther frigate of the same burthen drawing 11 feet, the last will have a body of six feet less fluid to penetrate, to make her hold a good wind, while the first has six feet perpendicular depth of her hull de- pressed, being about one-third of her real size. Therefore, she has a body of water to displace, and to force herself through, equal to the difference between 11 and 17. The resistance of the fluid also increases in proportion to the depth. Vessels in the coal-trade draw one-third less water than any other of British con- struction ; yet, when employed as trans- ports, they sail as fast as any others ; and, before the wind, in ballast, or half loaded, frequently beat the royal navy. When closed hauled on a wind they drop to leeward ; but, if they were furnished with sliding keels, they would be superior to all the other English vessels. The Dutch have vessels built almost flat, but all these have lee-boards, by the assistance of which they sail as fast as any that navi- gate the North Sea. Ships, or vessels of the larger classes, should always be so constructed as to sail on, or nearly on an even keel, — that is, so that when the ship is trimmed for sailing, she should have her keel parallel to the surface of the water ; therefore, as_ much as the effort of the wind on the sails and mast, in forcing the ship through the water, has a constant ten- dency to depress the bow, so much 282 CYCLOPEDIA OF THE USEFUL ARTS. [kel should the ship be properly trimmed at the stem. A sharp-huilt ship sinks under its car- go so fast, that by the time it comes to its bearings, it is frequently not loaded. Those having flat and long floors, on the other hand, sink slowly ; and after hav- ing taken in the quantity they measure, will have, frequently, plenty of room, and remain high out of the water. The only objection to the latter is, the unfit- ness of a flat-floored vessel to hold a good wind, but this difficulty is removed by the adoption of sliding" heels. The same principle, which causes flat-floored vessels to sail faster before the wind, to carry a larger cargo, and draw less water, operates with equal force in rendering them easy at anchor. Their form, with the fulness of their body fore and aft, enables them to rise and fall, according to the lift of the sea, while sharp and clean-built ships pitch with the utmost violence, frequently with such force as to endanger the masts ; to say nothing of the strain which the tremendous jerks give the hull and the injury of the an- chors and cables. The use of sliding keels is known, by actual experience, to be of the greatest importance. In fresh breezes, or in light winds, it is totally immaterial how much sail is set, or how it is disposed ; since the act of raising or lowering the keels will immediately counteract the inconve- nience that might otherwise arise from carrying too much sail, either forward or aft. The most trifling practice will ren- der the navigators perfectly acquainted with their use, and the easy steerage of this ship will convince him of their ad- vantage. In a gale of wind it is neces- sary tli at the main and fore-keels should be hauled close up, and the stern-keel let down to such depth as shall be found necessary to make the vessel steer per- fectly easy. KELP. A common term for sea-weed or vraic, which consists of different spe- cies of Fucus (varec). In a strict sense, the term kelp is confined to the produce of sea-weeds when burned, which con- sists of alkaline ashes used in the manu- facture of glass and soap. It has been recently found, however, that the alkali required for these purposes can be ob- tained more abundantly from sea-salt, and kelp is at present chiefly used as a manure. For this purpose it is eagerly sought after by all farmers on the sea- coast, and especially by those who have dry soils, the salt contained in tho kelp being a powerful absorbent of moisture from the atmosphere. It has lately ac- quired much importance as a source of iodine. The species used in the manufacture of this article grow attached to rocks, between high and low water mark. On the Scottish coast it is cut close to the rocks, during the summer season, and spread, and turned to dry. It is then stacked and sheltered, till covered with white saline efflorescence, and is then ready for burning, in a round pit or kiln, lined with brick or stone, about 2 ft. wide, 8 to 18 long, and from 2 to 3 deep. The bottom is covered with brush, upon which a little dried sea-weed is scatter- ed, and fire is applied at one extremity ; the sea-weed is now thrown on gradu- ally, as fast as the combustion reaches the surface. After the whole is burnt, the mass gradually softens, beginning at the sides, when it should be slowly stir- red up with a heated iron bar, and in- corporated till it acquires a semi-fluid consistence. This part of the process re- quires considerable dexterity ; and, if the mass continues dry, a little common salt should be thrown on it as a flux. When cold it is broken up, and is ready for sale. Kelp contains but 2 or 3 per cent, of carbonate of soda, while Spanish barilla often contains 20 or 30. One of the pro- ducts is iodine. The use of soda, in general, is the same with that of potash, but it is indispensa- ble in making plate and ground glass and hard soaps, and consumed in immense quantities by soap-boilers, bleachers, and glass-makers. It is well known that the shores of the sea, and salt-marshes, as well as the margins of interior salt-lakes and sa- lines, and, in general, all places to which water holding salt gains access, are in- habited by peculiar plants. In these maritime plants, soda replaces the pot- ash, which is always present in plants growing in ordinary situations, and if they are removed to a distance from the sea-shore, they gradually lose their soda, and acquire potash in its stead. The barilla obtained in France from the sali- cornia annua yields 14 or 15 per cent, of soda. The Highland Society of Scotland has published the following account of the manufacture of 115 tons of kelp in Harris. It was from cut- ware of two years' growth, in equal parts of lady-ware, which grows between the spring and neap high tides ; ker] CYCLOPEDIA OF THE USEFUL ARTS. 283 hell-ware, between high and low neap tides ; black-ware, low water, spring and neap. It is cut with a strong reaping- hook. Sand and mud is washed off, and it is spread by day, and cocked by night. Then put into large cocks, and left to heat for six or ei^ht days. It is burnt on a dry day, and a good breeze. The kilns are of hard stones, with turf out- side, from 15 to 18 feet long, 2i ft, broad and 2 feet high. Straw or heather is laid over this, set on fire, and dry- ware added on the top by degrees till the whole is in ashes. If it cakes, it must be raked. When all is burned, it has the appear- ance of a semi-vitrified solid. It is then broken into large lumps, and kept cover- ed until it is put up in the cask for ship- ment. The following two analyses of kelp, one from Cherbourg, made by Gi- rardin, and the other from Spain, made by Richardson, show it to be made up mainly of sulphate and chloride of potas- sium, and chloride of sodium, or common salt, Cherbourg Spain. Sulphate potash 4254 1585 Chloride potassium . . . 1964 1055 Chlorifle sodium 2538 6835 Carbonate of sqda 371 traces Sulphate lime 1-10 Insoluble matter -73 .... Iodine compounds . . . .traces .... Water 8- 4-00 10000 10000 KERASOPHANY. A new art has been discovered in Berlin, which consists in making pictures of a material, the principal ingredient of which is wax, in imitation oi transparent ones made in porcelain. To be seen, the picture must be placed between the observer and the light. The ingredients used with the wax destroy its' brittleness, and it with- stands a heat of more than one hundred and fifty degrees Fahrenheit. KERMES. An insect found in many parts of Asia and the south of Europe"; the Coccus ilicis of Linnasus. They were long taken for the seeds of the tree on which they live, and hence called grains of kermes. They are used as a red and scarlet dye, but very inferior to cochi- neal. Previously to 'the introduction of cochineal, by which it is now nearly wholly superseded, kermes had been the most esteemed drug for dyeing scarlet from a remote period of antiquity. Cloths dyed with kermes are of a deep-red co- lor ; and though much inferior in bril- liancy to the scarlet cloths dyed with real Mexican cochineal, they retain the color better and are less liable to stain. The tapestries of Brussels and other parts of Flanders, which have scarcely lost any thing of their original brilliancy, even after a lapse of 200 years, were all dyed with kermes. The principal varieties of kermes are the coccus quercus, the coccus polonicus, the coccus fragariai, and the coccus uva ursi. The coccus quercus insect lives in the south of Europe upon the kermes oak. The female has no wings, is of tho size of a small pea, of a brownish-red color, and is covered with a whitish dust. From the middle of May to the middle of June the eggs are collected, and ex- posed to the vapor of vinegar, to prevent their incubation. A portion of eggs is left upon the tree for the maintenance of the brood. In the department of the Bouches-du-Rhone, one-half of the kermes crop is dried. It amounts an- nually to about 60 quintals or cwts., and is warehoused at Avignon. The kermes of Poland, or coccus polo- nicus, is found upon the roots ot the scleranthus perennis and the scleran- thus annuus, in sandy soils of that country and the Ukraine. This species has the same properties as the preced- ing ; one pound of it, according to Wolfe, being capable of dyeing 10 pounds of wool ; but Ilermstaedt could not obtain a fine color, although he employed five times as much of it as of cochineal. The Turks, Armenians, and Cossacks, dye with kermes their morocco leather, cloth, silk, as well as the manes and tails of their horses. The kermes called coccus fragarice, is found principally in Siberia, upon the root of the common strawberry. The coccus vva ursi is twice the size of the Polish kermes, and dyes with alum a fine red. It occurs in Russia. Kermes is found not only upon the lycopodium complanatum in the Ukraine, but upon a great many other plants. Good kermes is plump, of a deep-red color, of an agreeable smell, and a rough and pungent taste. Its coloring matter is soluble in water and alcohol ; it be- comes yellowish or brownish with acids, and violet or crimson with alkalies. Sul- Shate of iron blackens it. With alum it yes a blood-red ; with copperas an agate gray ; with copperas and tartar, a lively gray ; with sulphate of copper and tartar, an olive green ; with tartar and salt of tin, a lively cinnamon yellow ; with more alum and tartar, a lilach ; with sulphate of zinc and tartar, a violet. 284 CYCLOPEDIA OF THE USEFUL ARTS. [L^B Scarlet and crimson dyed with kermes, were called grain colors ; and they are reckoned to be more durable than those of cochineal, as is proved by the bril- liancy of the old Brussels tapestry. He'llot says that previous to dyeing in the kermes bath, he threw a handful of wool into it, in order to extract a black- ish matter, which would have tarnished the color. The red caps of the Levant are dyed at Orleans with equal parts cf kermes and madder ; and occasionally with the addition of some Brazil wood. Cochineal and lac-dye have now nearly superseded the use of kermes as a tinc- torial substance, in England. Kermes Mineral. A name given by the old chemists to the hydrosulphuret of antimony, in consequence of its red- dish color. It may be obtained perfectly pure, by diluting the proto-chloride of antimony with solution of tartaric acid, and precipitating the metal with sulphu- reted hydrogen ; or by exposing the finely levigated native sulphuret to a boiling solution of carbonate of potash for some time, and filtering the liquor while boiling hot. The kermes falls down in a brown-red powder, as the liquor cools. KETCHUP, or CATSUP. A liquor used as a substitute for gravy. That made from the Tomato and Mushroom is most common. They can scarcely be called judicious mixtures, but rather an incongruous medley of strong tasting substances and spices, such as garlic, shallot, horse-radish, lemon-peel, beer, wine, mustard, anchovy, and spice. Mushroom catsup is usually made by ad- ding the grosser part of the mushrooms beaten up into a pulp, to a decoction of spice and salt — properly, the expressed juice of the mushroom should be pre- served in spice liquor. KILLAS. A name given to clay slate by Cornish miners. *KILN. The various forms of furnaces and stoves, by which strong heat may be applied to bodies, are so called. Thus there are brick kilus, lime kilns, malt kilns, and pottery kilns. Under the head of limestone, malt, and pottery, differ- ent forms of kiln are noticed. KINIC ACID. A peculiar acid found in Cinchona bark by Vauquelin. KINO. An extract obtained from the Nauclea cfamMr, a shrub growing at Su- matra and in the Islands of the Indian Ocean. It is of a red brown color, has a styptic taste, and consists chiefly of tan- nin. It is only used as an astringent in medicine. KIRSCHWASSER, is an alcoholic liquor by the fermentation and distilla- tion of bruised cherries. In Switzerland and Germany it is the morello cherry which is used. When ripe it is black, and has an unusually large kernel : the fruit is snatched off the trees, and all kinds thrown into tubs and crushed cither by hand or with a beater. These materials are allowed to ferment, and when this is completed it is transferred to a still covered with verdigris dust. The whole is conducted in the rudest way possible. The liquor has accordingly a rank smell, and is injurious to health from the empyreumatic oil and prussic acid it contains. KEY-BOARD. In music, the series of levers in a keyed instrument, as a piano- forte, organ, or harpsichord, upon which the ringers press to produce percussion of the strings, or in the organ the open- ing of valves. It consists of short black and long white keys. KEYSTONE. The middle voussoir in the arch of a bridge, or the archstone in the crown or immediately over the centre of the arch. The length of the keystone, or thickness of the archivolt at top, is al- lowed to be about 1-1 5th or l-16th of the span bv the best architects. KREASOTE. See Creosote. KYANIZING. That process of pre- serving vegetable fibre recommended by the late Mr. Kyan, of New-York. It con- sisted in the complete soakage and pene- tration into the timber of i\ solution of bichloride of mercury (corrosive subli- mate). This salt was proposed as a pro- tective agent against the attack of dry rot, which renders wood so utterly worthless after a few years. It was at one period much used in the British navy. (See Wood, preservation of) LABORATORY. ' The workshop of a chemist. Some laboratories are intended for private research, and some for the manufacture of chemicals on the large scale. Hence it is almost impossible to give a description of the apparatus and disposition of a laboratory which would be generally true of all. A manufacturing laboratory necessarily occupies a large space, while that of the scientific man is necessarily limited to a peculiar line of research. Those who study in organic chemistry have different arrangements from that of the mineral analyist. A laboratory is furnished with a fixed I. AC CYCLOPEDIA OF THE USEFUL ARTS. 285 furnace, and sundry auxiliaries and por- table furnaces. It ought also to contain blow-pipes and galvanic troughs, with crucibles, matresses, retorts, flasks, ves- sels, and bottles ; also a pestle and mor- tar, a vice, a lathe, and carpenters' tools ; a pneumatic trough, a sink for water, ta- bles, drawers, and shelves ; with thermo- meters, a barometer, pvrometer, hydro- meter, Argand's lamps, Wojlaston's scale, weights and measures, &c. It requires also a small stock of tests and test-paper, and of sulphuric, nitric, and acetic acids; with nitre, soda, ammonia, alcohol, &c, &c. ; and especially pasteboard and wire masks, and a stout apron for the stomach and abdomen. The cost varies from $200 to $2,000. The expense of fitting up a laboratory to furnish articles of common consump- tion is very small. The instruments in- dispensably necessary are — an alembic, with a refrigerator and portable furnace. If the operator should not choose to go to the expense of the alembic and its ap- paratus, a succedaneum may be found for them in a sand-bath or sand-heat, with retorts, under suitable precautions. Sand-7ieut is usually formed, in the large way, of an oblong shape, having bricks and mortar for its walls, plates of iron upon which to lay the sand, and around the top a ledge, of about six or eight inches deep, of free-stone, to retain the sand. Beneath the plates of iron is a wide flue, at the bottom of which is an non grating, upon which grating is laid the fire. The fire is, of course, when kindled, enclosed by a door, as in other furnaces, at the end of the sand-heat ; a flue communicates with a chimney, to cany off the smoke. The sand is com- monly of the depth of six or eight inches ; but the quantity and depth depend upon the size of the vessels. A retort is a vessel usually made of green or other glass, and may be made to hold from half a pint to eight or more gallons. It has a long narrow neck, which is so bent, that when the retort is placed with its contents in a sand-bath, or over a fire, it has a gentle inclination, and will conduct whatever liquid is con- densed in it, into a glass receiver, which is placed on a bench beside the sand-heat ; the receiver is luted to the neck of the retort, either by a caoutchouc skin, which is the neatest way^or by some other lute. A variety of chemical processes are thas conducted : the vapors raised by the heat being condensed in the neck of the re- tort, and cooled down in the receiver, (which is usually about the size of a re- tort,) by the large surface which it pre- sents to" the air. With Florence flasks and bent tubes fitted with cork many opera- tions requiring retorts maybe used; and even small glass tubes may supplant these latter in the more delicate applica- tions. On this, as on many other subjects, more is learnt in half an hour, by actual inspection, than by half a volume of de- scription. There are some very well-appointed laboratories in this country ; amongst others, that in the Lawrence Scientific School, Harvard University, Cambridge, Mass., and those in Philadelphia are pro- minent. LAC. Lac-dye, is produced by the Juncture of an" insect called the Cocus iacca, upon the branches of several plants as varieties of the ficus, rhamnus, and the croton. It is the female insect which punctures the twig, which then becomes surrounded with a resinous juice which hardens and has a crystalline fracture. This constitutes the stick-lac of commerce ; it is of a red color, more or less deep and transparent. According to Franke, the constituents of stick-lac are, resin, 65-7; substance of the lac, 23-2; coloring matter, 0-0. Seed-lac. When the resinous concre- tion is taken off the twigs, coarsely pound- ed, and triturated with water in a mortar, the greater part of the coloring matter is dissolved, and the granular portion which remains, being dried in the sun, consti- tutes seed-lac. It contains, of course, less coloring matter than the stick-lac, and is much less soluble. John found in 100 parts of it, resin, 66-7 ; wax, 1-7; matter of the lac, 16-7 ; bitter balsamic matter, 2*5 ; coloring matter, 3-9 ; dun yellow ex- tract, 0-4 ; envelopes of insects, 2-1 ; lac- tic acid, 0-0; salts of potash and lime, 1-0 ; earths, 6-6 ; loss, 4*2. In India the seed-lac is put into oblong bags of cotton cloth, which are held over a charcoal fire by a man at eacli end, and, as soon as it begins to melt, the bag is twisted so as to strain the liquefied resin through its substance, and to make it drop upon smooth stems of the banyan tree. In this way, the resin spreads into thin plates, and constitutes the substance known in commerce by the name of shellac. The Pegu stick -lac, being very dark- colored, furnishes a shellac of a corres- ponding deep hue, and therefore of infe- rior value. The palest and finest shel- 286 CYCLOPEDIA OF THE USEFUL ARTS. [lac lac is brought from the northern Circar. It contains very little coloring matter. A stick-lac of an intermediate kind comesv from the Mysore country, which yields a brilliant lac-dye and a good shellac. Lac-dye is the watery iufusion of the ground stick-lac, evaporated to dryness, and formed into cakes about two inches square, and half an inch thick. Dr. John found it to consist of coloring matter, 50 ; resin, 25 ; and solid matter, composed of alumina, plaster, chalk, and sand, 22. Dr. Macleod, of Madras, prepared a very superior lac-dye from stick-lack, by digesting it in the cold in a slightly alka- line decoction of the dried leaves of the Memecylon tinctorium. This solution be- ing used along with a mordant, consist- ing of a saturated solution of tin in muri- atic acid, was found to dye woollen cloth of a very brilliant scarlet hue. The cakes of lac-dye imported from In- dia, stamped with peculiar marks to de- signate their different manufacturers, are now employed exclusively in England for dyeing scarlet cloth, and are found to Jield an equally brilliant color, and one ass easily affected by perspiration than that produced by cochineal. When the lac-dye was first introduced, sulphuric acid was the solvent applied to the pul- verized cakes, but as muriatic acid has been found to answer so much better, it has entirely supplanted it. A good sol- vent (No. 1) for this dye-stuff may be prepared by dissolving three pounds of tin in 60 pounds of muriatic acid, of spe- cific gravity "1'19. The proper mordant for the cloth is made by mixing 27 pounds of muriatic acid of sp. grav. 1-17, with li pounds of nitric acid of 1-19 ; putting this mixture into a salt-glazed stone bot- tle, and adding to it, in small bits at a time, grain tin, till 4 pounds be dissolved. This solution (No. 2) may be used with- in twelve hours after it is made, pro- vided it has become cold and clear. For dyeing, three quarters of a pint of the solvent (No 1) is to be poured upon each ?)ound of the pulverized lac-dye, and al- owed to digest upon it for six hours. The cloth, before being subjected to the dye bath, must be scoured in the mill with fullers' earth. To dye 100 pounds of pelisse cloth, a tin boiler of 300 gallons capacity should be filled nearly brimful with water, and a fire kindled under it. Whenever the temperature rises to 150° Fahr., a handful of bran and half a pint of the solution of tin (No. 2) are to be introduced. The froth, which rises as it approaches ebullition, must be skimmed off ; and when the liquor boils, 10i pounds of lac-dye, previously mixed with 7 pints of the solvent No. 1, and 3£ pounds of solution of tin No. 2, must be poured in. An instant afterwards, 104 pounds of tartar, and 4 pounds of ground sumach, both tied up in a linen bag, are to be suspended in the boiling bath for five minutes. The fire being now with- drawn, 20 gallons of cold water, -with 101 pints of solution of tin, being poured into the bath, the cloth is to be immersed in it, moved about rapidly during ten mi- nutes ; the fire is to be then rekindled, and the cloth winced more slowly through the bath, which must be made to boil as quickly as possible, and maintained at that pitch for an hour. The cloth is to be next washed in the river ; and lastly, with water only, in the fulling mill. The above proportions of the ingredients pro- duce a brilliant scarlet tint, with a slight- ly purple cast. If a more orange hue be wanted, white Florence argal may be used, instead of tartar, and some more sumach. Lac-dye may be substituted for cochineal in the 'orange-scarlets; but for the more delicate pink shades, it does not answer so well, as the lustre is apt to be impaired by the large quantity of acid necessary to dissolve the coloring matter of the lac. Shellac, by Mr. Hatchett's analysis, consists of resin, 90~5 ; coloring matter, 0-5; wax, 4-0; gluten, 2-8; loss, 1-8; in 100 parts. The resin may be obtained pure by treating shellac 'with cold alcohol, and, filtering the solution in order to separate" a yellow gray pulverulent matter. When the alcohol is again distilled off, a brown, translucent, hard, and brittle resin, of specific gravity 1-139, remains. It melts into a viscid mass with heat, and diffuses an aromatic odor. Anhydrous alcohol dissolves it in all proportions. Accord- ing to John, it consists of two resins, one of which dissolves readily in alcohol, ether, the volatile and fat oils ; while the other is little soluble in cold alcohol, and is insoluble in ether and the volatile oils. Unverdorben, however, has detected no less than four different resins, and some other substances, in shellac. Shellac dis- solves with ease in dilute muriatic and acetic acids ; but not in concentrated sul- phuric acid. The resin of shellac has a hires often emit a beautiful play of co- ors, or chatoiement, when held in differ- ent positions relative to the eye or inci- dent light ; and some likewise present star-like radiations, whence they are called star-stones or asterias ; sending forth 6 or even 12 rays, that change their ?lace with the position of the stone. 'his property, so remarkable in certain blue sapphires, is not, however, peculiar to these gems. It seems to belong to transparent minerals which have a rhom- boid for their nucleus, and arises from the combination of certain circumstances in their cutting and structure. Lapida- ries often expose the light-blue variety of sapphire to the action of fire, in order to render it white and more brilliant; but with regard to those found at Ex- pailly, in France, fire deepens their color. 8. Ckrysoberyl, called by Haiiy, Cymo- phane, and by others, Prismatic corun- dum, ranks next in hardness to sapphire, being 8*5 on the same scale of estimation. Its specific gravity is 3*754. It usually occurs in rounded pieces about the size of a pea, but it is also found crystallized in many forms, of which 8-sided prisms with 8-sided summits are perhaps the most frequent. Lustre vitreous, color asparagus green, passing into greenish- white and olive-green. It shows a bluish opalescence, alight undulating, as it were, in the stone, when viewed in certain di- rections ; which property constitues its chief attraction to the jeweller. When polished, it has been sometimes mistaken for a yellow diamond ; and from its hard- ness and lustre is considerably valued. Good specimens of it are very rare. It has been found only in the alluvial de- posites of rivers, along with other species of gems. Thus it occurs in Brazil, along with diamonds and prismatic topaz ; also in Ceylon. Its constituents are alumina, 68-66; glucina, 16*00; silica, 6*00; pro- toxide of iron, 4*7 ; oxyde of titanium, 2*66; moisture, 0*66; according to Sey- bert's analysis of a specimen from Brazil. It is difficultly but perfectly fusible before the blow-pipe, with borax and salt of phosphorus. In composition it differs entirely from sapphire, or the rhombohe- dral corundum. 4. Spinelle Ruby, called Dodecahedral corundum, by some mineralogists, and Balas ruby, by lapidaries. Its hardness is 8. Specific gravity, 3*523. Its funda- mental form is the hexahedron, but it oc- curs crystallized in many secondary forms : octahedrons, tetrahedrons, and fhombo- hedrons. Fracture, conchoidal ; lustre, vitreous ; color, red, passing into blue and green, yellow, brown, and black ; and sometimes it is nearly white. Bed spi- nelle consists of alumina, 74*5; silica, 15*5 ; magnesia, 8*25; oxide of iron, 1*5; lime, 0*75. Vauquelin discovered 6*18 per cent. of chromic acid in the red spinelle. The red varieties exposed to neat become black and opaque ; on cooling, they ap- pear first green, then almost colorless, but at last resume their red color. Pleonaste is a variety which yields a deep green globule with borax. Crystals of spinelle from Ceylon have been observed imbedded in limestone, mixed with mica, or in rocks containing adularia, which seem to have belonged to a primitive district. Other varities like the pleonaste occur in the drusy cavities of rocks ejected by Vesuvius. Crystals of it are often found in diluvial and alluvial sand and gravel, along with true sap- phires, pyramidal zircon, and other gems; as also with octahedral iron ore, in Cey- lon. Blue and pearl-gray varieties occur in Siidermannland, in Sweden, imbedded in granular limestone. Pleonaste is met lap] CYCLOPEDIA OF THE USEFUL ARTS. 299 with also in the diluvial sands of Ceylon. Clear and finely colored specimens of'spi- nelle are highly prized as ornamental stones. When the weight of a good spi- nelle exceeds 4 carats, it is said to be val- ued at half the price of a diamond of the same weight. M. Brard has seen one at Paris which weighed 215 grains. 5. Zircon or Hyacinth. Its fundamental form is an isosceles 4-sided pyramid ; and the secondary forms have all a pyra- midal character. Fracture, conchoidal, uneven ; lustre, more or less perfectly adamantine ; colors, red, brown, yellow, gray, green, white; which, with the ex- ception of some red tints, are not briffht. Hardness, 7-5. Specific gravity, 4-5. Zir- con and hyacinth consist, according to Klaproth, of almost exactly the same con- stituents ; namely, zirconia, 70 , silica, 25 ; oxyde of iron, 5. In the white zir- conia there is less iron and more silica. Before the blowpipe the hyacinth loses its color, but does not melt. The brighter zircons are often worked up into alrilliant form, for ornamenting watch cases. As a gem, hyacinth has no high value. It has been often confounded with other stones, but its very great specific gravity makes it to be readily recognized. 6. Topaz. The fundamental form is a scalene 4-sided pyramid ; but the second- ary forms have a prismatic character ; and are frequently observed in oblique 4-sided }>risms, acuminated by 4 planes. The ateral planes of the prism are longitudin- ally striated. Fracture, conchoidal, un- even ; lustre, vitreous ; colors, white, yel- low, green, blue; generally of pale shades. Hardness, 8 ; specific gravity, 3-5. Pris- matic topaz consists, according to Berze- lius, of alumina, 57*45; silica, 34-24; flu- oric acid, 7*75. In a strong heat the faces of crystallization, but not those of cleav- age, are covered with small blisters, which however immediately crack. With borax, it melts slowly into a transparent glass. Its powder colors the tincture of violets green. Those crystals which possess dif- ferent faces of crystallization on opposite ends, acquire the opposite electricities on being heated. By friction, it acquires po- sitive electricity. Most perfect'crystals of topaz have been found in Siberia, of green, blue, and white colors, along with beryl, in the Uralian and Altai mountains, as also in Kams- chatka ; in Brazil, where they generally occur in loose crystals, and pebble form's of bright yellow 'colors; and in Mucla, in Asia Minor, in pale straw-yellow regular crystals. They are also met with in the granitic detritus of Cairngorm, in Aber- deenshire. The blue varieties are absurd ly called oriental aquamarine, by lapida- ries. If exposed to heat, the Saxon topaz loses its color and becomes white ; the deep yellow Brazilian varieties assume a pale pink hue; and are then sometimes mistaken for spinelle, to which, however, they are somewhat inferior in hardness. Topaz is also distinguishable by its double retractive property" Tavernier mentions a topaz, in the possession of the Great Mogul, which weighed 157 carats, and cost £27,000 sterling. There is a speci- men in the museum of natural history at Paris which weighs 4 ounces 2 grs. Topazes are not scarce enough to be much valued by the lapidary. 7. Emerald and Beryl are describee in their alphabetical places. Emerald la es its lustre by candle-light ; but as it ap- pears to most advantage when in the com- pany of diamonds, it is frequently sur- rounded with brilliants, and occasionally with pearls. Beryl is the aquamarine of the jewellers, and has very little estima- tion among lapidaries. 8 ; Garnet. See this stone in its alpha- betical place. 9. Chrysolite, called Peridot, by Hauy ; probably the topaz of the ancients, as our topaz was their chrysolite. It is the soft- est of the precious stones, being scratched by quartz and the file. It refracts double. 10. Qvartz, including, as sub-species, Amethyst, Bock - crystal, Bose - quartz, Prase, or Chrysoprase, and several vari- eties of calcedony, as Oafs-eye, Plasma, Chrysoprase, Onyx, Sardonyx, &c. Lus- tre, vitreous, inclining sometimes to re- sinous j colors, very various ; fracture, conchoidal; hardness, 7; specific gravity, 2-69. 11. Opal, or uncleavable quartz. Frac- ture, conchoidal ; lustre, vitreous or re- sinous; colors, white, yellow, red, brown, green, gray. Lively play of light; hard- ness, 5-5 to 6-5 ; specific gravity, 2-091. It occurs in small kidney-shaped and stal- actitic shapes, and large tuberose concre- tions. The phenomena of the play of co- lors in precious opal has not been satisfac- torily explained. It seems to be connect- ed with the regular structure of the min- eral. Hydrophane, or oculis mundi, is a variety of opal without transparency, but acquiring it when immersed in water, or in any transparent fluid. Precious opal was found by Klaproth to consist of silica, 90; water, 10; which is a very curious combination. Hungary has been long the only locality of precious opal, where it oc- 300 CYCLOPEDIA OF THE USEFUL ARTS. [lar curs near Caschau, along with common and semi-opal, in a kind of porphyry. Fine varieties have, however, been lately discovered in the Faroe islands ; and most beautiful ones, sometimes quite transpa- rent, near Gracias a Dios, in the province of Honduras, America. The red and yel- low bright colored varieties of fire-opal are found near Zimapan, in Mexico. Pre- cious opal, when fashioned for a gem, is generally cut with a convex surface ; and if large, pure, and exhibiting a bright play of colors, is of considerable value. In modern times, fine opals of moderate bulk have been frequently sold at the price of diamonds of equal size : the Turks being particularly fond of them. The estima- tion in which opal was held by the an- cients is hardly credible. They called it Paideros, or Child beautiful as love. No- nius, the Roman senator, preferred ban- ishment to parting with his favorite opal, which was coveted by Mark Antonv. Opal which appears quite red when held against the light, is called girasol by the French ; a name also given to the sapphire or corundum asterias or star-stone. 12. Turquois or Calaite. Mineral tur- quois occurs massive ; fine-grained, im- palpable ; fracture, conchoidal ; color, be- tween a blue and a green, soft, and rather bright ; opaqe ; hardness, 6 ; spec, grav., 2-83 to 3-0. Its constituents are alumina, 73 ; oxyde of copper, 4-5 ; oxyde of iron, 4 ; water, 18 ; according to Dr. John. But by Berzelius, it consists of phosphate of alumina and lime, silica, oxydes or cop- per, and iron, with a little water. It has been found only in the neighborhood of Nichabour in the Khorassan, in Persia; and is very highly prized as an ornamental stone in that country. There is a totally different kind of turquois, called bane tur- quois, which seems to be phosphate of lime colored with oxyde of copper. When the oriental stone is cut and polished, it forms a pleasing gem of inferior value. Malachite, or mountain green, a compact carbonate of copper, has been substituted sometimes for turquois, but their shades are different. Malachite yields a green streak, and turquois a white one. 13. Lapis lazuli is of little value, on ac- count ot its softness. (See Ultra Ma- bine.) LARD. The fat of swine, which dif- fers in situation from that of nil other animals, as it covers the hog all over, forming a distinct and continuous layer between the flesh and skin, like the blub- ber in whales. The usual mode of pre- paration is to melt it in a jar, placed in a kettle of water, and then to level it, and run it into bladders that have been clean- ed with great care. The smaller the bladders are, the better the lard will keep. The fat which adheres to the intestines differs from common lard, and is used for lubricating wheels of carriages. The great mass of lard business is done in Ohio, having Cincinnati for the centre ; and most of the lard oil is expressed there. In Cincinnati it is calculated that about 11,000,000 lbs. of lard was run into lard oil this last year, two-sevenths of which aggregate will make stearine, the residue oil, say about 20,000 barrels of 42 gallons each. Much the larger share of this is of inferior lard, made of mast-fed and still-fed hogs, the material, to a great extent, coming from a distance — hence the poor quality of western lard oil. Lard oil, besides being sold for what it actually is, is also used for adulterating sperm oil, and in France serves to mate- rially reduce the cost of olive oil — the skill of the French chemists enabling them to incorporate from 60 to 70 per cent, of lard oil with that of the olive. There is also an establishment in that city, which besides putting up hams, &c, is extensively engaged in extracting the grease from the rest of the hog. It has seven large circular tanks, six of capacity to hold each 15,000 lbs., and one 6,000 lbs. These receive the entire carcass with the exception of the hams, and the mass is subjected to the steam process, under a pressure of 70 lbs. to the square inch, the effect of which operation is to reduce the whole to one consistence, and every bone to powder. The fat is drawn off by cocks, and the residuum, a mere earthy substance, is taken away for manure. Besides the hogs which reach this factory in entire carcasses, the great mass of heads, ribs, back bones, tail- pieces, feet, and other trimmings of the hoes cut up at different pork-houses, are subjected to the same process, in order to extract every particle of grease. This concern only is expected to turn out this season, 3,000,000 lbs. of lard, five-sixths of which is No. 1. Six hundred hogs daily pass through these tanks, one day with another. The stearine expressed from the lard is used to make candles for being sub- jected to hydraulic pressure, by which three-eighths of it are discharged as an impure oleine ; this last is employed in the manufacture of soap. 3,000,000 lbs. of stearine have been made in one year into candles and soap in these factories, lea] CYCLOPEDIA OF THE USEFUL ARTS. 30 J and they can make 6,000 lbs. of candles per average day throughout the year. LARD OIL. This year (1851) there are 40 manufacturies of lard oil in Cin- cinnati, large and small, which consume on an average the year round 1000 pack- ages, of 300 lbs. each, per week, which is equal to 52,000 packages, or 15,600,000 lbs. per annum — from this there is to be deducted one third for stearine, equal to 5,120,000 lbs., leaving for the oil 10,480,000 lbs., which is equal to 1,310,000 gallons, allowing 8 lbs. to the gallon. Only a few years back the manufacture of lard oil was looked on as nothing, now it occu- pies a very prominent position, and has annually a "great influence upon the value of the hog. Lard oil may now be said to have taken the place of all other oils for all purposes at the West. Its manufac- ture has improved, and will continue until it is quite equal to anyother oil. As an application to machinery it is found quite equal to any other oil, on which account, added to its value for lighting purposes, its consumption is increasing in the Southern and Western States. Every town, of any size, when lard can be had, has its factory, as a ready sale is always found for the stearine. Lard, when pressed, yields more oil and less stearine in summer, and less oil and more stearine in winter. The oil is dearer in winter. The manufacture of lard oil is carried on mostly in Cincinnati, the country in every side drawing on it as a centre. Its manu- facture is as profitable as any other busi- ness of the same capital, its basis being cash. Many of the factories have now temporarily ceased working owing to the present high price of lard, and lard-oil in consequence, has risen from 50 cents up to 90 cents per gallon. (See Oils.) LATH-MAKING MACHINE. Mr. William Merrill, of Northampton, Por- tage Co., Ohio, has made some excellent improvements on machinery for making laths, for which he has taken measures to secure a patent. The machine makes the laths out of the slabs of logs. It has a circular saw which slits the lath out of a slab as it is fed in, and it has a revolving knife on the saw spindle, which turns the edge of the lath after the saw has cut it. The slab is carried forward the whole length, allowing the saw to cut a lath the whole length, when a projection on the saw frame" takes the slab," turns it over on revolving rollers, which bring it back to the person to feed it in, who stands at the end of the frame, and merely feeds in the slabs to the slitting saw. This machine has a register to it, which rings a bell when a hundred laths are finished, to tell the operator that a bunch is ready for binding, so that no counting is required for that purpose. LAYERS. In gardening, a mode of propagating plants by laying down shoots, and covering a portion of them with soil, so that the extremity of the shoot is left above ground, and the shoot itself not detached from the plant. In order to facilitate the rooting of such layers, the portion of the shoot buried in the soil is fractured by twisting or bruis- ing, or cut with a knife immediately under a bud. This operation, by ob- structing the return of the sap from the leaves, occasions its accumulation at tb* wounded part, when roots are there pro- duced from the effort of nature to perpet- uate life. LAYING. In architecture, the first coat on lath of plasterer's two-coat work, the surface whereof is roughed by sweep- ing it with a broom ; the difference be- tween laying and rendering being that the latter is the first coat upon brick. LEAD. This is one of the metals most anciently known, being mentioned in the books of Moses. It has a gray-blue color, with a bright metallic lustre when newly cut, but it becomes soon tarnished and earthy-looking in the air. Its texture is close, without perceptible cleavage or ap- pearance of structure ; the specific gravity of common lead is 11*352 ; but of the pure metal, from 11-38 to 11*44. It is very- malleable and ductile, but soft and desti- tute of elasticity ; fusible at 612° Fahr., by Crighton, at 634° by Kupfer, and crys- tallizable on cooling, into octahedrons im- planted into each other so as to form ar assemblage of four-sided pyramids. There are four oxides of lead. 1 The suboxide, of a grayish-blue coloi, which forms. a kind of crust upon a plate of lead long exposed to the air. It is procured in a perfect state by calcining oxalate of lead in a retort; the dark gray powder which remains, is the pure sub- oxide. 2. The protoxide is obtained by exposiug melted lead to the atmosphere, or, more readily, by expelling the acid from the nitrate of lead by heat in a plati- num crucible. It is yellow, and was at one time prepared as' a pigment by cal- cining lead, but is now superseded by the chromate of this metal. Litharge is mere- ly this oxide in the form of small spangles, from having undergone fusion ; it is more or less contaminated with iron, copper, and sometimes a little silver. It contains 302 CYCLOPEDIA OF THE USEFUL ARTS. [lea likewise some carbonic acid. The above oxide consists of 104 of metal, and 8 of oxygen — its prime equivalent being 112, upon the hydrogen scale; and it is the base of all the salts of lead. 3. The plum- beous suroxide of Berzelius, the sesqui- oxide of some British chemists, is the well-known pigment called red lead or minium. It consists of 100 parts of metal and 10 of oxygen. 4. The plumbic sur- oxide of Berzelius, or the peroxide of the British chemists, is obtained by putting red lead in chlorine water, or in dilute nitric acid. It is of a dark brown, almost black color, which gives out oxygen when heated, and becomes yellow oxide. It kindles sulphur when triturated with it. This oxide is used by the analytical che- mist to separate, by condensation, the sulphurous acid existing in a gaseous mixture. Among the ores of lead some have a metallic aspect; are black in substance, as well as when pulverized; others have a stony appearance, and are variously colored, with usually a vitreous or greasy lustre. The specific gravity of the latter ores is always less than 5. The whole of them, excepting the chloride, become more or less speedily black, with sul- phureted hydrogen or with hydrosul- phurets; and are easily reduced to the metallic state upon charcoal, with a flux of carbonate of soda, after they have been properly roasted. They diffuse a whitish or yellowish powder over the charcoal, which, according to the manner in which the flame of the blowpipe is directed upon it, becomes yellow or red ; thus in- dicating the two characteristic colors of the oxides of lead. The lead ores most interesting to the arts are: — 1. Galena, sulphuret of lead (See Ga- lena.) This ore has the metallic lustre of lead with a crystalline structure deriv- able from the cube. When heated cau- tiously at the blowpipe it is decomposed, the sulphur flies off, and the lead is left alone in fusion ; but if the heat be con- tinued, the colored surface of the char- coal indicates the conversion of the lead into its oxides. Galena is a compound of lead and sulphur, in equivalent propor- tions, and therefore consists, in 100 parts, of 865 of metal, and 13J of sulphur, with which numbers the analysis ot the galena of Clausthal by Westrumb exactly agrees. Its specific gravity, when pure, is 7*56. Its color is blackish gray, without any shade of red, and its powder is black, characters which distinguish it from blende or sulphuret of zinc. Its structure in mass is lamellar, passing sometimes into the fibrous or granular, and even compact. It is brittle. The specular galena, so called from its brightly polish- ed aspect, is remarkable for forming the slicken&ides of Derbyshire — thin seams, which explode with a loud noise when accidentally scratched in the mine. The argentiferous galena has in general all the external characters of pure galena. The proportions of silver vary from one- fifth part of the whole, as at'Tarnowitz, in Silesia, to three parts in ten thousand, as in the ore called by the German miners Weisgultigerz ; but it must be observed, that whenever this lead ore contains above 5 per cent, of silver, several other metals are associated with it. The mean pro- portion of silver in galena, or that which makes it be considered practically as an argentiferous ore, because the silver may be profitably extracted, is about two parts in the thousand. (See Silver.) The above rich silver ores were first observed in the Freyberg mines, called Himmels- furst and Beschertglnck, combined with sulphuret of antimony ; but they have been noticed since in the Hartz, in Mex- ico, and several other places. It is the most abundant lead ore in the United States, occupying an immense tract of country on the Missouri River. The antimonial galena (Bournonite) exhales at the blowpipe the odor peculiar to antimony, and coats the charcoal with a powder partly white and partly red. It usually contains some arsenic. 2. The Seleniuret of lead resembles galena, but its tint is bluer. At the blow- pipe it exhales a very perceptible smell of putrid radishes. Nitric acid liberates the selenium. When heated in a tube, oxide of selenium of a carmine red rises along with selenic acid, white and deliquescent. The specific gravity of this ore varies from 6-8 to 7-69. 3. Native minium or red lead has an earthy aspect, of a lively and nearly pure red color, but sometimes inclining to orange. It occurs pulverulent, and also compact, with a fracture somewhat la- mellar. When heated at the blowpipe upon charcoal, it is readily reduced to metallic lead. Its specific gravity varies from 4-6 to 8*9. This ore is rare. 4. White lead, carbonate of lead. — This ore, in its purest state, is colorless and transparent like glass, with an adaman- tine lustre. It may be recognized by the following characters :— Its specific gravity is from 6 to 6*7 ; lea] CYCLOPEDIA OF THE USEFUL ARTS. it dissolves with more or less ease, and with effervescence, in nitric acid; be- comes immediately black by the action of sulphureted hydrogen, and melts on charcoal before the blowpipe into a button of lead. According toKlaproth, the car- bonate of Leadhills contains 82 parts of oxide of lead, and 16 of carbonic acid, in 98 parts. This mineral is tender, scarcely scratches calc-spar, and breaks easily with a waved conchoidal fracture. It possesses the double refracting property m a very high degree ; the double image being very visible on looking through the Sat faces of the prismatic crystals. Its crystalline forms are very numerous, and are referrible to the octahedron, and the pyramidal prism. This ore has been found very sparingly in the United States. 5. Vitreous lead, or sulphate of lead. — This mineral closely resembles carbonate of lead ; so that the external characters are inadequate to distinguish the two. But the following are sufficient. When fmre, it has the same transparency and ustre. It does not effervesce with nitric acid ; it is but feebly blackened by sul- phureted hydrogen ; it first decrepitates and then melts before the blowpipe into a transparent glass, which becomes milky as it cools. By the combined action of heat and charcoal, it passes first into a red pulverulent oxide, and then into metallic lead. It consists, according to Klaproth, of 71 oxide of lead, 25 sulphuric acid, 2 water, and 1 iron. That specimen was from Anglesea; the Wanlockhead mineral is free from iron. The prevailing form of crystallization is the rectangular octahedron, whose angles and edges are variously modified. The sulphato-car- bonate, and sulphato-tricarbonate of lead, now called Leadhillite, are rare min- erals which belong to this head. 6. Phosphate of lead.— This, like all the combinations of lead with an acid, ex- hibits no metallic lustre, but a variety of colors. Before the blowpipe upon char- coal, it melts into a globule externally crystalline, which, by a continuance of the heat, with the addition of iron and boracic acid, affords metallic lead. Its constituents are 80 oxide of lead, 18 phosphoric acid, and 1*6 muriatic acid, according to Klaproth's analysis of the mineral from Wanlockhead. The con- stant presence of muriatic acid in the various specimens examined is a remark- able circumstance. The crystalline forms are derived from an obtuse rhomboid. Thosphate of lead is a little harder than white lead ; it is easily scratched, and its powder is always gray. Its specific gra- vity is 6-9. It has a vitreous lustre, some- what adamantine. Its lamellar texture is not very distinct ; its fracture is wavy, and it is easily frangible. The phos- phoric and arsenic acids being, according to M. Mitscherlich, isomorphous bodies, may replace each other in chemical com- binations in every proportion, so that the phosphate of lead may include any pro- portion, from the smallest fraction of arsenic acid to the smallest fraction of phosphoric acid, thus graduating inde- finitely into arseniate of lead. The yel- lowish variety indicates, for the most part, the presence of arsenic acid. This ore occurs at the lead mine near Frey- burg, in Maine. It is also found in Tennessee. 7. Muriate of lead. Horn-lead, or murio-carbonate. — This ore has a pale yellow color, is reducible to metallic lead by the agency of soda, and is not altered by the hydrosnlphurets. At the blow- pipe it melts first into a pale yellow trans- parent globule, with salt of phosphorus and oxide of copper; and it manifests the presence of muriatic acid by a bluish flame. It is fragile, tender, softer than carbonate of lead, and is sometimes almost colorless, with an adamantine lustre. Spec, grav., 606. Its constituents, ac- cording to Berzelius, are lead, 25-84; oxide of lead, 57-07 ; carbonate of lead, 6-25; chlorine, 8-84. silica, 1-46; water, 0-54 ; in 100 parts. The carbonate is an accidental ingredient, not being in equiv- alent proportion. Klaproth found chlo- rine, 13-67; lead, 39-98; oxide of lead, 22-57 ; carbonate of lead, 23-78. 8. Arseniate. of lead. — Its color of a pretty pure yellow, bordering slightly on the greenish, and its property of exhaling by the joint action of fire and charcoal a very distinct arsenical odor, are the only characters which distinguish this ore from the phosphate of lead. The form of the arseniate of lead, when it is crystal- lized, is a prism with six faces, of the same dimensions as that of phosphate of lead. When pure, it is reducible upon charcoal, before the blowpipe, into metallic lead, with the copious exhala- tion of arsenical fumes. Its spec, prrav. is 5-05. It consists of oxide of lead, 77*5 ; arsenic acid, 12-5; phosphoric acid, 7-5; hydrochloric acid, 1*5. 9. Molyhate of lead,, or yeUotv lead, is found at Southampton, Mass. It occurs in obtuse octohedrons and tabular crys- tab. Spec. grav. 5-05. It consists of 304 CYCLOPEDIA OF THE USEFUL ARTS. [lea 58-4 oxide of lead, 38 rnolybdic acid, and 2*08 oxide of iron. The foregoing are the most common ores of lead, all of which, except the chro- mate and molybdate, are used to procure metallic lead. It is, however, from the sulphuret (galena) that the great bulk of the lead of commerce is obtained. Under the article Metallurgy the treatment of lead ores is noticed, and it may therefore be here merely stated that the chief object to attain, after having procured a clean ore, is to get rid of the sulphur — which may be accomplished either by roasting in the open air or in reverberating furna- ces. In this way the sulphur is volatiliz- ed, and the lead, either as oxide or re- duced to the state of metal, runs into the basin or crucible of the furnace when it is deoxidized by being kept in contact with ignited charcoal. In Germany and France another mode is adopted, which consists in throwing into the reverberat- ing furnace 28 per cent, of old iron. In a short time the sulphur leaves the lead and passes over to the iron, and the lead is in the state of pure metal in the bot- tom of the furnace. This plan saves time and labor, but the iron is lost. Its value, however, is trifling. The uses of lead and its oxides are very numerous : the latter as paints, chiefly, and the former in roofing, and as gutters, cisterns, and pipes. For these this me- tal has many advantages ; it is soft and malleable, so that two edges may be fold- ed over and hammered water-tight with- out soldering ; this prevents rupture from expansion, which uften occurs in solder- ed vessels. As a means of carrying wa- ter it is in constant use, though liable to many objections. The metal, when pure, is perfectly insoluble in water, but the oxide and carbonate of lead are soluble in water containing an excess of carbonic acid. When water runs through a lead pipe it oxidizes it in a very short time, forming a white or yellow crust on the inside. This dissolves to a small extent in the water, and this latter, when drank, produces all the symptoms of poisoning by lead. On this account, lead pipes have been superseded by iron, zinc, gutta per- cha, and glass pipes. Dr. Christison has shown, that the purer the water, that is the more pure it is from saline matters, the greater is the corrosion of the pipe and the amount of lead dissolved : but that if the water contain much saline mat- ter, especially sulphates, the lead is pre- cipitated out of the water and no injury can arise. He recommended that new I leaden pipes should be plugged up for a I few days with a solution ol sulphate of I soda or phosphate of soda until the whole ! inside of the pipe was coated with a crust | of sulphate or phosphate of lead, which j effectually protects the pipe from any ! further action. If this cannot be conve- : niently done, a zinc cistern may be used j to receive the water which has flowed I through the pipe : after having lain a few | hours, the lead present in the water will ! be thrown down as a dark powder on the j surface of the zinc. Should this plan not be adopted, the water should be allowed to run freely through the pipes for *wo days before it be applied to any domei tic purpose. Vessels of lead should never be used for culinary or dairy purposes. Lead is used for making shot and solder. It forms an imperfect alloy with copper. The common brass cocks is an alloy of these two metals. The union is, how- ever, so partial, that on heating the cock the lead melts out and leaves the copper. This process is called liquation. The nitrate of lead is made by heating the me- tal with warm nitric acid, — a crude and weak solution of this salt of lead, consti- tuted the disinfecting liquid of Ledoyen & Calvert, which has been so preposter- ously overrated. It is capable of decom- posing animal sulphurets, phosphurets, and hence of removing the unpleasant smells of drains and water-closets, but beyond this action it has hardly any, and it is quite incapable of breaking up and rendering innocuous a miasm in the way in which chlorine does. Calvert fell a victim to his trials of this solution in the Fever Hospitals in Canada. Lead constituted the writing-table of the ancient Greeks and Eomans. When metallic lead is strongly heated in the reverberatory furnace it beomes of a dull color on the surface, loses its me- tallic appearance, and puts on the appear- ance ot a dross or powder. When this dross is heated to a low ignition, it be- comes of a dull yellow color, and is called common massicot ; and, by a higher heat and longer exposure to the air, it as- sumes a deeper yellow, and is then called massicot. This is the protoxide of lead. and consists, in 112 parts, of 104 lead and 8 oxygen. When it contains about four per cent, of carbonic acid 2 it is called li- tharge. It unites with acids, and is the base of all the salts of lead. If the pro- toxide, or metallic lead, be subjected, during 48 hours, to the heat of a rever- j beratory furnace, it passes to the condi- I tion of red oxide, or what is commonly lea] CYCLOPEDIA OF THE USEFUL ARTS. 305 called minium, or red lead. Its composi- tion is, in 116 parte, 104 lead, 12 oxygen. Lead forms a compound with chlorine. The union is effected by adding muriatic acid, or a solution of common salt, to the acetate or nitrate of lead dissolved in wa- ter. This chloride fuses at a temperature below redness, and forms, as it cools, a semi-transparent horny mass, sometimes called horn lead. The pigment called mineral, or patent yellow, is a compound of the chloride and protoxide of lead. It is prepared for the purposes of the arts by the action of moistened sea-salt on litharge, by which means a portion of the protoxide is con- verted into chloride. White-lead, or carbonate of lead, is prepared by exposing narrow slips, or thin lead, to the steam of vinegar, in a close vessel. The slips are laid on bars of wire above the surface of the boiling vinegar. For flake-white, dilute sulphu- ric acid is preferred. There is, (says Thomson.) only one direct poison among the salts of lead, which is the carbonate ; and, when the other salts of lead display poisonous ef- fects, these are to be attributed either wholly, or in part, to their conversion into the carbonate. This salt acts as a powerful sedative astringent on the liv- ing system, diminishing the nervous en- ergy, and, consequently, greatly depress- ing the powers of the circulation, and lowering the tone of the muscular system. It is probably taken into the blood, which may account for its slow operation when it is introduced into the stomach in mi- nute doses, for a considerable length of time, and also for its producing similar effects, when applied to the surface of the body denuded of the cuticle, or in a state of ulceration. Great mischief has been produced by the use of lead in dairies. If the milk runs into the slightest acidity, some lead will be dissolved, and injurious conse- quences will follow if it is taken into the stomach. Lead in Wines is detected by a black precipitate, which will be instantly pro- duced by the following mixture : — Ex- pose equal parts of sulphur and powder- ed oyster-shells to a white heat for a quarter of an hour. When cold, add an equal quantity of cream of tartar, and boil them with water in a strong bottle for an hour. Transfer to ounce phials, and add to each 20 drops of muriatic acid. To reduce Red Lead. Heat in a Hessian crucible 2 oz. of red lead with 2 drs. of powdered charcoal, and 1 oz. of common salt. The result will be 2 oz. of pure me- tal. When nitrate of lead or of bismuth is boiled with carbonate of lime, magnesia, or barytes, these salts are decomposed, and the oxides are so completely precipi- tated that hydrosulphuret of ammonia shows no traces of them in the solution. Carbonate of lime, when added to a cold solution of these metals, precipitates only the oxide of bismuth. Several methods have been proposed for separating the lead which is contained in the bismuth of commerce ; but carbonate of lime is pre- ferable. LEAD, BLACiv, See Plumbago. LEAD, eok Sounding. The common hand lead weighs 11 lbs. with about 20 fathoms of line. The leadsman stands somewhere on the side of the vessel, leaning against a band for the purpose : lets the lead descend near the water ; then, swinging it over his head once, or twice, if the ship is going fast, throws it forward. The line is marked at 5, 7, 10, 13, 17, and 20 fathoms. The numbers between are called deeps ; thus, u by the mark 7," " by the deep nine," indicates 7 and 9 fathoms. When the depth is great, the deep-sea lead of 28 lbs. is used. The lead is drop- J>ed from the fore part of the vessel, the ine being passed outside all. It is ge- nerally necessary to heave the ship to. LEAD-SHOT. The origin of most of the imperfections in the manufacture of lead-shot is the too rapid cooling of the spherules by their being dropped too hot into the water, whereby their surfaces form a solid crust, while*their interior re- mains fluid ; and, in its subsequent con- cretion, shrinks, so as to produce the ir- regularities of the shot. The patent shot towers obviate this evil, by exposing the fused spherules after they pass through the cullender, to a large body of air during their descent into the water tub placed on the ground. The greatest erection of this kind is pro- bably at Villach, in Carinthia, being 240 Vienna, or 249 English feet high. The quantity of arsenic added to the mass of melted lead, varies according to the quality of this metal ; the harder and less ductile the lead is, the more arsenic must be added. About 3 pounds of either white arsenic or orpiment is enough for one thousand parts of soft lead, and about 306 CYCLOPEDIA OF THE USEFUL ARTS. [leq 8 for the coarser kinds. The latter are employed preferably for shot, as they are cheaper and answer sufficiently well. The arsenical alloy is made either by in- troducing some of this substance at each melting, or by making a quantity of the compound considerably stronger at once, and adding a certain portion of this to each charge of lead. If the particles of the shot appear lens-shaped, it is a proof that the proportion of arsenic has been too great ; but if they are flattened upon one side, if they are hollowed in their middle, called cupping by the workman, or drag with a tail behind them, the pro- portion of arsenic is too small. The following is the process prescribed by the patentees, Ackerman and Martin. Melt a ton of soft lead, and sprinkle round its sides, in the iron pot, about two shovelfuls full of wood ashes, taking care to leave the centre clear ; then put into the middle about 40 pounds of arsenic, to form a rich alloy with the lead. Cover the pot with an iron lid, and lute the joints quickly with loam or mortar, to confine the arsenical vapors, keeping up a mode- rate fire to maintain the mixture fluid for three or four hours ; after which skim carefully, and run the alloy into moulds to form ingots or pigs. The composition thus made" is to be put in the proportion of one pis: or ingot into 1000 pounds of melted ordinary lead. When the whole is well combined, take a perforated skim- mer and let a few drops of it fall from some height into a tub of water. If they do not appear globular, some more arseni- cal alloy must be added. Lead which contains a good deal of pewter or tin must be rejected, because it tends to produce elongated drops or tails. LE ATH ER . See Tanning. LEATHER (Varnished French, man- ufacture of). This process consists of two operations : — First, the preparation of the skin, described under the_ head Tanning ; and, second, the varnishing of the leather thus dressed. In the prepa- ration of the leather, linseed oil, made to dry quick by means of metallic oxides and salt, is employed as the basis. For each twenty-two gallons of linseed oil, twenty- two lbs. of white lead and twenty-two lbs. of litharge are employed, and the oil boil- ed with those ingredients until it has at- tained the consistency of syrup. This preparation, mixed either with chalk, or ochres, is applied to leather by means of appropriate tools, and well worked into the pores ; three or four layers are applied in succession, taking care to dry each layer thoroughly before the application of the next coating. Four or five coatings of the dried linseed oil, without the admixture of the earthy substances, are then given ; the addition of very fine ivory black and some oil of turpentine is usually made to the oil. These coatings are put on very thin, and when carefully dried the leather is rubbed over with fine pumice stone powder to render the surface perfectly smooth and even, for the reception of the varnish. The varnish is composed as follows: — Ten lbs. of oil prepared as above, half a lb. of asphalt or Jewish bitu- men, five lbs. of copal varnish, and ten lbs. of turpentine. The oil and asphalt are first boiled together, the copal var- nish and turpentine added afterward, and the mixture well stirred. Instead of as- Ehalt, Prusian blue or Ivory black may e employed. This varnish must be kept in a warm place for two or three weeks before it is fit for use. The greatest pos- sible care must be taken both before and during the application of the varnish to ?>revent the adherence of any dust to the eather. The leather, when varnished, must be put into drying stoves, heated to about 200 degrees or more, according to the nature of the leather and the varnish employed. LEECH, ARTIFICIAL. Dr. Charles Rodgers, of Jefferson, Wisconsin, has in- vented a most ingenious little instrument as a substitute for the common cupping process, and as an artificial leech. In the first place the inflamed part of the patient, or on whatever part on which it is de- signed to operate, is perforated in one or more places by a lancet, impelled in a tube by blowing it like a Guinea arrow with the mouth. The artificial leech consists of a glass tube, which is set upon the wound, and by a small metal tube at the other end, all the air is exhausted, when the blood, &c, rises in the vacuum, and communication is then cut off from the atmosphere by an ingenious slide valve, which stops the mouth of the small me- tal tube. This invention is a neat im- provement in the art of surgery. Mea- sures have been taken to secure a patent. It appears to be similar to the artificial leech of Alexander, in London. LEGHORN HATS. It is chiefly in the neighborhood of Florence, Pisa, the district of Sienna, and in the upper part of the valley of the Arno, that the best platting is made for straw hats. The straw len] CYCLOPEDIA OF THE USEFUL ARTS. 307 used in working these hats is grown in districts mountainous and sterile. It is produced from a kind of wheat, of which the grain is very small. This straw, though slender, has nrnch consistence, and the upper part of the stalk being per- fectly hollow, is easily dried. It is pulled out of the earth before the grain begins to form. After being freed from the soil, which adheres to the root, it is form- ed into small sheaves, to be winnowed ; the part above the last joint of the stem is then plucked off, which is from four to six inches long, the ear remaining attach- ed to it. This being done, it is bleached by the dew and the sunshine. Eain is very injurious to it, and destroys much of its whiteness. The lower parts of the straw are treated in the same manner, and employed in forming hats of an inferior quality. The upper parts, torn off just to the knot, are sorted according to their degree of fineness. This stapling is made with much care, and usually affords straw of three different prices. A quantity of straw, worth 8 cents, after having under- gone this process, is sold for $1*25. The tress is formed of seven or nine straws, which are begun at the lower end, and are consumed, in platting, to within an inch and a half of the upper extremity, includ- ing the ear. All the ends of the straws that have been consumed are left out, so that, the ears are on the other side of the tress. As fast as it is worked, it is rolled on a cy- linder of wood. When it is finished, the projecting ends and ears are cut off; it is then passed with force between the hand and a piece of wood, cut with a sharp edge, to press and polish it. The tresses thus prepared are so used that a complete hat shall be formed of one piece. They are sewed together with raw silk. The diameter of the hat is in general the same ; the only difference consists in the degree of fineness, anu, consequently, the num- ber of turns which the tress has made in completing the hat ; some having from twenty to eighty such turns. LEMON (Citrus). One species of the genus, of which orange is another. The outer rind contains a fragrant oil. The juice is a very refreshing modification of citric acid with mucilage, sugar, and water. The trees produce thousands of the fruit. To keep, the juice is crystal- lized, and. when wanted, dissolved in any liquid. The essential oil is produced by distillation with water and alcohol. Lemon Drops. Mix £ lb. of sugar with 3 drs. of salt of sorrel in a little water, boil, add i lb. more sugar, and 8 drops of essence of lemon ; or, (tartaric acid, and citric acid, for the sorrel-salt, and le- mon) ; then with a crooked wire draw it out in drops on a slab. Lemonade Powders. Mix, and divide into 24 parts, 6 oz. of sugar, 10 drops of essence of lemon, and 1 oz. of tartaric acid. LENS. In Optics, a thin piece of glass or any other transparent substance, bounded on both sides by polished spher- ical surfaces, or on the one side W a spherical and on the other by a plain surface ; and having this property, that parallel rays of light, in passing through it, have their direction changed, so as to converge to a given point, called the principal focus of the lens, or to diverge as if they proceeded from that point. Lenses are, in fact, mere multiplying- glasses, with an infinite number of sides, producing an infinite number of images, whose visual resultant is one blended fig- ure, expanded over the whole visual angle of the glass, in length and in breadth, and therefore said to be magnified. The images produced by the inclined or ob- lique sides, owing to unequal refractions, are however highly-colored in the focus ; and, owing to the unequal inclinations of the spherical form, the rays do not all converge exactly to the same point. Len- ses have therefore been very properly com- posed of two kinds of glass, which re- fract differently or unequally, and then, by combining a convex and a concave, the inequality is destroyed, and the im- age free from color. The forms too have been varied from the spherical to the parabolic, with a view to concentrate the rays in one point. Lenses are manufac- tured w r ith great precision, by steam power, by Jenkins's machine, fixed in concave basins, and the friction proceeds on some hundreds at the same time. A spherical lens, shown at A, is a sphere or globule of glass. Lenses receive different denominations, according to their different forms. A double convex lens, shown at B, is a solid formed by two convex spherical sur- faces ; and is equally convex or unequally convex, according as the radii of ABC it3 two surfaces are equal or une- M qual. A plano-convex lens, C, is that of which one of the surfaces is plane and tho other convex. A double concave lens, D, is bounded by two concave spherical surfaces, which 308 CYCLOPEDIA OF THE USEFUL ARTS. [lev have either the same or a different cur- vature. *-;.•■'<«.•:-•" a A plano-con- cave lens, E, N has one sur- face plane, and the other con- cave. A meniscus, F (so called from its re- semblance to a little moon,) is a lens of which one of the surfaces is convex and the other concave, and which meet if con- tinued. The radius of the convex sur- face is consequently smaller than the radius of the concavo. A concavo-convex l-ens, G, is that of which one of the surfaces is concave and the other convex ; but in this case the surfaces will not meet though continued, the radius of the concave surface being smaller than that of the convex one. The straight line M N which passes through the centres of all the curved sur- faces, or is perpendicular to both surfaces of the same lens, is called the axis of the lens ; and it is in this line that the focus of the lens is situated. It was observed, at an early period, that a transparent body of a spherical form has the property of collecting at the focus the parallel rays of light which fali on its surface. But it was remarked, at the same time, that the illumination at these foci was extremely feeble, in consequence of the thickness of the glass which the light had to pass through. This incon- venience is removed by taking only two small segments instead of the entire sphere ; by which means, as the refrac- tion takes place only at the surfaces, and not in the interior of the glass, the very same refraction of the rays is produced as when the whole sphere is used ; and the thickness of the glass being greatly diminished, the rays pass through it in much greater number, and the intensity of the light in the focus is much more considerable. The rules for finding the focal distances of the different sorts of lenses are the following. They depend in some meas- ure on the refracting power of the glass. We shall here suppose the index of re- fraction to be 1 -500. Lenses of great power and correct form are made in this country. LEVEL. An instrument which shows the direction of a straight line parallel to the plane of the horizon. The plane of the sensible horizon is indicated in two ways : by the direction of the plummet or plumb-line, to which it is perpendicular ; and by the surface of a fluid at rest. Accordingly, levels are formed either by means of the plumb- line, or by the agency of a fluid applied in some particular manner. They all de- pend upon the same principle, namely, the action of terrestrial gravity. Levels in which the plumb-line forms the essential part are those most usually employed for the common purposes re- quired by bricklayers, masons, carpen- ters, &c. They are constructed under many different forms, but the general principle is as follows : A frame or board is prepared, having one edge perfectly straight, and a straight line is drawn on the frame at right angles to the straight edge. To some point of this straight line a thread canning a plummet is at- tached • consequently, when the frame is placed in such a position that the thread of the plummet, hanging freely, coincides with the straight line, the straight edge of the frame, which is perpendicular to it, must be horizontal. See Plummet. The Artillery Foot Level, and the Ghin- ner"s Level, besides the line and plum- met, have a scale for showing the incli- nation of a straight line to the horizon. The former has two equal legs or branches placed at right angles ; and from their point of junc- tion a thread and plummet hangs, and plays over a quadrant divided into twice 45° from the middle. The plane or line on which the two ends rest is horizontal when the thread falls over the zero point of the scale ; and when it falls over any other point, the degree marked on the scale indicates the incli- nation of the line to the horizon. The gunner's level is on the same principle, though differently constructed ; the thread or plummet being replaced by a solid piece of brass, loaded at the lower end, and the legs, or rather the edges, of the brass plate" making an angle of 45°. It is used in the same manner as the former. Spirit Level. — By far the most conven- ient and also the most accurate level is the spirit level, represented in the an- nexed figure; "which is nothing more than a glass tube nearly filled with a liquid (spirit of wine being now generally used, on ac- count of its mobility, and not being liable to freeze,) the bubble in which, when the lev] CYCLOPEDIA OF THE USEFUL ARTS. 309 tube is placed horizontally, would rest in- differently in any part it' the tube could be made mathematically straight ; but that being impossible to execute, and every tube having some slight curvature, if the convex side be placed upwards the bubble will occupy the higher part, as in the figure (where the curvature is pur- posely exaggerated.) The accuracy of the indications of the level depends in a considerable degree on the regularity of the interior surfaces of the tube. They are commonly made of glass tubes in the same state as they are obtained at the glass-house ; but when very great accuracy is required, as in as- tronomical observations, the interior sur- faces are sometimes ground so as to give them a regular cylindrical, or rather spindle form, with a slight spherical cur- vature. The tube and bubble must be of considerable length. The larger the bub- ble, the more freely it moves, and conse- quently, the more sensible is the level to a small inclination. With proper care they can be executed, it is said, with such delicacy as to indicate a single second of angular deviation from exact horizon- tal'ity. LEVEE. In Mechanics, an inflexible rod movable about afulcrvm or prop, and having forces applied to two or more points in it. The lever is one of the me- chanical powers ; and, being the simplest of them all, was the first that was attempt- ed to be explained. Its properties are treated of by Aristotle ; but the first ac- curate explanation was given by Archi- medes, in his Treatise De Equiponderanti- bus. In treating of the lever, it is convenient to distinguish the forces applied to it by different names. One is usually called the power, the other the weight or resistance. Fig. 1. Fig. 2. rT VQ woT 3 Levers are commonly divided into three kinds, according to the relative positions of the power, the weight, and the fulcrum. In a lever of the first kind (fig. 1), the fulcrum F is between the power P and the weight W. In a lever of the second kind, Fig. 3 Fig. 4. jL (fig. 2), the weight W is between the ful- crum F and the power P. In a lever of the third kind (fig. 3), the power P is be- tween the fulcrum F and the weight W. The general principle of the lever is, that when the power and weight are in equilibrio, they are to each other inverse- ly as their distances from the fulcrum. This property is almost an obvious conse- quence from the principle of virtual ve- locities ; but it may be deduced from more familiar considerations. Let A B be a cylinder or bar of homogeneous matter. If supported from the middle O, the two ends would evidently balance each other, and the pressure at O would be the same as if the whole matter of the bar were con- centrated in that point. Suppose it to consist of two parts, A C and B 0, these again would be separately supported at their middle points D and E ; or the whole of the matter in A C may be con- ceived to be concentrated at D, and the whole of that in B C at E, and the equili- brium would not be disturbed. Hence the weight of A C attached at D, and the weight of B C attached at E, would bal- ance the inflexible line D E, if supported at O, the centre of the whole bar A B. But O D=A O— A D=i A B-4 A C=i B ; and O E=0 B— E B=i A B— i C B =£ A C ; consequently, O D is to E as B C to A C ; or O D is to E as the weight concentrated at E to the weight concentrated at D. This demonstration is commonly ascribed to Archimedes. This proposition shows the advantage obtained by using the lever as a mechan- ical engine. The arm P F (fig. 1), is com- monly longer than W F, and, consequent- ly, when there is equilibrium the weight exceeds the power. The proportion in which the weight exceeds the power is called the mechanical advantage, or pur- chase. Suppose P F (figs. 1 and 2)=4 feet, and W F=l foot ; then a power of 1 lb. acting atP will overcome a resistance of 4 lbs. at W. Suppose the lever with the weights P and W to turn round the fulcrum, the two points to which P and W are attached will describe arcs proportional to the radii F P, F W ; consequently, the power P is to the weight W as the velocity of the weight to ~the velocity of the power. Therefore in this, as in all mechanical en- gines, when a small power raises a great weight, the velocity of the power is much greater than the velocity of the weight ; and what is gained in force is therefore said to be lost in time. When the power and the weight do not act on the lever in directions perpendicu- lar to its length, or when the arms of the 310 CYCLOPEDIA OF THE USEFUL ARTS. [lif lever are not in the same straight line, or are bent, then the power and the weight are not to each other reciprocally as the arms of the lever, but as the straight lines drawn from the fulcrum perpendicular to the respective directions in which the power and the weight take effect. LICHENS ; a family of plants, belong- ing to the class cryptogamia, containing about 1400 known species, are under sev- eral genera. Their substance is powdery, crustaceous, membranous, coriaceous, or even corneous. They are common every where, adhering to rocks, the trunks of trees, and barren soil. On .ascending mountains, they are found flourishing be- yond the limit of all other plants, even to the verge of perpetual snow. Many of them, fixing upon the hardest rocks, by retaining moisture, facilitate their decom- position and promote the formation of soil. Several of the species are used for sustenance in times of scarcity, by the in- habitants of the northern regions. Iceland moss is exceedingly abundant in the arctic regions, and often affords aliment to the inhabitants, either in the form of gruel or bread, which last is very nutritious. The taste is bitter, astringent, and extremely mucilaginous. It is fre- quently employed in pharmacy, in the composition of various pectoral lozenges and syrups, and is celebrated as an arti- cle of diet, in combination with milk, in coughs and pulmonary affections. Orchil {rocella tinctoHa) is also an im- portant article, though less used now than formerly, on account of the fugitiveness of the rich purple and rose-colored dyes which it yields. Some of its tints, how- ever, are capable of being fixed, and it is, besides, employed for staining marble, forming blue veins and spots. Several other lichens afford dyes of various colors, as litmus. Lichen, Liverwort, or Algse, are the stunted herbage of the arctic circle, and of barren heaths. In Iceland and Lap- land, it is eaten in broth and milk, and even made into bread, its bitterness be- ing removed by washing in hot waters. It contains much mucilage or gluten, and has been extensively used in pulmonary complaints, and as a demulcent, relieving cough, and correcting all acrid secretions. Lichen, Orchil, or Argol, alluded to above, is famous for its dye of purple, blue, violet, &c. It is mostly brought from the Canary Isles, and is there ground in a mill, mixed with pearl-ash and urine, and sold in cakes. It is used to heighten colors, but is very evanescent, except when used with a tin solution, which gives to it a per- manent red dve. LICK, or SALTLICK. A salt spring is called a lick in the Western States, from the^ circumstance that the earth about it, which is impregnated with saline parti- cles, is licked by the bison and the deer. Many of these licks appear to have exist- ed before the habitation of the earth by man, as the bones of the mastodon and other fossil animals are found abundantly in them. They appear to be situated in the upper secondary beds, and contain both iodine and bromine in combination dissolved in the water. The latter sub- stance is in such marked quantity as to make these springs the source of the bro- mine manufacture. LIFE-BOAT. A boat originally made at Shields, in 1789, by Mr. Greathead, for saving the crews of shipwrecked vessels. The following are the general principles : The boat is wide and shallow ; the head and stern are alike, for pulling in either direction, and raised, to meet the waves ; it pulls double-banked, the oars being fir, for lightness, and fitted with thole pins and grummets, and is steered with an oar. The boat is cased round inside, on the upper part, with cork, in order to se- cure her buoyancy with as many persons as she can carry, even though full of wa- ter; the cork likewise assists in main- taining, or, if overset, in recovering, the position of stable equilibrium. The boat is painted white, to be conspicuous in emerging from the hollow of the sea. It is a curious fact that the smugglers paint their boats white for the contrary reason, because dark-colored objects alone are discernible in dark nights. If a spheroid be divided into quarters, each quarter is elliptical, and resembles the half of a wooden bowl, having a cur- vature with -projecting ends. Such a ves- sel thrown into the sea cannot be upset, or lie with the bottom upwards, owing to the ends. The length is 30 feet, the breadth 10 feet ; the depth from the top of the gunwale to the lower part of the keel in midships, 3 feet 3 inches ; from the gunwale to the platform (within), 2 feet 4 inches ; from the top of the stems (both ends being similar) to the horizon- tal line of the bottom of the keel, 5 feet 9 inches. The keel is a plank of 3 inches thick, of a proportionate breadth in mid- ships, narrowing gradually towards the ends, to the breadth of the stems at the bottom, and forming a great convexity downwards. The stems are segments of a circle, with a considerable rake. The lif] CYCLOPEDIA OF THE USEFUL ARTS. 311 bottom section, to the floor-heads, is a curve fore and aft. with the sweep of the keel. The floor- timber has a small rise, curving from the keel to the floor-heads. A bilge-plank is wrought-in on each side, next the floor-heads, with a double-rab- bet groove, of a similar thickness with the keel ; and, on the outside of this, are fixed two bilge-trees, corresponding near- ly with the level of the keel. The ends of the bottom section form that fine kind of entrance observable in the lower part of the bow of the fishing-boat, called a cobble, much used in the north. From this part to the top of the stem it is more elliptical, forming a considerable projec- tion. The sides, from the floor-heads to the top of the gunwale, flaunch off on each side in proportion to above half the breadth of the floor. The breadth is con- tinued far forwards towards the ends, leaving a sufficient length of straight side at the top. The sheer is regular along the straight side, and more elevated to- wards the ends. The gunwale fixed to the outside is three inches thick. The sides, from the under part of the gunwale, along the whole length of the regular sheer, extending 21 feet 6 inches, are cased with layers of cork, to the depth of 16 inches downwards : and the thickness of this casing of cork being 4 inches, it projects at the top a little with- out the gunwale. The cork, on the out- side, is secured with thin plates or slips of copper, and the boat is fastened with copper nails. The thwarts, or seats, are five in number, double-banked; conse- quently, the boat may be rowed with 10 oars. The thwarts are firmly stanchion- ed. The side-oars are short, with iron tholes and rope grummets, so that the rower can pull either way. The boat is steered with an oar at each end ; and the steering-oar is one-third longer than the rowing-oar. The platform placed at the bottom, within the boat, is horizontal, the length of the midships, and elevated at the ends, for the convenience of the steersman, to give him a greater power with the oar. The internal part of the boat next the sides, from the under part of the thwarts down to the platform, is cased with cork ; the whole quantity of which, affixed to the life-boat, is nearly seven cwt. The cork contributes much to the buoyancy of the boat, and is a good defence in going alongside a vessel, and is of use in keeping the boat in an erect position in the sea, or rather for giving a very lively and quick disposition to reco- ver from any sudden cant or lurch, which she may receive from the stroke of a heavy wave. The boats, in general, of this descrip- tion, are painted white on the outside: this color being more conspicuoos when rising from a hollow of the sea. The bot- tom of the boat is varnished. The oars arc made of flr, of the best quality. In the management, she requires twelve men to work her, that is, five on each side, rowing double-banked, with an oar slung over an iron thole, with a grummet, so as to enable the rower to pull either way, and one man at each end to steer her, and to be ready at the opposite end to take the steer-oar, when wanted. The best method, if the direction will admit of it, is to head the sea. T li e steersman should keep his eye fixed upon the wave or breaker, and encourage the rowers not to give way, as the boat rises to it ; being then aided by the force of the oars, she launches over it with vast rapidity, with- out shipping any water. When a wreck is reached, if the wind blows to the land, the boat will come in shore, without any other effort than steering. Scheerboom & Co. have recently in- vented an apparatus for converting any boat or vessel into a life- boat, in cases of danger, and it is recommended by high authorities. Mr. Holbrook, of Hull, England, con- structed a life-boat, the hull of which is broad, and the framework composed of wrought iron covered with net. The body is divided into six compartments, containing bundles of floaters, perfectly air-tight, and separate from each other s'o that injury to one will not affect the rest. The peculiarity of the boat is, it has no bottom except a slight framework of cor- dage or netting, the object of the arrange- ment being to allow the water to rise within the boat to the level of that with- out, and so secure a permanent ballast of water which precludes the possibility of being capsized in a heavy sea. Thus the countervailing properties of buoyancy and steadiness are perfectly secured. The internal arrangements include means for carrying water, spirits, matches, wood, articles of wearing apparel, with appara- tus for boiling coffee and broiling meat. The boat also carries a reflecting lamp, fire balls, blue lights, rockets, 300 feet of line, a horn, and alarm bell, and is steered by means of an oar. This boat has been satisfactorily tested in severe weather. LIFE-BUOYS consist of two hollow copper cylinders, each as large as a pillow, and sufficient to support one man stand- 312 CYCLOPEDIA OF THE USEFUL ARTS. [' ing on them : they are connected to each other. Should more than one person re- quire support, they can lay hold of rope beckets fitted to the buoy, and so sustain themselves. Between the two copper vessels, there stands a hollow pole, or mast, into which is inserted, from below, an iron rod, whose lower extremity is loaded with lead, in such a manner that, when the buoy is let go, the iron sl?ps down to a certain extent, lengthens the lever, and enables the lead at the end to act as ballast. By this means the mast is kept upright, and the buoy prevented from upsetting. The weight at the end of the rod is arranged so as to afford se- cure footing for two persons, should that number reach it ; and there are, also, large rope beckets through which they can thrust their heads and shoulders, till assistance is rendered. At the top of the mast is fixed a port-fire calculated to burn about twenty minutes or half an hour ; this is ignited most ingeniously by the same process which lets the buoy fail into the water ; so that a man falling over- board at night is directed to the tiuoy by the blaze on the top of the mast. 'The person who has charge on board ship of the life-buoy sees it freshly primed every evening. In the morning the priming is taken out and the lock uncorked. LIFE-PRESERVERS. Apparatus used at sea in case of persons falling over- board. Mr. Scheffer, of England, in- vented a cylindrical tubular ring without seam or break ; it contains a stop cock and ivory pipe affixed ; by this air can be blown in by the mouth and retained by the stop cock. When not inflated it folds up into a very small compass, suita- ble for the pocket, and weighs only twelve ounces. An American invention of a similar character in the form of a straight cylin- der of a caoutchouc water-proof material. The simplest form is a rinsr of caoutchouc to go round the body under the arm-pits, previously blown up with air. LIGNIN. The woody fibre. This most important proximate principle of vegetables exhibits itself in a variety of forms, constituting the different textures of hard and soft wood : and various fibrous products, such as hemp, flax, cotton,