• ir r I r THE UNIVERSITY OF ILLINOIS LIBRARY G03 U»‘2d 187S PEEPACE. 5 tA- ip . Uke’s Dictionary of Arts, Manufactures, and Mines has long had the reputation of a standard authority upon the subjects of which it treats. But such is the inventive activity of the age, and the rapid improvement in art processes, that a work of this kind can only maintain its character by frequent and extensive additions. While the distinguished author was in the vigor of his intellect, the revisions of the work kept pace with the progress of improvement, but at his demise it was found necessary to organize a plan for bringing up the Dictionary to the present state of knowledge. Accordingly, Mr. Robert Hunt, a gentleman whose high scientific position gave warrant that the work would be well performed, assumed the editorship, and a corps of the ablest practical and scientific men in England was secured to prepare articles in their several depart- ments. The following remarks, condensed from the preface to the Eng- lish edition, will explain the purpose and plan of the editor. “ The objects which have been steadily kept in view are the follow- ing : To furnish a work of reference on all points connected with the sub- jects included in its design, which should be of the most reliable character. To give to the scientific student and the public the most exact details of those manufactures which involve the application of the discoveries of either physics or chemistry. To include so much of science as may render the philosophy of manufactures at once intelligible, and enable the technical man to appreciate the value of abstruse research. “ I commenced the new edition of lire’s Dictionary with an earnest determination to render the work as complete and as correct as it was possible for me to make it. In my necessities I have asked the aid ^ of the manufacturer, and the advice of the man of science, and never having been refused the aid solicited, I am led to hope that those who may pos- sess these volumes will find in them more practical knowledge than ex- ists in any work of a similar character.”. This volume of lire’s Dictionary contains the chief additions made to the late English edition. Those portions of the work which concerned mainly the English, their commercial and manufacturing resources and statistics, the least important historic notices, and some definitions in pure science, which seemed hardly embraced within the defined scope of the work, have been omitted. By this means the original and valuable contributions to the work have been brought within the limits of a single 585493 PREFACE. volume, which has lost nothing of its real value. This supplementary volume is rich with the latest results of inquiry, containing all the new and important matter and illustrations of the three English volumes costing |38, while the complete American edition of the work, in three volumes, comprising 3212 pages, with 2300 engravings, forms the com- pletest repertory of arts, manufactures, and mines, which has been yet published. Subjoined is a list of the contributors, whose initials will be found appended to their respective articles. JMr. Hunt avows the authorship of the rest. G. ANSELL, Esq., Royal Mint. H. K. BAMBER, Esq., F.C.S., &c. |e. W. BINNEY, Esq., F.G.S., &c., Manchester. Ih. W. bone. Esq. Euameller. HENRY W. BRISTOW, Esq., F.G.S. Geo- logical Survey of Great Britain. R. .1. COURTNEY, Esq. Superintendent of Messrs. Spottiswoode and Co.’s Printing office. JAMES DAFFORNE, Esq. Assistant Editor of the Art Journal. JOHN DARLINGTON, Esq. Mining Engi- neer. Author of Miner's Handbook. F. W. FAIRHOLT, Esq., F.R.A.S. Author of Costume in England., Dictionary of Terms in Art, &c. E. FRANKLAND, Esq., Pn.D., F.R.S., and C.S. Professor of Chemistry at St. Bartholo- mew’s Hospital, and Lecturer on Chemistry at the Royal Indian Military College, Addiscombe. ALFRED FRYER, Esq. Sugar Refiner, Man- chester. (T/ie late) T. H. HENRY, Esq., F.R.S. and C.S. R. HERRING, Esq. Author of History of Paper Manufacture. JAMES HIGGINS, Esq. Calico Printer, &c., Manchester. W. HERAPATH, Esq., M.D., &c. SAxMUEL HOCKING, Esq., C.E., Seville. RICHARD W. HUNT, Esq. Brewer, Leeds. T. B. JORDAN, Esq. Engineer, Inventor of Wood Carving Machinery. WILLIAM LINTON, Esq. Artist, Author of Ancient and Modern Colors. JAMES McADAM, Jun., Esq. Secretary of the Royal Society for the Cultivation of Flax in Ireland. (The late) HERBERT MACKWORTH, Esq., C.E., F.G.S. One of H. M. Inspectors of Coal Miners. HENRY MARLES, Esq., L.R.C.P. Author of English Grammar, Currying and Leather. DAVID MORRIS, Esq., of Manchester. Au- thor of Cottonopolis, &c. JAMES NAPIER, Esq.. F.C.S. Author of Manual of Dyeing, Electro-Metallurgy, An- cient Works in 3Ietal, &c. D. NAPIER, Esq., C.E., &c. A. NORMANDY, Esq., M.D., F.C.S. Author of Handbook of Commercial Chemistry. HENRY M. NOAD, Esq., Ph.D., F.R.S. Au- thor of A Manual of Electricity, &c. AUGST. B. NORTTICOTE, Esq. F.C.S. As- sistant Cheitiist, ITniver.Mty of Oxford. ROBERT OXLAND, Esq., F.C.S. One of the Authors of Metals and their Alloys. THOMAS JOHN PEARSALL, Esq., F.C.S. Secretary to London Mechanics’ Institution. SEPTIMUS PIESSE, Esq. Author of Treatise on Art of Perfumery, «&c. JOHN ARTHUR PHILLIPS, Esq. Graduate of the Imperial School of Mines, Paris, Author of Manual of Metallurgy. ANDREW CROMBIE RAMSAY, Esq., F.R.S. and G.S., Professor of Geology, Government School of Mines, Local Director of the Geologi- cal Survey of Great Britain. EBENEZER ROGERS, C.E., F.G.S. Late President of the South Wales Institute of En- gineers. CHARLES SANDERSON, Esq., Sheffield. Author of Papers on Steel and Iron. E. SCHUNCK, Esq., Ph.D., F.R.S., and C.S. R. ANGUS SMITH, Esq., Ph.D., F.R.S. Au- thor of various Papers on Air and Water, Life of Dalton, and History of Atomic Theory, &c. WARINGTON W. SMYTH, Esq., M. A., F.R.S. and G. S. Professor of Mining and Mineralogy, Government School of Mines, and Inspector of Crown Mines. THOMAS SOPWITH, Esq., C.E., F.R.S., and G.S. Author of Isometrical Drawing, &c. ROBERT DUNDAS THOMSON, Esq., M.D., F.R.S. Professor of Chemistry in St. Thomas’s Hospital College. ALFRED TYLOR, Esq., F.G.S. Author of Treatise on Metal Work. A. VOELCKER, Esq., Ph.D., F.C.S. Profes- sor of Chemistry, Agricultural College, Ciren- cester, and Consulting Chemist to the Royal Agricultural Society of England. CHARLES Y. WALKER, Esq., F.R.S., F.R.A.S. Engineer of Telegraphs and Time to the South Eastern Railway Company, Author of Electrotype Manipulation, Translator of Koemtz' Meteorology, Dela Riv^s Electricity, &c. » C. GREVILLE WILLIAMS, Esq. Author of A Handbook of Chemical Manipulation, &c. {The late) HENRY M. WITT, Esq., F.C.S. Assistant Chemist, Government School of Mines. With special assistance and information from the late Sir Wm. Reid, C.B., Governor of Malta ; Sir Wm. Armstrong, C.E., &c. ; Robert Mallet, Esq., C.E., F.R.S., &c. ; Captain Drayson, Royal Artillery ; George W. Lenox, Esq. ; and many others- SUPPLEMENT TO DICTIONARY OF ARTS, MANUFACTURES, AND MINES. ABA. A woollen stuff manufactured in Turkey. ABACA. A species of fibre obtained in the Philippine Islands in abundance. Some authorities refer those fibres to the palm-tree known as the Abaca, or Anim textilis. There seem, indeed, several well-known varieties of fibre under this name, some so fine that they are used in the most delicate and costly textures, mixed with fibres of the pine-apple, form- ing Pina muslins and textures equal to the best muslins of Bengal. Of the coarser fibres, mats, cordage, and sail-cloth are made. M. Duchesne states, that the well-known fibrous manufactures of Manilla have led to the manufacture of the fibres themselves, at Paris, into many articles of furniture and dress. Their brilliancy and strength give remarkable fitness for bonnets, tapestry, carpets, network, hammocks, &c. The only manufactured^ articles exported from the Philippine Islands, enumerated by Thomas de Comyn, Madrid, 1820 (transl. by Walton), besides a few tanned buffalo hides and skins, are 8,000 to 12,000 pieces of lio-ht sail-cloth, and 200,000 lbs. of assorted abaca cordage. ABIES {in Botany), the fir, a genus of trees which belong to the coniferous tribe.^ These trees are well known from their ornamental character, and for the valuable timber which they produce. They yield several resins or gum resins, which are useful in the arts. ABIES BALSAMEA (the Balm of Gilead fir) produces the Canadian balsam. This tree grows most abundantly in the colder regions of North America. ABIES CANADENSIS (the hemlock spruce fir). A considerable quantity of the es- sence of spruce is extracted from the shoots of this tree ; it is, however, also obtained from other varieties of the spruce fir. ABIES PICEA of Linnaeus {Abies pectinata of De Candole). The Silver fir, producing the Burgundy pitch and the Strasburg turpentine. ABLETTE, or ABI '' r ' ' '' Y ' '' Y — ' ' Acetate of lime. Acetate of soda. Double salt. Or, if sulphuric acid be considered as a bibasic acid, which this very reaction so strongly justifies — (Ca) 0* -f Na" S' 0® = H' (Na) 0^ -f j- S' 0« Acetate of lime. Sulphate of soda. Acetate of soda. Double salt. If this point be neglected, and only one equivalent of sulphate of soda be used, one-half of the acetate of lime may escape decomposition, and thus be lost. After the separation of the double salt, the solution of acetate of soda is drawn off, any impurities allowed to subside, and then concentrated by evaporation until it has a density of 4’3 — when the acetate of soda crystallizes out, and may be further purified, if requisite, by auother re-solution and re-crystallization. The contents of the mother liquors are con- verted into acetone and carbonate of soda, as before. The crystallized acetate of soda is now fused in an iron pot, at a temperature of about 400”’, to drive off the water of crystallization, the mass being kept constantly stirred. A stronger heat must not be applied, or we should effect the decomposition of the salt. For the production of the acetic acid from this salt, a quantity of it is put into a stout copper still, and a deep cavity made in the centre of the mass, into which sulphuric acid of specific gravity 1‘84 is poured in the proportion of 35 per cent, of the weight of the salt ; the walls of the cavity are thrown in upon the acid, the whole briskly agitated with a wooden spatula. The head of the still is then luted, and connected with the condensing worm, and the distillation carried on at a very gentle heat. The worm should be of silver or porcelain, as also the still head ; and even silver solder should be used to connect the joinings in the body of the still. The still is now generally heated by a steam “jacket.” See Distillation. The acid which passes over is nearly colorless, and has a specific gravity of 1*05. That ACETIC ACID. 13 which collects at the latter part of the operation is liable to be somewhat empyreumatic, and therefore, before this point is reached, the receiver should be changed ; and throughout, the entire operation, care should be taken to avoid applying too high a temperature, as the flavor and purity of the acid will invariably suffer. Any trace of empyreuma may be removed from the acid by digestion with animal char- coal and redistillation. A considerable portion of this acid crystallizes at a temperature of from 40° to 50° F., constituting what is called glacial acetic acid^ which is the compound C* 0^ (or 0^ HO). For culinary purposes, pickling, &c., the acid of specific gravity 1'05 is diluted with five times its weight in water, which renders it of the same strength as Revenue proof vinegar. Several modifications and improvements of this process have recently been introduced, which require to be noticed. The following process depends upon the difficult solubility of sulphate of soda in strong acetic acids : — 100 lbs. of the pulverized salt being put into a hard glazed stoneware re- ceiver, or deep pan, from 35 to 36 lbs. of concentrated sulphuric acid are poured in one stream upon the powder, so as to flow under it. The mixture of the salt and acid is to be made very slowly, in dfder to moderate the action and the heat generated, as much as possible. After the materials have been in intimate contact for a few hours, the decompo- sition is effected ; sulphate of soda in crystalline grains will occupy the bottom of the vessel and acetic acid the upper portion, partly liquid and partly in crystals. A small portion of pure acetate of lime added to the acid will free it from any remainder of sulphate of soda, leaving only a little acetate in its place ; and though a small portion of sulphate of soda may still remain, it is unimportant, whereas the presence of any free sulphuric acid would be very injurious. This is easily detected by evaporating a little of the liquid, at a moderate heat, to dryness, when that mineral acid can be distinguished from the neutral soda sulphate. This plan of superseding a troublesome distillation, which is due to M. Mollerat, is one of the greatest improvements in this process, and depends upon the insolubility of the sulphate of soda in acetic acid. The sulphate of soda thus recovered, and well drained, serves anew to decompose acetate of lime ; so that nothing but this cheap earth is consumed in carrying on the manufacture. To obtain absolutely pure acetic acid, the above acid has to be distilled in a glass retort, Vblckel recommends the use of hydrochloric instead of sulphuric acid for decomposing the acetate. The following is his description of the details of the process : — “ The crude acetate of lime is separated from the tarry bodies which are deposited on neutralization, and evaporated to about one-half its bulk in an iron pan. Hydrochloric acid is then added until a distinctly acid reaction is produced on cooling ; by this means the resinous bodies are separated, and come to the surface of the boiling liquid in a melted state, whence they can be removed by skimming, while the compounds of lime, with creo- sote, and other volatile bodies, are likewise decomposed, and expelled on further evapora- tion, From 4 to 6 lbs. of hydrochloric acid for every 33 gallons of wood vinegar is the average quantity required for this purpose. The acetate, having been dried at a high tem- perature on iron plates, to char and drive off the remainder of the tar and resinous bodies, is then decomposed, by hydrochloric acid, in a still with a copper head and leaden condens- ing tube. To every 100 lbs. of salt about 90 to 95 lbs. of hydrochloric acid of specific gravity 1T6 are required. The acid comes over at a temperature of from 100° to 120° C. (212° to 248° F.), and is very slightly impregnated with empyreumatic products, while a mere cloud is produced in it by nitrate of silver. The specific gravity of the product varies from 1’058 to 1'061, and contains more than 40 per cent, of real acid ; but as it is seldom required of this strength, it is well to dilute the 90 parts of hydrochloric acid with 25 parts of water. These proportions then yield from 95 to 100 parts of acetic acid of specific gravity 1*015. This process is recommended on the score of economy and greater purity of product. The volatile empyreumatic bodies are said to be more easily separated by the use of hydro- chloric than sulphuric acid ; moreover, the chloride of calcium being a more easily fusible salt than the sulphate of lime, or even than the double sulphate of lime and soda, the acetic acid is more freely evolved from the mixture. The resinous bodies also decompose sulphuric acid towards the end of the operation, giving rise to sulphurous acid, sulphuretted hydrogen, &c., which contaminate the product. Impurities and Adulterations . — In order to prevent the putrefactive change which often takes place in vinegar when carelessly prepared by the fermentation of malt wine, &c., it was at one time supposed to be necessary to add a small quantity of sulphuric acid. This notion has long since been shown to be false ; nevertheless, since the addition of 1 part of sulphuric acid to 1,000 of vinegar was permitted by an excise regulation, and thus the practice has received legal sanction, it is still continued by many manufacturers. So long as the quantity is retained within these limits, and if pure sulphuric acid be used (great care ACETIMETKY. 14 being taken that there is no arsenic present in such oil of vitriol, as is not unfrequently the case in inferior varieties), no danger can ensue from the habit ; but occasionally the quantity is much overpassed by dishonest dealers, of whom it is to be hoped there are but few. Dr. Ure mentions having found, by analysis, in a sample of vinegar, made by one of the most eminent London manufacturers, with which he supplied the public, no less than 116 grains of the strongest oil of vitriol per gallon, added to vinegar containing only per cent, of real acetic acid, giving it an apparent strength after all of only 4 per cent., whereas standard commercial vinegar is rated at 5 per cent. The methods of determining sulphuric acid will be given, once for all, under the head of Acidimetrt, and therefore need not be described in every case where it occurs ; the same remark applies to hydrochloric acid and others. Hydrochloric acid is rarely intentionally added to vinegar ; but it may accidentally be present when the pyroligneous acid has been purified by VolckeTs process. It is detected by the precipitate which it gives with solution of nitrate of silver in the presence of nitric acid. Nitric acid is rarely found in vinegar. For its method of detection, see Nitric Acid. Wine vinegar generally contains tartaric acid and tartrates ; but it is purified from them by distillation. Sulphurous acid is occasionally met with in pyroligneous acid. This is recognized by its bleaching action on delicate vegetable colors, and by its conversion, under the influence of nitric acid, into sulphuric acid, which is detected by chloride of barium. Sulphuretted hydrogen is detected by acetate of lead giving a black coloration or pre- cipitate. Metallic Salts. — If care be not taken in constructing the worm of the still of silver or earthenware, distilled acetic acid is frequently contaminated with small quantities of metal from the still, copper, lead, tin, &c. These metals are detected by the addition of sulphu- retted hydrogen, as is fully discussed under the head of the individual metals. Copper is the most commonly found, and it may be detected in very minute quantities by the blue color which the solution assumes on being supersaturated with ammonia. It is not uncommon to add to pyroligneous acid, a little coloring matter and acetic ether, to give it the color and flavor of wine or malt vinegar ; but this can hardly be called an adulteration. The presence of the products of acetification of cider may be detected by neutralizing the vinegar with ammonia, and then adding solution of acetate of lime. Tartrate of lime is, of course, precipitated from the wine vinegar, while the pearly malic acid of the cider affords no precipitate with the lime, but may be detected by acetate of lead, by the glistening pearly scales of malate of lead, hardly soluble in the cold. Acetic acid is extensively employed in the arts, in the manufacture of the various ace- tates, especially those of alumina and iron, so extensively employed in calico printing as mordants, sugar of lead, &c. It is likewise used in the preparation of varnishes, for dis- solving gums and albuminous bodies ; in the culinary arts, especially in the manufacture of pickles and other condiments ; in medicine, externally, as a local irritant, and internally, to allay fever, &c. For the treatment in cases of poisoning, we refer to Taylor, Pereira, and other medical authorities. — H. M. W. ACETIMETKY. Determination of the Strength of Vinegar . — If in vinegars we were dealing with mixtures of pure acetic acid and water, the determination of the density might, to a certain extent, afford a criterion of the strength of the solution ; but vinegar, especially that obtained from wine and malt, invariably contains gluten, saccharine, and mucilaginous matters, which increase its density and render this method altogether fallacious. The only accurate means of determining the strength of vinegar is by ascertaining the quantity of carbonate of soda or potash neutralized by a given weight of the vinegar under examination. This is performed by adding to the vinegar a standard solution of the alka- line carbonate of known strength from a bruette, until, after boiling to expel the carbonic acid, a solution of litmus previously introduced into the liquid is distinctly reddened. The details of this process, which is equally applicable to mineral and other organic acids, will be found fully described under the head of Acidimetrt. Roughly, it may be stated that every 63 grains of the pure anhydrous carbonate of soda, or every 69 grains of carbonate of potassa {i. e. one equivalent), correspond to 60 grains of acetic acid (C^ O'*).* It is obvious that preliminary examinations should be made to aseertain if sulphuric, hydrochloric, or other mineral acids are present ; and, if so, their amount determined, otherwise they will be reckoned as acetic acid. The British malt vinegar is stated in the London Pharmacopoeia to require a draehm * In most cases w'here, in commercial language, mention is made of real acetic acid, the hypotheti- cal compound is 'meant; but it would bo better in future always to give the percentage of acetic acid C'^TT^O'* — for the body is altogether hypothetical — never having yet been discovered. See the remarks on Anhydrous Acetic Acid at the commencement of this article. — II. M. "W. f ACETYL. 15 (60 grains) of crystallized carbonate of soda (which contains 10 equivalents of water of crystallization) for saturating a fluid ounce, or 4’46 grains ; it contains, in fact, from 4-6 to 6 per cent, of real acetic acid. The same authorities consider that the purified pyroligneous acid should require 87 grains of carbonate of soda for saturating 100 grains of the acid. Dr. Ure suggests the use of the bicarbonate of potash. Its atomic weight, referred to hydrogen as unity, is 100’584, while the atomic weight of acetic acid is 51-563 ; if we estimate 2 grains of the bicarbonate as equivalent to 1 of the real acid, we shall commit no appreciable error. Hence a solution of the carbonate containing 200 grains in 100 measures will form an acetimeter of the most perfect and convenient kind ; for the meas- ures of test liquid expended in saturating any measure — for instance, an ounce or 1,000 grains of acid — will indicate the number of grains of real acetic acid in that quantity. Thus, 1,000 grains of the above proof would require 50 measures of the acetimetrieal alka- line solution, showing that it contains 50 grains of real acetic acid in 1,000, or 5 per cent. Although the bicarbonate of potash of the shops is not absolutely constant in compo- sition, yet the method is no doubt accurate enough for all practical purposes. The acetimetrieal method* employed by the Excise is that recommended by Messrs. J. and P. Taylor,* and consists in estimating the strength of the acid by the specific gravity which it acquires when saturated by hydrate of lime. Acid which contains 5 per cent, of real acid is equal in strength to the best malt vinegar, called by the makers No. 24, and is assumed as the standard of vinegar strength, under the denomination of “ proof vinegar.”f Acid which contains 40 per cent, of real acetic acid is, therefore, in the language of the Revenue, 35 per cent, oyer proof; it is the strongest acid on which duty is charged by the acetimeter. In the case of vinegars which have not been distilled, an allowance is made for the increase of weight due to the mucilage present ; hence, in the acetimeter sold by Bate, a weight, marked m, is provided, and is used in trying such vinegars. As the hydrate of lime employed causes the precipitation of part of the mucilaginous matter in the vine- gar, it serves to remove this difficulty to a certain extent. {Pereira.) — H. M. W. ACETONE, s?/n. pyroacetic spirit, mesitic alcohol, pyroacetic ether. C® H° 0^ A volatile fluid usually obtained by the distillation of the acetates of the alkaline earths. It is also obtained in a variety of operations where organic matters are exposed to high tem- perature. Tartaric and citric acids yield it when distilled. Sugar, gum, or starch, when mixed with lime and distilled, afford acetone. If crude acetate of lime be distilled, the acetone is accompanied by a small quantity of ammonia and traces of methylamine. The ' latter is due to the nitrogen contained in the wood ; the distillate from which was used in the preparation of the acetate of lime. Crude acetone may be purified by redistilling it in a water-bath. A small quantity of slaked lime should be added previous to distillation, to combine with any acid that may be present. When pure, it forms a colorless mobile fluid, boiling at 133° F. Its density at 18° is 0-'7921, at 32° it is 0-8140. The density of its vapor was found by experiment to be 2-00; theory requires 2.01, supposing six volumes of carbon vapor, twelve volumes of hydrogen, and two volumes of oxygen to be condensed to four volumes. When acetone is procured from acetate of lime, two equivalents of the latter are decomposed, yielding one equivalent of acetone, and two equivalents of car- bonate of lime. It has been found that a great number of organic acids, when distilled under similar circumstances, yield bodies bearing the same relation to the parent acid that acetone does to acetic acid : this fact has caused the word acetone to be used of late in a more extended sense than formerly. The word ketone is now generally used to express a neutral substance derived by destructive distillation from an acid, the latter losing the elements of an equivalent of carbonic acid during the decomposition. Theoretical chemists are somewhat divided with regard to the rational formulae of the ketones. An overwhelm- ing weight of evidence has been brought by Gerhardt and his followers, to prove that they should be regarded as aldehydes in which an equivalent of hydrogen is replaced by the radical of an alcohol. Thus common acetone (C® H® 0'^) is aldehyde (C^ 0*^), in which one equivalent of hydrogen is replaced by methyle, H®. Acetone dissolves several gums and resins, amongst others sandarach. Wood spirit, which sometimes, owing to the presence of impurities, refuses to dissolve sandarach, may be made to do so by the addition of a small quantity of acetone. When treated with sulphuric acid and distilled, acetone yields a hydrocarbon called mesitylene or mesitylole, C'® — C. G. W. ACETYL. Two radicals are known by this name, namely, and 0^. Their nomenclature has not, as yet, been definitely settled. Dr. Williamson proposes to call it othyl. The hydrocarbon is now assumed to exist in aldehyde, which can be regarded as formed on the type two atoms of water, thus : — In the above formula we have two atoms of water, in which 1 equivalent of hydrogen is ♦ Quarterly Journal of Science, vi, 255. t 58 Geo, III., c. 65. ACID. 16 replaced by the non-oxidized radical H®, which may very conveniently be named aldylc, to recall its existence in aldehyde. — C. G. W. ’ ACID. {Acidus^ sour, L.) The term acid was formerly applied to bodies which were sour to the taste, and in popular language the word is still so used. It is to be regretted that the necessities of science have led to the extension of this word to any bodies com- bining with bases to form salts, whether such combining body is sour or otherwise. Had not the term acid been established in language as expressing a sour body, there would have been no objection to its use ; but chemists now apply the term to substances which arc not sour, and which do not change blue vegetable colors ; and consequently they fail to convey a correct idea to the popular mind. Hobbes, in his “ Computation or Logic,” says, “ A name is a word taken at pleasure to serve for a mark which may raise in our mind a thought like to some thought we had before, and which, being pronounced to others, may be to them a sign of what thought the speaker had, or had not, before in his mind.” This philosopher thus truly expresses the purpose of a name ; and this purpose is not fulfilled by the term acid, as now employed. Mr. John Stuart Mill, in his “System of Logic,” thus, as it appears not very happily, endeavors to show that the term acid, as a scientific term, is not inappropriate or incorrect. “ Scientific definitions, whether they are definitions of scientific terms, or of common terms used in a scientific sense, are almost always of the kind last spoken of : their main purpose is to serve as the landmarks of scientific classification. And, since the classifica- tions in any science are continually modified as scientific knowledge advances, the defini- tions in the sciences are also constantly varying. A striking instance is afforded by the words acid and alkali, especially the former. As experimental discovery advanced, the substances classed with acids have been constantly multiplying ; and, by a natural conse- quence, the attributes connoted by the word have receded and become fewer. At first it connoted the attributes of combining with an alkali to form a neutral substance (called a salt), being compounded of a base and oxygen, causticity to the taste and touch, fluidity, &c. The true analysis of muriatic acid into chlorine and hydrogen caused the second property, composition from a base and oxygen, to be excluded from the connotation. The same discovery fixed the attention of chemists upon hydrogen as an important element in acids ; and more recent discoveries having led to the recognition of its presence in sul- phuric, nitric, and many other acids, where its existence was not previously suspected, there is now a tendency to include the presence of this element in the connotation of the word. But carbonic acid, silica, sulphurous acid, have no hydrogen in their composition ; that property cannot, therefore, be connoted by the term, unless those substances are no longer to be considered acids. Causticity and fluidity have long since been excluded from the characteristics of the class by the inclusion of silica and many other substances in it ; and the formation of neutral bodies by combination with alkalis, together with such electro- chemical peculiarities as this is supposed to imply, are now the only differentia which form the fixed connotation of the word acid as a term of chemical science.” The term Alkali, though it is included by Mr. J. S. Mill in connection with acid in his remarks, does not stand, even as a scientific term, in the objectional position in which we find acid. Alkali is not, strictly speaking, a common name to which any definite idea is attached. Acid, on the contrary, is a word commonly employed to signify sour. With the immense increase which organic chemistry has given to the number of acids, it does appear necessary, to avoid confusion, that some new arrangement, based on a strictly logical plan, should be adopted. This is, however, a task for a master mind ; and possibly we must wait for another generation before such a mind appears among us. In this Dictionary all the acids named will be found under their respective heads ; as Acetic, Nitric, Sulphuric Acids, &c. ACIDIFIER. Any simple or compound body whose presence is necessary for the pro- duction of an acid ; as oxygen, chlorine, bromine, iodine, fluorine, sulphur, &c., &c. ACIDIMETER. An instrument for measuring the strength or quantity of real acid contained in a free state in liquids. The construction of that instrument is founded on the principle that the quantity of real acid present in any sample is proportional to the quan- tity of alkali which a given weight of it can neutralize. The instrument, like the alkalim- eter (see Alkalimeter), is made to contain 1,000 grains in weight of pure distilled water, and is divided accurately into 100 divisions, each of which therefore represents 10 grains of pure distilled water ; but as the specific gravity of the liquids which it serves to measure may be heavier or lighter than pure water, 100 divisions of such liquids are often called 1,000 grains’ measure, irrespectively of their weight (specific gravity), and accordingly 10-20, &c. divisions of the acidimeter are spoken of as 100-200, &c. grains’ measure ; that is to say, as a quantity or measure which, if filled with pure water, would have weighed that number of grains. ACIDIMETRY. Acidimetry is the name of a chemical process of analysis by means of which the strength of acids — that is to say, the quantity of pure free acid contained in a liquid — can be ascertained or estimated. The principle of the method is based upon Dal- ACIDIMETRY. 17 ton’s law of chemical combinations ; or, in other words, upon the fact that, in order to pro- duce a complete reaction, a certain definite weight of reagent is required. If, for example, we take 1 equivalent, or 49 parts in weight, of pure oil of vitriol of specific gravity 1-8485, dilute it (of course within limits) with no matter what quantity of water, and add thereto either soda, potash, magnesia, ammonia, or their carbonates, or in fact any other base, until the acid is neutralized — that is to say, until blue litmus-paper is no longer, or only very faintly, reddened when moistened with a drop of the acid liquid under examination, — it will be found that the respective weights of each base required to produce that effect will greatly differ, and that with respect to the bases just mentioned these weights will be as follows : — Soda (caustic) 1 equiv. = 31 parts in weight Potash (caustic) “ = 47 (( Ammonia “ = 17 U Carbonate of soda “ = 53 U Carbonate of potash “ = 69 u Saturate or neutralize 1 eqv. = 49 parts in weight of pure oil of vitriol (sp. gr. 1-8485), or 1 equiv. of any other acid. This being the case, it is evident that if we wish to ascertain by such a method the quantity of sulphuric acid or of any other acid contained in a liquid, it will be necessary, on the one hand, to weigh or measure accurately a given quantity of that liquid to be examined, and, on the other hand, to dissolve in a known volume of water the weight above mentioned of any one of the bases just alluded to, and to pour that solution gradually into that of the acid until neutralization is obtained ; the number of volumes of the basic solution which will have been required for the purpose will evidently indicate the amount in weight of acid which existed in the liquid under examination. Acidimetry is therefore exactly the reverse of alkalimetry, since in principle it depends on the number of volumes of a solu- tion of a base diluted with water to a definite strength, which are required to neutralize a known weight or measure of the different samples of acids. The solution containing the known weight of base, and capable therefore of saturating a known weight of acid, is called a “ test-liquor and an aqueous solution of ammonia, of a standard strength, as first proposed by Dr. Ure, affords a most exact and convenient means of effecting the purpose, when gradually poured from a graduated dropping-tube or acidimeter into the sample of acid to be examined. The strength of the water of ammonia used for the experiment should be so adjusted that 1,000 grains’ measure of it (that is, 100 divisions of the alkalimeter) really contain one equivalent (17 grains) of ammonia, and consequently neutralize one equivalent of any one real acid. The specific gravity of the pure water of ammonia employed as a test for that purpose should be exactly 0-992, and when so adjusted, 1,000 grains’ measure (100 divisions of the acidimeter) will then neutralize exactly 40 grains, or one equivalent, of sulphuric acid (dry). 49 (( “ oil of vitriol, sp, gr. 1.8485. 37.5 U “ hydrochloric acid (gas, dry). 54 u u nitric acid (dry). 60 u “ u crystallized acetic acid. 45 it “ oxalic acid. 150 u (( u tartaric acid. 51 u u acetic acid. And so forth with the other acids. A standard liquor of ammonia of that strength becomes, therefore, a universal acid- imeter, since the number of measures or divisions used to effect the neutralization of 10 or of 100 grains of any one acid, being multiplied by the atomic weight or equivalent number of the acid under examination, the product, divided by 10 or by 100, will indicate the per- centage of real acid contained in the sample ; the proportion of free acid being thus determined with precision, even to Jj of a grain, in the course of five minutes, as will be shown presently. The most convenient method of preparing the standard liquor of ammonia of that specific gravity is by means of a glass bead, not but that specific gravity bottles and hydrometers may, of course, be employed ; but Dr. Ure remarks, with reason, that they furnish incomparably more tedious and less delicate means of adjustment. The glass bead, of the gravity which the test-liquor of ammonia should have, floats, of course, in the middle of such a liquor, at the temperature of 60° F. ; but if the strength of the liquor becomes attenuated by evaporation, or its temperature increased, the attention of the operator is immediately called to the fact, since the difference of a single degree of heat, or the loss of a single hundredth part of a grain of ammonia per cent,, will cause the bead to sink to the bottom — a degree of precision which no hydrometer can rival, and which could not otherwise be obtained, except by the troublesome operation of accurate weighing. Whether the solution remains uniform in strength is best ascertained by introducing into the bottle containing the ammonia test-liquor two glass beads, so adjusted that one, being VoL. III.— 2 18 AOIDIMETRY. very slightly heavier than the liquid, may remain at the bottom ; whilst the other, being very slightly lighter, reaches the top, and remains just under the surface as long as the liquor is in the normal state ; but when, by the evaporation of some ammonia, the liquor becomes weaker, and consequently its specific gravity greater, the bead at the bottom rises towards the surface, in which case a few drops of strong ammonia should be added to restore the balance. An aqueous solution of ammonia, of the above strength and gravity, being prepared, the acidimetrical process is in every way similar to that practised in alkalimetry ; that is to say, a known weight, for example, 10 or 100 grains of the sample of acid to be examined are poured into a sufficiently large glass vessel, and diluted, if need be, with water, and a little tincture of litmus is poured into it, in order to impart a distinct red color to it ; 100 divisions, or 1,000 grains’ measure, of the standard ammonia test-liquor above alluded to, are then poured into an alkalimeter (which, in the present case, is used as an acidimeter), and the operator proceeds to pour the ammonia test-liquor from the alkalimeter into the vessel containing the acid under examination, in the same manner, and with the same precautions used in alkalimetry (see Alkalimetry), until the change of color, from red to blue, of the acid liquor in the vessel indicates that the neutralization is complete, and the operation finished. Let us suppose that 100 grains in weight of a sample of sulphuric acid, for example, have required 61 divisions (610 water-grains’ measure) of the acidimeter for their complete neutralization, since 100 divisions (that is to say, a whole acidimeter full) of the test-liquor of ammonia are capable of neutralizing exactly 49 grains — one equivalent — of oil of vitriol, of specific gravity, 1-8485, it is clear that the 61 divisions employed will have neutralized 29-89 of that acid, and, consequently, the sample of sulphuric acid examined contained that quantity per cent, of pure oil of vitriol, representing 24-4 per cent, of pure anhydrous sulphuric acid ; thus — Divisions. Oil of Vitriol. 100 : 49 :: 61 : » = 29-89. Anhydrous Acid. 100 : 40 :: 61 : 2 = 24-4. The specific gravity of an acid of that strength is 1-21'78. In the same manner, suppose that 100 grains in weight of hydrochloric acid have required 90 divisions (900 grains’ measure) of the acidimeter for their complete neutraliza- tion, the equivalent of dry hydrochloric acid gas being 36-5, it is clear that since 90 divisions only of the ammonia test-liquor have been employed, the sample operated upon must have contained per cent, a quantity of acid equal to 33-30 of dry hydrochloric acid gas in solution, as shown by the proportion : — Divis. Hydrochloric acid. 100 : 36-5 :: 90 : a; = 32-85. The specific gravity of such a sample would be 1-1646. Instead of the ammonia test-liquor just alluded to, it is clear that a solution containing one equivalent of any other base — such as, for example, carbonate of soda, or carbonate of potash, caustic lime, &c. — may be used for the purpose of neutralizing the acid under examination. The quantity of these salts required for saturation will of course indicate the quantity of real acid, and, by calculation, the percentage thereof in the sample, thus : — The equivalent of pure carbonate of soda 53, and that of carbonate of potash 69, either of these weights will represent one equivalent, and consequently 49 grains of pure oil of vitriol, 36-5 of dry hydrochloric acid, 60 of crystallized, or 61 of anhydrous acetic acid, and so on. The acidimetrical assay is performed as follows : — If with carbonate of soda^ take 630 grains of pure and dry carbonate of soda, obtained by igniting the bicarbonate of that base (see Alkalimetry), and dissolve them in 10,000 water grains’ measure (1,000 acidimetrical divisions) of distilled water. It is evident that each acidimeter full (100 divisions) of such a solution will then correspond to one equivalent of any acid ; and accordingly, if the test-liquor of carbonate of soda be poured from the acidimeter into a weighed quantity of any acid, with the same precautions as before, until the neutralization is complete, the number of divisions employed in the operation will, by simple rule of proportion, indicate the quantity of acid present in the sample as before. Pure carbonate of soda is easily obtained by recrystallizing once or twice the crystals of carbonate of soda of commerce, and carefully washing them. By heating them gradually they melt, and at a very low red heat entirely lose their water of crystallization and become converted into pulverulent anhydrous neutral carbonate of soda, which should be kept in well closed bottles. When carbonate of potash is used, then, since the equivalent of carbonate of potash is 69, the operator should dissolve 690 grains of it in the 10,000 grains of pure distilled water, and the acidimeter being now filled with this test-liquor, the assay is carried on again precisely in the same manner as before. Neutral carbonate of potash for acidimetrical use ACIDIMETRY. 19 is prepared by heating the bicarbonate of that base to redness, in order to expel one equivalent of its carbonic acid ; the residue left is pure neutral carbonate of potash ; and in order to prevent its absorbing moisture, it should be put, whilst still hot, on a slab placed over concentrated sulphuric acid, or chloride of calcium, under a glass bell, and, when sufficiently cool to be handled, transferred to bottles carefully closed. To adapt the above methods to the French weights and measures, now used also gener- ally by the German chemist, we need only substitute 100 decigrammes for lOO- grains, and proceed with the graduation as already described. A solution of caustic lime in cane sugar has likewise been proposed by M. Peligot for acidimetrical purposes. To prepare such a solution, take pure caustic lime, obtained by heating Garara marble among charcoal in a furnace ; when sufficiently roasted to convert it into quicklime, slake it with water, and pour upon the slaked lime as much water as is necessary to produce a milky liquor ; put this milky liquor in a bottle, and add thereto, in the cold,, a certain quantity of pulverized sugar-candy ; close the bottle with a good cork, and shake the whole mass well. After a certain time it will be observed that the milky liquid has become very much clearer, and perhaps quite limpid ; filter it, and the filtrate will be found to contain about 50 parts of lime for every 100 of sugar employed. The liquor should not be heated, because saccharate of lime is much more soluble in cold than in hot water, and if heat were applied it would become turbid or thick, though on cooling it would become clear again.* A concentrated solution of lime in sugar being thus obtained, it should now be diluted to such a degree that 1,000 water grains’ measure of it may be capable of saturating exactly one equivalent of any acid, which is done as follows : — Take 100 grains of hydrochloric acid of specific gravity 1’1812, that weight of acid contains exactly one equivalent = 36*5 of pure hydrochloric acid gas ; on the other hand, fill the acidimeter up to 0 (zero) with the solution of caustic lime in sugar prepared as abovesaid, and pour the contents into the acid until exact neutralization is obtained, which is known by testing with litmus paper in the usual manner already described. If the whole of the 100 divisions of the acidimeter had been required exactly to neutralize the 100 grains’ weight of hydrochloric acid of the specific gravity mentioned, it would have been a proof that it was of the right strength ; but suppose, on the contrary, that only 60 divisions of the lime solution in the acidimeter have been sufficient for the purpose, it is evident that it is half too strong, or, in other words, one equivalent of lime (=28) is contained in those 50 divisions instead of in 100. Pour, there- fore, at once, 50 divisions or measures of that lime-liquor into a glass cylinder accurately divided into 100 divisions, and fill up the remaining 50 divisions with water ; stir the whole well, and 100 divisions of the lime-liquor will, of course, now contain as much lime as was contained before in the 60 ; or, in other words, 100 acidimetrical divisions will now contain 1 equivalent of lime, and therefore will be capable of exactly neutralizing 1 equivalent of any acid. When, however, saccharate of lirpe is used for the determination of sulphuric acid, it is necessary to dilute it considerably, for otherwise a precipitate of sulphate of lime would be produced. This reagent, moreover, is evidently applicable only to the determination of such acids the lime salts of which are soluble in water. Instead of a solution of caustic lime in sugar, a clean dry piece of white Garara marble may be used. Suppose, for example, that the acid to be assayed is acetic acid, the instruc- tions giv^n by Brande are as follows : — A clean dry piece of marble is selected and accu- rately weighed ; it is then suspended by a silk thread into a known quantity of the vinegar or acetic acid to be examined, and which is cautiously stirred with a glass rod, so as to mix its parts, but without detaching any splinters from the weighed marble, till the whole of the acid is saturated, and no further action on the marble is observed. The marble is then tal^en out, washed with distilled water, and weighed ; the loss in weight which it has sustained may be considered as equal to the quantity of acetic acid present, since the atomic weight of carbonate of lime (=60) is very nearly the same as that of acetic acid (=51'). Such a process, however, is obviously less exact than those already described. But whichever base is employed to prepare the test-liquor, it is clear that the acid tested with it must be so far pure as not to contain any other free acid than that for which it is tested, for in that case the results arrived at would be perfectly fallacious. Unless, therefore, the operator has reason to know that the acid, the strength of which has to be examined by ^ that process, is genuine of its kind, he must make a qualitative analysis to satisfy himself that it is so ; for in the contrary case the acid would not be in a fit state to be submitted to an acidimetrical assay. We shall terminate this article by a description of Liebig’s acidimetrical method of determining the amount of prussic acid contained in solutions ; for example, in medicinal prussic acid, in laurel and bitter almond water, essence of bitter almonds, and cyanide of potassium. The process is based upon the following reaction : — When an excess of caustic * The directions priven by M. Violette for the preparation of Saccharate of Lime are as follows: — Digest in the cold 50 grammes of slaked caustic lime in 1 litre of water containing 100 grammes of sugar. ACIPENSEE. 20 potash is poured in a solution which contains prussic acid, cyanide of potassium is, of course, formed ; and if nitrate of silver be then poured in such a liquor, a precipitate of cyanide of silver is produced, but it is immediately redissolved by shaking, because a double cyanide of silver and of potassium (Ag Cy -f- K Cy) is formed, which dissolves, without alteration, in the excess of potash employed. The addition of a fresh quantity of nitrate of silver produces again a precipitate which agitation causes to disappear as before ; and this reaction goes on until half the amount of prussic acid present in the liquor has been taken up to produce cyanide of silver, the other half being engaged with thg potassium in the formation of a double cyanide of silver and of potassium, as just said. As soon, however, as this point is reached, any new quantity of nitrate of silver poured in the liquor causes the cyanide of potassium to react upon the silver of the nitrate, to produce a permanent precipitate of cyanide of silver, which indicates that the reaction is complete, and that the assay is terminated. The presence of chlorides, far from interfering, is desirable, and a certain quantity of common salt is accordingly added, the reaction of chloride of silver being analogous to that of the cyanide of the same metal. To determine the strength of prussic acid according to the above process, a test or normal solution should be first prepared, which is as follows : — Since 1 equivalent of nitrate of silver (=1'70) represents, as we have seen, 2 equivalents of prussic acid (=54), dissolve, therefore, 170 grains of pure fused nitrate of silver in 10,000 water-grains’ measure of pure water; 1,000 water-grains’ measure (1 acidimeter full) of such solution will therefore represent 5-4 grains of prussic acid ; and consequently each acidimetrical division 0*054 grain of pure prussic acid. Take now a given weight or measure of the sample of prussic acid, or cyanide of potas- sium, or laurel, or bitter-almond water, or essence of bitter almonds ; dilute it with three or four times its volume of water, add caustic potash until the whole is rendered alkaline, and carefully pour into it a certain quantity of the normal silver solution from the acidimeter, until a slight precipitate begins to appear which cannot be redissolved by agitation ; observe the number of acidimetrical divisions of the test silver solution employed, and that number multiplied by 0*054 will, of course, indicate the proportion of prussic acid present in the quantity of the sample operated upon. For such liquids which, like laurel water, contain very little prussic acid, it is advisable to dilute the test silver liquor with nine times its bulk of water ; a decimal solution is thus obtained, each acidimetrical division of which will only represent 0*0054 of prussic acid, by which figure the number of divisions employed should then be multiplied. As the essence of bitter almonds mixed with water is turbid, it is absolutely necessary to add and shake it with a sufficient quantity of water to dissolve the particles of oil to which the milkiness is due, and render it quite clear. Instead of an acidimeter, an ordinary balance may be used, as follows ; — Take 63 grains of fused nitrate of silver, and dissolve them in 5,987 grains’ weight of pure distilled water, making altogether 6,000 grains’ weight of test silver solution. Weigh off now in a beaker any quantity, say 100, or, if very weak, 1,000 grains’ weight of the sample of prussic acid to be examined, dilute it with three or four times its bulk of water, mix with it a certain quantity of a solution of common salt, and a few drops of caustic potash over and above the quantity necessary to make it alkaline. Pour now carefully into the liquid so prepared a portion of the test solution of silver alluded to, until a turbidness or milkiness begins to be formed, which does not disappear by agitation, and which indicates that the reaction is complete. Every 300 grains of the test silver solution employed represent 1 grain’s weight of pure anhydrous prussic acid. The rationale of these numbers is evident : since 1 equiv. r= 170 of nitrate of silver corresponds to 2 equiv. = 54 of prussic acid ; 63 of nitrate of silver correspond to 20 of prussic acid, and consequently 300 of a solution containing 63 of nitrate of silver in 6,000 correspond to 1 of prussic acid, thus : — 170 : 54 :: 63 : 20 6,000 : 20 :: 300 : 1 Lastly, the strength of prussic acid may also be determined with an ordinary balance by a method proposed by Dr. Ure, which method, however, is much less convenient than that of Liebig ; it consists in adding peroxide of mercury, in fine powder, to the liquor which contains prussic acid, until it ceases to be dissolved. As the equivalent of peroxide of mercury = 108, is exactly four times that of prussic acid = 27, the weight of peroxide of mercury employed divided by four will give the quantity of prussic acid present. — A. N. ACIPENSER. See Isinglass. ACONITINE. H” NO'^. A poisonous alkaloid constituting the active principle of the Aconite, Aconitnm Napelhis. — C. G. W. ACORNS. The seed of the oak {querc^is). These possess some of the properties of the bark ; but in a very diluted degree. Acorns are now rarely used. Pigs are sometimes fed upon them. 308 bushels were imported in 1855. ADHESION. 21 • ACORUS CALAMUS. The common sweet flag. This plant is a native of England, growing abundantly in the rivers of Norfolk ; from which county the London market is chiefly supplied. The radix calami aromatici of the shops occurs in flattened pieces about one inch wide, and four or five inches long. It is employed medicinally as an aromatic, and it is said to be used by some distillers to flavor gin. The essential oil {oleum acori calami) of the sweet flag is used by snuff-makers for scenting snuff, and it sometimes enters as one of the aromatic ingredients of aromatic vinegar. — Pereira. ACROSPIRE. {Plumule., Fr. ; Blattkeim., Germ.) The sprout at the end of seeds when they begin to germinate. The name is derived from two Greek words, signifying highest and spire., and has been adopted on account of its spiral form. It is the plume or plumule of modern botanists. Malsters use the name to express the growing of the barley. “ The first leaves that appear when corn sprouts.” — Lindley. ACRYLAMINE or ALLYLAMINE. (G'' N.) A new alkaloid obtained by Hoff- mann and Cahorns, by boiling cyanate of allyle with a strong solution of potash. It boils at about 365°.— C. G. W. ACTINISM. (From oktIi/, a ray ; signifying merely the power of a ray, without defining what character of ray is intended.) As early as 1812, M. Berard (in a communication to the Academy of Sciences, on some observations made by him of the phenomena of solar action) drew attention to the fact that three very distinct sets of physical powers were manifested. Luminous power. Heat-produc- ing power, and Chemical power. The actual conditions of the sun-beam will be understood by reference to the annexed woodcut, and attention to the following description. Jig. 4 : a 6 represents the prismatic spectrum — as obtained by the decomposition of white light by the prism — or Newtonian luminous spectrum, 4 5 consisting of certain bands of color. Newton deter- mined those rays to be seven in number ; red, orange, yellow, green, blue, indigo, and violet ; recent re- searches, by Sir John Herschel and others, have proved the existence of two other rays ; one, the extreme red or crimson ray c, found at the least refrangible end of the spectrum, the other occurring at the most frangible end, or beyond the violet rays, which is a lavender or gray ray. Beyond this point up to /, Professor Stokes has discovered a new set of rays, which are only brought into view when the light is received upon the surfaces of bodies which possess the property of altering the refrangibility of the rays. Those rays have been called the jluorescent rays, from the circumstance that some of the varieties of Fluor Spar exhibit this phenomenon in a remarkable manner. In the engraving {Jig. 4,) the curved line l from atoc indicates the full extent of the luminous spectrum, the point marked l showing the maximum of illuminating power, which exists in the yellow ray. Sir William Herschel and Sir Henry Englefield de- termined, in the first instance, the maximum point for the calorific rays, and Sir John Herschel subsequently confirmed their results, proving that the greatest heat was found below the red ray, and that it gradually diminished in power with the increase of refrangibility in the rays, ceasing entirely in the violet ray. Heat rays have been detected down to the point d, and the curved line h indicates the extent of their action. Now, if any substance capable of undergoing chemical change be exposed to this spec- trum, the result will be found to be such as is represented in the accompanying figure and Jig. 5. Over the space upon which the greatest amount of light falls, i. e. the region of the yellow and orange rays l, no chemical change is effected : by prolonged action a slight change is brought about where the red ray falls, ?*, but from the mean green ray g up to the point /, a certain amount of chemical action is maintained ; the maximum of action being in the blue and violet rays a. Thus the curve line {Jig. 4) from c to f represents the extent and degree of chemical power as manifested in the solar spectrum. Two maxima are marked a a, differing widely however in their degree. ADHESION {sticking together). The union of two surfaces. With the phenomena which are dependent upon bringing two surfaces so closely together that the influence of cohesion is exerted, we have not to deal. In arts and manufactures, adhesion is effected by interposing between the surfaces to be united, some body possessing peculiar properties, ADIPOSE SUBSTANCE or ADIPOSE TISSUE. 22 such as gum, plaster, resin, marine or ordinary glue, and various kinds of cement. {Sifi those articles.') In many treatises, there has been a sad confusion between the terms adhesion and cohesion. It is to be regretted that our literature shows a growing careless- ness in this respect. Adhesion should be restricted to mean, sticking together by means of some interposed substance ; cohesion., the state of union effected by natural attraction. Not only is adhesion exhibited in works of art or manufacture, we find it very strikingly exhibited in nature. Fragments of rocks which have been shattered by convulsion are found to be cemented together by silica, lime, oxide of iron, and the like. We sometimes find portions of stone cemented together by the ores of the metals ; and, again, broken parts of mineral lodes are frequently reunited by the earthy minerals. ADIPOSE SUBSTANCE or ADIPOSE TISSUE. {Tissu graissenx, Fr.) An animal oil, resembling in its essential properties the vegetable oils. During life, it appears to exist in a fluid or semi-fluid state ; but in the dead animal, it is frequently found in a solid form, constituting suet, which, when divested of the membrane in which it is contained, is called tallow. See Tallow, Oils, &c. ADIT or ADIT LEVEL. The horizontal entrance to a mine ; a passage or level driven into the hill-side. The accompanying section gives, for the purpose of distinctness, an exaggerated section of a portion of the subterranean workings of a metal- liferous mine. It should be understood that d represents a mineral lode, upon which the shaft, a, has been sunk. At a certain depth from the surface of the hill the miners would be inconvenienced by water, consequently a level driven in from the side of the hill, h, through which the water flows off, and through which also the miner can bring out the broken rock, or any ores which he may obtain. Proceeding still deeper, sup- posing the workings to have com- menced, as is commonly the case, at a certain elevation above the sea-level, similar conditions to those described again arising, another level is driven so as to intersect the shaft or shafts, as shown at c. In this case, b would be called the shallow, and cthe deep adit. The economy of such works as these is great, saving the cost of expensive pumping machinery, and, in many cases, saving also considerable labor in the removal of ores or other matter from the mine. ADZE. A cutting instrument ; differing from the axe by the edge being placed at nearly right angles to the handle, and being slightly curved up or inflected towards it. The instrument is held in both hands, whilst the operator stands upon his work in a stooping position ; the handle being from twenty-four to thirty inches long, and the weight of the blade from two to four pounds. The adze is swung in a circular path almost of the same curvature as the blade, the shoulder-joint being the centre of motion, and the entire arm and tool forming, as it were, one inflexible radius ; the tool, therefore, makes a succession of small arcs, and in each blow the arm of the workman is brought in contact with the thigh, which serves as a stop to prevent accident. In coarse preparatory works, the work- man directs his adze through the space between his two feet ; he thus surprises us by the quantity of wood removed ; in fine works he frequently places his toes over the spot to be wrought, and the adze penetrates two or three inches beneath the sole of the shoe ; and he thus surprises us by the apparent danger, yet perfect working of the instrument, which, in the hands of a shipwright in particular, almost rivals the joiner’s plane ; it is with him the nearly universal paring instrument, and is used upon works in all positions. — Holtzapffel. AERATED WATER. The common commercial name of water artificially impregnated with carbonic acid. AEROLITES. Meteoric stones. It cannot be denied that masses of solid matter have fallen from the atmosphere upon the earth. It is evident that meteoric stones are of cosmical origin ; and the composition, there- fore, of such as have been examined, shows us the composition of masses of matter exist- ing beyond the earth. A few analyses of meteoric stones will exhibit the chemical charac- ter of these extraordinary masses. (1) (2) (3) (4) Iron, - SQ'VS . . 90-88 88-98 86-64 Nickel, - - 8-88 . . 8-45 10-35 13-t)4 Cobalt, - . 0-66 . . 0-65 — — Copper, - . . 0-02 0-21 0-27 Tin, - — 0-84 — Phosphorus, 0-10 . . 0-05 —Brook and Miller. AIR. 23 A meteorite fell at Dharwar, in the East Indies, on the 15th of February, 1848, which gave 68-3 per cent, of silicates insoluble in aqua regia; 2’5 of sulphur, 6’76 of nickel, and 22.18 of iron. Another stone from Singhur, near Ponna, in the Deccan, gave earthly sili- cate, 19*5 ; iron, 69*16 ; and nickel, 4*24. Ehrenberg examined a black inky rain-water which fell in Ireland on the 15th of April, 1849, and found the black color to consist of minute particles of decayed plants, which had probably been brought by the trade winds, and, floating in clouds of aqueous vapor, had decayed. AEROSTATION; AERONAUTICS. The ascent into the atmosphere by means of balloons. See Balloons. AGARIC of the oak ; called also surgeon's agaric, spunk, touchwood, A fungus found growing on the oak, birch, willow, and other trees. See Amadou. AGATE. An instrument used by gold-wire drawers, so called from the agate fixed in the middle of it. AGATE. {Agate, Fr. ; Achat, Gr. ; Achates, Lat.) A siliceous mineral ; a varie- gated variety of chalcedony. This stone is the ’AxavTjs of the Greeks, by whom it was so called after the river in Sicily of that name, whence, according to Theophrastus, agates were first procured. Bo- chart, with much probability, deduces the name from the Punic and Hebrew, nakad, spotted. The colors of agate are either arranged in parallel or concentric bands, or assume the form of clouds or spots, or arborescent and moss-like stains. These colors are due to the presence of metallic oxides, and when indistinct, they are frequently artificially developed or produced. By boiling the colorless sl;one in oil, and afterwards in sulphuric acid, the oil is absorbed by the more porous layers of the stone ; it subsequently becomes carbonized, and thus the contrast of the various colors is heightened. The red varieties, also, are arti- ficially produced by boiling them in a solution of proto-sulphate of iron ; after which, upon exposing the stones to heat, peroxide of iron is formed, and thus red bands, or rings, of varying intensities, are produced. Cornelians are thus very commonly formed ; the color- ing matter of the true stone being a peroxide of iron. Agates never occur in a crystalline form, but in the form of rounded pebbles ; they are translucent by transmitted light, but are not transparent, have a wax-like fracture, and they are susceptible of a brilliant polish. Agates are used in the arts for inlaying, and for bur- nishing gold and silver : they are also made into mortars for chemical purposes ; and when cut and polished, they are converted, in considerable quantities, into brooches, bracelets, and other ornamental articles. Agates are brought to this country from Arabia, India, and Oberstein, in Saxony ; they are also found in Perthshire, and other parts of Scotland. The Scotch Pebble is a variety of the agate, known by its zig-zag pattern as the Fortification Agate. Agates are found frequently in the amygdaloid rocks of Galgenburg, near Ober- stein. They are usually ground into form, cut, and polished, at water-mills in the neigh- borhood, where a considerable trade in them is carried on. Moss Agate, or Mocha Stone, is a chalcedony, containing within it dendritic or moss-like delineations, of an opaque brownish-yellow color, which are due to oxide of manganese, or of iron. — H. "W. B. Agates are found in the Canton markets, as articles of commerce, in abundance, and of the following varieties : — The white-veined agate, called also Mocha Stone, varies from 1 to 8 inches in diameter. The dull, milky agate, not so valuable, occurs in sizes of 1 to 10 inches. Lead-colored agate, sometimes uniform, and sometimes spotted, occurs of large size, and is used for cups and boxes. Flesh-colored. Blood-colored. This is sometimes variegated with pale blue and brown ; the blue always surrounds the red ; the brown has the tint of horn. Clouded and spotted flesh-colored agate is found subject to many flaws. Red agate, with yellow, is of 1 to 4 inches in diameter. The yellow has various tints. Sometimes the pebbles are 1 inches in length. The yellow agate is used for knife-handles. The pale yellow agate is very scarce ; it is called also Leonina, being variegated with white, black, and green, and bearing some resemblance to a lion’s skin. Blackish-veined brown agate, in pieces from 2 to Y inches in diameter, is very hard, and is cut into seals, buttons, and heads of canes, &c., with natural veins, or fictitious colors, sunk into the stone. It appears to be of much value. — Oriental Commerce. Agate is found sufficiently large to be formed into mortars for chemical purposes. “ The royal collection at Dresden contains a table-service of German agate ; and at Vienna, in the Imperial cabinet, there is an oval dish, twenty-two inches in length, formed of a single stone.”— jDawa. Agates may be stained artificially by soaking in a solution of nitrate of silver, and after- wards exposing them to the sun. These artificial colors disappear on laying the stone for a night in aquafortis. A knowledge of the practicability of thus staining agates naturally leads to the suspicion of many of the colors being the work, not of nature, but of art. AIR. The gaseous envelope which surrounds this Earth is emphatically so called ; it consists of the gases nitrogen and oxygen. About 79 measures of nitrogen, or azote, and 21 of oxygen, with yi^jth of carbonic acid. 24 AIR-ENGINE. constitute the air we breathe. The term air is applied to any permanently gaseous body. And we express different conditions of the air, as good air, bad air, foul air, &c. AIR-ENGINE. The considerable expansibility of air by heat naturally suggested its use as a motive power long before theoretical investigation demonstrated its actual value. The great advance made during the few last years in our knowledge of the mechanical action of heat, has enabled us to determine with certainty the practical result which may be obtained by the use of any contrivance for employing heat as a prime mover of machinery. We are indebted to Professor Wm. Thomson for the fundamental theorem which decides the economy of any thermo-dynamic engine. It is — that in any perfectly constructed engine the fraction of heat converted into work is equal to the range of temperature from the highest to the lowest point, divided by the highest temperature reckoned from the zero of absolute temperature. Thus, if we have a perfect engine in which the highest temperature is 280" and the lowest 80° F., the fraction of heat converted into force will be 280-|-460, or rather more than one quarter. So that, if we use a coal of which one pound in combus- tion gives out heat equivalent to 10,380,000 foot pounds, such an engine as we have just described would produce work equal to 2,805,405 foot pounds for each pound of coal consumed in the furnace. From the above formula of Professor Thomson, it will appear that the economy of any perfect thermo-dynamic engine depends upon the range of tem- perature we can obtain in it. And as the lowest temperature is generally nearly constant, being ruled by the temperature of the surface of the earth, it follows that the higher we can raise the highest temperature, the more economical will be the engine. The question is thus reduced to this : — In what class of engine can we practically use the highest tempera- ture ? In the steam-engine worked with saturated vapor, the limit is obviously deter- mined by the amount of pressure which can be safely employed. In the steam-engine worked with super-heated vapor — i. e. in which the vapor, after passing from the boiler, receives an additional charge of heat without being allowed to take up more water — and also in the air-engine, the limit will depend upon the temperature at which steam or air acts chemically upon the metals employed, as well as upon the power of the metals themselves to resist the destructive action of heat. It thus appears that the steam-engine worked with superheated steam possesses most of the economical advantages of the air-engine. But when we consider that an air-engine may be made available where a plentiful supply of water cannot be readily obtained, the importance of this kind of thermo-dynamic engine is incontestable. The merit of first constructing a practical air-engine belongs to Mr. Stirling. Mr. Ericsson has subsequently introduced various refinements, such as the respirator — a reticulated mass of metal, which, by its extensive conducting surface, is able, almost instan- taneously, to give its own temperature to the air which passes through it. But various practical difficulties attend these refinements, which, at best, only apply to engines worked between particular temperatures. The least complex engine, and that which.would probably prove most effectual in practice, is that described in the “ Philosophical Transactions,”- 1852, Part I. It consists of a pump, which compresses air into a receiver, in which it receives an additional charge of heat ; and a cylinder, the piston of which is worked by the heated air as it escapes. The difference between the work produced by the cylinder and that absorbed by the pump constitutes the force of the engine ; which, being compared with the heat communicated to the receiver, gives results exactly conformable with the law of Professor Thomson above described. — J. P. J. Dr. Joule has proposed various engines to be worked at temperatures below redness, which, if no loss occurred by friction or radiation, would realize about one-half the w’ork due to the heat of combustion ; or about four times the economical duty which has, as yet, been attained by the most perfect steam-engine, A detailed account of Ericsson's Calorific Engine may be useful, especially as a certain amount of success has attended his efforts in applying the expansive power of heat to move machinery. It is stated in Hunt’s “ Merchant’s Magazine” that Ericsson’s engines are at work in the foundry of Messrs. Hogg and Delamater, in New York ; one engine being of five and another of sixty-horse power. The latter has four cylinders. Two, of seventy-two inches in diameter, stand side by side. Over each of these is placed one much smaller. Within these are pistons exactly fitting their respective cylinders, and so connected, that those within the lower and upper cylinders move together. Under the bottom of each of the lower cylinders a fire is applied, no other furnaces being employed. Neither boilers nor water are used. The lower is called the working cylinder ; the upper, the supply cylinder. As the piston in the supply cylinder moves down, valves placed in its top, open, and it becomes filled with cold air. As the piston rises within it, these valves close, and the air within, unable to escape as it came, passes through another set of valves into a receiver, from whence it has to pass into the working cylinder to force up the working piston within it. As it leaves the receiver to perform this duty, it passes through what is called the regenerator, where it becomes heated to about 450° ; and upon entering the working cylin- der, it is further heated by the supply underneath. For the sake of illustration, merely, let ALABASTER. 25 us suppose that the working cylinder contains double the area of the supply cylinder ; the cold air which entered the upper cylinder will, therefore, but only half fill the lower one. In the course of its passage to the latter, however, it passes through the regenerator ; and as it enters the working cylinder, we will suppose that it has become heated to about 480°, by which it is expanded to double its volume, and with this increased capacity it enters the working cylinder. We will further suppose the area of the piston within this cylinder to contain” 1,000 square inches, and the area of the piston in the supply cylinder above to contain but 500. The air presses upon this with a mean force, we will suppose, of about eleven pounds to each square inch ; or, in other words, with a weight of 5,500 pounds. Upon the surface of the lower piston the heated air is, however, pressing upwards with a like force upon each of its 1,000 square inches ; or, in other words, with a force which, after overcoming the weight abovo^ leaves a surplus of 5,600 pounds, if we make no allow- ance for friction. This surplus furnishes the working power of the engine. It will be seen that after one stroke of its piston is made, it will continue to work with this force so long as sufficient heat is supplied to expand the air in the working cylinder to the extent stated ; for, so long as the area of the lower piston is greater than that of the upper and a like pressure is upon every square inch of each, so long will the greater piston push forward the smaller, as a two-pound weight upon one end of a balance will be sure to bear down a one- pound weight placed on the other. We need hardly say, that after the air in the working cylinder has forced up the piston within it, a valve opens ; and as it passes out, the pistons, by the force of gravity, descend, and cold air again rushes into and fills the supply cylinder. In this manner the two cylinders are alternately supplied and discharged, causing the pistons in each to play up and down substantially as they do in the steam-engine. The regenerator must now be described. It has been stated that atmospheric air is first drawn into the supply cylinder, and that it passes through the regenerator into the working cylinder. The regenerator is composed of wire net, like that used in the manufacture of sieves, placed side by side, until the series attains a thickness of about 12 inches. Through the almost innumerable cells formed by the intersections of the wire, the air must pass on its way to the working cylinder. In passing through these it is so minutely divided that all parts are brought into contact with the wires. Supposing the side of the regenerator nearest the working cylinder is heated to a high temperature, the air, in passing through it, takes up, as we have said, about 450° of the 480° of heat required to double the volume of the air ; the additional 30° are communicated by the fire beneath the cylinder. The air has thus become expanded, it forces the piston upwards ; it has done its work — valves open, and the imprisoned air, heated to 480°, passes from the cylinder and again enters the regenerator, through which it must pass before leaving the machine. It has been said that the side of this instrument nearest the cylinder is kept hot ; the other side is kept cool by the action upon it of the air entering in the opposite direction at each up-stroke of the pistons ; consequently, as the air from the working cylinder passes out, the wires absorb the heat so effectually, that when it leaves the regenerator it has been robbed of it all, except about 30°. The regenerator in the 60-horse engine measures 26 inches in height and width, inter- nally. Each disk of wire composing it contains 676 superficial inches, and the net lias 10 meshes to the inch. Each superficial inch, therefore, contains 100 meshes, which, multiplied by 676, gives 67,600 meshes in each disk ; and, as 200 disks are employed, it follows that the regenerator contains 13,520,000 meshes; and consequently, as there are as many spaces between the disks as there are meshes, we find that the air within it is distributed in abqut 27,000,000 minute cells. Thence every particle of air, in passing through the regen- erator, is brought into very close contact with a surface of metal which heats and cools it alternately. Upon this action of the regenerator, Ericsson’s Calorific Engine depends. In its application on the large scale, contemplated in the great Atlantic steamer called the “ Ericsson,” the result was not satisfactory. We may, however, notwithstanding this result safely predicate, from the investigation of Messrs. Thomson and Joule, that the expansion of air by heat will eventually, in some conditions, take the place of steam as a motive power. AIR-GUN. This is a weapon in which the elastic force of air is made use of to project the ball. It is so arranged, that in a cavity in the stock of the gun, air can be, by means of a piston, powerfully condensed. Here is a reserved force, which, upon its being relieved from pressure, is at once exerted. When air has been condensed to about A_ of its bulk, it exerts a force which is still very inferior to that of gunpowder. In many other respects the air-gun is but an imperfect weapon, consequently it is rarely employed. AIRO-HYDROGEN BLOWPIPE. A blowpipe in which air is used in the place of oxygen, to combine with and give intensity of heat to a hydrogen flame for the purposes of soldering. See Autogenous Soldering. ALABASTER, Gypsum^ Plaster of Paris {Alhdtre^ Fr. ; Alabaster^ Germ.), a sulphate of lime. (See Alabaster, Oriental.) When massive, it is called indifferently alabaster or gypsum ; and when in distinct and separate crystals, it is termed selenite. Massive alabas- 26 ALABASTER, ORIENTAL. ter occurs in Britain in the new red or keuper 'marl : in Glamorganshire, on the Bristol Channel ; in Leicestershire, at Syston ; at Tutbury and near Burton-on-Trent, in Stafford- shire ; at Chellaston, in Derbyshire ; near Droitwich it is associated in the marl with rock salt, in strata respectively 40 and 75 feet in thickness ; and at North wich and elsewhere the red marl is intersected with frequent veins of gypsum. At Tutbury it is quarried in the open air, and at Chellaston in caverns, where it is blasted by gunpowder ; at both places it is burned in kilns, and otherwise prepared for the market. It lies in irregular beds in the marl, that at Chellaston being about 30 feet thick. There is, however, reason to suppose that it was not originally deposited along with the marl as sulphate of lime, but rather that calcareous strata, by the access of sulphuric acid and water, have been converted into sul- phate of lime, — a circumstance quite consistent with the bulging of the beds of marl with which the gypsum is associated, the lime, as a sulphate, occupying more space than it did in its original state as a carbonate. At Tutbury and elsewhere, though it lies on a given general horizon, yet it can scarcely be said to be truly bedded, but ramifies among the beds and joints of the marl in numerous films, veins, and layers of fibrous gypsum. A snow-white alabaster occurs at Volterra, in Tuscany, much used in works of art in Florence and Leghorn. In the Paris basin it occurs as a granular crystalline rock, in the Lower Tertiary rocks, known to geologists as the upper part of the Middle Eocene fresh- water strata. It is associated with beds of white and green marls ; but in the Thuringewald there is a great mass of sulphate of lime in the Permian strata. It has been sunk through to a depth of 70 feet, and is believed to be metamorphosed magnesian limestone or Zech- stein. In the United States this calcareous salt occurs in numerous lenticular masses in marly and sand strata, of that part of the Upper Silurian strata known as the Onondaga salt group. It is excavated for agricultural purposes. For mineralogical character, &c., see Gypsum, — A. C. R. The gypsum of our own country is found, in apparently inexhaustible quantities, in the red marl formation in the neighborhood of Derby, and has been worked for many centuries. The great bulk of it is used for making plaster of Paris, and as a manure ; and it is the basis of many kinds of cements, patented — as Keene’s, Martin’s, and others. To get it for these purposes, it is worked by mining underground, and the stone is blasted by gunpowder ; but this shakes it so much as to be unfit for working into orna- ments, &c. ; to procure blocks for which it is necessary to have an open quarry. By removing the superincumbent marl, and laying bare a large surface of the rock, the alabaster being very irregular in form, and jutting out in several parts, allows of its being sawn out in blocks of considerable size, and comparatively sound, (as is illustrated by the large tazza in the Museum of Practical Geology.) This stone, when protected from the action of water, is extremely durable, as may be seen in churches all over the country, where monumental effigies, many centuries old, are now as perfect as the day they were made, excepting, of course, wilful injuries ; but exposure to rain soon decomposes the stone, and it must be borne in mind that it is perfectly unsuited for garden vases or other^out-door work in tliis country. In working, it can be sawn up into slabs with toothed saws, and for working mouldings and sculptures, fine chisels, rasps, and files are the implements used ; the polishing is per- formed by rubbing it with pieces of sandstone, of various degrees of fineness, and water, until it is quite free from scratches, and then giving a gloss by means of polishing powder (oxide of tin) applied on a piece of cloth, and rubbed with a considerable degree of friction on the stone. This material gives employment in Derby to a good many hands in forming it into useful and ornamental articles, and is commonly called Derbyshire Spar ; most of the articles are turned in the lathe, and it works something like very hard wood. Another kind of gypsum also found in Derbyshire is the fibrous or silky kind ; it occurs in thin beds, from one to six inches in depth, and is crystallized in long needle-like fibres ; being easily worked, susceptible of a high polish, and quite lustrous, it is used for making necklaces, bracelets, brooches, and such like small articles. — S. H. ALABASTER, ORIENTAL. Oriental alabaster is a form of stalagmitic or stalactitic carbonate of lime, an Egyptian variety of which is highly esteemed. It is also procured from the Pyrenees, from Chili, and from parts of the United States of America. Ancient quarries are still in existence in the province of Oran, in Algeria. ALBATA PLATE, a name given to one of the varieties of white metal now so com- monly employed. See Copper, and Alloys. ALBUM GR^CUM. The white faeces of dogs. After the hair has been removed from skins, this is used to preserve the softness of them, and prepare them for the tan-pit. Fowls’ dung is considered by practical tanners as superior to the dung of dogs, and this is obtained as largely as possible. These excreta may be said to be essentially phosphate of lime and mucus. We are informed that various artificial compounds which represent, chemically, the conditions of those natural ones, have been tried without producing the same good results. It is a reflection on our science, if this is really the case. ALBUMEN. {Album Ovi.) Albumen is a substance which forms a constituent part ALCOHOL. 27 of the animal fluids and solids, and which is also found in the vegetable kingdom. It exists nearly pure in the white of egg. Albumen consists of — Carbon, . . . . . • . 53’32 Hydrogen, . . . . • • V’29 Nitrogen, ....... IS’Y Sulphur, . . . . . . 1'3 Oxygen, ....... 22-39 Its Formula being S’ N” H*®’ 0®®. Albumen coagulates by heat, as is illustrated in the boiling of an egg. The salts of tin, bismuth, lead, silver, and mercury form with albumen white insoluble precipitates ; therefore, in cases of poisoning by corrosive sub- limate, nitrate of silver, or sugar of lead, the white of egg is the best antidote which can be administered. Albumen is employed in Photography, which see. We imported the following quantities of albumen : — in 1855, 275 cwts. ; in 1856, 382 cwts. ALCOHOL. (^Alcool., Fr. ; Alkohol^ or Weingeist, Germ.) The word alcohol is de- rived from the Hebrew word “ kohol,'^ to paint. The oriental females were and are still in the habit of painting the eyebrows with various pigments ; the one generally em- ployed was a preparation of antimony, and to this the term was generally applied. It became, however, gradually extended to all substances used for the purpose, and ultimately to strong spirits, which were employed, probably, as solvents for certain coloring principles. The term was subsequently exclusively used to designate ardent spirits, and ultimately the radical or principle upon which their strength depends. As chemistry advanced, alcohol was found to be a member only of a class of bodies agreeing with it in general characters ; and hence the term is now generic, and we speak of the various alcohols. Of these, common or vinous alcohol is the best known ; and, in common life, by “ alcoholic liquors,” we invariably mean those containing the original or vinous alcohol. When the characters of ordinary alcohol have been stated, allusion will be made to i;he class of bodies of which this is the type. Fermented liquors were known in the most remote ages of antiquity. We read (Gene- sis ix.) that after the flood “ Noah planted a vineyard, and he drank of the wine and was drunken.” Homer, who certainly lived 900 years before the Christian era, also frequently mentions wine, and notices its effects on the body and mind (Odyssey IX. and XXL) ; and Herodotus tells us that the Egyptians drank a liquor fermented from barley. The period when fermented liquors were submitted to distillation, so as to obtain “ ardent sph'its^^ is shrouded in much obscurity. Raymond Lully^ was acquainted with “ spirits of wine,” which he called aqua ardens. The separation of absolute alcohol would appear to have been first effected about this period (1300), by Arnauld de Villeneuve, a celebrated physician residing in Montpellier (Gerhardt), and its analysis was first performed by Th. de Saussure.f The preparation of alcohol may be divided into three stages ; — 1. The production of a fermented vinous liquor — the Fermentation. 2. The preparation from this of an ardent spirit — the Distillation. 3. The separation from this ardent spirit of the last traces of water — ^the Rectification. 1. Fermentation. The term “fermentation” is now applied to those mysterious changes which vegetable (and animal) substances undergo when exposed, at a certain tem- perature, to contact with organic or even organized bodies in a state of change. There are several bodies which suffer these metamorphoses, and under the influence of a great number of different exciting substances, which are termed the “ ferments ;” more- over, the resulting products depend greatly upon the temperature at which the change takes place. The earliest known and best studied of these processes is the one commonly recognized as the vinous or alcoholic fermentation. In this process solutions containing sugar — either the juice of the grape (see Wine) or an infusion of germinated barley, malt, (see Beer) — are mixed with a suitable quantity of a ferment ; beer or wine yeast is usually employed (see Yeast), and the whole maintained at a temperature of between 70° and 80° F. (21° to 26° C.) Other bodies in a state of putrefactive decomposition will effect the same result as the yeast, such as putrid blood, white of egg, &c. The liquid swells up, a considerable quantity of froth collects on the surface, and an abundance of gas is disengaged, which is ordinary carbonic acid (CO’). The composition of (pure) alcohol is expressed by the formula C* H® O’, and it is produced in this process * Thomson’s History of Chemistry, i. 41. (1830.) t Annales de Chimie, xlii. 225. ALCOHOL. 28 by the breaking up of an equivalent of grape sugar^ 0*®, into 4 equivalents of alco- hol, 8 of carbonic acid, and 4 of water — JJ-^S 028 016 JJ24 08 - 4 (04 06 02) 08 J£4 020 0^ =4 HO C“ O'® = 8 C0= It is invariably the grape sugar which undergoes this change ; if the solution contains cane sugar, the cane sugar is first converted into grape sugar under the influence of the ferment. See Sugar. Much diversity of opinion exists with respect to the office which the ferment performs in this process, since it does not itself yield any of the products. See Fermentation. The liquid obtained by the vinous fermentation has received different names, according to the source whence the saccharine solution was derived. When procured from the ex- pressed juice of fruits — such as grapes, currants, gooseberries, &c. — the product is denomi- nated wine ; from a decoction of malt, ale or beer ; from a mixture of honey and water, mead; from apples, cider ; from the leaves and small branches of the spruce-fir {ahies excelsa, &c.), together with sugar or treacle, spruce ; from rice, rice beer (which yields the spirit arrack) ; from cocoa-nut juice, palm wine. It is an interesting fact that alcohol is produced in very considerable quantities (in the aggregate) during the raising of bread. The carbonic acid which is generated in the dough, and which during its expulsion raises the bread, is one of the products of the fermentation of the sugar in the flour, under the influence of the yeast added ; and of course at the same time the complementary product, alcohol, is generated. As Messrs. Ronalds and Richardson remark :* “ The enormous amount of bread that is baked in large towns — in London, for instance, 8.8 millions of cwts. yearly — would render the small amount of alcohol contained in it of sufficient importance to be worth collecting, provided this could be done sufficiently cheaply.” In London it has been estimated that in this way about 800,000 gallons of spirits are annually lost ; but the cost of collecting it would far exceed its value. 2. Distillation. By the process of distillation., ardent spirits are obtained, which have likewise received different names according to the sources whence the fermented liquor has been derived : viz. that produced by the distillation of wine being called brandy, and in France cognac, or eau de vie ; that produced by the distillation of the fermented liquor from sugar and molasses, rum. There are several varieties of spirits made from the fer- mented liquor procured from the cereals (and especially barley), known according to their peculiar methods of manufacture, flavor, &c. — as whiskey, gin, Hollands — the various compounds and liqueurs. In India, the spirit obtained from a fermented infusion of rice is called arrack. 3. Rectification ; preparation of absolute alcohol. It is impossible by distillation alone to deprive spirit of the whole of the water and other impurities — to obtain, in fact, pure or absolute alcohol. This is effected by mixing with the liquid obtained after one or two distillations, certain bodies which have a powerful attraction for water. The agents commonly employed for this purpose are quicklime, carbonate of potash, anhydrous sulphate of copper, or chloride of calcium. Perhaps the best adapted for the purpose, especially where large quantities are required, is quicklime ; it is powdered, mixed in the retort with the spirit (previously twice distilled), and the neck of the retort being securely closed, the whole left for 24 hours, occasionally shaking ; during this period the lime combines with the water, and then on carefully distilling, avoiding to continue the process until the last portions come over, an alcohol is obtained which is free from water. If not quite free, the same process may be again repeated. In experiments on a small scale, an ordinary glass retort may be employed, heated by a water-bath, and fitted to a Liebig’s condenser cooled by ice-water, which passes lastly into a glass receiver, similarly cooled. Although alcohol of sufficient purity for most practical purposes can be readily ob- tained, yet the task of procuring absolute alcohol entirely free from a trace of water, is by no means an easy one. Mr. Drinkwaterf effected this by digesting ordinary alcohol of specific gravity .850 at 60° F. for 24 hours with carbonate of potash previously exposed to a red heat ; the alcohol was then carefully poured off and mixed in a retort with as much fresh-burnt quicklime as was sufficient to absorb the whole of the alcohol ; after digesting for 48 hours, it was slowly * Chemical Technology, by I)r. F. Knapp : edited by Messrs. Eonalds and Eichardson. Yol. iii. 198. t On the Preparation of Absolute Alcohol, and the Composition of Proof Spirit. See Memoirs of the Chemical Society, vol. iii. p. 447. ALCOHOL. 29 distilled in a water-bath at a temperature of about 180'’ F. This alcohol was carefully re- distilled, and its specific gravity at 60° F. found to be •'7947, which closely agrees with that given by Gay-Lussac as the specific gravity of absolute alcohol. He found, moreover, that recently ignited anhydrous sulphate of copper was a less efficient dehydrating agent than quicklime. Graham recommends that the quantity of lime employed should never exceed three times the weight of the alcohol. Chloride of calcium is not so well adapted for the purification of alcohol, since the alcohol forms a compound with this salt. Many other processes have been suggested for depriving alcohol of its water. A curious process was proposed many years ago by Soemmering,* which is dependent upon the peculiar fact, that whilst water moistens animal tissues, alcohol does not, but tends rather to abstract water from them. If a mixture of alcohol and water be enclosed in an ox bladder, the water gradually traverses the membrane and evaporates, whilst the alcohol does not, and consequently by the loss of water the spirituous solution becomes con- centrated. This process, though an interesting illustration of exosmo'Je, is not practically applicable to the production of anhydrous alcohol ; it is, however, an economical method, and well suited for obtaining alcohol for the preparation of varnishes. Smugglers, who bring spirits into France in bladders hid about their persons, have long known, that although the liquor decreased in bulk, yet it increased in strength ; hence the people preferred the article con- veyed clandestinely. Prof. Graham has ingeniously proposed to concentrate alcohol as follows : “ A large shallow basin is covered, to a small depth, with recently burnt quicklime, in coarse powder, and a smaller basin, containing three or four ounces of commercial alcohol, is made to rest upon the lime ; the whole is placed under the low receiver of an air-pump, and the exhaustion continued till the alcohol evinces signs of ebullition. Of the mingled vapors of alcohol and water which now fill the receiver, the quicklime is capable of uniting with the aqueous only, which is therefore rapidly withdrawn, while the alcohol vapor is un- affected ; and as water cannot remain in the alcohol as long as the superincumbent atmos- phere is devoid of moisture, more aqueous vapor rises, which is likewise abstracted by the lime, and thus the process goes on till the whole of the water in the alcohol is removed. Several days are always x’equired for this purpose. Properties of Alcohol. — Absolute. In the state of purity, alcohol is a colorless liquid, highly inflammable, burning with a pale blue flame, very volatile, and having a density of 0‘792 at 16’5° C. (60° F.) {Drink- water.) It boils at 78-4° C. (173° F.) It has never yet been solidified, and the density of its vap^r is 1-6133. Anhydrous alcohol is composed by weight of 52*18 carbon, 13’04 hydrogen, and 34‘78 of oxygen. It has for its symbol 0‘^ = IP 0 HO, or hydrated oxide of ethyle. It has a powerful affinity for water, removing the water from moist substances with which it is brought in contact. In consequence of this property, it attracts water from the air, and rapidly becomes weaker, unless kept in very well-stopped vessels. In virtue of its attraction for water, alcohol is very valuable for the preservation of organic substances, and especially of anatomical preparations, in consequence of its causing the coagulation of albuminous substances ; and for the same reason it causes death when injected into the veins. When mixed with water a considerable amount of heat is evolved, and a remarkable contraction of volume is observed ; these effects being greatest with 54 per cent, of alco- hol and 46 of water, and thence decreasing with a greater proportion of water. For alco- hol which contains 90 per cent, of water, this condensation amounts to 1’94 per cent, of the volume ; for 80 per cent., 2*87 ; for 70 per cent., 3*44 ; for 60 per cent., 3’73 ; for 40 per cent., 3*44 ; for 30 per cent., 2*72 ; for 20 per cent., 1*72 ; for 10 per cent., 0*72. Alcohol is prepared absolute for certain purposes, but the mixtures of alcohol and water commonly met with in comrq£rce are of an inferior strength. Those commonly sold are “Rectified Spirit,” and “Proof Spirit.” “Proof Spirit” is defined by Act of Parliament, 58 Geo. III. c. 28, to be “such as shall, at the temperature of fifty-one degrees of Fahrenheit’s thermometer, weigh exactly twelve-thirteenth parts of an equal measure of distilled water,” And by very careful experi- ment, Mr. Drinkwater has determined that this proof spirit has the following composition : — Alcohol and Tratcr. Specific Gravity at 00° F. Bulk of the mixture of 100 measures of Alcohol, By weight. By measure. and S1*S2 of Water. Alcohol. W ater. 100 -f 103*09 49-100 -j- 50*76 Alcohol. 100 ■\V ater. 81*82 •919. 175*25 * Soummering. “Denkschriften d. K. Akad. d. Wissenchaften zu Munschen,” 1711 to 1S24. 30 ALCOHOL. Spirit which is weaker is called “ under proof and that stronger, “ above proof.” The origin of these terms is as follows : — Formerly a very rude mode of ascertaining the strength of spirits was practised, called the proof; the, spirit was poured upon gunpowder and inflamed. If, at the end of the combustion, the gunpowder took fire, the spirit was said to be above or over proof. But if the spirit contained much water, the powder was rendered so moist that it did not take fire : in which case the spirit was said to be under or below proof. Rectified spirit contains from 64 to 64 per cent, of absolute alcohol ; and its specific gravity is fixed by the London and Edinburgh Colleges of Physicians at 0*838, whilst the Dublin College fixes it at 0.840. In commerce the strength of mixtures of alcohol and water is stated at so many degrees, according to Sykes's hydrometer, above or below proof. This instrument will be explained under the head of Alcoholometry. As will have been understood by the preceding remarks, the specific gravity or density of mixtures of alcohol and water rises with the diminution of the quantity of alcohol present ; or, in other words, with the amount of water. And since the strength of spirits is deter- mined by ascertaining their density, it becomes highly important to determine the precise ratio of this increase. This increase in density, with the amount of water, or diminution with the quantity of alcohol, is, however, not directly proportional, in consequence of the contraction of volume which mixtures of alcohol and water suffer. It therefore became necessary to determine the density of mixtures of known composi- tion, prepared artificially. This has been done recently with great care by Mr. Drink- water and the following table by him is recommended as one of the most accurate : Table of the Quantity of Alcohol, by weight, contained in Mixtures of Alcohol and Water of the following Specific Gravities : — Specific Gravity at 60“ F. Alcohol, per cent, by weight. Specific Gravity at 60° F. Alcohol, per cent, by weight. Specific Gravity at 60° F. Alcohol,^ per 1 cent, by weight. Specific Gravity at 60° F. Alcohol, I)cr cent, by weight. Specific Gravity at 60° F. Alcohol, per cent. by 1 weight. 1-0000 0*00 •9907 1-78 •9934 3-67 •9901 5-70 •9869 7-85 •9999 0-05 •9966 1-83 •9933 3*73 •9900 5-77 •9868 7-92 •9998 0-11 •9905 1-89 •9932 3-78 •9899 6-83 •9867 7-99 •9997 0-16 •9964 1-94 •9931 3-84 •9898 5*89 •9866 8-06 •9996 0-21 •9963 1-99 •9930 3-90 •9897 5-96 •9865 8-13 •9995 0*26 •9962 2-05 •9929 3-96 •9896 6-02 •9864 8-20 •9994 0-32 •9961 2-11 •9928 4*02 •9895 6-09 •9863 8*27 •9993 0-37 •9900 2-17 •9927 4-08 •9894 6-15 •9862 8-34 •9992 0-42 •9959 2-22 •9926 4-14 •9893 6-22 •9861 8-41 •9991 0-47 •9958 2-28 •9925 4-20 •9892 6*29 •9860 8*48 •9990 0*53 •9957 2*34 •9924 4-27 •9891 6*35 •9859 8-55 •9989 0-58 •9956 2-39 •9923 4*33 •9890 6-42 •9858 8-62 •9988 0-64 •9955 2*45 •9922 4*39 •9889 6-49 •9857 8-70 •9987 0*69 •9954 2-51 •9921 4-45 •9888 6*55 •9856 8-77 •9986 0*74 •9953 2*57 •9920 4-51 •9887 6-62 •9855 8-84 •9985 0-80 •9952 2*62 •9919 4-57 •9886 6*69 •9854 8-91 •9984 0*85 •9951 2-68 •9918 4*64 •9885 6*75 •9853 8*98 •9983 0-91 •9950 2-74 ■ •9917 4-70 •9884 6-82 •9852 9*05 •9982 0-96 •9949 2-79 •9916 4-76 •9883 6-89 •9851 9-12 •9981 1*02 •9948 2*85 •9915 4-82 •9882 6-95 •9850 9-20 •9980 1*07 •9947 2-91 •9914 4*88 •9881 7*02 •9849 9-27 •9979 1-12 •9946 2-97 •9913 4-94 •9880 7-09 •9848 9-34 •9978 1-18 •9945 3-02 •9912 5*01 •987" 7*16 •9847 9-41 •9977 1-23 •9944 3-08 •9911 5*07 •9878 7-23 •9846 9*49 •9976 1-29 •9943 3-14 •9910 5*13 •9877 7-30 •9845 9-56 •9975 1-34 •9942 3-20 •9909 5*20 •9876 7*37 •9844 9*63 •9974 1-40 •9941 3-26 •9908 5*26 •9875 7*43 •9843 9-70 •9973 1-45 •9940 3*32 •9907 5*32 •9874 7-50 •9842 9-78 •9972 1-51 •9939 3*37 •9906 5-39 •9873 7*57 •9841 9-85 •9971 1-56 •9938 3*43 •9905 5-45 •9872 7-64 •9840 9-92 •9970 1-01 •9937 3*49 •9904 5-51 •9871 7*71 •9839 9*99 •9969 1*67 •9936 3-55 •9903 5*58 •9870 7-78 ■9838 10*07 •9908 1-73 •9935 3-61 •9902 5*64 * Memoirs of tho Chemical Society, vol. iii. p. 454. ALCOHOL. 31 The preceding table, though very accurate so far as it goes, is not sufficiently extensive for practical purposes, only going, in fact, from 6 to 10 per cent, of alcohol ; the table of Tralle’s (below) extends to 50 per cent, of absolute alcohol. Moreover, Drinkwater’s table has the (practical) disadvantage (though scientifically more correct and useful) of stating the percentage by weight ; whereas, in Trade’s table, it is giveji by volume. And since liquors are vended by measure, and not by weight, the centesimal amount by volume is usually preferred. But as the bulk of liquids generally, and par- ticularly that of alcohol, is increased by heat, it is necessary that the statement of* the den- sity in a certain volume should have reference to some normal temperature. In the construction of Trade’s table the temperature of the liquids was 60° F. ; and, of course, in using it, it is necessary that the density should be observed at that temperature. In order to convert the statement of the composition hg volume into the content by weight, it is only necessary to multiply the percentage of alcohol by volume by the specific gravity of absolute alcohol, and then divide by the specific gravity of the liquid. Trailers Table of the Composition, by volume, of Mixtures of Alcohol and Water of different Densities. Per- centage of Alcohol by volume. Specific Gravity at 60“ F. Differ- ence of the spe- cific gra- vities. Per- centage of Alcohol by volume. Specific Gravity at 60* F. Differ- ence of the spe- cific gra- vities. Per- centage of Alcohol by volume. Specific Gravity at 60“ F. Differ- ence of the spe- cific gra- vities. 0 0-9991 34 0-9596 13 68 0-8941 24 1 0-9976 15 35 0-9583 13 69 0-8917 24 2 0-9961 15 , 36 0-9570 13 70 0-8892 25 3 0-9947 14 37 0-9556 14 71 . 0-8867 25 4 0-9933 14 38 0-9541 15 72 0-8842 25 6 0-9919 14 39 0-9526 15 73 0-8817 25 6 0-9906 13 40 0-9510 16 74 0*8791 26 V 0-9893 13 41 0-9494 16 75 0-8765 26 8 0-9881 12 42 0-9478 16 76 0-8739 26 9 0-9869 12 43 0-9461 17 77 0-8712 27 10 0-9857 12 44 0-9444 17 78 0-8685 • 27 11 0*9845 12 45 0-9427 17 79 0-8658 27 12 0-9834 11 46 0-9409 18 80 0-8631 27 13 0-9823 11 47 0-9391 18 81 0-8603 28 14 0-9812 11 48 0*9373 18 82 0-8575 1 28 15 ■ 0-9802 10 49 0-9354 19 83 0-8547 : 28 16 0-9791 11 50 0-9335 19 84 0-8518 29 17 0-9781 10 51 0-9315 20 85 0-8488 30 18 0-9771 10 52 0-9295 20 86 0-8458 30 19 0-9761 10 53 0*9275 20 87 0*8428 30 20 0-9751 10 54 0-9254 21 88 0*8397 31 21 0*9741 10 55 0-9234 20 89 0-8365 32 22 0-9731 10 56 0*9213 21 90 0*8332 33 23 0-9720 11 57 0*9192 21 91 0-8299 ! 33 24 0-9710 10 68 0-9170 22 92 0-8265 34 25 0-9700 10 59 0*9148 22 93 0-8230 35 26 0*9689 11 60 0-9126 22 94 0*8194 36 27 0*9679 10 61 0-9104 22 95 0-8157 37 28 0*9668 11 62 0-9082 22 96 0-8118 39 29 0-9657 11 63 0-9059 23 97 0-8077 41 30 0*9646 11 64 0-9036 23 98 0-8034 43 31 0-9634 12 65 0*9013 23 99 0-7988 46 32 0-9622 12 66 0*8989 24 100 0-7939 49 33 0-9609 13 67 0*8965 24 In order, however, to employ this table for ascertaining the strength of mixtures of alcohol and water of different densities (which is the practical use of such tables), it is absolutely necessary that the determinatibn of the density should be performed at an inva- riable temperature, — viz. 60° F. The methods of determining the density will be hereafter described ; but it is obvious that practically the experiment cannot be conveniently made at any fixed temperature, but must be performed at that of the atmosphere. ALCOHOL. 32 The boiling point of mixtures of alcohol and water likewise differs with the stength of such mixtures. According to Gay-Lussac, absolute alcohol boils at '78*4° C. (1'73° F.) under a pressure of 760 millimetres {the millimetre being 0*03937 ]£7iglish inches). When mixed with water, of course its boiling point rises in proportion to the quantity of water present, as is the case in general with mixtures of two fluids of greater and less volatility. A mixture of alcohol and water, however, presents this anomaly, according to Soemmering : when the mixture contains less than six per cent, of alcohol, those portions which first pass off are saturated with water, and the alcoholic solution in the retort becomes richer, till absolute alcohol passes over ; but when the mixture contains more than six per cent, of water, the boiling ^ point rises, and the quantity of alcohol in the distillate steadily diminishes as the distillation proceeds. According to Groning’s researches, the following temperatures of the alcoholic vapors correspond to the accompanying contents of alcohol in percentage of volume which are disengaged in the boiling of the spirituous liquid. Temperature. Alcoholic con- tent of the vapoi*. Alcoholic con- tent of the boiling liquid. Temperature. Alcoholic con- tent of the vapor. Alcoholic con- tent of the boiling liquid. Fahr. 170*0 93 92 Fahr. 189*8 71 20 171*8 92 90 192*0 68 18 172 91 85 164 66 15 172*8 90i 80 196*4 61 12 174 90 70 198*6 65 10 174*6 89 70 201 50 7 176 87 65 203 42 6 178*3 85 60 205*4 36 3 180*8 82 40 207*7 28 2 183 80 85 210 13 1 185 78 30 212 0 0 187*4 76 25 Groning undertook this investigation in order to employ the thermometer as an alcoho- lometer in the distillation of spirits ; for which purpose he thrust the bulb of the thermom- eter through a cork inserted into a tube fixed in the capital of the still. The state of the barometer ought also to be considered in making comparative experiments of this kind. Since, by this method, the alcoholic content may be compared with the temperature of the vapor that passes over at any time, so, also, the contents of the whole distillation may be found approximately ; and the method serves as a convenient means of making continual observations on the progress of the distillation. Density of the Vapor. — One volume of alcohol yields 488*3 volumes of vapor at 212° F. The specific gravity of the vapor, taking air as unity, was found by Gay-Lussac to be 1*6133. [Its vapor-density, referred to hydrogen, as unity, is 13*3605 ?] Spirituous vapor passed through an ignited tube of glass or porcelain is converted into carbonic oxide, water, hydrogen, carburetted hydrogen, olefiant gas, naphthaline, empyreu- matic oil, and carbon ; according to the degree of heat and nature of the tube, these products vary. Anhydrous alcohol is a non-conductor of electricity, but is decomposed by a powerful voltaic battery. Alcohol burns in the air with a blue flame into carbonic acid and water ; the water being heavier than the spirit, because 46 parts of alcohol contain 6 of hydrogen, which form 54 of water. In oxygen the combustion is accompanied with great heat, and this flame, directed through a small tube, powerfully ignites bodies exposed to it. Platinum in a finely divided state has the property of determining the combination of alcohol with the oxygen of the air in a remarkable manner. A ball of spongy platinum, placed slightly above the wick of a lamp, fed by spirit, and communicating with the wick by a platinum wire, when once heated, keeps at a red heat, gradually burning the spirit. This has been applied in the construction of the so-called “ philosophical pastilles ; ” eau-de- cologne or other perfumed spirit being thus made to diffuse itself in a room. Mr. Gill has also practically applied this in the construction of an alcohol lamp without flame. A coil of platinum wire, of about the one-hundreth part of an inch in thickness, is coiled partly round the cotton wick of a spirit lamp, and partly above it, and the lamp lighted to heat the wire to redness ; on the flame being extinguished, the alcohol vapor keeps the wire red hot for any length of time, so as to be in constant readiness to ignite a match, for example. This lamp affords sufficient light to show the hour by a watch in the night, with a very small consumption of spirit. ALCOHOL. 33 i: This property of condensing oxygen, and thus causing the union of it with combustible bodies, is not confined to platinum, but is possessed, though in a less degree, by other porous bodies. If we moisten sand in a capsule with absolute alcohol, and cover it with previously heated nickel powder, protoxide of nickle, cobalt powder, protoxide of cobalt, protoxide of uranium, or oxide of tin (these six bodies being procured by ignition of their oxalates in a crucible), or finely powdered peroxide of manganese, combustion takes place, and continues so long as the spirituous vapor lasts. Solvent Power, — One of the properties of alcohol most valuable in the arts is its solvent power. It dissolves gases to a very considerable extent, which gases, if they do not enter into com- binations with the alcohol, or act chemically upon it, are expelled again on boiling the alcohol. Several salts, especially the deliquescent, are dissolved by it, and some of them give a color to its flame ; thus the solutions of the salts of strontia in alcohol burn with a crimson flame^ those of copper and borax with a green one, lime a reddish^ and baryta with a yellow flame. This solvent power is, however, most remarkable in its action upon resins, ethers, essen- tial oils, fatty bodies, alkaloids, as well as many organic acids. In a similar way it dissolves iodine, bromine, and in small quantities sulphur and phosphorus. In general it may be said to be an excellent solvent for most hydrogenized organic substances. In consequence of this property it is most extensively used in the chemical arts ; e. g. for the solution of gum-resins, &c., in the manufacture of varnishes ; in pharmacy, for the separating of the active principles of plants, in the preparation of tinctures. It is also em- ployed in the formation of chloroform, ether, spirits of nitre, &c. Methylated Spirit. — It was, therefore, for a long time a great desideratum for the manufacturer to obtain spirit free from duty. The Government, feeling the necessity for this, have sanctioned the sale of spirit which has been flavored with methyl-alcohol, so as to render it unpalatable, free of duty under the name of “ methylated spirit."'^ This methylated spirit can now be obtained, in large quantities only, and by giving suitable security to the Board of Inland Revenue of its employment for manufacturing purposes only, and must prove of great value to those manufacturers who are large consumers. Professors Graham, Hoffmann, and Redwood, in their “ Report on the Supply of Spirit of Wine, free of duty, for use in the Arts and Manufactures,” addressed to the Chairman of the Board of Inland Revenue, came to the following conclusions : — “ From the results of this inquiry, it has appeared that means exist by which spirit of wine, produced in the usual way, may be rendered unfit for human consumption, as a beverage, without materially impairing it for the greater number of the more valuable pur- poses in the arts to which spirit is usually applied. To spirit of wine, of not less strength than corresponds to density 0‘830, it is proposed to make an addition of 10 per cent, of purified wood naphtha {wood or methylic spirit)^ and to issue this mixed spirit for consump- tion, duty free, under the name of Methylated Spirit. It has been shown that methylated spirit resists any process for its purification ; the removal of the substance added to the spirit of wine being not only difficult, but, to all appearance, impossible ; and further, that no danger is to be apprehended of the methylated spirit being ever compounded so as to make it palatable. . . It may be found safe to reduce eventually the proportion of the mixing ingredient to 5 per cent., or even a smaller proportion, although it has been recommended to begin with the larger proportion of 10 per cent.” And further, the authors justly remark : — “ The command of alcohol at a low price is sure to suggest a multitude of improved processes, and of novel applications, which can scarcely be anticipated at the present moment. It will be felt far beyond the limited range of the trades now more immediately concerned in the consumption of spirits ; like the repeal of the duty on salt, it will at once most vitally affect the chemical arts, and cannot fail, ultimately, to exert a beneficial influence upon many branches of industry.” And in additional observations, added subsequently to their original report, the chem- ists above named recommend the 'following restriction upon the sale of the methylated spirit : — “ That the methylated spirit should be issued by agents duly authorized by the Board of Inland Revenue, to none but manufacturers, who should themselves consume it ; and that application should always be made for it according to a recognized form, in which, besides the quantity wanted, the applicant should state the use to which it is to be applied, and undertake that it should be applied for that purpose only. The manufacturer might be permitted to retail varnishes and other products containing the methylated spirit, but not the methylated spirit itself, in an unaltered state.” They recommend that the methylated spirit should not be made with the ordinary crude, very impure wood naphtha, since this could not be advantageously used as a solvent for resins by hatters and varnish-makers, as the less volatile parts of the naphtha would be retained by the resins after the spirit had evaporated, and the quality of the resin would be thus impaired. If, however, the methy- lated spirit be originally prepared with the crude wood naphtha, it may be purified by a simple distillation from 10 per cent, of potash. VoL. III.— 3 34 ALCOHOLOMETKY. It appears that the boon thus afforded to the manufacturing community of obtaining spirit duty free has been acknowledged and appreciated ; and now for most purposes, where the small quantity of wood-spirit does not interfere, the methylated spirit is generally used. It appears that even ether and chloroform, which one would expect to derive an un- pleasant flavor from the wood-spirit, are now made of a quality quite unobjectionable from the methylated spirit ; but care should be taken, especially in the preparation of medicinal compounds, not to extend the employment of the methylated spirit beyond its justifiable limits, lest so useful an article should get into disrepute.* Methylated spirit can be pro- cured also in small quantities from the wholesale dealers, containing in solution 1 oz. to the gallon of shellac, under the name of “ finish.” Alcoholates. — Graham has shown that alcohol forms crystallizable compounds with several salts. These bodies, which he calls “ Alcoholates f are in general rather unstable combinations, and almost always decomposed by w^ater. Among the best known are the following : — Alcoholate of chloride of calcium ... 2 C^H'^0^, Ca Cl “ “ of zinc - - - Zn Cl “ bichloride of tin ... CMPO^, Tn Cl “ nitrate of magnesia • - . 3 Mg 0, NO 5 ALCOHOLOMETKY, or ALCOOMETRY. Determination of the Strength of Mixtures of Alcohol and Water. Since the commercial value of the alcoholic liquors, commonly called “ spirits,” is determined by the amount of pure or absolute alcohol present in them, it is evident that a ready and accurate means of determining this point is of the highest importance to all persons engaged in trade in such articles. If the mixture contain nothing but alcohol and water, it is only necessary to determine the density or specific gravity of such a mixture ; if, however, it contain saccharine matters, coloring principles, &c., as is the case with wine, beer, &c., other processes become neces- sary, which will be fully discussed hereafter. The determination of the specific gravity of spirit, as of most other liquids, may be effected, with perhaps greater accuracy than by any other process, by means of a stoppered specific gravity bottle. If the bottle be of such a size as exactly to hold 1,000 grains of distilled water at 60° F., it is only necessary to weigh it full of the spirit at the same tem- perature, when (the weight of the bottle being known) the specific gravity is obtained by a very simple calculation. See Specific Gravity. This process, though very accurate, is somewhat troublesome, especially to persons unaccustomed to accurate chemical experiments, and it involves the possession of a delicate balance. The necessity for this is however obviated by the employment of one of the many modifications of the common hydrometer. This is a floating instrument, the use of which depends upon the principle, that a solid body immersed into a fluid is buoyed upwards with a force equal to the weight of the fluid which it displaces, i. c. to its own bulk of the fluid ; consequently, the denser the spirituous mixture, or the less alcohol it contains, the higher will the instrument stand in the liquid ; and the less dense, or the more spirit it contains, the lower will the apparatus sink into it. There are two classes of hydrometers : 1st. Those which are always immersed in the fluid to the same depth, and to which weights are added to adjust the instrument to the density of any particular fluid. Of this kind are Fahrenheit’s, Nicholson’s, and Guyton de Morveau’s hydrometers. 2d. Those which are always used with the same weight, but which sink into the liquids to be tried, to different depths, according to the density of the fluid. Of this class are most of the common glass hydrometers, such as Beaume’s, Curteis’s, Gay-Lussac’s, Twaddle’s, &c. Sykes’s and Dicas’s combine both principles. See Hydrometers. Sykes’s hydrometer, or alcoholometer, is the one employed by the Board of Excise, and therefore the one most extensively used in this country. This instrument does not immediately indicate the density or the percentage of absolute alcohol, but the degree above or below proof — the meaning of which has been before detailed ; (p. 30.) It consists of a spherical ball or float, «, with an upper and lower stem of brass, b and c. The upper stem is graduated into ten principal divisions, which are each subdivided into five parts. The lower stem, c, is made conical, and has a loaded bulb at its extremity. There are nine movable weights, numbered respectively by tens from 10 to 90. Each of these circular weights has a slit in it, so that it can be placed on the conical stem, c. The instrument is adjusted so that it floats with the surface of the fluid coincident with zero on the scale in a spirit of specific gravity *825 at 60° F., this being accounted by the Excise as “ standard alcohol.'’"' In weaker spirit, which has therefore a greater density, the hydrom- * Some difference of opinion appears to exist whether Chloroform can he obtained pure from me- thylated spirit. ALCOHOLOMETRY. 35 eter will not sink so low ; and if the density be much greater, it will be necessary to add one of the weights to cause the entire immersion of the bulb of the instrument. Each weight represents so many principal divisions of the stem as its number indicates; thus, the heaviest weight, marked 90, is equivalent to 90 7 divisions of the stem, and the instrument, with the weight added, floats at 0 in distilled water. As each principal division on the stem is divided into five subdivisions, the instrument has a range of 600 degrees be- if ^ tween the standard alcohdi (specific gravity -825) and water. There is a E 1 line on one of the side faces of the stem, 6, near division 1 of the draw- ^ I ing, at which line the instrument with the weight 60 attached to it, floats ||^ if I in spirits exactly of the strength of proofs at a temperature of 51° F. |6_ In using this instrument, it is immersed in the spirit, and pressed down If by the hand until the whole of the graduated portion of the upper stem /lift ^ is wet. The force of the hand required to sink it will be a guide to the ^ selection of the proper weight. Having taken one of the circular weights necessary for the purpose, it is slipped on to the lower conical stem. The instrument is again immersed, and pressed down as before to 0, / « ® and then allowed to rise and settle at any point. The eye is then brought Iv Mi to the level of the surface of the spirit,* and the part of the stem cut by the surface as seen from below^ is marked. The number thus indicated by the stem is added to the number of the weight, and the sum of these, /pik | | ja|, together with the temperature of the spirit, observed at the same time by l|||m '1 1| means of a thermometer, enables the operator, by reference to a table ^,1 1| which is sold to accompany the instrument, to find the strength of the |ii| spirit tested. These tables are far too voluminous to be quoted here ; and this is S||) » iMi unnecessary, since the instrument is never sold without them. ILp/ A modification of Sykes’s hydrometer has been recently adopted for testing alcoholic liquors, which is perhaps more convenient, as the neces- sity for the loading weights is done away with, the stem being sufficiently long not to require them. It is constructed of glass, and is in the shape VillljF of a common hydrometer, the stem being divided into degrees; it carries a small spirit thermometer in the bulb, to which a scale is fixed, ranging from 30° to 82° F. (0 to 12° C.) There are tables supplied with the hydrometer, which are headed by the degrees and half degrees of the thermometric scale ; and the corresponding content of spirit, over or under proof at the respective degrees of the table, is placed opposite each degree of the hydrometer. See Spirits, vol. ii. In France, Gay-Lussac’s alcoolomUre is usually employed. It is a common glass hydrometer, with the scale on the stem divided into 100 parts or degrees. The lowest division, marked 0, denotes the specific gravity of pure water ; and 100, that of absolute alcohol, both at 15° C. (69° F.) The intermediate degrees, of course, show the percentage of absolute alcohol by volume at 15° C. ; and the instrument is accompanied by the tables already given for ascertaining the percentage at any other temperature. Alcoholometry of Liquids containing besides Alcohol^ Saccharine Matters, Coloring Principles, ^c., such as Wines, Beer, Liqueurs, ^'c. In order to determine the proportion of absolute alcohol contained in wines or other mixtures of alcohol and water with saccharine and other non-volatile substances, the most accurate method consists in submitting a known volume of the liquid to distillation, (in a glass retort, for instance ;) then, by determining the specific gravity of the distilled product, to ascertain the percentage of alcohol in this distillate, which may be regarded as essentially a mixture of pure alcohol and water. The distillation is carried on until the last portions have the gravity of distilled water ; by then ascertaining the total volume of the distillate, and with the knowledge of its percentage of alcohol and the volume of the original liquor used, the method of calculating the quantity of alcohol present in the wine, or other liquor, is sufficiently obvious. In carrying out these distillations, care must be taken to prevent the evaporation of the spirit from the distillate, by keeping the condenser cool. And Professor Mulder recom- mends the use of a refrigei'ator, consisting of a glass tube fixed in the centre of a jar, so that it may be kept filled with cold water. The tube must be bent at a right angle, and terminate in a cylindrical graduated measure-glass, shaped like a bottle.* It is well to continue the distillation until about two-thirds of the liquid has passed over. This process, though the most accurate for the estimation of the strength of alcoholic * The Chemistry of Wine, by G. J. Mulder, edited by H. Bence Jones, M. D. > ALCOHOLOMETRY. 36 liquors, is still liable to error. The volatile acids and ethers pass over with the alcohol into the distillate, and, to a slight extent, affect the specific gravity. This error may be, to a great extent, overcome by mixing a little chalk with the wine, or other liquor, previous to distillation. By this method Professor Brande made, some years ago, determinations of the strength of the following wines, and other liquors * : — Proportion of Spirit per Cent, hy Measvite. Lissa - - average 25-41 Orange average 11*26 Raisin - - - u 25-12 Elder , u 8-79 Marsala - - (i 25-09 % Port (of 7 samples) u 22-96 Cider average 5-21 to 9-87 Madeira - a 22-27 Perry ii 7-26 Sherry (of 4 samples) 19-17 Mead ii 7-32 Teneriflfe - . 19-79 Ale, Burton I ( 8*88 Lisbon - - - 18-94 Ale, Edinburgh V average 6*87 6-20 Malaga - - - 18-94 Ale, Dorchester ) ( 5-55 Bucellas - - 18-49 Brown Stout - 6-80 Cape Madeira - average 20-51 London Porter - average 4-20 Roussillon - ii 19.00 London Small Beer “ 1-28 Claret - - ii 15-10 Sauterne - ii 14-22 Brandy . ii 63-39 Burgundy - ii 14-57 Rum . ii 53-68 Hock - , - - ii 12 08 Gin _ ii 67-60 Tent - - ii 13-30 Scotch Whiskey ii 54-32 Champagne - - ii 12-61 Irish Whiskey - _ . ii 63-90 Gooseberry - - ii 11-84 The following results were obtained by the writer more recently by this process, (1854.) Percentage of Alcohol hy Volume. Port (1834) - 22-46 Sherry (Montilla) 19-95 Madeira 22*40 Claret (Haut Brion) 10-0 Chambertin 11-7 Sherry (low quality) 20-7 Sherry (brown) 23-1 Amontillado 20-6 Mansanilla 14.4 Port (best) 20-2 Marcobrunner 8-3 Champagne (1st) 12-12 Champagne (2d) 10-85 Home Ale 6-4 Export Ale 6-4 Strong Ale 9-0 Stout . . - 5-7 Porter - - - 4-18 M. I’Abbe Brossard-Yidal, of Toulonf , has proposed to estimate the strength of alcoholic liquors by determining their boiling point. Since water boils at 100° C. (212° F.), and absolute alcohol at '78’4° (1'73° F.), it is evident that a mixture of water and alcohol will have a higher boiling point the larger the quantity of water present in it. This method is even applicable to mixtures containing other bodies in solution besides spirit and water, since it has been shown that sugar and salts, when present, (in moderate quantities,) have only a very trifling effect in raising the boiling point ; and the process has the great advan- tage of facility and rapidity of execution, though, of course, not comparable to the method by distillation, for accuracy. Mr. Field’s patent (1847) alcoholometer is likewise founded upon the same principle. The instrument was subsequently improved by Br. Ure. The apparatus consists simply of a spirit-lamp placed under a little boiler containing the alcoholic liquor, into which fits a thermometer of very fine bore. When the liquor is stronger than proof-spirit, the variation in the boiling point is so small that an accurate result cannot possibly be obtained ; and, in fact, spirit approaching this strength should be diluted with an equal volume of water before submitting it to ebulli- tion, and then the result doubled. Another source of error is the elevation of the boiling point, when the liquor is kept heated for any length of time ; it is, however, nearly obviated by the addition of common salt to the solution in the boiler of the apparatus, in the proportion of 35 or 40 grains. In order to correct the difference arising from higher or lower pressure of the atmosphere, the scale on which the thermometric and other divisions are marked is made movable up and * Brande’s Manual of Chemistry ; also Philosophical Trans., 1811. + Comptes Eendus, xxvii. 374. ALCOHOLOMETRY. 37 down the thermometer tube ; and every time, before commencing a set of experiments, a preliminary experiment is made of boiling some pure distilled water in the apparatus, and the zero point on the scale (which indicates the boiling point of water) is adjusted at the level of the surface of the mercury. But even when performed with the utmost care, this process is still liable to very considerable errors, for it is extremely difficult to observe the boiling point to within a degree ; and after all, the fixed ingredients present undoubtedly do seriously raise the boil- ing point of the mixture — in fact, to the extent of from half to a whole degree, according to the amount present. SilbermanrCs Method. — M. Silbermann* has proposed another method of estimating the strength of alcoholic liquors, based upon their expansion by heat. It is well known that, between zero and 100° C. (212° F.), the dilatation of alcohol is triple that of water, and this difference of expansion is even greater between 25° C. g (77° F.) and 60° C. (122° F.) ; it is evident, therefore, that the expansion between these two temperatures becomes a measure of the amount of al- cohol present in any mixture. The presence of salts and organic sub- stances, such as sugar, coloring, and extractive matters, in solution or suspension in the liquid, is said not materially to affect the accuracy of the result ; and M. Silbermann has devised an apparatus for applying this principle, in a ready and expeditious manner, to the estimation of the strength of alcoholic liquors. The instrument may be obtained of the philosophical instrument-makers of London and of Liverpool. It consists of a brass plate, on which are fixed — 1st, An ordinary mer- curial thermometer graduated from 22° to 60° C. (77° to 122° F.), these being the working temperatures of the dilatatometer ; and 2dly, the dilatatometer itself, which consists of a glass pipette, open at both ends, and of the shape shown in the figure. A valve of cork or india-rubber closes the tapering end, a, which valve is attached to a rod, h 6, fastened to the supporting plate, and connected with a spring, w, by which the lower orifice of the pipette can be opened or closed at will. The pipette is filled, exactly up to the zero point, with the mixture to be examined — this being accomplished by the aid of a piston working tightly in the long and wide limb of the pipette ; the action of which serves also another valuable purpose, viz., that of drawing any bubbles of air out of the je-o liquid. By now observing the dilatation of the column of liquid when the temperature of the whole apparatus is raised, by immersion in a water-bath, from 25° to 50°, the coefficient of expansion of the liquid is obtained, and hence the proportion of alcohol — the instrument being, in fact, so graduated, by experiments previously made upon mixtures of known composition, as to give at once the percentage of alcohol. Another alcoholometer, which, like the former, is more remarkable for the great facility and expedition with which approximative results can be obtained than for a high degree of accuracy, was invented by M. Geisler, of Bonn, and depends upon the measurement of the tension of the vapor of the liquid, indicated by the height to which it raises a column of mercury. Geisler's Alcoholometer . — It consists of a closed vessel in which the alco- 9 holic mixture is raised to the boiling point, and the tension of the vapor ob- served by the depression of a column of mercury in one limb of a tube, the indication being rendered more manifest by the elevation of the other end of the column. The wine or other liquor of which it is desired to ascertain the strength, is put into the little flask, f, which, when completely filled, is screwed on to the glass which contains mercury, and is closed by a stopcock at s. The entire apparatus, which at present is an inverted position, is now stood erect, the flask and lower extremity of the tube being immersed in a water-bath. The vinous liquid is thus heated to a boiling point, and its vapor forces the mercury up into the long limb of the tube. The instrument having been graduated, once for all, by actual ex- periment, the percentage of alcohol is read off at once on the stem by the height to which the mercurial column rises. f To show how nearly the results obtained by this instrument agree with those obtained by the distillation process, comparative experiments were made on the s same wines by Dr. Bence Jones, f * Comptes Eendus, xxvii. 418. t On the Acidity, Sweetness, and Strength of different Wines, by H. Bence Jones, M. D., F. K. S., Proceedings of the Eoyal Institution, February, 1854. 38 ALOOHOLOMETRY. Port, 1834, Sherry, Montilla, . Madeira, , Haut Brion claret, . Chambertin, Low-quality sherry, Brown sherry, . Amontillado, . Mansanilla, Port, best, . Marcobrunner, . Home ale, . Export ale. Strong ale, . By Distillation (Mr. Witt) per cent, by measure. . 22-46 19- 95 . . 22-40 10-0 . 11-7 20- 7 . 23-1 20-5 . 14-4 20-2 8-3 6-4 6-4 2-0 By Alcobolometer per cent, by measure. ( 23-2 } 23-5 ( 20-7 \ 20-6 (20-6 j 23-5 ■j 23-2 ] 11-1 ■j 11-1 j 13-2 I 13-0 j 21-1 I 20-9 j 23-0 I 23-3 j 21-0 ] 21-0 ] 16-4 I 15-4 j 21-1 ■j 21-0 j 9-7 I 9-5 j 7-0 I 7-1 j 7-0 I 6-9 ] 10-7 ( 10-8 TabariPs Method . — There is another method of determining the alcoholic contents of mixtures, which especially recommends itself on account of its simplicity. The specific gravity of the liquor is first determined, half its volume is next evaporated in the open air, sufficient water is then added to the remainder to restore its original volume, and the spe- cific gravity again ascertained. By deducting the specific gravity before the expulsion of the alcohol from that obtained afterwards, the difference gives a specific gravity indicating the percentage of alcohol, which may be found by referring to Gay-Lussac’s or one of the other Tables. Tabarie has constructed a peculiar instrument for determining these specific gravities, which he calls an oenometer ; but they may be performed either by a specific- gravity bottle or by a hydrometer in the usual way. Of course this method cannot be absolutely accurate ; nevertheless, Prof. Mulder’s ex- perience with it has led him to prefer it to any of the methods before described, especially where a large number of samples have to be examined. He states that the results are almost as accurate as those obtained by distillation. The evaporation of the solution may be accelerated by conducting hot steam through it. • Adulterations . — Absolute alcohol should be entirely free from water. This may be recognized by digesting the spirit with pure anhydrous sulphate of copper. If the spirit contain any water, the white salt becomes tinged blue, from the formation of the blue hydrated sulphate of copper. Rectified spirit, proof spirit, and the other mixtures of pure alcohol and water, should be colorless, free from odor and taste. If containing methylic or amylic alcohols, they are immediately recognized by one or other of these simple tests. Dr. Ure states, that if wood spirit be contained in alcohol, it may be detected to the greatest minuteness by the test of caustic potash, a little of which, in powder, causing wood spirit to become speedily yellow and brown, while it gives no tint to alcohol. Thus 1 per cent, of wood spirit may be discovered in any sample of spirits of wine. The admixture with a larger proportion than the due amount of water is of course de- termined by estimating the percentage of absolute alcohol by one or other of the several methods just described in detail. The adulterations and sophistications to which the various spirits known as rum, brandy whiskey, gin, &c., are subjected, will be best described under these respective heads, since these liquors are themselves mixtures of alcohol and water with sugar, coloring matters, flavoring ethers, &c. ALDEHYDE. By this word is understood the fluid obtained from alcohol by the removal of two equivalents of hydrogen. Thus, alcohol being represented by the formula C* H® 0^, aldehyde becomes H* 0^ ALDER. 39 Preparation . — Aldehyde is prepared by various processes of oxidation. Liebig has published several methods, of which the following is perhaps the best : Three parts of peroxide of manganese, three of sulphuric acid, two of water, and two of alcohol of 80 per cent., are well mixed and carefully distilled in a spacious retort. The extreme volatility of aldehyde renders good condensation absolutely necessary. The contents of the retort are to be distilled over a gentle and manageable fire until frothing commences, or the distillate becomes acid. This generally takes place when about one-third has passed over. The fluid in the receiver is to have about its own weight of chloride of calcium added, and, after slight digestion, is to be carefully distilled on the water-bath. The distillate is again to be treated in the same way. By these processes a fluid will be obtained entirely free from water, but containing several impurities. To obtain the aldehyde in a state of purity, it is necessary, in the first place, to obtain aldehyde-ammonia ; this may be accomplished in the following manner : — The last distillate is to be mixed in a flask with twice its volume of ether, and, the flask being placed in a vessel surrounded by a freezing mixture, dry ammo- niacal gas is passed in until the fluid is saturated. In a short time crystals of the com- pounds sought separate in considerable quantity. The aldehyde-ammonia, being collected on a filter, or in the neck of a funnel, is to be washed with ether, and dried by pressure between folds of filtering paper, followed by exposure to the air. It now becomes neces- sary to obtain the pure aldehyde from the compound with ammonia. For this purpose two parts are to be dissolved in an equal quantity of water, and three parts of sulphuric acid, mixed with four of Avater, are to be added. The whole is to be distilled on the water-bath, the temperature, at first, being very low, and the operation being stopped as soon as the water boils. The distillate is to be placed in a retort connected with a good condensing apparatus, and, as soon as all the joints are known to be tight, chloride of calcium, in frag- ments, is to be added. The heat arising from the hydration of the chloride causes the dis- tillation to commence, but it is carried on by a water-bath. The distillate, after one more rectification over chloride of calcium, at a temperature not exceeding 80° F., will consist of pure aldehyde. Aldehyde is a colorless, very volatile, and mobile fluid, having the den- sity 0’800 at 32°. It boils, under ordinary atmospheric pressure, at '70° F. Its vapor density is 1'532. Its formula corresponds to four volumes of vapor; we consequently obtain the theoretical vapor density by multiplying its atomic weight = 44 by half the density of hydrogen, or .0346. The number thus found is 1*5224, corresponding as nearly as could be desired to the experimental result. Aldehyde is produced in a great number of processes, particularly during the destructive distillation of various organic matters, and in processes of oxidation. From alcohol, alde- hyde may be pi'ocured by oxidation with platinum black, nitric acid, chromic acid, chlorine (in presence of water), or, as we have seen, a mixture of peroxide of manganese and sul- phuric acid. Certain oils, by destructive distillation, yield it. Wood vinegar in the crude state contains aldehyde as well as wood spirit. Lactic acid, when in a combination with weak bases, yields it on destructive distillation. Various animal and vegetable products alFord aldehyde by distillation with oxidizing agents, such as sulphuric acid and peroxide of manganese, or bichromate of potash. The word aldehyde, like that of alcohol, is gradually becoming used in a much more extended sense than it Avas formerly. By the term is now understood any organic sub- stance Avhich, by assimilating two equivalents of hydrogen, yields a substance having the properties of an alcohol, or, by taking up tAvo equivalents of oxygen, yields an acid. It is this latter property Avhich has induced certain chemists to say that there is the same relation between an aldehyde and its acid as between inorganic acids ending in ous and ic. Several very interesting and important substances are noAV known to belong to the class of alde- hydes. The essential oils are, in several instances, composed principally of bodies having the properties of aldehydes. Among the most prominent may be mentioned the oils of bitter almonds, cumin, cinnamon, rue, &c. An exceedingly important character of the aldehydes is their strong tendency to combine Avith the bisulphites of ammonia, potash, and soda. By availing ourselves of this property, it becomes easy to separate bodies of this class from complex mixtures, and, consequently, enable a proximate analysis to be made. Now that the character of the aldehydes is becoming better understood, the chances of arti- ficially producing the essential oils above alluded to in the commercial scale become greatly increased. Several have already been formed, and, although in very small quantities, the success has been sufficient to Avarrant sanguine hopes of success. A substitute for one of them has been for some years known under the very incorrect name of artificial oil of bitter almonds. See Nitrobenzole. — C. G. W. ALDER. (Awne, Fr. ; Eric., Germ. ; Ahma glutinosa, Lin.) A tree, different species of which are indigenous to Europe, Asia, and America. The common alder seldom grows to a height of more than 40 feet. The Avood is stated to be very durable under water. The piles at Venice, and those of Old London Bridge, are stated to have been of alder; and it is much used for pipes, pumps, and sluices. The charcoal of this Avood is used for gunpoAvder. 40 ALEMBIC. ALEMBIC, a still {which see). The term is, however, applied to a still of peculiar con- struction, in which the head., or capital, is a separate piece, 10 fitted and ground to the neck of the boiler, or cucurbit, or ^ otherwise carefully united with a lute. The alembic has this advantage over the common retort, that the residue of distilla- easily cleared out of the body. It is likewise M) capable, when skilfully managed, of distilling a much larger quantity of liquor in a given time than a retort of equal capa- Af 1| % city. In France the term alembic, or rather alamhic. is used ji % to designate a glass still. k ALGAROTH, POWDER OF. Powder of Algarotti , — English Powder. This salt was discovered by Algarotti, a ^ ^ m physician of Verona. Chloride of antimony is formed by fe boiling black sulphide of antimony with hydrochloric acid : on pouring the solution into water, a white flocky precipitate falls, liiiiiiiiiiiiiliiiiiiiiilliiiiM which is an oxichloride of antimony. If the water be hot, the precipitate is distinctly crystalline ; this is the powder of algaroth. This oxichloride is used to furnish oxide of antimony in the preparation of tartar emetic. ALG.E. {Varech, Fr. ; Seegras, or Alge, Germ.) A tribe of subaqueous plants, in- cluding the seaweeds { fiicus) and the lavers (ulva) growing in salt water, and the fresh water confervas. We have only to deal with those seaweeds w'hich are of any commercial value. These belong to the great division of the jointless algce, of which 160 species are known as natives of the British Isles. In the manufacture of Kelp, (see Kelp,) all the varie- ties of this division may be used. The edible sorts, such as the birds’ nests of the Eastern Archipelago, those which we consume in this country, as lavers, carrageen, or Irish moss, &c., belong to the same group, as do also those which the agriculturalists employ for manure. Dr. Pereira gives the following list of esculent seaweeds : — Phodomenia pahnata (or Dulse). Iridcea edulis. lihodomenia ciliafa. Alaria escxdenta. Laminaria saccharina. Ulva latissima. Phodomenia pahnata passes under a variety of names, dulse, dylish, or delUsh, and amongst the Highlanders it is called dulling, or waterleaf. It is employed as food by the poor of many nations ; when well washed, it is chewed by the peasantry of Ireland without being dressed. It is nutritious, but sudorific, has the smell of violets, imparts a mucila- ginous feel to the mouth, leaving a slightly acrid taste. In Iceland the dulse is thoroughly w%ished in fresh water and dried in the air. When thus treated it becomes covered with a white powdery substance, which is sweet and palatable ; this is mannite, (see Manna,) which Dr. Stenhouse proposes to obtain from seaweeds. “ In the dried state it is used in Iceland with fish and butter, or else, by the higher classes : boiled in milk with the addition of rye flour. It is preserved packed in close casks ; a fermented liquor is produced in Kam- schatka from this seaweed, and in the north of Europe and in the Grecian Archipelago cattle are fed upon it.” — Stenhoxise. Laminaria saccharina yields 12*15 per cent, of mannite, while the Phodomenia pal- mata contains not more than 2 or 3 per cent. Iridcea edulis. — The fronds of this weed are of a dull purple color, flat, and succulent. It is employed as food by fishermen, either raw or pinched between hot irons, and its taste is then said to resemble roasted oystei’s. Alaria csculenta. — Mr. Drummond informs us that, on the coast of Antrim, “ it is often gathered for eating, but the part used is the leaflets, and not the midrib, as is commonly stated. These have a very pleasant taste and flavor, but soon cover the mouth with a tena- cious greenish crust, which causes a sensation somewhat like that of the fat of a heart or kidney.” Ulva latissima, (Broad green laver.) — This is rarely used, being considered inferior to the Porphyra laciniata, (Laciniated purple laver.) This alga is abundant on all our shores. It is pickled with salt, and sold in England as laver, in Ireland as sloke, and in Scotland as slaak. The London shops are mostly supplied with laver from the coasts of Devonshire. When stewed, it is brought to the table and eaten with pepper, butter or oil, and lemon- juice or vinegar. Some persons stew it with leeks and onions. The pepper dulse, {Lau- rencia pinnatijida,) distinguished for its pungent taste, is often used as a condiment when other seaweeds are eaten. “ Tangle,” {Laminaria digitata,) so called in Scotland, is termed “red-ware” in the Orkneys, “sea-wand” in the Highlands, and “sea-girdles” in England. The flat leathery fronds of this weed, when young, are employed as food. Mr. Simmonds tells us, “ There was a time when the cry of ‘ Buy dulse and tangle ’ was as com- mon in the streets of Edinburgh and Glasgow, as is that of ‘ water-cresses ’ now in our me- tropolis.” — Society of Arts' Journal. ALKALI. 41 Laminaria potatorum. — The large sea tangle is used abundantly by the inhabitants of the Straits of Magellan and by the Fuegians. Under the name of “ Bull Kelp” it is used as food in New Zealand and Van Diemen’s Land. It is stated to be exceedingly nutritive and fattening. Chondrus crispus^ (chondrus, from cartilage.) — Carrageen, Irish, or pearl moss. For purposes of diet and for medicinal uses, this alga is collected on the west coast of Ire- land, washed, bleached by exposure to the sun, and dried. It is not unfrequently used in Ireland by painters and plasterers as a substitute for size. It has also been successfully applied, instead of isinglass, in making of blanc-mange and jellies ; and in addition to its use in medicine, for which purpose it was introduced by Dr. Todhunter, of Dublin, about 1831, a thick mucilage of carrageen, scented with some prepared spirit, is sold as bando- line., fixature., or clysphitique., and it is employed for stitfening silks. According to Dr. Davy, carrageen consists of Gummy matter, . . . . . . 28'5 Gelatinous matter, . . . . . 49*0 Insoluble matter, . . . . . . 22’5 100-0 Plocaria Candida. — Ceylon moss ; edible moss. This moss is exported from the islands of the Indian Archipelago, forming a portion of the cargoes of nearly all the junks. It is stated by Mr. Crawford, in his “ History of the Indian Archipelago,” that on the spots where it is collected, the prices seldom exceed from 5s. M. to 7s. 6o?. per cwt. The Chinese use it in the form of a jelly with sugar, as a sweetmeat, and apply it in the arts as an excel- lent paste. The gummy matter which they employ for covering lanterns, varnishing paper, &c., is made chiefly from this moss. This moss, as ordinarily sold, appears to consist of several varieties of marine produc- tions, with the Plocaria intermixed. The Agar-Agar of Malacca belongs to this variety ; and probably seaweeds of this character are used by the Salangana or esculent swallow in constructing their nests, which are esteemed so great a delicacy by the Chinese. The plant is found on the rocks of Pulo Ticoos and on the shores of the neighboring islands. It is blanched in the sun for two days, or until it is quite white. It is obtained on submerged banks in the neighborhood of Macassar, Celebes, by the Bajow-laut, or sea-gipsies, who send it to China. It is also col- lected on the reefs and rocky submerged ledges in the neighborhood of Singapore. Mr. Montgomery Martin informs us that this weed is the chief staple of Singapore, and that it produces in China from six to eight dollars per pecul in its dry and bulky state. The har- vest of this seaweed is from 6,000 to 12,000 peculs annually, the pecul being equal to 100 catties of 1-333 lbs. each. Similar to this, perhaps the same in character, is the Agal-Agal., a species of seaweed. It dissolves into a glutinous substance. Its principal use is for gumming silks and paper, as nothing equals it for paste, and it is not liable to be eaten by insects. The Chinese make a beautiful kind of lantern, formed of netted thread washed over with this gum, and which is extremely light and transparent. It is brought by coasting vessels to Prince of Wales Island, and calculated for the Chinese market. — Oriental Commerce. ALIMENT. {Alimentum., from a/o, to feed.) The food necessary for the human body, and capable of maintaining it in a state of health. 1. Nitrogenous substances are required to deposit, from the blood, the organized tissue and solid muscle ; ' 2. And carbonaceous, non-nitrogenous bodies, to aid in the processes of respiration, and in the supply of carbonaceous elements, as fat, «&c., for the due support of animal heat. For information on these substances, consult Liebig’s “ Animal Chemistry,” the investi- gations of Dr. Lyon Playfair, and Dr. Robert Dundas Thompson’s “Experimental Researches on Food,” 1846. ALKALI. A term derived from the Arabians, and introduced into Europe when the Mahometan conquerors pushed their conquests westward. Al, el, or ul, as an Arabic noun, denotes “ God, Heaven, Divine.” As an Arabic particle, it is prefixed to words to give them a more emphatic signification, much the same as our particle the ; as in Alcoran., the Koran ; alchymist., the chemist. Kali was the old name for the plant produeing potash, (the glasswort, so called from its use in the manufacture of glass,) and alkali signified no more than the kali plant. Potash and soda were for some time confounded together, and were hence called alkalis. Ammonia, which much resembles them when dissolved in water, was also called an alkali. Ammonia was subsequently distinguished as the volatile alkali., potash and soda being fixed alkalis. Ammonia was also called the animal alkali. Soda was the mineral alkali, being derived from rock salt, or from the ocean ; and potash received the name of vegetable alkali, from its source being the ashes of plants growing upon the land. Alkalis are characterized by 42 ALKALIS, ORGANIC. being very soluble in water, by neutralizing the strongest acids, by turning brown vegetable yellows, and to green the vegetable reds and blues. Some chemists classify all salifiable bases under this name. In commercial language, the term is applied to an impure soda, the imports of which were — Imports. Alkali and Barilla. 1S53. 1854. 1855. 1856. Cwts. Cwts. Cwts. Cwts. Portugal - - - 2,540 Spain - - - 15,220 5,480 7,840 1,000 3,660 Canary Islands - - 9,240 2,520 3,480 Greece - - - - ■ - 3,160 Two Sicilies - - - 7,920 2,400 10,640 9,320 Egypt - . - - 4,800 Peru - - 2,040 1,900 - 4,760 Other parts - - - 20 160 600 80 Total - - - 36,980 25,740 14,660 21,200 Our Exports during the same periods being as follows : — Alkali and Barilla. 1853. 1854. 1855. 1856. Cwts. Cwts. Cwts. Cwts. Russia — Northern Ports - - 13,845 4,208 - 82,667 “ Southern Ports - - 7,079 200 Sweden - - - - 7,804 13,478 14,908 14,924 Denmark . . - 39,366 40,329 62,721 39,417 Prussia - . - - 82,735 96,839 104,111 18,871 85,364 Hanover - - - 13,989 9,715 25,029 Hanse Towns - - - 97,939 93,774 77,648 83,385 Holland - . . 112,370 112,023 16,837 114,068 121,645 Belgium _ . . 10,069 21,293 39,650 France - 9,972 Spain and the Canaries - - - - 0,921 4,090 11,042 Sardinia - 7,326 Austrian Territories - - 28,957 21,023 22,587 27,124 Turkey - 13,010 9,142 37,790 Australia . - - 49,377 52,390 19,882 British North America - - - 12,271 14,344 16,102 25,520 723,089 United States . . 550,735 659,942 494,254 Brazil . . . 12,281 20,153 23,805 26,149 Chili . . - - 10,392 33,747 5,185 Other Countries - - - 29,771 42,469 39,666 Total - - - 1,070,624 1,100,316 1,045,004 1,405,901 ALKALIS, ORGANIC. During the last few years the number of organic alkaloids has so greatly increased, that a considerable volume might be devoted to their history. There are, however, only a few which have become articles of commerce. The modes of prepa- ration will be given under the heads of the alkalis themselves. The principal sources from whence they are obtained are the following : — 1. The animal kingdom. 2. The vegetable kingdom. 3. Destructive distillation. 4. The action of potash on the cyanic, and cyanuric ethers. 5. The action of ammonia on the iodides, &c., of the alcohol radicals. 6. The action of reducing agents on nitro-compounds. The principal bases existing in the animal kingdom are creatine and sarcosine. The vegetable kingdom is much richer in them, and yields a great number of organic alkalis, of which several are of extreme value in medi- cine. Modern chemists regard all organic alkalis as derived from the types ammonia or oxide of ammonium. Their study has led to results of the most startling character. ^ It has been found that not only may the hydrogen in ammonia and oxide of ammonium be replaced by metals and compound radicals without destruction of the alkaline character, but even the nitrogen may be replaced by phosphorus or arsenic, and yet the resulting com- pounds remain powerfully basic. In studying the organic bases, chemists have constantly ALKALIMETRY. 43 had in view the artificial production of the bases of cinchona bark. It is true that this result has not as yet been attained ; but, on the other hand, bodies have been formed hav- ing so many analogies, both in constitution and properties, with the substances sought, that it cannot be doubted the question is merely one of time. The part performed by the bases • existing in the juice of flesh has not been ascertained, and no special remedial virtues have been detected in them ; but this is not the case with those found in vegetables ; it is, in fact, among them that the most potent of all medicines are found — such, for example, as quinine and morphia. It is, moreover, among vegetable alkaloids that yve find the sub- stances most inimical to life, for aconitine, atropine, brucine, coniine, curarine, nicotine, solanine, strychnine, &c., &c., are among their number. It must not be forgotten, how- ever, that, used with proper precaution, even the most virulent are valuable medicines. The fearfully poisonous nature of some of the organic bases, together with an idea that they are difficult to detect, has unhappily led to their use by the poisoner ; strychnine, especially, has acquired a painful notoriety, in consequence of its employment by a medical man to destroy persons whose lives he had insured. Fortunately for society, the skill of the analyst has more than kept pace with that of the poisoner ; and without regarding the extravagant assertions made by some chemists as to the minute quantities of vegetable poisons they are able to detect, it may safely be asserted that it would be very difficult to administer a fatal dose of any ordinary vegetable poison without its being discovered. Another check upon the poisoner is found in the fact that those most difficult of isolation from complex mixtures are those which cause such distinct symptoms of poisoning in the victim, that the medical attendant, if moderately observant, can scarcely fail to have his suspicions aroused. Under the heads of the various alkaloids will be found (where deemed of sufficient importance) not merely the mode of preparation, but also the easiest method of detection. — C. G. W. ALKALIMETER. There are various kinds of alkalimeters, but it will be more conven- ient to explain their construction and use in the article on Alkalimetry, to which the reader is referred. ALKALIMETRY. 1. The object of alkalimetry is to determine the quantity of caustic alkali or of carbonate of alkali contained in the potash or soda of commerce. The prin- ciple of the method is, as in acidimetry, based upon Dalton’s law of chemical combining » ratios — that is, on the fact that in order to produce a complete reaction^ a certain definite weight of reagent is required, or, in other words, in order to saturate or completely neu- tralize, for example, one equivalent of a base, exactly one equivalent of acid must be em- ployed, and vice versa. This having been thoroughly explained in the article on Acidim- etry, the reader is referred thereto. 2 . The composition of the potash and of the soda met with in commerce presents very great variations ; and the value of these sulistances being, of course, in proper- ^ \ tion to the ouantitv of real alkali which thev contain, an easv and rapid method of determining that quantity is obviously of the greatest importance both to the ' ^ manufacturer and to the buyer. The process b^y which this object is attained, ■ = though originally contrived exclusively for the determination of the intrinsic ^ ^ value of these two alkalis, (whence its name. Alkalimetry,) has since been ex- •-§ >o tended to that of ammonia and of earthy bases and their carbonates, as will be i is shown presently. 20 3 . Before, however, entering into a description of the process itself, we will 2a give that of the instrument employed in this method of analysis, which instru- = ment is called an alkalimeter. E 4. The common alkalimeter is a tube closed at one end, (see figure in mar- = gin,) of about f of an inch internal diameter, about inches long, and is thus capable of containing 1,000 grains of pure distilled water. The space occupied by the water is divided accurately into 100 divisions, numbering from -= so above downwards, each of which, therefore, represents 10 grains of distilled e 55 water. ^ ^ J 6 . When this alkalimeter is used, the operator must carefully pour the acid ; from it by closing the tube with his thumb, so as to allow the acid to trickle in " drops as occasion may require ; and it is well also to smear the edge of the tube ~e with tallow, in order to prevent any portion of the test acid from being wasted -f by running over the outside after pouring, which accident would, of course, -5 so render the analysis altogether inaccurate and worthless ; and, for the same rea- = gg son, after having once begun to pour the acid from the alkalimeter by allowing J; gg it to trickle between the thumb and the edge of the tube, as above mentioned, the thumb must not be removed from the tube till the end of the experiment, 1 Zj for otherwise the portion of acid which adheres to it would, of course, be wasted v— ✓ and vitiate the result. This uncomfortable precaution is obviated in the other forms of alkalimeter now to be described. 44 ALKALIMETRY. 12 o j- -0 1 -10 \ -zo 1 -30 A f f -50 -60 1 -70 \ -80 = -SO -ic^ 6. That represented in^^. 12 is Gay-Lussac’s alkalimeter ; it is a glass tube about 14 inches high, and ^ an inch in diameter, capable of holding more than 1,000 grains of dis- tilled water ; it is accurately graduated from the top down- wards into 100 divisions, in such a way that each division may contain exactly 10 grains of water. It has a small tube, 6, communicating with a larger one, which small tube is bent and bevelled at the top, c. This very ingenious instrument, known also under the name of “ burette''' and pouret^" was contrived by Gay-Lussac, and is by far more convenient than the common alkalimeter, as by it the test acid can be unerringly poured, drop by drop, as wanted. The only drawback is the fragility of the small side-tube, 6, on which account the com- mon alkalimeter, represented in^^. 11 is now generally used, especially by workmen, because, as it has no side-tube, it is less liable to be broken ; but it gives less accurate results, a portion of the acid being wasted in various ways, and it is, besides, less manageable. Gay-Lussac’s “ burette ” is there- fore preferable ; and if melted wax be run between the space of the large and of the small tube, the instrument is rendered much less liable to injury ; it is generally sold with a separate wooden foot or socket, in which it may stand vertically. '7. The following form of alkalimeter, {fig. 13,) which I contrived several years ago, will, I think, be found equally delicate but more convenient still than that of Gay-Lussac. It consists of a glass tube, a, of the same dimensions, and grad- uated in the same manner as that of Gay-Lussac ; but it is provided with a glass foot, and the upper part, b, is shaped like the neck of an ordinary glass bottle ; c is a bulb blown from a glass tube, one end of which is ground to fit the neck, b, of the alkalimeter, like an ordinary glass stopper. This bulb is drawn to a capillary point at d, and has a somewhat large opening at e. With this instrument the acid is perfectly under the control of the operator, for the globular joint at the top enables him to see the liquor before it actually begins to drop out, and he can then regulate the pouring to the greatest nicety, whilst its more substantial form renders it much less liable to accidents than that of Gay-Lussac ; the glass foot is extremely convenient, and is at the same time a great additional security. The manner of using it will be described further on. 8. Another alkalimeter of the same form as that which I have just described, except that it is ail in one piece, and has no globular enlargement, is represented in fig. 14. Its con- struction is otherwise the same, and the results obtained are equally delicate ; but it is less under perfect control, and the test acid is very liable to run down the tube outside : this defect might be easily remedied by drawing the tube into a finer and more delicate point, instead of in a thick, blunted projection, from which the last drop cannot be detached, or only with difficulty, and imperfectly. A glass foot would, moreover, be an improvement. 9. With Schuster’s alkalimeter, (represented in 15,) the strength of alkalis is determined by the weight., not by the measure., of the acid employed to neutralize the alkali ; it is, as may be seen, a small bottle of thin glass, having the form of the head of the alkalimeter repre- sented 'mfig. 13. We shall describe further on the process of analysis with this alkalimeter. 10. There are several other forms of alkalimeter, but those which have been alluded to are almost exclusively used, and whichever of them is employed, the process is the same — namely, pouring carefully an acid of a known strength into a known weight of the alkali under examination, until the neutralizing point is obtained, as will be fully explained presently. 11. Blue litmus-paper being immediately red- dened by acids is the reagent used for ascertaining the exact point of the neutralization of the alkali to be tested. It is prepared by pulverizing one part of commercial litmus, and digesting it in six parts of cold water, filtering, and dividing the blue liquid into two equal portions, adding carefully to one of the portions, and one drop at a time, as much very dilute sulphuric acid as is sufficient to impart to it a slight red color, and pouring the portion so treated into the second portion, which is intensely bhie, and stirring the 15 70 . 9(1 ALKALIMETRY. 45 whole together. The mixture so obtained is neutral, and by immersing slips of white blot- ting-paper into it, and carefully drying them by hanging them on a stretched piece of thread, an exceedingly sensitive test paper of a light blue color is obtained, which should be kept in a wide-mouth glass-stoppered bottle, and sheltered from the air and light. 12. Since the principle on which alkalimetry is based consists in determining the amount of acid which a known weight of alkali can saturate or neutralize, it is clear that any acid having this power can be employed. 13. The test acid, however, generally preferred for the purpose is sulphuric acid, because the normal solution of that acid is more easily prepared, is less liable to change its strength by keeping, and has a stronger reaction on litmus-paper than any other acid. It is true that other acids — tartaric acid, for example — can be procured of greater purity, and that, as it is dry and not caustic, the quantities required can be more comfortably and accurately weighed off; and on this account some chemists, after Buchner, recommended its use, but the facility with which its aqueous solution becomes mouldy is so serious a drawback, that it is hardly ever resorted to for that object. 14. When sulphuric acid is employed, the 'pure acid in the maximum state of concen- tration, or, as it is called by chemists, the pure hydrate of sulphuric acid, specific gravity 1*8485, is preferable. Such an acid, however, is never met with in commerce, for the ordinary English oil of vitriol is seldom pure, and never to the maximum state of concen- tration ; the operator, however, may prepare it by distilling ordinary oil of vitriol, but as the specific caloric of the vapor of sulphuric acid is very small, the distillation is a some- what hazardous operation, unless peculiar precaution be taken. The following apparatus, however, allows of the acid being distilled in a perfectly safe and convenient manner ; it consists of a plain glass retort, charged with oil of vitriol, a little protosulphate of iron is added, for the purpose of destroying any nitrous products which the acid may evolve, and it is then placed into a cylinder of iron, the bottom of which is perforated with holes about three-quarters of an inch in diameter, except in the middle, where a large hole is cut of a suitable size for the retort to rest upon ; the sides of the cylinder are likewise perforated, as represented in fg. 16. Ignited charcoal is then placed all round the retort, the bottom of which protruding, out of the influence of the heat, allows the ebullition to proceed from the sides only. It is well to put into the retort a few frag- ments of quartz or a few lengths of platinum wire, the effect of which is to render the ebullition more regular. 15. In order to prevent the acid fumes from condensing in the neck of the retort, it should be covered with a cover of sheet iron, as repre- sented in fig. 16. 16. The first fourth part which dis- tils over should be rejected, because it is too weak ; the next two-fourths are kept, and the operation is then stopped, leaving the last fourth part of the acid in the retort. The neck of the retort should be about four feet long, and about one and a half inches in the bore, and be connected with a large re- ceiver ; and as the necks of retorts are generally much too short for the purpose, an adapter tube should be adjusted to it and to the receiver, but. very loosely; this precaution is ab- solutely necessary, for otherwise the hot acid falling on the sides of the receiver would crack it ; things, in fact, should be so arranged that the hot drops of the distilling acid may fall into the acid which has already distilled over. Do not surround the receiver with cold water, for the hot acid dropping on the refrigerated surface would also certainly crack it. The acid so obtained is pure oil of vitriol, or monohydrated sulphuric acid, SO^, HO, and it should be kept in a well-stoppered and dry flask. lY. For commercial assays, however, and, indeed, for every purpose, the ordinary con- centrated sulphuric acid answers very well : when used for the determination of the value of potashes, it is made of such a strength that each division (or 10 water-grains’ measure) of the alkalimeter saturates exactly one grain of pure potash : an acid of that particular strength is prepared as follows : — 18. Take 112*Y6 grains of pure neutral and anhydrous carbonate of soda, and dissolve them in about 5 fluid ounces of hot water.* This quantity, namely, 112*76 grains, of neutral carbonate of soda will exactly saturate the same quantity of pure sulphuric acid (SO^) that 100 grains of pure potash would. It is advisable, however, to prepare at once a larger quantity of test solution of carbonate of soda, which is of course easily done, as will be shown presently. * Anhydrous, or dry, neutral carbonate of soda may be obtained by keeping a certain quantity of pure bicarbonate of soda for a short time, at a dull red heat, in a platinum crucible: the bicarbonate is converted into its neutral carbonate, of course free from water. 46 ALKALIMETEY. 19. Mix, now, 1 part, by measure, of concentrated sulphuric acid with 10 parts of water, or rather — as it is advisable, where alkalimetrical assays have frequently to be made, to keep a stock of test acid — mix 1,000 water-grains’ measure of concentrated sulphuric acid with 10,000 grains of water, or any other larger proportions of concentrated sulphuric acid and water, in the above respective proportions ; stir the whole well, and allow it to cool. The mixture of the acid with the water should be made by first putting a certain quantity of the water into a glass beaker or matrass of a suitable size, then pouring the concentrated acid slowly therein, while a gyratory motion is imparted to the liquid. The vessel containing the acid is then rinsed with the water, and both the rinsing and the rest of the water are then added to the whole mass. When quite cold, fill the graduated alka- limeter with a portion of it up to the point marked 0°, taking the under line of the liquid as the true level ; and, whilst stirring briskly with a glass rod the aqueous solution of the 11 2. 76 grains of neutral carbonate of soda above alluded to, drop the test acid from the alkalimeter into the vortex produced by stirring, until, by testing the alkaline solution with a strip of reddened litmus-paper after every addition of acid, it is found that it no longer shows an alkaline reaction, (which is known by the slip of reddened litmus-paper not being rendered blue,) but, on the contrary, indicates that a very slight excess of acid is present, (which is known by testing with a slip of blue litmus-paper, which will then turn slightly red.) 20. If, after having exhausted the w^hole of the 100 divisions (1,000 water-grains’ measure) of the diluted acid in the alkalimeter, the neutralization is found to be exactly attained, it is a proof that the test acid is right. 21. But suppose, on the contrary, (and this is a much more probable case,) suppose that only 80 divisions of the acid in the alkalimeter have been required to neutralize the alka- line solution, it is then a proof that the test acid is too strong, and accordingly it must be further diluted with water, to bring it to the standard strength ; and this may at once be done, in the present instance, by adding 20 measures of water to every 80 measures of the acid. This is best accomplished by pouring the whole of the acid into a large glass cylin- der, divided into 100 equal parts, until it reaches the mark or scratch corresponding to 80 measures ; the rest of the glass, up to 100, is then filled up with water, so that the same quantity of real acid will now be in the 100 measures as w^as contained before in 80 measures. 22. The acid adjusted as just mentioned should be labelled '■'■Test Sulphuric Acid for Potashf and kept in well-stoppered bottles, otherwise evaporation taking place would ren- der the remaining bulk more concentrated, consequently richer in acid than it should be, and it would thus, of course, become valueless as a test acid until readjusted. Each degree or division of the alkalimeter of such an acid represents 1 grain of pure potash. 23. The alkalimetrical assay of soda is also made with sulphuric acid, in preference to other acids, but it must be so adjusted that 100 alkalimetrical divisions (1,000 w^ater-grains’ measure) of acid will exactly neutralize 170’98 of pure anhydrous carbonate of soda, that quantity containing 100 grains of pure soda. 24. Dissolve, therefore, 171 grains of pure anhydrous neutral carbonate of soda, ob- tained as indicated before, in five or six ounces of hot w'ater, and prepare in the meantime the test sulphuric acid, by mixing 1 part, by measure, of ordinary concentrated sulphuric acid, wuth about 9 parts, by measure, of w'ater, exactly as described before ; stir the whole thoroughly, let the mixture stand until it has become quite cold, then pour 1,000 water- grains’ measure of the dilute acid so prepared into an alkalimeter — that is to say, fill that instrument up to 0°, taking the under line as the true level, and then, whilst stirring briskly the aqueous solution of the 171 grains of carbonate of soda with a glass rod, pour the acid, with increased precaution as the saturating point is approaching, into the vortex produced, until by testing the liquor alternately with reddened and with blue litmus-paper, or with gray litmus-paper, as before mentioned, the exactly neutralized point is hit. 25. If the whole of the 100 alkalimetrical divisions (1,000 water-grains’ measure) have been required to effect the neutralization, it is a proof that the acid is of the right strength ; but if this be not the case, it must be adjusted as described before — that is to say : — 26. Suppose, for example, that only 75 alkalimetrical divisions or measures of the acid in the alkalimeter have been required to neutralize the 171 grains of neutral carbonate of soda operated upon, then 75 measures of the acid should be poured at once into a glass cylinder accurately divided into 100 parts ; the remaining 25 divisions should then be filled with water, and the whole being now stirred up, 100 parts of the liquor will of course con- tain as much real acid as 75 parts contained before, and accordingly the acid may now be used as a test acid for the alkalimetrical assay of soda, each degree or division of the alka- limetcr representing one grain of pure soda. 27. The stock of test acid should be kept in well-stoppered flasks, that it may not vary in strength by evaporation, and be labelled “ Test Sulphuric Acid for SodaT 28. Instead, however, of keeping two kinds of “ test sulphuric acid,” of different satu- rating powers as described, the one for potash^ the other for soda^ one kind only may be ALKALIMETRY. 47 prepared so as to serve for both alkalis, by constructing, as is very often done, an alkalime- ter adjusted so as to indicate the quantities of the acid of a given strength required for the saturation or neutralization of both potash or soda, or of their respective carbonates ; and this, in fact, is the alkalimeter most in use in the factory. It should be in shape similar to that of Gay-Lussac’s, (see jig. 12,) or that described in jigs. 13 and 14 ; but, like that represented by jig. 11, it generally consists of a tube closed at one end, about three-fourths of an inch internal diameter and about 9^ inches in length ; it is graduated into 100 equal parts, and every division is numbered from above downwards (see jig. 17). The following directions for their construction are given by Professor Faraday : “ Let the tube represented in the margin have 100° grains of water weighed into it ; then let the space it occupies be graduated into 100 equal parts, and jy every ten divisions numbered from above downwards. At 22-1 parts, or 77‘99 parts from the bottom, make an extra line, a little on one side or even on the opposite side of the graduation, and write at it with a scratching dia- mond, soda; lower down, at 48‘62 parts, make another line, and write potash; still lower, at 54'43 parts, a third line marked carh. soda; and at 65 part, a fourth, marked carb. potash. It will be observed that portions are measured off beneath these marks in the inverse order of the equivalent number of these substances, and consequently directly proportionate to the quantities of any particular acid which will neutralize equal weights of the alkalis and their carbonates. As these points are of great importance, it will be proper to verify them by weighing into the tubes first 350, then 513‘8, and lastly 779 ‘9 grains of water, which will correspond with the marks if they are correct, or the graduation may be laid down from the surface of the four portions of fluid when weighed in, without reference to where they fall upon the general scale. The tube is now completed, except that it should be observed whether the aperture can be perfectly and securely cov- cred by the thumb of the left hand, and if not ; or, if there be reason to think carb.soqa- it not ultimately secure, then it should be heated and contracted until suffi- ciently small.” cARa . 29. The test acid for this alkalimeter should have a specific gravity of 1.1268 ; and such an acid may be prepared by mixing one part, by weight, of sulphuric acid, specific gravity 1'82, with four parts of water, and allow- ing the mixture to cool. In the meantime, 100 grains of pure anhydrous carbonate of soda, obtained as indicated before, should be dissolved in water, and the test sulphtiric acid, of specific gravity 1T268, prepared as abovesaid, having become quite cool, is poured into the alkalimeter up to the point marked carbonate of soda, the remaining divisions are filled up with water, and the whole should be well mixed by shaking. 30. If the whole of the sulphuric acid, adjusted as was said, being poured carefully into the solution of the 100 grains of the neutral carbonate of soda, neutralize them exactly — which is ascertained, as usual, by testing the solution with litmus-paper, which should not be either reddened or rendered bluer by it — it is of course a sign that the test is as it should be — that is to say, is of the proper strength ; in the contrary case, it must be finally adjusted in the manner already indicated, and which need not be repeated. See §§ 20 , 21 . 31. The best and most cqjivenient process for the anal)^st, however, consists in prepar- ing a test acid of such a strength that it may serve not only for all alkalis, but indeed for every base ; that is to say, by adjusting the test acid so that 100 alkalimetrical divisions of it (1,000 water-grains’ measure) may exactly saturate or neutralize one .equivalent of every base. This method, which was first proposed by Dr. Ure, is exceedingly convenient, and the possession of two reciprocal test liquids, namely the ammonia test liquor of a standard strength, of which we gave a description in the article on Acidimetry, and the standard test acid of which we are now speaking, affords, as Dr. Ure observes, ready and rigid means of verification. For microscopic analysis of alkaline and of acid matter, a graduated tube of a small bore, mounted in a frame, with a valve apparatus at top, so as to let fall drops of any size and at any interval, is desirable ; and such an instrument Dr. Ure employed for many years ; but instead of a tube with a valve apparatus at top, the operator may use a graduated tube of a small bore, terminated by a small length of vulcanized india-rubber tube pinched in a clamp, which may be relaxed in such a way as to permit also the escape of drops of any size at any interval of time, the little apparatus being under perfect command. 32. The test sulphuric acid, of such a strength that 100 alkalimetrical divisions of it can saturate one equivalent of every base, should have a specific gravity of 1‘032, and is prepared as follows : — Take 53 grains (one equivalent) of pure anhydrous neutral carbonate of soda, obtained L |-i0 |-26 |-30 |-35 ^40 ^45 |-sa §-S5 i-60 ^65 §-7i) 1-75 |_80 |-85 E _90 I - S 5 ^3/ ALKALBIETKY. 48 in the manner indicated before, (see § 18,) and dissolve them in about one fluid ounce of water. Prepare, in the meantime, the test sulphuric acid by mixing one part, by measure, of concentrated sulphuric acid with about 11 or 12 parts of water, and stir the whole well. The mixture having become quite cold, fill the alkalimeter with the cold diluted acid up to the point marked O'", taking the under line of the liquid as the true level, and, whilst stir- ring briskly the aqueous solution of the 63 grains of carbonate of soda above alluded to, pour the acid carefully from the alkalimeter into the vortex produced by stirring, until, by testing the liquor alternately with reddened and with blue litmus-paper, or, more conve- niently still, with gray litmus-paper, the neutralizing point is exactly hit. 33. If the whole of the 100 divisions of the alkalimeter had been required to neutralize exactly the 53 grains of pure anhydrous carbonate of soda, it would be a proof that the acid is of the right strength ; but if this is not the case, it must be adjusted in the manner described before, that is to say : — 34. Let us suppose, for example, that only 60 measures in the alkalimeter have been required to saturate or neutralize the 53 grains of carbonate of soda, then 50 measures should be poured at once into a glass cylinder accurately divided into 100 parts, the remain- ing 60 divisions should be filled up with water, and the whole being well stirred, 100 parts of the acid liquor will now contain as much real acid as was contained before in the 50 parts. 35. The acid may now be labelled simply, “ Test or Normal Sulphuric AcidT Each one hundred alkalimetrical divisions, or 1,000 water-grains’ measure of it, contain one equivalent, or 40 grains of real sulphuric acid ; and, consequently, each 100 alkalimetrical divisions of it will neutralize one equivalent, or 31 grains of soda, 47 of potash, 17 of ammonia, 28 of lime, and so forth, with respect to any other base. 36. The stock of test or normal sulphuric acid should, as usual, be kept in well-stop- pered bottles, in order to prevent concentration by evaporation. By keeping in the flask containing it a glass bead, exactly adjusted to the specific gravity of 1*032, the operator may always ascertain, at a glance, whether the acid requires readjusting. 37. With a Schiister’s alkalimeter, it is convenient to prepare the test acid of such a strength that, according as it has been adjusted for potash or for soda, 10 grains of it will exactly saturate one grain of one or the other of these bases in a pure state. It is consid- ered that the alkalimeter may be charged with a known weight of any of the other sul- phuric test acids of a known strength. Suppose, for example, that the test sulphuric acid taken have a specific gravity of 1*032, we know, as we have just shown, that 1*032 grains’ weight of that acid contains exactly one equivalent of pure sul- phuric acid = 40, and is capable, therefore, of neutralizing one equivalent of any base ; and, consequently, by taking a certain weight of this acid before beginning the assay, and weighing what is left of it after the assay, it is very easy to calculate, from the quantity of acid consumed in the experiment, what quantity of base has been neutralized. Thus a loss of 21*96 — 60*70 — 33*29 grains’ w*eight of this test acid represents one grain of potash, of ammonia, of soda respectively, and so on with the other bases. 38. The operator being thus provided with an appropriate test acid, we shall now describe how he should proceed with each of them in making an alkalimetrical assay with potash. In order to obtain a reliable result, a fair average sample must be operated upon. To secure this the sample should be taken from various parts of the mass, and at once put in a wide-mouth bottle, and well corked up until wanted ; when the assay has to be made, the contents of the bottle must be reduced to powder, so as to obtain a fair mixture of the whole ; of this weigh out 1,000 grains exactly — or less, if that quantity cannot be spared — and dissolve them in a porcelain capsule in about 8 fluid ounces of distilled hot water, or in that proportion ; and if there be left any thing like an insoluble residue, filter, in order to separate it, and wash it on the filter with small quantities of distilled water, and pour the whole solution, with the washings and rinsings, into a measure divided into 10,000 water-grains’ measure. If the water used for washing the insoluble residue on the filter has increased the bulk of the solution beyond 10,000 water-grains’ measure, it must be reduced by evaporation to that quantity ; if, on the contrary, the solution poured in the measure stands below the mark 10,000 water-grains’ measure, then as much w*ater must be added thereto as will bring the whole mass exactly to that point. In order to do this cor- rectly, the cylindrical measure should stand well on a table, and the under or lower line formed by the liquid, as it reaches the scratch 10,000, is taken as the true level. 39. This being done, 1,000 grains’ measure of the filtrate, that is to say, one-tenth part of the whole solution, is transferred to a glass beaker, in which the saturation or neutraliza- tion is to be effected, which is best done by means of a pipette capable of containing ALKALIMETRY. 49 exactly that quantity when filled up to the scratch, a. In order to fill such a pipette it is sufficient to dip it into the alkaline solution and to suck up the liquor a little above the scratch, a ; the upper orifice should then be stopped with the first finger, and by momentarily lifting it up, the liquor is allowed slowly to fall from the pipette back again into the 10,000 grains’ measure until its level reaches exactly the seratch, a. The last drop which remains hanging from the point of the pipette may be readily detached by touching the sides of the glass measure with it. The 1,000 grains being thus rigorously measured in the pipette should then be transferred to the glass beaker, in which the neutralization is to take place, by removing the finger alto- gether, blowing into it to detach the last drop, and rinsing it with a little water. ’ 40. Or, instead of the pipette just described, the operator may measure 1,000 grains by taking an alkalimeter full of the alkaline solution, and emptying it into the glass beaker in which the neutralization is to take place, rinsing it with a little water, and of course adding the rinsing to the mass in the said glass beaker. 41. Whichever way is adopted, a slight blue color should be imparted to the 1,000 grains’ measure of the alkaline solution, by pouring into it a small quantity of tincture of litmus. The glass beaker should then be placed upon a sheet of white paper, or a slab of white porcelain, in order that the change of color produced by the gradual addition of the test acid may be better observed. 42. This being done, if the operator have decided upon using the test sulphuric^ for potash (§§ l'7-22), he should take one of the alkalimeters, represented in fgs. 11, 12, 13, or 14, and fill it up to 0°, (taking the under line of the liquid as the true level ;) then taking the alkalimeter thus charged in his right hand, and in his left the glass beaker containing the alkaline solution colored blue by tincture of litmus, he should gradually and carefully pour the acid liquor into the alkaline solution in the glass beaker, to which a circular motion should be given whilst pouring the acid, or which should be briskly stirred, in order to insure the rapid and thorough mixing of the two liquors, and therefore their complete reac- tion ; moreover, in order at once to detect any change of color from blue to red, the glass beaker should be kept over the white sheet of paper or the white porcelain slab, as before stated. 43. At first no effervescence is produced, because the carbonic acid expelled, instead of escaping, combines with the portion of the alkaline carbonate as yet undecomposed, which it converts into bicarbonate of potash, and accordingly no sensible change of color is per- ceived ; but as soon as a little more than half the quantity of the potash present is satu- rated, the liquor begins to effervesce, and the blue color of the solution is changed into one of a vinous, that is, of a purple or bluish-red hue, which is due to the action of the car- bonic acid upon the blue color of the litmus. More acid should be still added, but from this moment with very great care and with increased caution, gradually as the point of neu- tralization is approached, which is ascertained by drawing the glass rod used for stirring the liquor across a slip of blue litmus-paper. If the paper remains blue, or if a red or reddish streak is thereby produced which disappears on drying the paper and leaves the latter blue, it is a proof that the neutralization is not yet complete, and that the reddish streak was due only to the action of the carbonic acid ; more acid must accordingly be poured from the alkalimeter, but one drop only at a time, stirring after each addition, until at last the liquor assumes a distinct red or pink color, which happens as soon as it contains an extremely slight excess of acid ; the streaks made now upon the litmus-paper will remain permanently red, even after drying, and this indicates that the reaction is complete, and that the assay is finished. 44. If the potash under examination were perfectly caustic, the solution would suddenly change from blue to pink, because there would be no evolution of carbonic acid at all, and consequently no vinous or purple color produced ; if, on the other hand, the potash was altogether in the state of bicarbonate, the first drops of test acid would at once decompose part of it and liberate carbonic acid, and impart a vinous color to the solution at the very outset, which vinous color would persist as long as any portion of the bicarbonate would remain undecomposed. 45. The neutralizing point being attained, the operator allows the sides of the alkalim- eter to drain, and he then reads off the number of divisions which have been employed. If, for example, 50 divisions have been used, then the potash examined contained 50 per cent, of real potash. See observ., §48-49. 46. Yet it is advisable to repeat the assay a second time, and to look upon this first de- termination only as an approximation 'which enables the operator, now that he knows about where the point of neutralization lies, to arrive, if need be, by increased caution as he reaches that point, at a much greater degree of precision. He should accordingly take again an alkalimeter full (1,000 water-grains’ measure) — that is to say, another tenth part of the liquor left in the 10,000 grains’ measure — and add thereto at once 48 or 49 alka- lirnetrical divisions of the test acid, and after having thoroughly agitated the mixture, pro- ceed to pour the acid carefully, two drops only at a time, stirring after such addition, and VoL. III.— 4 ALKALIMETRY. 60 touching a strip Of litmus-paper with the end of the glass rod used for stirring ; and so he should go on adding two drops, stirring, and making a streak on the litmus-paper, until the liquor assumes suddenly a pink or onion-red color, and the streak made on the litmus-paper is red also. The alkalimeter is then allowed to drain as before, and the operator reads off the number of divisions employed, from which number two drops (or of a division) should be deducted ; Gay-Lussac having shown that, in alkalimetrical assays, the sulphates of alkalis produced retard the manifestation of the red color in that proportion. One alka- limetrical division generally consists of 10 drops, but as this is not always the case, the operator should determine for himself how many drops are necessary to make up one division, and take account of them in the assay according to the ratio thus found. In the example given before, and supposing 10 drops to form one alkalimetrical division, then tho percentage value of the sample of potash under examination would probably be as follows Number of divisions of acid employed, 50*0 — 2 drops acid in excess, 0*2 Real percentage of potash, 49*8 47. When the alkalimeter described in 13 is employed, the test acid may, at the beginning of the experiment, be poured from the larger opening, e ; but towards the end — that is, when the neutralizing point is approaching — the acid should be carefully poured from the point, d, in single drops, or only two drops cU a time, until the saturating point is hit, as we have just said. If the operator wishes to pour only one drop, he should close the larger opening, e, of the bulb with the thumb, and then fill the bulb with the test acid by inclining the alkalimeter ; putting now the alkalimeter in an upright position, and removing the thumb, a certain quantity of acid will be retained in the capillary point, d ; and if the thumb be now pressed somewhat forcibly against the opening, e, the acid contained in the capillary point will be forced out and form one drop, which will then fall into the alkaline solution if it be held over it. If the saturation be complete, the operator, without remov- ing the bulb stopper, may, by applying his lips to the large opening, e, suck the acid em gaged in the capillary point back into the alkalimeter. 48. If there should be in the mind of the operator any doubt as to what is meant by the onion-red color which the liquor tinged blue with tincture of litmus acquires when slightly supersaturated, he may pour into a glass beaker a quantity of pure water equal to, or even larger than, the alkaline solution operated upon, and tinge it blue with a little tincture of litmus, to about the same degree of intensity as the alkaline liquor under examination. If he now pour into the pure water colored blue with litmus, one single drop of the test acid, it will acquire at once, by stirring, the onion-red color alluded to, and which he may now use as a standard of comparison. 49. Considering the rapidity with which these alkalimetrical operations can be per- formed, the operator, unless he has acquired sufficient practice, or unless a great degree of accuracy be not required, should repeat the assay two or three times, looking upon the first determination only as an approximation, and as a sort of guide as to the quantity of acid which will be required in the subsequent experiments, whereby he will now be enabled to proceed with increased caution as he approaches, the point of saturation; but, at any rate, if he will not take the little extra trouble of a repetition, he should, before he begins to pour the acid, take a little of the filtered alkaline solution out of the glass beaker, as a corps de reserve, which he adds to the rest after the saturating point has been approximated, and from that moment he may proceed, but with great care, to complete the neutralization of the whole. 50. Do not forget that, as the test sulphuric acid must always he added in slight excess to obtain a distinct red streak on the litmus-paper, a correction is absolutely necessary ; that is to say, the excess of sulphuric acid employed must be deducted if a strictly accurate result is sought. 51. If, instead of the special alkalimeter for potash above described, the operator pre- fers using that prepared of such a strength that 100 divisions of the alkalimeter (100 water- grains’ measure) contain exactly one equivalent of each alkali or base, which test sulphuric acid, as we have se^n, has a specific gravity of 1.032, {see §§ 31-36,) he should proceed exactly as indicated in § 38, and following ; and the alkalimeter being filled with that test acid, of specific gravity 1.032 up to 0°, it (the acid) should be poured carefully into the aqueous solution of the alkali tinged blue with litmus, until exact neutralization is attained, precisely in the same manner as in § 38, and following. 52. The neutralizing point being hit, let us suppose that the whole of the contents of the alkalimeter have been employed, that the aqueous solution tinged blue with litmus, is not yet saturated, and that, after having refilled the alkalimeter, the 4 divisions more (alto- gether 104 divisions) have been required to neutralize the alkali in the aqueous solution ; then, since 100 divisions (1,000 water-grains’ measure) of the test acid now employed satu- ALKALIMETRY. 51 rate exactly one equivalent, that is, 47 of potash, the question is now. What quantity of potash will have been saturated by the 104 divisions of acid employed ? The answer is found by a simple rule of proportion, to be nearly 49. 100 : 47 :: 104 : x = 48*88. The sample of potash examined contained, therefore, nearly 49 per cent, of pure potash. 58. If, instead of the special test sulphuric acid for potash, (§ 17,) or of the test sul- phuric acid for potash, and other bases, (§ 28,) the operator uses the potash and soda alka- limeter, (§§ 31-36,) the method to be followed is exactly similar to that described in § 42, and following. Some of the test sulphuric acid, of specific gravity 1*1268, is to be po\ired into the alkalimeter until it reaches the point marked “pofa.sA,” (that is to say, 48*62 divisions of the alkalimeter,) taking the under line of the liquid as the true level, and the remaining divisions up to 0° are carefully filled with water. The operator then closes the aperture of the alkalimeter with the thumb of his left hand, and the whole is violently shaken so as to obtain a perfect mixture. 54. The acid so mixed must now be carefully poured from the alkalimeter into the alka- line solution of the potash under examination until neutralization is attained, precisely as described in § 42, and following. 55. The neutralizing point being hit, the operator allows the sides of the alkalimeter to drain, and he then reads off the number of divisions employed in the experiment, which number indicates the percentage of real potash contained in the sample. 56. Had the operator wished to estimate the quantity of potash as carbonate of potash, he should have poured the test acid into the alkalimeter up to the point marked “ carbonate of potash f filled the remaining divisions of the alkalimeter up to 0° with water, and pro- ceeding exactly as just mentioned, the number of divisions of acid employed would indi- cate the percentage of potash contained in the sample as carbonate of potash. 57. If a Schuster’s alkalimeter {fig. 15) be used, and supposing, for example, that the acid to be employed therewith is so adjusted that 10 grains’ weight of it neutralize exactly 1 grain in weight of potash, proceed as follows: — Take 100 grains in weight of a fair average of the sample, previously reduced to powder, dissolve them in water, Mter with the precautions which have already been described before, (§ 38, and following,) and pour this solution into a glass cylinder graduated into 100 parts, and capable of containing 10,000 water-grains ; fill it up with water exactly as described before ; of this take now 100 alka- limetrical divisions, that is to say, -i- of the whole solution, and pour it into a glass beaker. On the other hand, charge the Schuster’s alkalimeter with a certain quantity of the test acid, and weigh it, along with the alkalimeter itself, in a good balance. This done, pro- ceed with the neutralization of the solution in the glass beaker, by pouring the acid from the alkalimeter in the usual way, and with the usual precautions, until the saturation is completed. Replace the alkalimeter, with the quantity of unconsumed acid, in the scale of the balance, weigh accurately, and since every grain of acid represents of a grain of potash, the number of grains of acid used in the experiment indicates at once the per- centage of real potash present in the sample. 58. When, however, potash is mixed with soda, as is frequently the case with the pot- ash of commerce, either accidentally or for fraudulent purposes, the determination of the amount of the cheaper alkali could not, until a comparatively recent period, be estimated, except by the expensive and tedious process of a regular chemical analysis. In 1844, how- ever, M. Edmund Pesier, Professor of Chemistry at Valenciennes, published an easy and commercial method for the estimation of the quantity of soda which potash may contain, by means of an areometer of a peculiar construction, to which the name of “ Natrometer” has been given by the talented professor. 59. The rationale of the method is grounded upon the increase of specific gravity which sulphate of soda produces in a solution saturated with pure sulphate of potash, and is de- duced from the fact that a solution saturated with neutral sulphate of potash possesses a uniform and constant density when the saturation is made at the same temperature, and that the density of such a solution increases progressively in proportion to the quantity of sulphate of soda present ; an increase of density so much the more readily observable, that the solubility of the sulphate of potash is greatly augmented by the presence of sulphate of soda. It had at first been thought that, in order to obtain any thing like accuracy, it would be necessary to combine all the potash with one same acid, preferably sulphuric acid ; and, consequently, that as the potash of commerce always contains a little, and sometimes a rather considerable quantity, of chloride of potassium, the latter salt should first be decomposed. Further experiments, however, established the fact, that in dissolving chlo- ride of potassium in a saturated solution of sulphate of potash, the specific gravity of the liquor is not materially increased, since the introduction of as much as 50 per cent, of chloride of potassium does not increase that density more than 3 per cent, of soda would do when examined by the natrometer — a degree of accuracy quite sufficient for commercial purposes. When soda is added to a saturated solution of sulphate of potash, the further 62 ALKALIMETEY, 21 addition of chloride of potassium thereto renders the specific gravity of the liquor less than it would have been without that addition — an apparent anomaly due to the fact that chlorine, in presence of sulphuric acid, of potash, and of soda, combines with the latter base to form chloride of sodium ; and it is this salt which increases the solubility of sulphate of potash, though in a somewhat less degree than sulphate of soda. Thus, if to a saturated solution of sulphate of potash 0*14 of soda be added along with 0‘20 of chloride of potas- sium, the natrometer indicates only 0*125 of soda. Seeing, therefore, that in such an exceptional case the error does not amount to more than 0*015 of error, it will probably be found unnecessary in most cases to decompose the chloride contained in the potashes of commerce, that quantity being too small to materially affect the result. Yet, as the accurate determination of soda in potash was a great desideratum, M. Pesier contrived two processes, one of which, in the hands of the practised chemist, is as perfect as, but much more rapid than, those ordinarily resorted to ; the other, which is a simplification of the first, yields results of sufficient accuracy for all commercial purposes. 60. First process. — Take 500 grains of a fair average sample of the potash to be examined, dissolve them in as little water as possible, filter, and wash the filter until the washings are no longer alkaline. This filtering, however, may be dispensed with when the potash is of good quality and leaves but a small residue, or when an extreme degree of accuracy is not required. 61. The potash being thus dissolved, a slight excess of sulphuric acid is added thereto ; the excess is necessary to decompose the chlorides and expel the muriatic acid. The liquor so treated is then evaporated in a porcelain capsule, about six inches in diameter ; and when it begins to thicken it should be stirred with a glass rod, in order to avoid projections. When dry, the fire must be urged until the residue fuses, and it is then kept in a state of tranquil fusion for a few minutes. The capsule should then be placed upon, and surrounded wit, hot sand, and allowed to cool down slowly, to prevent its cracking, which would happen without this precaution. 62. The fused mass in the capsule having become quite cold, should now be treated with as little hot water as possible, that is to say, with less than 3,000 grains of hot water ; and this is best done by treating it with successive portions of fresh water. All the liquors thus successively obtained should then be poured into a flask capable of holding about 10,000 grains of water, and the excess of sulphuric acid must he accurately neutral- ized by a concentrated solution of pure carbonate of potash — that is to say, until the color of litmus-paper is no longer affected by the liquor, just as in ordinary alkalimetrical or acidimetrical assays. During this operation, a pretty considerable precipitate of sulphate of potash is, of course, produced. 63. The neutralizing point being exactly hit, a saturated solu- tion of sulphate of potash is prepared, and brought to the atmos- pheric temperature ; a condition which is expedited by plunging the vessel which contains the solution into a basin full of cold water, and stirring it until the thermometer plunged in the liquor indicates that the temperature of the latter is about the same as, and preferably less than, that of the air ; because, in the latter case, it may be quite correctly adjusted by grasping the vessel with a warm hand. In order, however, to secure exactly the prop- er temperature, the whole should be left at rest for a few min- utes after having withdrawn the vessel from the basin of cold water used for refrigerating it, taking care simply to stir it from time to time, and to ascertain that the thermometer remains at the same degree of temperature. This done, the liquor is filtered into a glass cylinder, c, on which a scratch, h-i, has been made, cor- responding to 3,000 water-grains’ measure. If the directions given have been exactly followed, it will be found that the filtrate is not sufficient to fill it up to that mark ; the necessary volume, however, should be completed by washing the deposit of sulphate of potash in the filter, n, with a saturated solution of the same salt (sulphate of potash) previously prepared. It is advisable to use a saturated solution of sulphate of potash wTiich has been kept for some time, and not one immediately prepared for the purpose, be- cause sulphate of potash, in dissolving, produces a certain amount of cold, which would create delay, since it would be necessary to wait until the temperature of the mass had become the same as that of the air. 64. The liquor occupying 3,000 water-grains’ measure in the cylinder, should be next rendered homogeneous by stirring it well, after which the natrometer may be immersed in ALKALIMETRY. 53 it. The natrometer is simply an areometer of a peculiar construction, provided with two scales : the one of a pink color shows the degrees of temperature, and indicates, for each degree of the centigrade thermometer, the level at which a solution saturated with pure sulphate of potash would stand ; on the other scale, each degree represents 1 per cent, of soda, (oxide of sodium,) as represented in fig. 21. 65. The 0° of the two scales coincide with each other. If the experiment take place at the temperature of 0°, the quantity of soda will be directly determined by observing the number of degrees on the soda scale ; but if the experiment be performed at 25°, for exam- ple, it will be seen that the point at which the instrument would sink in the liquor saturated with pure sulphate of potash corresponds to of soda ; and, in this case, it is from this point that the 0° of the soda scale should be supposed to begin, which is easily accom- plished by a simple subtraction, as will be seen presently. 66. Experiment having shown that the degrees of soda cannot be equidistant, but that, on the contrary, they become smaller and smaller as the quantity of soda increases, the number of degrees of soda are obtained as follows : — From the number of degrees of tem- perature now indicated on the pink scale of the natrometer, subtract the number of degrees of temperature indicated by an ordinary thermometer at starting; then look at the soda scale for the number of soda degrees which correspond to the number of degrees of tem- perature left after subtraction, and each of the soda degrees, beginning from the 0° of the natrometer, represents 1 per cent. 67. For example: — Suppose the experiment to have been made. at starting, and as indicated by an ordinary thermometer, at -f- 20° centigrades, and that the level of the solution is now found to stand at 59° on the pink scale of temperature of the natrometer, then by deducting 20 (the original temperature) from 69 (number of degrees indicated by the floating point on the pink scale of temperatures of the natrometer) there remains, of coui-se, 39. Draw the instrument out, and looking now on the said pink scale for 39°, there will be found exactly opposite, on the soda scale, the number 13, which number signifies that the potash under examination contains 13 per cent, of soda, (oxide of sodium.) 68. As the deposit of sulphate of potash separated by filtering might retain some sul- phate of soda, it is advisable, in order to avoid all chance of error, to wash it with a saturated solution of sulphate of potash, adding as much of it as is necessary to bring the whole mass of the liquor up to the mark 3,000 water-grains’ measures, in which the natrometer being again immersed, the minute quantity of soda indicated should be added to the percentage found by the first operation. 69. If a great degree of accuracy is required, the fractions of degree of the instrument must be taken account of ; otherwise they may be neglected with- out the result being materially affected, since 3 degrees of the scale of temperature correspond only to about 1 per cent, of soda. 70. For commercial purposes, the process may be slightly varied, as follows : — Take 500 grains of a fair average sample of the potash to be examined, previously reduced to powder, and throw them into a flask {fig. 22) capable of containing about 6,000 grains of water ; pour upon them about 2,000 grains of water, and shake until dis- solved. Add now sulphuric acid thereto ; this will produce a smart effervescence, and in all probability a deposit of sulphate of potash. We say in all probability, because it is clear that if the potash in question is largely adulterated with soda, or was altogether nothing else than carbonate of soda, as has occasionally happened, it is evi- dent that no deposit of sulphate of potash would take place ; and yet, as it is necessary to the success of the operation that the liquor should contain an excess of this latter salt, a certain quantity of it previously reduced to fine powder must in that case be purposely added to the solution. 71. After the disengagement of gas has ceased, it is necessary to pour the dilute acid cautiously, and only drop by drop, until the neutralizing point is correctly hit, which will be known as usual by testing with litmus-paper. But if, by accident, too much acid has been used, which is known by the reddening of the litmus-paper, the slight overdose may be neutralized by adding a small quantity of weak solution of potash. 72. As this reaction produces heat, it is necessary to lower the liquor down to the temperature of the atmosphere, decant in a filter placed over the glass cylinder, and fill it up to the scratch 3,000, by washing the residue on the filter with a saturated solution of sul- phate of potash, exactly as described in § 63. 73. The glass cylinder being properly filled up to the scratch, remove the funnel, close the orifice of the glass cylinder with the palm of the hand, and shake the whole violently •> ALKALIMETKY. 54 holdincr the natrometer, which should be perfectly clean, by its uppen extremity, slowly immerse it in the solution. If the potash under examination be pure, the pink scale will indicate the degree of temperature at which the experiment has been made, taking the under line as the true level of the liquid ; but if, on the contrary, it contains soda, the pink scale of temperatures will indicate a few degrees more than the real temperature, and this surplus number of degrees, being compared with those of the soda scale contiguous to it, on the opposite side, will express the percentage of soda present in the sample. V4. For example : — Suppose the experiment to have been made at -{- 12° centigrade, and to have given a solution marking 25° on the pink scale of temperatures of the natrometer, that is, 13” more than the real temperature ; — looking therefore at number 13 on the pink scale of temperature, it will be seen that the number exactly opposite on the soda scale, and corresponding to it, is 4, which indicates that the sample of potash examined contains 4 per cent, of soda. It is important to bear in mind that all commercial potashes contain naturally a small quantity of soda, which quantity, in certain varieties, may even be considerable ; it is only when the proportion of soda is more considerable than that which is naturally contained in the species of potash submitted to analyisis, that it should be considered as fraudulently added. The following table, published by M. Pesier, shows the average composition of the principal varieties of potash found in commerce, when in an unadulterated state. Average Composition of Potashes. Tuacan Potash. Russian Potash. American Potash. j <9 CU Potash of the Vosges. Potashes obtain- ed in the Labo- r.rv V ssl- Salts of Iwuy dissolved and calcined. 1851. 1855. cini 1 M Molasses obtain'd from the Cistern , of a Distillery. ! Potash purified, de Valenciennes. Potash purified, de Valenciennes, Sulphate of potash 13-47 14-111 15-32 14.38 38-84 4-27 2-98 16-19 1-50 0-70 Chloride of potassium - 0-95 2-091 8-15 3-64 9-16 18.17 19-69 33*89 1-60 1*70 Carbonate of potash 74-10 69-61 68-07* 71-38 38-63 51-83 53-90 26-64 89-95 95-24 Carbonate of soda (dry) 3-01 3-09 5-85 2-31 4-17 24-17 23-17 19-60 5-12 2-12 Insoluble residue - 0-65 1-21 3-35 0-44 2.66 Moisture . - . - 7-28 8-82 unde- 4-56 5.34 0-50 ter- mined Phosphoric acid, lime, silica, &c. 0-54 1-OT ditto 3-29 1-20 1-56 0-26 3-6S 1-33 0-24 100-00 100-00 100-00 100-00 100-00 100.00 i 100-00 100-00 100-00 Alkalimetric degrees 56 531 55 54-4 31-6 60 59-7 1 36.5 68-5 69-5 75. The alkalimetrical assay of soda is performed exactly in the same manner as that of potash — that is to say : From a fair average sample of the soda to be examined, take 1,000 grains’ weight, (or less, if that quantity cannot be spared) and boil it five or six minutes in about eight fluid ounces of water ; filter, in order to separate the insoluble por- tion, and wash the residue on the filter with boiling water until it no longer drops from the filter with an alkaline reaction, and the bulk of the filtered liquid and the washings received in a graduated glass cylinder form 10,000 grains’ measure. Should the water which may have been required to wash the residue have increased the bulk of the solution beyond that quantity, it should be evaporated to reduce it to the bulk mentioned. 76. This being done, 1,000 water-grains’ measure — that is to say, Jjj- part of the aqueous solution of the soda ash above mentioned (§ 75) — is transferred to the glass beaker or vessel in which the saturation is intended to take place, it is tinged distinctly blue with tincture of litmus, and the operation is performed in the same manner and with the same precautions as for potash ; the glass beaker containing the blue alkaline solution being placed upon a sheet of white paper, or a slab of white porcelain, the better to observe the change of color which takes place when the saturating point is approaching. 77. Having put into a glass beaker the 1,000 grains’ measure of the aqueous solution of soda ash to be examined, (§ 75,) and of the test sulphuric acid for soda, described before, (§§ 23-27,) the alkalimeter, fgs. 12, 13, 14, should be filled with that test acid up t:> the point marked 0°, (taking the under line of the liquid as the true level,) and poured therefrom with the precaution already indicated, stirring briskly, at the same time, the liquid in the beaker. As is the case with the alkalimetrical assay of potash, the carbonic acid expelled * In the impossibility of estimating exactly the loss by calcination, and the qnantity of oxide of potassium in the caustic state, (hydrate of potash,) we have reduced the potash to the state of carbon- ite, to make comparison more easy. ALKALIMETRY. 55 by the test acid reacting upon the as yet undecomposed portion of the soda ash, converts it into bicarbonate of soda, so that at first no effervescence is produced ; but as soon as half the quantity of the soda in the solution is saturated, a brisk effervescence takes place. At first, therefore, the operator may pour at once, without fear, a pretty large quantity of the test acid into the alkaline solution, but as soon as this effervescence makes its appearance, he should proceed with increased precaution gradually as the saturating point is approached. The modus operandi is, in fact, precisely as already detailed for the assay of potash, pre- cisely the same kind and amount of care is requisite, and the assay is known to be termi- nated when the streaks made upon the litmus-paper with the stirring rod remain distinctly and permanently of a pink color. V8. After saturation, and after having allowed the sides of the alkalimeter to drain, the number of divisions at which the test acid stands in the alkalimeter indicate at once the percentage of the soda assayed, since, as we said, each division of this particular test acid represents one grain of pure soda. If, therefore, the test acid stands at 52 in the alkalimeter, then the soda assayed contained 52 per cent, of real soda. See, besides, the observations of § 48 and following, and also § 81. 79. If, instead of the special test acid for soda just alluded to, the operator employs that which has a specific gravity of 1'032, and 100 alkalimetrical divisions of which saturate one equivalent of each base, the modus operandi is the same — that is to say, the alkalimeter is filled with it up to 0°, and it is poured therefrom carefully into the alkaline solution ; but as the equivalent of soda is 31, and 100 alkalimetrical divisions of the test sulphuric acid now employed are capable of saturating only that quantity of soda, it is clear that with the soda ash taken as an example in the preceding case, and containing 52 per cent, of real soda, the operator will have to refill his alkalimeter with the same test acid, and that a certain number of divisions of this second filling will have to be employed to perfect the saturation. In this instance the operator will find that nearly 68 divisions more, altogether 168 divisions (correctly, 167° 74) have been required to effect the saturation. 80. If, instead of the special test sulphuric acid for soda, (§§ 23-27,) or the test sulphuric acid for potash, soda, and other bases, (g§ 31-34,) the operator uses the potash and soda alkalimeter, (§§ 28-35,) the method is always the same (§§ 74, 75) — that is to say, the aqueous solution of the soda ash is poured into the glass beaker, the difference being merely that instead of the alkalimeter being quite filled up with the test sulphuric acid, which, in the present instance, has a specific gravity of 1*268 (§ 29), the said test acid is poured into the alkalimeter only up to the point marked “ soc?a,” (taking the under line of the liquid as the true level,) and the remaining divisions of the alkalimeter are carefully filled up with water. The mouth of the tube should then be thoroughly closed with the thumb of the left hand, and the whole violently shaken until perfectly mixed, taking great care, of course, not to squirt any of the acid out of the tube, which evidently would cause an amount of error proportionate to the quantity of the test acid which would have thus been lost. The acid should then be poured from the alkalimeter with the usual precaution (§ 76) into the glass beaker containing the aqueous solution of the soda ash under examination, until com- plete neutralization is attained, stirring briskly all the time, or after each addition of the test acid. The neutralization point being hit, the sides of the alkalimeter are allowed to drain, and the operator then reads olF the number of divisions employed, which number indicates the percentage of real soda contained in the sample assayed. Thus, if the sample operated upon be the same as that alluded to before, the number of divisions employed being 52 would indicate 52 per cent, of real soda, 81. If the operator wishes to estimate the amount of soda in the sample as carbonate of soda^ he should fill the alkalimeter with the test acid in question (specific gravity 1*268) up to the point marked carbonate of soda, and fill the remaining divisions with water, shake the whole well, and proceed with the neutralization of the aqueous solution of the sample in the glass beaker as just described. Supposing, as before, that the sample in question contains 52 per cent, of real soda, it will now b^e found that the number of divisions employed altogether to saturate the sample completely are very nearly 89, for 52 of caustic soda correspond to 88*90 of the carbonate of that alkali. 82. If the soda ash is very poor, instead of operating upon 1,000 water-grains’ measure, or one-tenth part of the whole solution, (=i 100 grains’ weight of the soda ash, §§ 76-77,) it is advisable to take three or four thousand water-grains’ measure of the alkaline solution, and to divide, by three or four, the result obtained by saturation. Suppose, for example, that the quantity of real soda found is 46 ; this, if only 1,000 grains’ measure had been taken, would, of course, indicate 46 per cent. ; but as 4,000 water-grains’ measure of solu- tion has been taken instead, that number 46 must, accordingly, be divided by 4, which gives IH per cent, only of real soda contained in the sample under examination. 83. The soda ash of commerce contains generally a percentage of insoluble substances, which are removed by filtering, as we said, and a greater or less quantity of chloride of sodium (common salt) and of sulphate of soda, which, however, do not in the slightest degree interfere with the accuracy of the result. But there is a source of error resulting from the ALKALIMETRY. 56 presence in the soda ash of sulphuret of calcium, of sulphite, and sometimes also, though more rarely, of hyposulphite, of soda. When sulphuret of calcium is present in the ash, on heating the latter by hot water, a double decomposition takes place, the sulphuret of cal- cium, reacting upon the carbonate of soda, forms sulphuret of sodium and carbonate of lime. Now sulphuret of sodium saturates the test acid just as carbonate of soda ; but as it has no commercial value, it is clear that if the ash contains a quantity of the useless sulphuret at all considerable, a very serious damage may be sustained by the purchaser if the percentage of that substance present in the ash be taken account of as being soda. Sulphite of sodals produced from the oxidization of this sulphuret of sodium, and is objectionable inasmuch that, when the test acid is added slowly to the aqueous solution of the ash, the effect is to convert the sulphite into bisulphite of soda, before any evolution of sulphuric acid, and con- sequently before the pink reaction on litmus-paper is produced. 84. In order to obviate the inaccuracies resulting from the neutralization of a portion of the test acid by these substances, it is necessary to convert them into sulphates of soda, which is easily done by calcining a quantity of the sample with five or six per cent, of chlorate of potash, as recommended by Gay-Lussac and Welter. The operator, therefore, should intimately mix 50 or 60 grains’ weight of pulverized chlorate of potash with 1,000 grains of the pulverized sample, and fuse the mixture in a platinum crucible, for which purpose a blowpipe gas-furnace will be found exceedingly convenient. The fused mass should be washed, and the filtrate being received into a 10,000 water-grains’ measure, and made up with water to occupy that bulk, may then be assayed in every respect as described before with one or other of the test acids mentioned. 85. When, however, the soda ash contains. some hyposulphite of soda — which fortunately is seldom the case, for this salt is very difficultly produced in presence of a very large excess of alkali — it should not be calcined with chlorate of potash, because in that case one equiv- alent of hyposulphite becomes transformed not into one equivalent of sulphate^ but, reacting upon one equivalent of carbonate of soda, expels its carbonic acid, and forms with the soda of the decomposed carbonate a second equivalent of sulphate of soda, each equivalent of hyposulphite becoming thus converted into two equivalents of sulphate, and therefore creat- ing an error proportionate to the quantity of the hyposulphite present, each equivalent of which would thus destroy one equivalent of real and available alkali, and thus render the estimation of the sample inaccurate, and possibly to a very considerable extent. 86. When this is the case, it is therefore advisable, according to Messrs. Fordos and Gelis, to change the condition of the sulphurets, sulphites, and hyposulphites, by adding a little neutral chromate of potash to the alkaline solution, whence result sulphate of chro- mium, water, and a separation of sulphur, which will not affect the accuracy of the alkalimet- rical process. 87. Whether the sample to be analyzed contains any sulphuret, sulphite, or hyposul- phite, is easily ascertained as follows : — If, on pouring sulphuric acid upon a portion of the sample of soda ash under examination, an odor of sulphuretted hydrogen — that is, an odor of rotten eggs — is evolved, or if a portion of the soda ash, being dissolved in water, and then filtered, produces a black precipitate (sulphuret of lead) wh^en solution of acetate of lead is poured into it, then the sample contains a sulphuret. 88. And if, after adding to some dilute sulphuric acid as much bichromate of potash as is necessary to impart to it a distinct reddish-yellow tinge, and a certain quantity of the solu- tion of the soda ash under examination being poured into it, but not in sufficient quantity to neutralize the acid, the reddish-yellow color becomes green, it is a proof that the sample contains either sulphite or hyposulphite of soda, the green tinge being due to the transforma- tion of the chromic acid into sesquioxide of chromium. 89. And if, muriatic acid being poured into the clear solution of the soda ash, a turbid- ness supervenes after some time if left at rest, or at once if heat is applied, it is due to a deposit of sulphur, an odor of sulphurous acid being evolved, and hyposulphite of soda is probably present. We say probably, because if sulphurets and sulphites are present, the action of muriatic acid would decompose both, and liberate sulphuretted hydrogen and sul- phurous acid ; but as these two gases decompose eaeh other, a turbidness due to a separation of sulphur is also formed ; thus 2HS -f S 0^ = 2HO 2S. 90. As we have already had occasion to remark, the soda ash of commerce frequently contains some, and occasionally a large quantity of caustic soda, the proportion of which is at times important to determine. This may be done, according to Mr. Barreswill, by adding a solution of chloride of barium to the aqueous solution of the soda ash, by which the carbonate of soda is converted into carbonate of ba^rytes, whilst the caustic soda, react- ing upon the chloride of barium, liberates a quantity of caustic barytes proportionate to that of the caustic soda in the soda ash. After this addition of chloride of barium, the liquor is filtered in order to separate the precipitated carbonate of barytes produced, and which re- mains on the filter, on which it should be washed with pure water. A few lumps of chalk are then put into a Florence flask, a, and some muriatic acid being poured upon it, an effervescence due to a disengagement of carbonic acid is produced, the flask is then closed ALKALIMETRY. 57 with a good cork, provided with a bent tube, 6, reaching to the bottom of the vessel, c, and the stream of carbonic acid produced is then passed through the liquor, c, filtered from the carbonate of barytes above mentioned. The stream of car- bonic acid produces a precipitate of carbonate of barytes, which should be also collected on a separate filter, washed, dried, and weighed. Each gain of this second precipitate of carbonate of barytes corresponds to 0‘3157 of caustic soda. 91. As the soda ash of commerce almost invariably con- tains earthy carbonates, the sample operated upon should always be dissolved in hot water, and filtered, in order to separate the carbonate of lime, which otherwise would saturate a proportionate quantity of the test acid, and thus render the analysis worthless. 92. The quantity of water contained in either potash or soda ash is ascertained by heating a weighed quantity of the sample to redness in a covered platinum capsule or crucible. The loss after ignition indicates the proportion of water. If any caustic alkali is present, 1 equivalent, =9 of water, is retained, which cannot be thus eliminated, but which may, of course, be determined by calculation after the proportion of caustic soda has been found, as shown before, each 31 grains of caustic soda containing 9 grains of water. 93. Besides the alkali metrical processes which have been explained in the preceding pages, the proportion of available alkali contained in the sample may be estimated from the amount of carbonic acid which can be expelled by supersaturating the alkali with an acid. The determination of the value of alkalis, from the quantity of carbonic acid thus evolved by the supersaturation of the carbonate acted upon, has long been known. Dr. Ure, in the “Annals of Philosophy,” for October, 1817, and then in his “ Dictionary of Chemistry,” 1821, and more recently in his pamphlet “ Chemistry Simplified,” described several instru- ments for analyzing earthy and alkaline carbonates, for a description of which the reader is referred to the article on Acidimetry. The ingenious little apparatus of Drs. Fresenius and Will for the same purpose, and to which we have already alluded in the same article, gives accurate results ; but it should be observed that when the potash or soda of commerce contains any caustic alkali, or bicarbonate, or earthy carbonates, or sulphuret of alkali — which, as we have seen, is frequently, and, indeed, almost invariably, the case, the process is no longer applicable without first submitting the sample to several operations — which render this process troublesome and unsuited to unpractised hands. Thus, if caustic potash is present, the sample must be first mixed and triturated with its own weight of pure quartz- ose sand and about one-third of its weight of carbonate of ammonia. The mass is then moistened with aqueous ammonia, and then put into a small iron capsule and evaporated to dryness, so as to expel completely the ammonia and carbonate of ammonia. The mass is then treated by water, filtered, washed, and concentrated to a proper bulk by evaporation, transferred to the apparatus, and treated as will be seen presently. If the sample contains caustic soda, instead of one-third, at least half of its weight of carbonate of ammonia should be employed. But for the estimation of pure carbonates, Drs. Fresenius and Will’s method is both accurate and easy. The apparatus consists of two flasks, A and b ; the first should have a capacity of from two to two ounces and a half ; the second, or flask b, should be of a somewhat smaller size, and hold about one and a half or two ounces. Both should be provided with per- fectly sound corks, each perforated with two holes, through which the tubes a, c, c?, are passing. The lower extremity of the tube a must be adjusted so as to reach nearly to the bottom of the flask a, and its upper extremity is closed by means of a small pellet of wax, 6; c is a tube bent twice at right angles, one end of which merely protrudes through the cork into the flask a, but the other end reaches nearly to the bottom of the flask b. The tube d of the flask b merely protrudes through the cork into the flask. 94. The apparatus being so constructed, a certain quan- tity — 100 grains, for example — of the potash or soda ash under examination, (and which may have been previously dried,) is weighed and introduced into the flask a, and water is next poured into this flask to about one-third of its capacity. Into the other flask, or flask B, concentrated ordinary sulphuric acid is poured, and the corks are firmly put in the flasks, which thus become connected, so^as to form a twin-apparatus, which is then car- ried to a delicate balance, and accurately weighed. This done, the operator removes the apparatus from the balance, and applying his lips to the extremity of the tube c?, sucks out ' 58 ALKALINE EARTHS. a few air-bubbles, which, as the other tube, os, is closed by the wax pellet, rarefies the air in the flask a, and consequently causes the sulphuric acid of flask n to ascend a certain height (after the suction) into the tube c ; and if, after a short time, the column of sulphuric acid maintains its height in the tube c, it is a proof that the apparatus is air-tight, and therefore as it should be. This being ascertained, suction is again applied to the extremity of the, tube d, so that a portion of the sulphuric acid of the flask b ascends into the tube c, and presently falls into the flask a ; the quantity which thus passes over being, of course, pro^ portionate to the vacuum produced by the suction. As soon as the acid thus falls in the water containing the alkaline carbonate in the flask a, an effervescence is immediately pro- duced, and as the carbonic acid disengaged must, in order to escape, pass, by the tube c, through the concentrated sulphuric acid of the flask b, it is thereby completely dried before it can finally make its exit through the tube d. The effervescence having subsided, suction is again applied to the tube d, in order to cause a fresh quantity of sulphuric acid to flow over into the flask a, as before ; and so on, till the last portion of sulphuric acid sucked over produces no effervescence, which indicates, of course, that all the carbonate is decom- posed, and that, consequently, the operation is at an end. A powerful suction is now ap- plied to the tube d, in order to cause a tolerably large quantity of sulphuric acid, but not all, to flow into the flask a, which thus becomes very hot, from the combination of the concentrated acid with the water, so that the carbonic acid is thereby thoroughly expelled from the solution. The little wax pellet which served as a stopper is now removed from the tube a, and suction applied for some time, in order to sweep the flasks with atmos- pheric air, and thus displace all the carbonic acid in the apparatus, which is allowed to become guife cold, and weighed again, together with the wax pellet, the difference between the first and the second weighing — that is to say, the loss — indicating the quantity of car- bonic acid which was contained in the carbonate, which has escaped, and from which, of course, the quantity of the carbonated alkali acted upon may be calculated. Suppose, in effect, that the loss is 19 grains : taking the Equivalent of soda - - - - - -=31 do carbonic acid =22 1 equivalent of carbonate of soda - - = 53, it is clear that the 19 grains of carbonic acid which have been expelled represent 45'77 grains of carbonate of soda, or, in other words, 100 grains of soda ash operated upon con- tained 45‘77 of real carbonate of soda, thus : — CO^ NaO'CO* CO^ NaO> CO’ 22 : 53 :: 19 : a; = 45*77 95. As the soda ash of commerce always contains earthy carbonates, and very frequently sulphurets, sulphites, and occasionally hyposulphites, instead of putting the 100 grains to be operated upon directly into the flask a, it is absolutely necessary first to dissolve them in boiling water, to filter the solution, and to wash the precipitate which may be left on the filter with boiling water. The solution and the washings being mixed together, should then be reduced by evaporation to a proper volume for introduction into the flask a, and the process is then carried on as described. If sulphuret, sulphites, or hyposulphites are present, the ash should be treated exactly as mentioned in §§ 83-91, previous to pouring the solution into the flask a, since otherwise the sulphuretted hydrogen and sulphurous acid, which would be disengaged along with the carbonic acid, would apparently augment the proportion of the latter, and render the result quite erroneous. 96. The balance used for this mode of analysis should be capable of indicating small weights when heavily laden. — A. N. ALKALINE EARTHS — Barytes, Lime, and Strontta. These earths are so called to distinguish them from the earths Magnesia and Alumina. They are soluble in water, but to a much less extent than the alkalies. Their solutions impart a brown color to turmeric paper, and neutralize acids. They are, however, distinguished from the alkalies by their combination with carbonic acid, being nearly insoluble in water. AL-KENNA, or AL-HENNA, is the name of the root and leaves of Lawsonia inermis, which have been long employed in the East to dye the nails, teeth, hair, garments, &c. The leaves, ground, and mixed with a little limewater, serve for dyeing the tails of horses in Persia and Turkey. It is the same as the herb Henna frequently referred to by the Oriental poets. The powder of the leaves, being wet, forms a paste, which is bound on the nails for a night, and the color thus given will last for several weeks. This plant is sometimes called the true alkanet root, the alkanet of the shops being termed the spurious alkanet root, {radix alkannce ftpurue.) ALLIOLE. One of the hydrocarbons which can be obtained from naphtha. It is one of the most volatile of bodies. Alliole is obtained by distilling crude naphtha, and collect- ALLOY 59 ing all that leaves the still in the first distillation before the boiling temperature reaches 194° F; and on the second distillation, all below 176° F. This substance combines with, or is altered by, oil of vitriol, and hence it is better obtained from the crude naphtha, and afterwards purified by agitation with dilute sulphuric or hydrochloric acid, and redistillation. It boils, when nearly free from benzole^ at a temperature of from 140° to 158° F., and possesses an alliaceous odor somewhat resembling sulphide of carbon. — Richardson. ALLOTROPY. Allotropic Condition. A name introduced by Berzelius to signify another form of the same substance, derived from another, and rpovosy habit. Car- bon, for example, exists as the diamond, a brilliant gem, with difficulty combustible ; as graphite, a dark, heavy, opaque mass, often crystalline, also of great infusibility ; and as charcoal, a dark porous body, which burns with facility. An extensive series of bodies appears to assume similar allotropic modifications. The probability is that, with the advance of physical and chemical science, many of the substances now supposed to be elementary will be proved to be but allotropic states of some one form of matter. Deville has already shown that silicon and boron exist, like the dia- mond, in three allotropic states— one of the conditions of boron being much harder than -the diamond. ALLOY. The experiments of Crookewitt upon amalgams appear to prove that the combination of metals in alloys obeys some laws of a similar character to those which prevail between combining bodies in, solution ; i. e. that a true combining proportion existed. By amalgamation and straining through chamois leather, he obtained crystalline metallic compounds of gold, bismuth, lead, and cadmium, with mercury, which appeared to exist in true definite proportions. With potassium he obtained two amalgams, KHg^“ and KHg^ With silver, by bringing mercury in contact with a solution of nitrate of silver, according to the quantity of mercury employed, he obtained such amalgams as Ag °Hg‘®, Ag Hg'\ Ag Hg^ Ag Hg^ Beyond those there are many experiments which appear to prove that alloys are true chemical compounds ; but, at the same time, it is highly probable that the true chemical alloy is very often dissolved (mechanically disseminated) in tliat metal which is largely in excess. Some years since, the editor carried out an extensive series of experiments in the labo- ratory of the Museum of Practical Geology, with the view of obtaining a good alloy for soldiers’ medds, and the results confirmed liis views respecting the laws of definite, propor- tional combiiRtion among the metals. Many of those alloys were struck at the Mint, and yielded beautiful impressions ; but there were many objections urged against the use of any alloy for a medal of honor. The alloys of the following metals have been examined by Crookewitt, and he has given their specific gravities as in the following table ; the specific gravity of the unalloyed metals being — Copper - - 8-794 1 ’ Zinc - 6-860 Tin - 7-305 1 Lead - 11-354 That of the alloys was — Cu^ Sn^ 7-652 Cu Pb - 10-375 Cu Sn 8-072 Sn Zn" 7-096 Cu® Sn 8-512 Sn Zn 7-115 Cu^Zn® 7-939 Sn" Zn 7-235 Cu=* Zn^ 8-224 Sn Pb" 9-965 Cu" Zn 8-392 Sn Pb 9-394 Cu" Pb" - - 10-753 Sn" Pb 9-025 There are many points of great physical as well as chemical interest in connection with alloys, which require a closer study than they have yet received. There are some striking facts, brought forward by M. Wertheim, deduced from experiments carried on upon fifty- four binary alloys and nine ternary alloys of simple and known composition, which will be found in the “ Journal of the French Institute,” to which we would refer the reader. On the Melting Point of Certain Alloys. Centigrade Centigrade Thermometer. Thermometer. Lead . - - - - 334° Tin, 2 atoms ; lead. 1 atom - 196° Tin - - - - - 230° (( 1 “ 1 “ - 241° Tin, 5 atoms ; lead, 1 atom - 194° (( 1 “ “ 3 “ - 289° 4 “ “1 “ - 189° u 2 vols. ; “ 1 vol. - 194° “ 3 “ “1 “ - 186° In these experiments of M. Kupffer, the temperatures were determined with thermom- ALLOY. 60 eters of great delicacy, and the weighings were carefully carried out. — Ann. de Chinne^ xl. 286-302 ; Brewster's Edin. Jour. Sci. i. N.S. p. 299. It may prove convenient to give a general statement of the more striking peculiarities of the important alloys. More detailed information will be found under the heads of the respective metals. Gold and Silver Alloys. — The British standard for gold coin is 22 parts pure gold and 2 parts alloy ; and for silver, 222 parts pure silver to 18 parts of alloy. The alloy for the gold is an indefinite proportion of silver and copper : some coin has a dark red color, from the alloy being chiefiy copper ; the lighter the color a larger proportion of silver is indicated, sometimes even (when no copper is present) it approaches to a greenish tinge, but the proportion of pure gold is the same in either case. The alloy for silver coinage is always copper ; and a very pure quality of this metal is used for alloying, both for the gold and silver coinage, as almost any other metal being present, even in very small quantities, would make the metals unfit for coinage, from ren- dering the gold, silver, and copper brittle, or not sufficiently malleable. The standard for plate (silver) is the same as the coin, and requires the same quan- tity of copper, and carefully melting with two or three bits of charcoal on the surface while in fusion, to prevent the oxidation of the copper by heat and exposure to the atmos- phere. The gold standard for plate and jewellery varies, by a late act of Parliament, from the 22 carats pure, to 18, 12, and 9 : the alloys are gold and silver, in various proportions, according to the taste of the workmen ; the color of the articles manufactured depending, as with the coin, on the proportions ; if no copper is used in qualities under 22 carats fine gold, the color varies from a soft green to a greenish white, but a proportion of copper may be used so as to bring the color to nearly that of 22 fine, 1 silver, and 1 copper. Wire of either gold or silver may be drawn of any quality, but the ordinary wire, for fine purposes, such as lace, contains from 5 to 9 pennyweights of copper in the pound of 240 pennyweights, to render it not so soft as it would be with pure silver. Gold, silver, and copper, may be mixed in any proportions without injury to the ductil- ity, but no reliable scale of tenacity appears to have been constructed, although gold and silver in almost any proportions may be drawn to the very finest wire. The alloys of silver and palladium may be made in any proportions ; it has been found that even 3 per cent, of palladium prevents silver tarnishing so soon as without it ; 10 per cent, very considerably protects the silver, and 30 per cent, of palladium will prevent the silver being affected by fumes of sulphuretted hydrogen unless very long expoUd : the latter alloy has been found useful for dental purposes, and the alloy with less proportions — say 10 to 15 per cent. — has been used for graduated scales of mathematical instruments. The alloy of platinum and silver is made for the same purposes as those of palladium, and, by proper care in fusion, are nearly equally useful, but the platinum does not seem to so perfectly combine with the silver as the palladium. Any proportion of palladium with gold injures the color, and even 1 per cent, may be detected by sight, and 6 per cent, ren- ders it a silver color, while about 10 per cent, destroys it ; but the ductility of the alloy is not much injured. Gold leaf for gilding contains from 3 to 12 grains of alloy to the ounce. Sixteen- carat gold, which is f fine gold and ^ alloy, the alloy being nearly always equal portions of silver and copper, is not in the slightest degree injurious for dentists’ purposes. Antimony in the proportion of jcVo destroys the ductility of gold. Gold and 'platinum alloy forms a” somewhat elastic metal. Hermstadt’s imitation of gold consists of 16 parts of platinum, 1 parts of copper, and 1 of zinc, put in a crucible, covered with charcoal powder, and melted into a mass. — P. J. Dentists' amalgam is prepared by rubbing together, in a mortar, or even in the hollow of the hand, finely divided silver and mercury, and then pressing out all the uncombined mercury. This alloy, when put into the hollow of a decayed tooth, very soon becomes exceedingly hard. Some dentists add a little copper, or gold, or platinum leaf, under the impression that the amalgam becomes harder. Copper Allots. — Copper alloyed with zinc forms Brass, and with tin, we have Bronze. (See those articles.) The alloys of the ancients were usually either brasses or bronzes. The following analyses of ancient coins, &c., by Mr John Arthur Phillips, are of great value. It is not a little curious to find that some of the coins of high antiquity contain zinc, which does not appear to have been known as a metal before 1280 a.d., when Albertus Magnus speaks of zinc as a semi-metal, and calls the alloy of copper and zinc golden marca- site ; or rather, perhaps, he means to apply that name to zinc, from its power of imparting a golden color to copper. The probability is that calamine was known from the earliest times as a peculiar earth, although it was not thought to be an ore of zinc or of any other metal. — See Watson's Chemical Essays. ALLOY. 61 Date. o o u i ci i a N tZ Oi -3 2 0 0 B. c. A. D. - 500 69-69 7-16 21-82 •47 trace trace •57 Semis - - • - 500 — 62.04 7-66 29-32 •18 — — trace •19 •23 Quadrans - 500 — 72 22 7-17 19-56 •40 — — trace •20 •28 Hiero I. - - - 470 — 94-15 5-49 — •32 Alexander the Great - 335 — 86-77 12-99 — — — — •06 Philippus III. 323 — 90 27 9-43 Philippus V. - - 200 — 85 15 11 - 12 - 2-85 •42 — — trace Copper coin of Athens ? — 88-34 9-95 •63 •26 — — — trace trace Egyptian, Ptolemy IX. 70 — 84-21 15-64 — trace — — trace — trace Pompey, First Brass - 53 — 74-17 8-47 ! 16-15 •29 Coin of the Atilia Family 45 — 68-69 4-86 25-43 •11 — — — trace trace Julius and Augustus - 42 — 79-13 8-00 12-81 trace — — trace Augustus and Agrippa 30 — 78-45 12-96 8-62 trace — — trace Large Brass of the Cas- 1 sia Family - j 20 - ' 82-26 - - •35 17-31 - trace Sword-blade — — 89-69 9-58 — •33 — — trace Broken sword-blade — — 85-62 10-02 — •44 Fragment of sword-blade — 91-79 8-17 — trace — — trace Broken spear-head ’ - — — 99-71 — — — — — •28 Celt .... — — 90-68 7-43 1-28 trace — — trace Celt .... — — 90-18 9-81 — trace Celt .... — 89-33 9-19 — •33 — — •24 Celt .... 1 — 83-61 10-79 3-20 •58 — — trace •34 Large Brass of Nero 60 81-07 1-05 — 17-81 Titus .... 79 83-04 — — •50 15-84 Hadrian ... — 120 85-67 1-14 1-73 •74 10.85 Faustina, Jun. 165 79-14 4 97 9-18 •23 6-27 Greek Imperial Samosata — 212 70.91 6-75 21-96 trace Victorinus, Sea. (No. 1) — 262 95-37 •99 trace trace — 1-60 Victorinus, Sen. (No. 2) 262 97-13 -10 trace 101 — 1-76 Tetrius, Sen. (No. 1) - — 267 98-50 •37 trace •46 •76 Tetrius, Sen. (No. 2) - — 268 98-00 •51 — •05 — 1-15 Claudius Gothicus (No. 1) — l_ OAQ 81-60 7-41 811 — — 1-86 Claudius Gothicus (No. 2) — 84-70 3-01 2 67 •31 trace 7-93 Tacitus (No. 1) - — L OTPv 86-08 3-63 4-87 — 4-42 Tacitus (No. 2) - 91-46 — 2-31 — 5-92 Probus (No. 1) - — l_ OTK 90-68 2-00 2 33 •61 1*39 2-24 Probus (No. 2) - — 94-65 •45 •45 •80 — 3-22 Copper, when united with half its weight of lead, forms an inferior alloy, resembling gun-metal in color, but is softer and cheaper. This alloy is called pot-metal and cock-metal^ because it is used for large measures and in the manufacture of tap-cocks of all de- scriptions. Sometimes a small quantity of zinc is added to pot-metal ; but when this is considerable, the copper seizes the zinc to form brass, and leaves the lead at liberty, a large portion of which separates on cooling. Zinc and lead are not disposed to unite ; but a little arsenic occasions them to combine. Of the alloys of copper and lead, Mr. HoltzapfFel gives the following description : — Lead Alloys. — Two ounces lead to one pound copper produce a red-colored and duc- tile alloy. Four ounces lead to one pound copper give an alloy less red and ductile. Neither of these is so much used as the following, as the object is to employ as much lead as possible. Six ounces lead to one pound copper is the ordinary pot-metal, called dry pot-metal^ as this quantity of lead will be taken up without separating on cooling ; this alloy is brittle when warmed. Seven ounces lead to one pound copper form an alloy which is rather short, or disposed to break. Eight ounces lead to one pound copper is an inferior pot-metal, called wet pot-metal, as the lead partly oozes out in cooling, especially when the new metals are mixed ; it is there- fore always usual to fill the crucible in part with old metal, and to add new for the remain- der. This alloy is very brittle when slightly warmed. More lead can scarcely be used, as it separates on cooling. Antimony twenty parts and lead eighty parts form the printing-type of France ; and lead and antimony are united in various proportions to form the type-metal of our printers. See Type. Mr. James Nasmyth, in a letter to the “ Athenaeum,” (No. 1176, p. 611,) directed atten- tion to the employment of lead, and its fitness as a substitute for all works of art hitherto executed in bronze or marble. He says the addition of about 5 per cent, of antimony to the lead will give it, not only great hardness, but enhance its capability to run into the most delicate details of the work. Baron Wetterstedt’s patent sheathing for ships consists of lead, with 2 to 8 per cent, of antimony ; a,bout 3 per cent, is the usual quantity. The alloy is rolled out into sheets. — Holtzapffel. W e are not aware that this alloy has ever been employed. ALLOY. 62 Emery wheels and grinding tools for the lapidary are formed of an alloy of antimony and lead. Organ pipes are sometimes made of lead and tin, the latter metal being employed to harden the lead. The pipes, however, of the great organ in the Town Hall of Birmingham are principally made of sheet zinc. Lead and arsenic form shot-metal. The usual proportions are said to be 40 lbs. of metallic arsenic to one ton of lead. Tabular Statement of the Physical Peculiarities of the Principal Alloys, adopted, with some alterations, from the '‘''Encyclopedic Technologique." BRITTLE METALS. Aesenic. Antimony. Bismuth. With Zinc, rendering it brittle. This alloy is very brittle. Unknown, With Iron and Steel, hard- ending, whitening, and rendering those metals susceptible of a fine pol- ish : much used for steel chains and other orna- ments. 30 of iron and 70 of anti- mony are fusible ; very hard, and white. An alloy of two of iron and one of antimony is very hard and brilliant. Doubtful, With Gold, a gray metal, very brittle. Forms readily a pale-yellow alloy, breaking with a fracture like porcelain. Similar to antimony; of a yellow-green color. With Copper. Composed of 62 parts of copper and 32 arsenic, a gray, brilliant, brittle metal. Increasing the quantity of copper, the alloy be- comes white and slightly ductile : used in the man- ufacture of buttons un- der the name of white copper, or Tombac. Alloys readily: the alloys are brittle. Those form- ed with equal parts of the two metals are of a fine violet color. Pale-red brittle metal. With Silver. 23 of silver and 14 of arsenic form a grayish-white brittle metal. These have a strong affini- ty ; their alloys are al- ways brittle. Alloys brittle and lamel- lated. With Lead. Arsenic ren- ders lead brittle. The combination is very inti- mate ; not decomposed by heat. Antimony gives hardness to lead. 24 parts of an- timony and 76 of lead, corresponding to Pb^Sb, appear the point of satu- ration of the two metals. The alloys of bismuth and lead are less brittle and more ductile than those with antimony; but the alloy of 3 parts of lead and 2 of bismuth is harder than lead. These alloys are very fusible. With Tin. Brittle, gray, lamellated ; less fusible than tin. The alloys of antimony and tin are very white. They become brittle when the arsenic is in large quan- tity. Tin and bismuth unite in all proportions by fusion. All the alloys are more fusible than tin. With Mercury. Without * interest. A gritty white alloy. Mercury dissolves a large quantity of bismuth with- out losing its fluidity; but drops of the alloy elongate, and form a tail. • ALLOY. 63 DUCTILE METALS. Ikon. With Zinc. See Galvanized Iron. With Iron or Steel. With Gold • With Copper With Lead, does not appear to form any alloy. With Tin. A very little iron dimin- ishes the mallea- bility of tin, and gives it hardness. With Mercury. Mercury has no action on iron. Gold. A greenish-yellow alloy, which will take a fine polish. Gold and iron alloy with ease, and form yellowish al- loys, varying in color with the proportions of the metals. Three or four parts of iron united with one of gold is very hard, and is used in the manufacture of cutting instru- ments. A very brittle alloy. A thousandth pt. of lead is suflScient to alter the duc- tility of gold. The alloys of gold and tin are brit- tle ; they preserve, however, some ductility when the proportion of tin does not exceed J,. Mercury has a most powerful action on gold. See Amal- gam. Copper. See Brass. Iron and copper do not form true al- loys. When fused together, the iron, however, retains a little copper. — Several methods for coating iron with copper and brass will be de- scribed. Copper and gold al- loy in all propor- tions, the copper giving hardness to the gold. This al- loy is much used in coin and in the metal employed in the manufacture of jewellery. T . Do not appear to form a true alloy. Of great importance. See Bronze. An amalgam which is formed with dif- ficulty, and with- out interest. Silver. Silver and zinc com- bine easily, form- ing a somewhat brittle alloy. When 1 of silver and 600 of steel are fused, a very perfect button is formed. — Stodart and Faraday. Gold and silver mix easily together ; but they do not appear to form a true combination.* Jewellers often employ Vor vert, which is composed of 70 parts of gold and 30 of silver, which corresponds very nearly to the alloy possessing the maximum hardness. Silver and copper alloy in all pro- portions. These al- loys are much used in the arts. The . maximum hard- ness appears to be produced when the alloy contains a fifth of copper. Unite in all propor- tions ; but a very small quantity of lead will greatly diminish the duc- tility of silver. Alloys readily. A very small quan- tity of tin destroys the ductility of silver. The amalgamation of these two metals is a little less ener- getic than between mercury and gold. See Amalgama- tion. - 64 , ALLOY. In addition to these, the alloys of iron appear of suflScient importance to require some further notice. Iron and Manganese. — Mr. Mushet concludes, from his experiments, that the maximum combination of manganese and iron is 40 of the former to 100 of the latter. The alloy 71 ’4 of tin and 28-6 of manganese is indifferent to the magnet. ^ Iron and Silver ; Steel and Silver. — Various experiments have been made upon alloys of iron and steel with other metals. The only alloys to which sufficient importance has been given are those of iron and silver and steel and silver. M. Guyton states, in the “ Annales de Chimie,” that he found iron to alloy with silver in greater quantity than the silver with the iron. “ Iron can,” he says, “ therefore no longer be said to refuse to mix with silver ; it must, on the contrary, be acknowledged that those two metals, brought into perfect fusion, contract an actual chemical union ; that whilst cooling, the heaviest metal separates for the greatest part ; that, notwithstanding each of the two metals retains a portion of the other, as is the case in every liquidation, the part that remains is not simply mixed or inter- laid, but chemically united; lastly, the alloy in these proportions possesses peculiar properties, particularly a degree of hardness that may render it extremely useful for various purposes.” The experiments of Faraday and Stodart on the alloys of iron and steel are of great value ; the most interesting being the alloy with silver. The words of these experimen- talists are quoted : — “ In making the silver alloys, the proportion first tried was 1 silver to 160 steel ; the re- sulting buttons were uniformly steel and silver in fibres, the silver being likewise given out in globules during solidifying, and adhering to the surface of the fused buttons ; some of these, when forged, gave out more globules of silver. In this state of mechanical mixture the little bars, when exposed to a damp atmosphere, evidently produced voltaic action ; and to this we are disposed to attribute the rapid destruction of the metal by oxidation, no such destructive action taking place when the two metals are chemically combined. These results indicated the necessity of diminishing the quantity of silver, and 1 silver to 200 steel was tried. Here, again, were fibres and globules in abundance ; with 1 to 300 the fibres diminished, but still were present ; they were detected even when 1 to 400 was used. The successful experiment remains to be named. When 1 of silver to 500 steel were properly fused, a very perfect button was produced ; no silver appeared on its surface ; when forged and dissected by an acid, no fibres were seen, although examined by a high magnifying power. The specimen forged remarkably well, although very hard ; it had in every respect the most favorable appearance. By a delicate test every part of the bar gave silver. This alloy is decidedly superior to the very best steel ; and this excellence is unquestionably owing to a combination with a minute quantity of silver. It has been repeatedly made, and always with equal success. Various cutting tools have been made from it of the best qual- ity. This alloy is, perhaps, only inferior to that of steel and rhodium, and it may be procured at small expense ; the value of silver, where the proportion is so small, is not worth naming ; it will probably be applied to many important purposes in the arts.” Messrs. Faraday and Stodart show from their researches that not only silver, but plati- num, rhodium, gold, nickel, copper, and even tin, have an affinity for steel sufficiently strong to make them combine chemically. Iron and Nickel unite in all proportions, producing soft and tenacious alloys. Some few years since, Mr. Nasmyth drew attention to the combination of silicon with steel. Fresh interest has been excited in this direction by the investigations of a French chemist, M. St. Claire Deville, who has examined many of the alloys of silicon. Silicon and Iron combine to form an alloy which is a sort of fusible steel in which car- bon is replaced by silicon. The siliciurets are all of them quite homogeneous, and are not capable of being separated by liquidation. Copper and Silicon unite in various proportions, according to the same chemist. A very hard, brittle, and white alloy, containing 12 per cent, of silicon, is obtained by melting together three parts silico-fluoride of potassium, one part sodium, and one part of copper, at such a temperature that the fused mass remains covered with a very liquid scoria. The copper takes up the whole of the silicon, and remains as a white substance less fusible than silicon, which may serve as a base for other alloys. An alloy with 5 per cent, silicon has a » beautiful bronze color, and will probably receive important applications. Mr. Oxland and Mr. Truran have given, in “ Metals and their Alloys,” the following use- ful tabular view of the composition of the alloys of copper. The principal alloys of copper with other metals are as follows : — ALOE. 65 Copper. Zinc. Tin. Nickel. Antimony. Lead. Antique bronze sword 87-000 - - 13-000 “ springs 97-000 - - 3-000 Bronze for statues 91-400 6-530 1-700 - - - 1-370 “ for medals 90-000 10-000 “ for cannon 90-000 - 10-000 “ for cymbals 78-000 - - 22-000 “ for gilding 82-257 17-481 0-238 - - - 0-024 80-000 16-500 2-500 - - * 1-000 Speculum metal 66-000 - - 33-000 Brass for sheet - - - 84-700 15-300 Gilding metal - 73-730 27.270 Pinchbeck - 80-200 20-000 Prince’s metal - 75-000 25-000 - 60-000 50-000 Dutch metal ... 84-700 15-300 English wire - 70-290 29-260 0-17 > - - 0-28 Mosaic gold ... 66-000 33-000 Gun metal for bearings, stocks, &c. 90-300 9-670 0-03 Muntz’s metal - 60-000 40-000 Good yellow brass 66-000 33-000 Babbitt’s metal for bushing 8-300 - - 83-00 - - 8-3 Bell metal for large bells 80-000 - - 20-00 Britannia metal 1-000 2-00 81-00 - - 16-00 Nickel silver, English 60-000 17-8 - - 22-2 “ “ Parisian 60-000 13-6 - - 19-3 German silver - - - 50-000 25-0 • ■ 25-0 ALLOY, NATIVE. Osmium and Iridium, in the proportions of 72*9 of the former and 24‘5 of the latter. See Osmium, Iridium. ALLSPICE. Pimento, or Jamaica pepper, so called because its flavor is thought to comprehend the flavor of cinnamon, cloves, and nutmegs. The tree producing this spice {Eugenia 'pimenia) is cultivated in Jamaica in what are called Pimento walks. It is im- ported in bags, almost entirely from Jamaica. ALMOND. {Amande^ Fr. ; Mandelus^ Germ. ; Amygdal communis.) De Candolle admits five varieties of this species. A. amara^ bitter almond ; A. didcis, sweet almond ; A. fragilis., tender-shelled almond ; A. ?nacrocarpa, large-fruited almond ; A. persicoides^ peach almond. Three varieties are known in commerce : 1. Jordan Almonds., which are the finest, come from Malaga. Of these there are two kinds : the one above an inch in length, flat, with a clear brown cuticle, sweet, mucilagi- nous, and rather tough ; the other more plump and pointed at one end, brittle, but equally sweet with the former. 2. Valentia Almonds are about three-eighths of an inch broad, not quite an inch long, round at one end, and obtusely pointed at the other, flat, of a dingy brown color, and dusty cuticle. 3. Barhary and Italian almonds resemble the latter, but are generally smaller and less flattened. — Brands., Dictionary of Pharmacy. ALMOND OIL. A bland fixed oil, obtained by expression from either bitter or sweet almonds ; usually from the former, on account of their cheapness as well as the greater value of the residual cake. The average produce is from 48 to 62 lbs. from 1 cwt. of almonds. — Pereira. ALMOND POWDER {farina amygdalae) is the ground almond cake, and is employed as a cake for washing the hands, and as a lute. ALOE. {Aides., Fr. ; Glauindes aloe.. Germ.) In botany a genus of the class Hexan- dria monogynia. There are many species, all natives of warm climates. In Africa the leaves of the Guinea aloe are made into durable ropes. Of one species are* made lines, bow-strjngs, stockings, and hammocks ; the leaves of another species are used to hold rain water. A patent has been taken (January 27th, 1847) for certain applications of aloes to dyeing. Although it has not been employed, the coloring matter so obtained promising to be very permanent and intense, it is thought advisable to describe the process by which it is pro- posed to prepare the dye. It is as follows ; Into a boiler or vessel capable of holding about 100 gallons, the patentee puts 10 gallons of water, and 132 lbs. of aloes, and heats the same until the aloes are dissolved ; he then adds 80 lbs. of nitric or nitrous acid in small proportions at a time, to prevent the disen- VoL. III.— 5 66 ALPACA. gagement of such a quantity of nitrous gas as would throw part of the contents out of the boiler. When the whole of the acid has been introduced, and the disengagement of gas has ceased, 10 lbs. of liquid caustic soda, or potash of commerce, of about 30°, are added to neutralize any undecomposed acid remaining in the mixture, and to facilitate the use of the mixture in dyeing and printing. If the coloring matter is required to be in a dry state, the mixture may be incorporated with 100 lbs. of china day and dried in stones, or by means of a current of air. The coloring matter is used in dyeing by dissolving a sufficient quan- tity in water, according to the shade required, and adding as much hydrochloric acid or tar- tar of commerce as will neutralize the alkali contained in the mixture, and leave the dye bath slightly acidulated. The articles to be dyed are introduced into the bath, Avhich is kept boiling until the desired shade is obtained. When the coloring matter is to be used in printing, a sufficient quantity is to be dis- solved in water, according to the shade required to be produced ; this solution is to be thickened with gum, or other common thickening agent, and hydrochloric acid, or tartar of commerce, or any other suitable supersalt, is to be added thereto. After the fabrics have been printed with the coloring matter, they should be subjected to the ordinary process of steaming, to fix the color. — Napier. Aloetic acid, on which the coloring matter of the aloes depends, has been examined by Schunck and Mulder. Aloetic acid is deposited, from nitric acid which has been heated with aloes, as a yellow powder ; it dissolves in ammonia with a violet color ; when treated with, protochloride of tin, it forms a dark-violet heavy powder ; and this, again, when treated with potash, evolves ammonia, and assumes a violet-blue color. The solution of aloetic acid in ammonia is violet. ALPACA. {Alpaga^ Fr.) An animal of Peru, of the Llama species; also the name given to a woollen fabric woven from the wool of this animal. ALUM. {Alun., Fr. ; Alaun., Germ.) A saline body or salt, consisting of alumina, or the peculiar earth of clay, united with sulphuric acid, and these again united with sulphate of potash or ammonia. In other words, it is a double salt, consisting of sulphate of alumina and sulphate of potash, or sulphate of alumina and sulphate of ammonia. The common alum crystallizes in octahedrons, but there is a kind which takes the form of cubes. It has a sour or rather subacid taste, and is peculiarly astringent. It reddens the blue color of litmus or red cabbage, and acts like an acid on many substances. Other alkalies may take the place of the ammonia or potash, and other metals that of the aluminium. The composition of alum is expressed by chemists in the following manner : APO^ 3SO® KOSO^ 24HO. This peculiar combination is that of the original substance as far as it appeared to the chemists of last century, and the form is now held as a type, after which many other alums are composed. Ammonia-alum was occasionally made, even as early as Agricola’s time, 16th century. Its composition is APO^ 3SO^ NH* OSO® + 24HO. The same thing occurs with soda ; soda alum is APO® 3SO^ NaOSO^ -(- 24HO. Every salt hav- ing this form is called an alum. Sometimes, instead of the alkali being changed, the earth is changed. Thus we have chrome-alum, Cr^O^SSO^ KOSO’ + 24HO ; or we have an iron- alum, Fe^ 0^ 3SO^ KOSO^ -f- 24HO. These may be varied to a great extent, but all have a characteristic of alum. The twenty-four atoms of water are one of the peculiar characteristics. Composition of pure Potash Alum. Per Cent. Per Cent. Potash - - 9-89 or 1 atom 47 1 ( Sulphate of potash - 18-32 or 1 atom 27 Alumina -10-94 1 ^2 f ) ^ u j u Sulphuric acid 33-68 “ 4 “ 160 ( I _ ...g » j 216 Water- - 45-49 “24 “216) I vvater Its specific gravity is 1-724. 100 parts of water dissolve, at 32 degrees Fahrenheit, 3-29 alum. “ “ “ 60 “ “ 9-52 “ “ “ “ 86 “ “ 22-01 “ u u u 122 “ “ 30-92 “ “ » “ 158 “ “ 90-67 “ « “ “ 212 “ “ 357*48 “ These Tables of Poggiale should be re-examined, and gradations made more useful for this country. Solubility. — 1 part of crystallized potash alum is soluble — At 54 degrees Fahrenheit in 13-3 water. “ 70 “ “ 8-2 “ (( lJ^J U « 4.5 Peroxide of iron ----- Insoluble m acid, j Magnesia Lime [Coal Water 7- 533 0-060 0- 966 1- 833 0- 400 trace 60-066 8- 900 1- 300 1-000 trace 22-833 2- 208 10-166 0-100 2- 466 3- 166 1-000 1-022 62-200 17-900 3-566 1-133 trace 0-805 6-080 Other shales will be found of interest ; the following are by G. Kersten : — Hermann- Gluckauf- Blucher- schachte. gUDg. schachte. Carbonaceous matter . . 41-10 27-92 34-20 Silica - - - 44-02 61-32 60-21 Peroxide of iron - 6-23 8-40 0-42 Alumina - - - 6-60 7-62 6-21 Magnesia - 0-32 0-26 0-53 Sulphur - - - 1-25 2-89 1-72 Oxide of manganese - 0-12 traces traces Sulphate of lime * • traces traces traces 98-64 98-41 - 98-39 ALUM. 71 Shales from Freienwalde, Shales from Piizherg^ by Klaproth. by Bergemann. 10-80 45-30 3-94 5-95 5- 50 0-60 6- 73 1-20 1-71 1-75 0-35 0-47 16-50 99-70 Here the sulphur has evidently existed in combination with iron, which has been united to oxygen by the analysts. The amount of sulphate shows a partial disintegration and other changes. Lampadius gives another with much more sulphur : — Alum Shale from Siehda. Sulphate of alumina, 2-68 Potash-alum, 0-47 Sulphate of iron, 0-95 Sulphate of lime, 1-70 Silica, 10-32 Alumina, ---------- - 9-21 Magnesia, -- - traces Oxide of iron, 2-30 Oxide of manganese, 0-31 Sulphur, 7-13. Water, 33-90 Carbon, 31-03 Alumina - 16-000 Silica - - - 40-00 Magnesia - - - 0-25 Sulphur - - - 2-85 Carbon - - - 19*65 Protoxide of iron 6*40 Oxide of manganese - Sulphate of protoxide of iron 1*80 “ “ alumina “ “ lime 1*50 “ “ potash 1-50 Chloride of potassium 0*50 Sulphuric acid Water - - - 10-75 101-20 100-00 When alum is made of such shale, the object is first of all to oxidize the sulphur, form- ing sulphuric acid. This acid then dissolves the alumina. The result may be accomplished by allowing the shale to disintegrate spontaneously in the air, the sulphur oxidizing and dis- solving the alumina. But in general, as at Whitby and Campsie, combustion must be resorted to. This can be accomplished without the use of coal, further than is needful sim- ply to set fire to that portion which exists in the shale itself. Indeed, the Campsie one, having more coal than is desirable for slow combustion, is mixed with some spent material, in order to diminish the force of the heat. ' The sulphur is united with the iron, forming a bisulphuret, each atom of which must therefore take up seven atoms of oxygen, reS^+70=FeO SO^-^SO^ When combustion takes place, the sulphur oxidizes ; if rapid combustion is used, then sulphurous acid gas escapes; if slow combustion, the sulphurous acid penetrates the mass slowly, receives another atom of oxygen, unites to a base, and a sulphate is the consequence. Sulphate of iron is formed and pure sulphuric acid. In the process it is probable that the oxidation is completed by means of the iron. Protoxide of iron readily becomes peroxide ; the sul- phurous acid readily decomposes peroxide, forming sulphuric acid and protoxide of iron. This protoxide of iron is again converted into peroxide, and if not dissolved is rendered, to a great extent, difficult to dissolve, by reason of the heat of the mass. For this reason, partly, there is less sulphate of iron in the alum than might be expected. To effect these changes it is desirable to burn very slowly, so as to allow no loss of sulphurous acid, and, in washing, to allow the water to stand a long time on the burnt .ore. Another method, by which the sulphuric acid is transferred to the alumina, is the peroxidation of the protoxide in the sulphate of iron ; acid is by this means set free and begins to act on the alumina. The protosulphate of iron being formed, it is removed by boiling down the liquor until the protosulphate of iron crystallizes out, at the same time the solution becoming saturated with the aluminous salt. The sulphate of iron is soluble in 0-3 of hot water, the alum in 0-06. The liquid around the crystals on the remaining mother liquor contains iron also ; this is washed off by adding pure liquors. % ^2 ALUM. The presence of lime or magnesia in the ores is, of course, a means of abstracting acid, preventing the alumina being dissolved, and even precipitating it when dissolved. Knapp says that at Salzweiler, near Duttweiler, in Rhenish Prussia, the roasting of the ore takes place in the pit or mine. The stratum of brown coal which lies under it, having been accidentally set fire to in 1660, has smouldered till the present time without inter- inission. When the ores are roasted, one-half of the sulphur is freed and sent into the mass or escapes as sulphurous acid ; and the remaining, protosulphuret of iron, is afterwards con- verted into green vitriol. After calcining and washing the Campsie ores, the residue had the following compo- sition : — Silica, 38-40 Alumina, 12 -70 Peroxide of iron, 20’80 Oxide of manganese, - - - ~ ^ - - - traces. Lime, 2-07 Magnesia, 2-00 Potash, 1-00 Sulphuric acid, 10-76 Water, 12-27 100-00 It is, therefore, very far from being a complete process ; but it is not considered profitable to remove the whole of the alumina. In some places the exhausted ore is burnt a second time with fresh ore, as at Campsie, but we are not told the estimated exhaustion. In preparing alum from clay or shale, it is of infinite importance that so much and no more heat be applied to the clay or shale, in the first instance, as will expel the water of combination without inducing contraction. A temperature of 600° F. is well adapted to effect this object, provided it be maintained for a sufficient period. When this has been carefully done, the silicate of alumina remaining is easily enough acted upon by sulphuric acid, either slightly diluted or of the ordinary commercial strength. The best form of apparatus is a leaden boiler, divided into two parts by a perforated septum or partition, also in lead ; though on a very large scale, brickwork set in clay might be employed. Into one of the compartments the roasted clay or shale should be put, and diluted sulphuric acid being added, the bottom of the other compartment may be exposed to the action of a well- regulated fire, or, what is better, heated by means of steam through the agency of a coil of leaden pipe. In this way a circulation of the fluid takes place throughout the mass of shale ; and, as the alumina dissolves, the dense fluid it produces, falling continually towards the bottom of the boiler, is replaced by dilute acid, which, becoming in its turn saturated, falls like the first ; and so on in succession, until either the whole of the alumina is taken up, or the acid in great part neutralized. The solution of sulphate of alumina thus ob- tained is sometimes evaporated to dryness, and sold under the name “ concentrated alum but more generally it is boiled down until of the specific gravity of about 1-35 ; then one or other of the carbonates or sulphates of potash or ammonia, or ehloride of either base, or a mixture of these, is added to the boiling fluid, and as soon as the solution is complete, the whole is run out into a cooler to crystallize. The rough alum thus made is sometimes puri- fied by a subsequent recrystallization, after which it is “ roched ” for the market — a process intended merely to give it the ordinary commercial aspect, but of no real value in a chemi- cal point of view. The manufacture of alum is now taking an entirely new shape, and the two processes of Mr. Spence and Mr. Pochin threaten to absorb the whole of the manufacture in the northwest. Mr. Spence, who has a manufactory of ammonia-alum at Manchester, called the Pendle- ton Alum Works, and another at Goole, in Yorkshire, has now become the largest maker of this substance in the world, as his regular production amounts to upwards of 100 tons per week. In this process, which he has patented, he uses for the production of his sul- phate-of-alumina solution the carbonaceous shale of the coal measure. This substance con- tains from 5 to 10 per cent, of carbonaceous matter, and, when ignited by a small quantity of burning coal, the combustion continues of itself. To insure this the shale is spread into long heaps not exceeding 18 inches in height, and having a brick drain running along each to supply air ; in this manner it slowly calcines : this process must be so conducted as not to vitrify the shale. After calcination it is boiled and digested in large leaden pans, heated by fire, with sulphuric acid of 1-4 specific gravity. After 30 to 40 hours of digestion the sulphate of alumina formed is run into another leaden pan, and the boiling vapor from the ammonia liquor of the gas works is passed into it, until so much alumina is combined with the solution as to form ammonia-alum. The solution is then run into shallow leaden cool- ALUMINA, ACETATE OF. 73 ers, and the alum crystallizes. It is then purified and washed much in the usual way, only that the process is conducted so as to cause much less labor than at other alum works. Alum Cake. — This substance owes its value to the amount of sulphate of alumina it contains, and is in fact another means of making soluble alumina accessible. We have already seen the many attempts to obtain alumina from clay, and the tedious nature of the operation of solution in acid, as well as the long after-processes of lixiviation and conver- sion into sulphate of alumina, or into alum, by reboiling or crystallizing. Mr. Pochin, of Manchester, has found a method of removing all the difficulties, both of the first and after- processes. He uses very fine China clay, free from iron, heats it in a furnace, mixes it thoroughly with acid, and finds that, when the process is managed carefully, the combina- tion of the alumina and sulphuric acid is not only complete, but so violent that he is obliged to dilute his acid considerably, in order to calm the action. When mixed, it is passed into cisterns with movable sides, where, in a few minutes, it heats violently and boils. The thick liquid gradually becomes thicker, until it is converted into a solid porous mass — the pores being made by the bubbles of steam which rise in the mass, which is not fluid enough to contract to its original volume. The porous mass is perfectly dry, although retaining a large amount of combined water. It retains, of course, all the silica of the original clay, but this is in such fine division that every particle appears homogeneous. The silica gives it a dryness to the touch not easily gained by the sulphate only. When pure sulphate of alumina is wanted in solution, the silica is allowed to precipitate before using it, but, in many cases, the fine silica is no hindrance ; then the solution is made use of at once. — R. A. S. ALUMINA. (APO^, 51*4.) This is the only oxide which the metal aluminium forms, and it is assumed to be a sesquioxide on account of its isomorphism with sesquioxide of iron. The occurrence of alumina in the native state has been before mentioned, and the sev- eral minerals will be found described elsewhere. It is obtained in the state of hydrate from common alum (KO, SO® ; APO®, 8S0®-f- 24HO) by adding a solution of ammonia (or better, carbonate of ammonia) to the latter salt, and boiling. The precipitate is white, and gelatinous in a high degree, and retains the salts, in the presence of which it has been formed, with remarkable pertinacity, so that it is very difficult to wash. By drying and igniting this hydrate, the anhydrous alumina is produced ; but it may be obtained more readily by heating ammonia-alum, (NH^O, SO® ; A1®0® 3SO® 24HO.) All the constituents of this salt are volatile, with the exception of the alumina. It is insoluble in water, but soluble both in acids and alkalies. Towards the former it plays the part of a base, producing the ordinary alumina salts ; whilst, with the latter, it also enters into combination, but in this case it is an acid, forming a series of compounds which may be called aluminates. The important application of alumina and its compounds in the arts of dyeing .and calico- printing, depends upon a peculiar attraction which it possesses for organic bodies. This affinity is so strong, that when digested in solutions of vegetable coloring matters, the alumina combines with and carries down the coloring matter, removing it entirely from the solution. Pigments thus obtained, which are combinations of alumina with the vegetable coloring matters, are called “ Alumina has not only an affinity for the coloring matters, but at the same time also for the vegetable fibres, cotton, silk, wool, &c. ; and hence, if alumina be precipitated upon cloth in the presence of a coloring matter, a most intimate union is effected between the cloth and the color. Alumina, when employed in this way, is called a “ mordant.” Other bodies have a similar attraction for coloring matters, e. g. binoxide of tin and sesquioxide of iron : each of these gives its peculiar shade to the color or combination, alumina changing it least. Soluble Modification of Alumina — Mr. Walter Crum* has discovered a peculiar soluble modification of alumina. The biacetate of alumina has been found by Mr. Crum to possess the very curious property of parting with its acetic acid until the whole is expelled, by the long-continued application of heat to a solution of this salt ; the alumina remains in the solution, in a soluble allotropic condition. Its coagulum with dyewoods is translucent, and entirely different from the opaque cakes formed by ordinary alumina ; hence this solution cannot act as a mordant. But this solution of alumina, which is perfectly colorless and transparent, has the alumina separated from it by the slightest causes. A minute quantity of either an acid, an alkali, even of a neutral salt, or of a vegetable coloring matter, effects the change. The precipitated alumina is insoluble in acids, even boiling sulphuric ; this shows another allotropic condition. But it is dissolved by caustic alkalies, by which it is restored to its common state. — II. M. W. ALUMINA, ACETATE OF. The acetates of alumina are extensively used in the arts on account of the property which they possess of being readily decomposed with deposition of their alumina on the fibre of cloth ; hence they are used as mordants, in the manner de- * Chemical Society’s Quarterly Journal, vi. 216. 4 74 ALUMINA, SILICATES OF. scribed under Calico Printing ; and sometimes in dyeing they are mixed with the solution of a coloring matter ; in this the textile fabric is immersed, whilst, on heating, the alumina is precipitated upon the fabric, which, in consequence of its affinities before alluded to, car- ries down the coloring matter with it, and fixes it on the cloth. The acetate of alumina thus employed is obtained by treating sulphate of alumina with neutral acetate of lead, and filtering off the solution from the precipitate of sulphate of lead. Acetate of lime is also used ; but the sulphate in this case does not leave the solu- tion so clear or so rapidly. According to Mr. Walter Crum,* the solution resulting from the decomposition of sul- phate of alumina (APO^, 3SO^) by monobasic acetate of lead contains the salt APO^, 2C'‘H^O^, (biacetate of alumina,) together with one equivalent of free acetic acid, the com- pound APO®, SC^H^O^ not appearing to exist. By evaporating this solution at low tem- peratures, e. g. in a very thin layer of fluid below 38° C., (100° F.,) Crum obtained a fixed residue completely soluble in water, the composition of which, in the dry state, approached APO^ 2C'H=>03-f4H0.— II. M. W. ALUMINA, SILICATES OF. Silicate of alumina is the chief constituent of common clay, {which see ;) it occurs also associated with the silicates of iron, magnesia, lime, and the alkalies in a great variety of minerals, which will be found described elsewhere. The most interesting of these are the felspars and the zeolites. See Clay. Of course, being present in clay, silicate of alumina is the essential constituent of por- celain and earthenware. See Porcelain. — H. M. W. ALUMINA, SULPHATE OF. The neutral sulphate of alumina, APO^ 3SO^-{-18HO, which is obtained by dissolving alumina in sulphuric acid, crystallizes in needles and plates ; but sulphuric acid and alumina combine in other proportions, e. g. a salt of the formula APO®, 3SO®-|— obtained by Mons, and the solution of this salt, when largely diluted with water, splits into the neutral sulphate and an insoluble powder containing APO®, 3SO^ 2APO^ -{- OHO. This subsalt forms the mineral aluminite, found near Newhaven, and was found by Humboldt in the schists of the Andes. The sulphate of alumina is now extensively used in the arts instead of alum, under the name of “ concentrated alum.” For most of the purposes for which alum is employed, the sulphate of potash is an unnecessary constituent, being only added in order to facilitate the purification of the compound from iron ; for in consequence of the ready crystallizability of alum, this salt is easily purified. Nevertheless, Wiesmann has succeeded in removing the iron from the crude solution of sulphate of alumina obtained by treating clay with sul- phuric acid, by adding ferrocyanide of potassium, which throws down the iron as Prussian blue ; the solution, when evaporated to dryness, is found to consist of sulphate of alumina, containing about 7 per cent, of potash-alum. 1,500 tons of this article were produced at Newcastle-on-Tyne alone in the year 1854. See also Alum. — H. M. W. ALUMINIUM. {Sgm. Ah, equiv. 13 *'7.) The name Aluminium is derived from the Latin alumen^ for alum, of which salt this metal is the notable constituent. The following is the method described by M. Beville for the preparation of this interest- ing metal ; — Having obtained the chloride of aluminium, he introduces into a wide glass (or porce- lain) tube 200 or 300 grammes of this salt between two plugs of asbestos, (or in a boat of porcelain or even copper,) allows a current of hydrogen to pass from the generator through a desiccating bottle containing sulphuric acid and tubes containing chloride of calcium, and finally through the tube containing the chloride ; at the same time applying a gentle heat to the chloride, to drive off any free hydrochloric acid which might be formed by the action of the air upon it. He now introduces at the other extremity of the tube a porcelain boat containing sodium ; and when the sodium is fused the chloride of aluminium is heated, until its vapor comes in contact w'ith the fused sodium. A powerful reaction ensues, con- siderable heat is evolved, and by continuing to pass the vapor of the chloride over the sodium until the latter is all consumed, a mass is obtained in the boat of the double chloride of aluminium and sodium, (NaCl, APCP,) in -wdiich globules of the newly reduced metal are suspended. It is allowed to cool in the hydrogen, and then the mass is treated with water, in winch the double chloride is soluble, the globules of metal being unacted upon. These small globules are finally fused together in a porcelain crucible, by heating them strongly under the fused double chloride of aluminium and sodium, or even under com- mon salt. This process, which succeeds without much difficulty on a small scale, is performed far more successfully as a manufacturing operation. Two cast-iron cylinders are now employed instead of the glass or porcelain tube, the anterior one of which contains the chloride of aluminium, whilst in the posterior one is placed the sodium in a tray, about 10 lbs. being employed in a single operation. A smaller iron cylinder intermediate between the two for- mer is filled with scraps of iron, which serve to separate iron from the vapor of chloride of * Chemical Society’s Quarterly Journal, vi. 216. ALUMINIUM. 75 aluminium, by converting the perchloride of iron into the much less volatile protochloride. They also separate free hydrochloric acid and chloride of sulphur. During the progress of the operation the connecting tube is kept at a temperature of about 400^ to 600° F. ; but both the cylinders are but very gently heated, since the chloride of aluminium is volatile at a comparatively low temperature, and the reaction between it and the sodium when once commenced generates so much heat that frequently no external aid is required. Preparation of Aluminium hy Electrolysis. — Mr. Gore has succeeded in obtaining plates of copper coated with aluminium by the electrolysis of solutions of chloride of aluminium, acetate of alumina, and even common alum ;* but the unalloyed metal cannot be obtained by the electrolysis of solutions. Deville, however, produced it in considerable quantities by the method originally suggested by Bunsen, viz., by the electrolysis of the fused double chloride of aluminium and sodium, (NaF, Al^F^ ;) but since this process is far more troublesome and expensive than its reduction by sodium, it has been altogether superseded. Preparation of Aluminium from Kryolite . — So early as March 30, 1855, a specimen of aluminium was exhibited at one of the Friday evening meetings of the Royal Institu- tion, which had been obtained in Dr. Percy’s laboratory by Mr. Allan Dick, by a process entirely different from that of Deville, which promised, on account of its great simplicity, to supersede all others, f It consisted in heating small pieces of sodium, placed in alter- nate layers with powdered kryolite, a mineral now found in considerable abundance in Greenland, which is a double fluoride of aluminium and sodium, analogous to the double chloride of aluminium and sodium, its formula being NaF, APF^ The process has the advantage that one of the materials is furnished ready formed by nature. The experiment was only performed on a small scale by Mr. Dick in a platinum crucible lined with magnesia ; the small globules of metal, which were obtained at the bottom of the mass of fused salt, being subsequently fused together under chloride of potassium or common salt. Before the description of these experiments was published, M. Rose, of Berlin, pub- lished a paper in September, 1855, on the same subject.:}; In Rose’s experiments he em- ployed cast-iron crucibles, in which were heated ten parts of a mixture of equal weights of kryolite and chloride of potassium with 2 parts of sodium. The aluminium was obtained in small globules, which were fused together under chloride of potassium, as in Mr. Dick’s experiments. Rose experienced a slight loss of aluminium by fusion under chloride of potassium, and found it more advantageous to perform this fusion under a stratum of the double chloride of aluminium and sodium, as Deville had done. He never succeeded in extracting the whole quantity of aluminium present in the kryo- lite, (13 per cent.,) chiefly on account of the ready oxidizability of the metal when existing in a very finely divided state, as some of it invariably does. It does not appear that any attempt has since been made to obtain aluminium on the large scale from kryolite, probably from the supply of the mineral not proving so abundant as was at one time anticipated. In all the processes which have been found practicable on any considerable scale, for the manufacture of aluminium, the powerful affinities of sodium are employed for the purpose of eliminating it from its compounds. The problem of the diminution of the price of aluminium therefore resolves itself into the improvement of the methods for procuring sodium, so as to diminish the cost of the latter metal. M. Deville’s attention was therefore directed, in the early steps of the inquiry, to this point ; and very considerable improve- ments have been made by him, which will be found fully described under the head of Sodium. Deville§ has since suggested the employment at once of the double salt of chloride of aluminium and chloride of sodium, (NaCl, APCP,) instead of the simple chloride of aluminium, so as to obtain the metal by means of sodium. He uses 400 parts of this double salt, 200 of common salt, 200 of fluor spar, and 75 to 80 of sodium. The above- mentioned salts are dried, powdered, and mixed together ; then with these the sodium, in small pieces, is mixed, and the whole heated in a crucible under a layer of common salt. After the reaction is complete, the heat is raised so as to promote the separation of the aluminium in the form of a button. It was found, however, that kryolite was, with advan- tage, substituted for the fluor spar. C. Brunner! employs artificially prepared fluoride of aluminium ; but this method can- not offer any advantage over the employment of the chloride, which is cheaper, or the kryolite, which nature affords. Properties . — The metal is white, but with a bluish tinge ; and even when pure has a lustre far inferior to silver. ♦ Phil. Mas. Tii. 207. t Phil. Mag. x. 364. $ Pogzendorf, Annalen, and Phil. Mag, x. 233. § Ann. de China, et Phys. xlvL 415. |1 Chemical Gazette, 1856, 338. — — — V \ V6 ALUMINIUM. Specific gravity, 2*56, and, when hammered, 2'67. Conducts electricity eight times better than iron, and is feebly magnetic. Its fusing point is between the melting points of zinc and silver. By electrolysis it is obtained in forms which Deville believes to be regular octahedra ; but Rose, who has also occasionally obtained aluminium in a crystalline state, (from kryo- lite,) denies that they belong to the regular system. When pure, it is unoxidized even in moist air ; but most of the commercial specimens (probably from impurities present in the metal) become covered with a bluish-gray tarnish. It is unatfected by cold or boiling water ; even steam at a red heat is but slowly decomposed by it. It is not acted upon by cold nitric acid, and only very slowly dissolved even by the boil- ing acid ; scarcely attacked by dilute sulphuric acid, but readily dissolved by hydrochloric acid, with evolution of hydrogen. Sulphuretted hydrogen and sulphides have no action upon it ; and it is not even attacked by fused hydrated alkalies. Professor Wheatstone* has shown that in the voltaic series, aluminium, although having so small an atomic number, and so low a specific gravity, is more electro-negative than zinc ; but it is positive to cadmium, tin, lead, iron, copper, and platinum. Impurities in Aluminium. — Many of the discrepancies in the properties of aluminium, as obtained by different experimenters, are due to the impurities which are present in it. If the naphtha be not carefully removed from the sodium, the aluminium is liable to contain carbon. Frequently, in preparing aluminium, by the action of the chloride on sodium, by De- ville’s original process, copper boats have been used for holding the sodium ; in this case the metal becomes contaminated, not only with copper, but also with any other metal which may be present in the copper— c. g. Salm-Horstmar found copper in the aluminium sold in Paris, and Erdmann detected zinc ; ^ and in every case the metal is very liable to become mixed with silicon, either from the earthenware tubes, boats, or crucibles ; hence Salvetat found, even in the aluminium prepared by Deville himself, 2’8'7 per cent, of silicon, 2-40 of iron, 6 ’38 of copper, and traces of lead. The following analysis of commercial aluminium was communicated to the British Asso- ciation, at its meeting in 185V, by Professor Mallet Made in Paris. Made in Berlin. A1 * - - - - - 92-969 96-253 Fe 4-882 3*293 Si 2-149 0-454 Ti trace trace 100-00 100-00 Alloys of Aluminium. — Very small quantities of other metals suffice to destroy the malleability and ductility of aluminium. An alloy containing only of iron or copper cannot be worked, and the presence of -jL copper renders it as brittle as glass. Silver and gold produce brittleness in a less degree. An alloy of 5 parts of silver with 100 of aluminium, is capable of being worked like the pure metal, but it is harder, and therefore susceptible of a finer polish ; whilst the alloy, containing 10 per cent, of gold, is softer, but, nevertheless, not so malleable as the pure metal. The presence of even part of bismuth renders aluminium brittle in a high degree. These statements by Tissier,§ however, require confirmation ; for Debray states that aluminium remains malleable and tough when containing as much as 8 per cent, of iron, or 10 per cent, of copper, but that a larger quantity of either of these metals renders it brittle. It is curious that only 3 per cent, of silver are sufficient to give aluminium the hrih liance and color of pure silver., over which the alloy has the great advantage of not being blackened by sulphuretted hydrogen. On the other hand, small quantities of aluminium combined with other metals change their properties in a remarkable manner. Thus copper alloyed with only of its weight of aluminium has the color and brilliance of gold, and is still very malleable, {Tissier ;) and when the aluminium amounts only to Vs, (i. e. 20 per cent.,) the alloy is quite white, (Dcbray.) An alloy of 90 parts of copper and 10 of aluminium is harder than common bronze, and is capable of being worked at high tempei-atures easier than the best varieties of iron. Larger quantities of aluminium render the metal harder and brittle. — Debray. || An alloy of 100 parts of silver with 5 of aluminium is as hard as the alloy employed in ♦ Phil. Mag. X. 143. + Journal pr. Chem. Ixvii, 498. $ Journal pr. Chem. Ixvii. 494 § C. and J. Tissier, Comptes Eendus, xliii. 885. U Comptes Eendus, xliii, *925. * ALUM, NATIVE. . 77 the silver coinage, although the other properties of the silver remain unchanged, {Tissier.) Similar alloys have likewise been prepared by Dr. Percy.* Messrs. Calvert and Johnson describef an alloy of 25 parts aluminium to 75 of iron, which has the valuable property of not oxidizing by exposure to moist air. Uses of Aluminium,. — No very important application of aluminium has yet been made, although, at the time M. Deville’s experiments were commenced, sanguine hopes were entertained that aluminium might be produced at a price sufficiently low to admit of its practical application on a large scale, these anticipations have not been realized ; and as yet, on account chiefly of its high price,:}; the applications which have been made of this inter- esting metal are but few. Its low specific gravity, combined with sufficient tenacity, recommends it for many interesting uses. The fractional weights used by chemists, which are made of platinum, are so extremely small that they are constantly being lost ; their much greater volume in aluminium renders this metal peculiarly suitable. In the construction of the beams of bal- ances, strength combined with lightness are desiderata ; and M. Deville has had very beau- tiful balance beams made of this metal ; but at present its high price has prevented their extensive adoption. These same qualities render this metal suitable for the construction of helmets and other armor ; but at present these are but curiosities, and are likely to remain so, unless some cheaper method of eliminating the metal than by the agency of sodium be discovered. Its quality of being unacted upon by oxygen, sulphuretted hydrogen, and many acids, would suggest numerous applications, if it were sufficiently cheap ; e. g. it might be used for coating other metals, as iron, lead, &c., to protect them from rust, instead of paint. § It would be particularly useful for covering the pipes and cisterns employed in water supply, and thus preventing the accidents which are constantly resulting from the action of water on lead. This metal has been proposed for making spoons, &c., instead of silver. It certainly has the advantage of not being blackened by sulphuretted hydrogen ; but those which the writer has seen have a dull leaden hue, — far inferior, even, to somewhat tarnished silver in brilliance, — and would certainly not be held in high esteem by the public. It has been suggested to employ aluminium, on account of its sonorousness and duc- tility, for making piano-forte wires. It was also imagined that it might be used in making bells ; but Mr. Denison has quite set this question at rest. No one who heard the sound of his aluminium bell will again think of such an application. Probably one of the most interesting of the applications of aluminium (at least in a scientific point of view) that has been made, is the recent one by Deville and Wohler, of employing it in the production of crystalline allotropic modifications of certain other ele- ments hitherto unknown in that state ; e. g. boron, silicon, and titanium, {which see.) It depends upon the fact that these elements, in the amorphous state, dissolve in fused alumin- ium, and, on cooling the molten solution, they slowly separate from the aluminium in the crystalline state. Our first importation of aluminium was in 1856, to the value of £35. — H. M. W. ALUMINIUM, CHLORIDE OF, (APCP— 133-9.) Preparation.— ChXovAe of alumin- ium cannot be prepared by treating alumina with hydrochloric acid, as in the case of most chlorides ; for on evaporating the solution to dryness, hydrochloric acid is evolved and alumina alone remains. The method at present used is, in principle, the same as that originally suggested by Qilrsted, which has since found numerous other applications. It is impossible to convert alumina into the chloride by the direct action of chlorine alone ; at any temperature the chlorine is as incapable of displacing the oxygen from the alumina as it would from lime. But if the attraction of the chlorine for the metal be supported by the aifinity of carbon for the oxygen, then the compound is, as it were, torn asunder, carbonic acid or carbonic oxide resulting on the one hand, and the chloride of aluminium on the other. On the large scale the chlorine is passed over a previously ignited mixture of clay and coal tar, contained in retorts like those used in the manufacture of coal gas, which are heated in a furnace ; the chloride, which on account of its volatility is carried off, being condensed in a chamber lined with plates of earthenware, where it is deposited in a crystal- line mass. Properties. — It is a yellowish crystalline solid, readily decomposed by the moisture of the air into hydrochloric acid and alumina, volatile at a dull red heat. It is very soluble in water, but cannot be recovered by evaporating the solution. — H. M. W. ALUM, NATIVE. This term includes several compounds of sulphate of alumina with the sulphate of some other base, as magnesia, potash, soda, the protoxides of iron, manga- * Proceedlnzs of the Royal Institution, March 14. 1856. + Phil. Ma?. x. 245. $ The pre.sent price of Aluminium in Londem is 5s-. per ounce, whilst only in March, 1856, just after M. Deville\s experiments had been made, it eost 3Z. per ounce. § It is calculated that more than a million sterling is annually expended in the metropolis on the paint necessary to protect the iron-work from decay. — Rev. J. Barlow. ALUM SHALE. 78 nese, &c. They occur generally as efflorescences, or in fibrous masses ; when crystallized, they assume octahedral forms. Native alum is soluble in water, and has an astringent taste, like that of the alum of commerce. — H. W. B. ALUM SHALE. The chief natural source from which the alum of commerce is de- rived in this country. It occurs in a remarkable manner near Whitby, in Yorkshire, and at Hurlet and Campsie, near Glasgow. A full description of the alum shale, and of the J)rocesses by which the crystallizable alum is separated, will be found under Alum. AMALGAM. When mercury is alloyed with any metal, the compound is called an amalgam of that metal ; as for example, an amalgam of tin, bismuth, &c. Some amalgams are solids and others fluids ; the former are often crystalline, and the latter may be probably regarded as the solid amalgam dissolved in mercury. Silver Aynalgam may be formed by mixing finely-divided silver with mercury. The best process is to precipitate silver from its solution by copper, when we obtain it in a state of fine powder, and then to mix it with the mercury. A native amalgam of mercury and silver occurs in fine crystals in the mines of the Palatinate of Moschellandsberg : it is said to be found where the veins of copper and silver intersect each other. Dana reports its existence in Hungary and Sweden, at Allemont, in Dauphine ; Almaden, in Spain, and in Chili ; and he quotes the following analyses : — Moschellandsberg, . Silver. - 36*0 Mercury. - 64*0 by Klaproft. Ditto, - - 25*0 - - 73.3 “ Heyer. Allemont, - - - - - 27*5 - - 72*5 “ Cordier. If six parts of a saturated solution of nitrate of silver with two parts of a saturated solution of the protonitrate of mercury are mixed with an amalgam of silver one part and mercury seven, the solution is speedily filled with beautiful arborescent crystals— the Arbor Diance, the tree of Diana, — or the silver tree. Gold Amalgam is made by heating together mercury with grains of gold, or gold-foil ; when the amalgam of gold is heated, the mercury is volatilized and the gold left. This amalgam is employed in the process known as that of fire-gilding, although, since electro- gilding has been introduced, it is not so frequently employed. A gold amalgam is obtained from the platinum region of Columbia ; and it has been reported from California, especially from near Mariposa. Schneider give its composition, mercury, 5'7‘40 ; gold, 88*89 ; sil- ver, 5*0. Tin Amalgam. — By bringing tin-foil and mercury together, this amalgam is formed, and is used for silvering looking-glasses. (See Silvering Glass.) If melted tin and mer- cury are brought together in the proportion of three parts mercury and one part tin, the tin amalgam is obtained in cubic crystals. Electric Machine Amalgam. — Melt equal parts of tin and zinc together, and combine these with three parts of mercury : the mass must be shaken until it is cold ; the whole is then rubbed down with a small quantity of lard, to give it the proper consistence. Amalgam Copper.,-ioY stopping teeth. The French dentists have long made use of this for stopping teeth. It is sold in small rolls of about a drachm and a half in weight ; it is covered with a grayish tarnish, has a hardness much greater than that of bone, and its cohesion and solidity are considerable. When heated nearly to the point of boiling water this amalgam swells up, drops of mercury exuding, which disappear again on the cooling of the substance. If a piece, thus heated, be rubbed up in a mortar, a plastic mouldable mass, like poor clay, is obtained, the consistence of w*hich may, by continued kneading, be increased to that of fat clay. If the moulded mass be left for ten or twelve hours, it hardens, acquiring again its former properties, without altering its specific gravity. Hence, the stopping, after it has hardened, remains tightly fixed in the hollow of the tooth. The softening and hardening may be repeated many times with the same sample. Pettenkofer ascribes these phenomena to a state of amorphism, with which the amalgam passes from the crystalline condition in the process of softening. All copper amalgams containing be- tween 0*25 to 0*30 of copper exhibit the same behavior. The above chemist recommends as the best mode of preparing this amalgam, that a crystalline paste of sulphate of sub- oxide of mercury (prepared by dissolving mercury in hydrated sulphuric acid at a gentle heat) be saturated under water at a temperature of from 60° to 70°, with finely divided reguline copper, (prepared by precipitation from sulphate of copper with iron.) One por- tion of the copper precipitates the mercury, with formation of sulphate of copper ; the other portion yields with mercury an amalgam : 100 parts of dissolved mercury require the copper precipitated, by iron, from 232*5 parts of sulphate of copper. As in dissolving the mercury the protoxide is easily formed instead of the suboxide, particularly if too high a temperature be maintained, it is advisable, in order to avoid an excess of mercury in the amalgam, to take 223 parts of sulphate of copper, and to add to the washed amalgam, which is kept stirred, a quantity of mercury in minute portions, corresponding to the AMMONIA. 79 amount of suboxide contained in the mercury salt, until the whole has become sufficiently plastic. This amalgam may be obtained by moistening finely-divided copper with a few drops of a solution of nitrate of suboxide of mercury, and then triturating the metal with mercury in a warmed mortar. The rubbing may be continued for some time, and may be carried on under hot water, mercury being added until the required consistence is attained. A remarkable depression of temperature during the combination of amalgams has been observed by several chemists. Dobereiner states that when 816 grains of amalgam of lead (404 mercury and 412 lead) were mixed, at a temperature of OS'", with 688 grains of the amalgam of bismuth, (404 mercury and 284 bismuth,) the temperature suddenly fell to SO’', and by the addition of 808 grains of mercury (also at 68°) it became as low as 17° ; the total depression amounting to.51°. In certain proportions of mixture of the constituents of fusible metal (tin, lead, and bismuth) with mercury, Dobereiner formed surprising depressions of temperature ; the tem- perature, he records of one experiment, sank instantly from 65° to 14°. AMBER VARNISH. Amber is composed of a mixture of two resins, which are soluble in alcohol and ether, and in some of the recently-discovered hydro-carbon compounds. Varnishes are therefore prepared with them, and sold under the name of amber spirit var- nishes ; but these are frequently composed of either copal or mastic. They have been much used for varnishing collodion pictures. AMBERGRIS. It is found on various parts of the east coast of Africa, as well as in the eastern seas. The best is ash-colored, with yellow or blackish veins or spots, scarcely any taste, and very little smell unless heated or much handled, when it yields an agreeable odor. Exposed in a silver spoon it melts without bubble or scum, and on the heated point of a knife it vaporizes completely away. The chemical composition of ambergris is represented by the following formula, C33jj32q. True ambergris is very rarely met with, by far the largest proportion of that which is sold as ambergris being a preparation scented with civet or musk. In France the duty upon ambergris is 62 francs per kilogramme when imported in French vessels, and 67 francs when imported in foreign vessels. Ambergris is at this time (1858) worth 16.s. an ounce in England. Mr. Temple, of Belize, British Honduras, speaks of an odorous substance thrown ofI‘ by the alligator, which appears to resemble ambergris. AMETHYST. {Amethyste occidentale^ Fr. ; Eisenkeisel^ Germ.) One of the vitreous varieties of quartz, composed of pure silica in the insoluble state — that is, it will not dis- solve in a potash solution. It belongs to the rhombohedral system, and is found either in groups of crystals or lining the interior of geodes and pebbles. It is infusible before the blowpipe, and is not affected by acids. It is of a clear purple or bluish-violet tint ; but the color is frequently irregularly diffused, and gradually fades into white. The color is sup- posed to be due to the presence of a small percentage of manganese, but Heintz attributes it to a compound of iron and soda. The amethyst, from the beauty of its color, has always been esteemed and used in jewellery. It was one of the stones called by the ancients apeOvcr- ros, a name which they conferred on it from its supposed power of preserving the wearer from intoxication. The most beautiful specimens are procured from India, Ceylon, and Persia, where they occur in geodes and pebbles : it is also found at Oberstein, in Sax- ony ; in the Palatinate ; in Transylvania ; near Cork, and in the Island of May, in Ireland. — H. W. B. AMETHYST, ORIENTAL. {AmHhyste orientate., Fr. ; Bemanthspath., Germ.) This term is applied to those varieties of corundum which are of a violet color. See Corundum. — H. W. B. AMIANTHUS is the name given to the whiter and more delicate varieties of asbestus, which possess a satin-like lustre, in consequence of the greater separation of the fibres of which they are composed. A variety of amianthus (the amianthoide of Haiiy) is found at Oisans, in France, the fibres of which are in some degree elastic. The word amianthus (from ayiavTos, undefiled) is expressive of the easy manner by which, when soiled, it may be cleansed and restored to its original purity, by being heated to redness in a fire. See Asbestus. — H. W. B. AMMONIA. ^ NH^, eqv. 17. {Ammoniaque, Fr. ; Ammoniak., Germ.) The name given to the alkaline gas which is the volatile alkali of the early chemists. The real origin of this word is not known. Some suppose it to be from Ammon., a title of Jupiter, near whose temple in Upper Egypt it was generated. Others suppose it to be from Ammonia., a Cyrenaic territory ; whilst others again have deduced it from sand, as it was found in sandy ground. It is probable that Pliny was acquainted with the pungent smell of ammonia. Dr. Black, in 1756, first isolated it, proving the distinction between it and its carbonate, with which it had been confounded up to that time ; and it was soon afterwards more fully inves- tigated by Priestley. AMMONIA. 80 Ammonia being a product, not only of the destructive distillation of organic bodies con- taining nitrogen, but also of their decay, it exists in the atmosphere, in a large amount, if considered in the aggregate, although, by examining any particular specimen of air, the quantity appears small. Nevertheless, this small quantity of ammonia would seem to be exceedingly important in developing the nitrogenized constituents of plants. Liebig be- lieves that the nitrogen of plants is exclusively derived from the ammonia present in the air ; but the opinions of chemists are divided on this point. Boussingault * supports Lie- big’s view, but it is opposed by Mulder and Ville. From the air, aipmonia and its salts are carried down by the rain. This fact has been placed beyond all doubt by Liebig ; and even the variations in the quantity have been de- termined by Boussingault, and more recently by Mr. Way. By the rain water it is carried into rivers, and ultimately into the sea, in which chloride of ammonium has been detected by Dr. Marcet. It has likewise been detected in mineral springs, especially brine springs, and even in common salt. — Vogel. Ammonia is present in the exhalations from volcanoes. During the eruption of Vesu- vius in IVOI, the quantity of sal ammoniac discharged by the mountain was so great, that the peasants collected it by hundredweights, {Bischof ;) and in the last eruption of Hecla, in Sept., 1845, a similar phenomenon was observed ; and, aecording to Ferrara, it is some- times found in such quantity at Etna, that a very profitable trade has been carried on in it. Dr. Daubeny thinks that the volcanic ammonia is produced by the action of water upon mineral nitrides, (perhaps the nitrides of silicon,) similar in properties to the nitrides of Titanium and Boron, which have been recently more carefully examined by M. St. Claire Deville. Ammoniacal salts have likewise been found as a sublimate arising from the com- bustion of coal strata. The great supply of ammonia and its salts is derived from the destructive distillation of organic bodies, animal and vegetable, containing nitrogen ; but its salts exist in plants, and to a much larger extent in the liquid and solid excrements of animals. As a urate, it forms the chief constituent of the excrement of the boa, as well as that of many birds, hence the large quantity of ammoniacal salts in guano. See Guano. Formation of Ammonia . — No process has yet been devised for inducing the direct com- bination of nitrogen and hydrogen to produce ammonia ; but under the disposing influence of the production of other compounds, in the presence of these elements, as well as when these gases are presented to each other in the nascent state, their union is effeeted. Thus, when electric sparks are passed through a mixture of nitrogen and oxygen in the presence of hydrogen and aqueous vapor, nitrate of ammonia is generated. If, while zinc is being dissolved in sulphuric acid, nitric acid be added, much ammonia is formed, {Nes- hit ;) so again, if hydrogen and binoxide of nitrogen be passed over spongy platinum, tor- rents of ammonia are produced, the hydrogen converting the oxygen of the binoxide into water, when the nitrogen, at the moment of its liberation, combines with the hydrogen to form ammonia. It has even been proposed to carry out this last method on a manufacturing scale. Messrs. Crane and Jullien, in their patent of January 18, 1848, deseribe a method of manufacturing ammonia in the state of carbonate, hydrocyanate, or free ammonia, by pass- ing any of the oxygen compounds of nitrogen, together with any compound of hydrogen and carbon, or any mixture of hydrogen with a compound of carbon or even free hydrogen, through a tube or pipe containing any catalytic or contact substance, as follows : — Oxides of nitrogen, (such, for instance, as the gases libarated in the manufacture of oxalic acid,) however procured, are to be mixed in such proportion with any compound of carbon and hydrogen, or such mixture of hydrogen and carbonic oxide or acid as results from the con- tact of the vapor of water with ignited carbonaceous matters, and the hydrogen compound or mixture containing hydrogen may be in slight excess, so as to ensure the conversion of the whole of the nitrogen contained in the oxide so employed into either ammonia or hydro- cyanic acid, which may be known by the absence of the characteristic red fumes on allowing some of the gaseous matter to come in contact with atmospheric air. The catalytic sub- stance which Messrs. Crane and Jullien prefer is platinum, which may be in the state of sponge, or it may be asbestos coated with platinum. This catalytic substance is to be placed in a tube, and heated to about G00° F., so as to increase the temperature of the product, and at the same time prevent the deposition of carbonate of ammonia, which passes onwards into a vessel of the description well known and employed for the purpose of ‘condensing carbonate of ammonia. The condenser for this purpose must be furnished with a Safety pipe, to allow of the escape of uncondensed matter, and made to dip into a solution of any substance capable of combining with hydrocyanic acid or ammonia where they would be condensed. A solution of salt of iron is preferable for this purpose, f Chemical Characters . — The gaseous ammonia liberated from its salts by lime (in a man- ner to be afterwards described) is a colorless gas of a peculiar pungent odor. It is com- posed, by weight, of 1 equivalent of nitrogen and 3 of hydrogen ; or, by volume, of 2 * Annale.s de Chimie et de Physique, xliii. 149. t Pharm. Journ. xiii. 114. AMMONIA. 81 measures of nitrogen and 6 of hydrogen, condensed to four ; and may be resolved into these constituent gases by passing over spongy platinum heated to redness. By a pressure of 6 5 atmospheres at 50° F., it is condensed into a colorless liquid. It is combustible, but less so than hydrogen, on account of the incombustible nitrogen which it contains ; biit its inflammability may be readily seen by passing it into an argand gas flame reduced to a minimum. Upon this variation in density of solutions of ammonia in proportion to their strength, Mr. J. J. Griffin has constructed a useful instrument called an Ammonia-metre. It is founded upon the following facts ; — That mixtures of liquid ammonia .with water possess a specific gravity which is the mean of the specific gravities of their components ; that in all solutions of ammonia, a quantity of anhydrous ammonia, weighing 212^ grains, which he calls a test-atom., displaces 300 grains of water, 'and reduces the specific gravity of the solu- tion to the extent of .00125 ; and, finally, that the strongest solution of ammonia which it is possible to prepare at the temperature of 62° F., contains in an imperial gallon of solu- tion 100 test-atoms of ammonia. We extract the following paragraph from Mr. Griffin’s paper in the Transactions of the Chemical Society, explanatory of the accompanying Table : — “ The first column shows the specific gravity of the solutions ; the second column the weight of an imperial gallon in pounds and ounces ; the third column the percentage of ammonia by weight ; the fourth column the degree of the solution, as indicated by the instrument, corresponding with the number of test-atoms of ammonia present in a gallon of the liquor ; the fifth column shows the number of grains of ammonia contained in a gal- lon ; and the sixth column the atomic volume of the solution, or that measure of it which contains one test-atom of ammonia. For instanee, one gallon of liquid ammonia, specific gravity 880, weighs 8 lbs. 128 oz. avirdupois; its percentage of ammonia, by weight, is 38-1 17 ; it contains 96 test-atoms of ammonia in one gallon, and 20400.0 grains of ammo- nia in one gallon; and, lastly, 104G6 septems containing one test-atom of ammonia. Although no hydrometer, however aceurately constructed, is at all equal to the Centigrade mode of chemical testing, yet the Ammonia-meter, and the Table aecompanying it, will be found very useful to the manufacturer, enabling him not only to determine the actual strength of any given liquor, but the precise amount of dilution necessary to convert it into a liquor of any other desired strength, whilst the direct quotation of the number of grains of real ammonia contained in a gallon of solution of any specific gravity will enable him to judge at a glance of the money- value of any given sample of ammonia. Table of Liquid Ammonia., (Griffin.) One Test-Atom of Anhydrous Ammonia = NH® weighs 212'5 grains. Specific Gravity of Water = 1-00000. One Gallon of Water weighs 10 lbs. and contains 10,000 Septems. Temperature 62° F. Specific Gravity of the Liquid Ammonia. Weight of an Imperial Gallon in 1 Avoirdupois lbs. and ozs. Percentage of Ammonia by Weight. Test-atoms of Ammonia in one Gallon. Grains of Ammonia in one Gallon. Septems containing one Test-atom of Ammonia. lb. oz. •87500 8 12-0 34-694 100 21250-9 100-00 •87625 8 12-2 34-298 99 21037-5 101-01 •87750 • 8 12-4 33-903 98 20825-0 102-04 •87875 8 12-6 33-509 97 20612-5 103-09 •88000 8 12-8 • 33-117 96 20400-0 104-16 •88125 8 13-0 32-725 95 20187-5 105-26 •88250 8 13-2 32-335 94 19975-0 106-38 •88375 8 13-4 31-946 93 19762-5 107-53 •88500 8 13-6 31-558 92 19550-0 108-70 •88625 8 13-8 31-172 91 19337-5 109-89 •88750 8 14-0 30-785 90 19125-0 111-11 •88875 8 14-2 30-400 89 18912-5 112-36 •89000 8 14-4 30-016 88 18700-0 113-64 •89125 8 14-6 29-633 87 18487-5 114-94 •89250 8 14-8 29-252 86 18275-0 116-28 •89375 8 15-0 28-871 85 18062-5 117-65 1 -89500 8 15-2 28-492 84 17850-0 119-05 •89625 8 15*4 28-113 83 17637-5 120-48 •89750 8 15-6* 27-736 82 17425-0 121-95 •89875 8 15-8 27-359 81 17212-5 123-46 •90000 9 0*0 26-984 80 17000-0 125-00 •90125 9 0-2 26-610 79 16787-5 126-58 1 VoL. III.— 6 82 AMMONIA. Table of Liquid Ammonia^ (continued.) Specific Gravity of the Liquid Ammonia. Weight of an Imperial Gallon in Avoirdupois lbs. and ozs. Percentage of Ammonia by Weight. Test-atoms of Ammonia in one Gallon. Grains of Ammonia in one Gallon. Septems containing one Test-atom of Ammonia. lb. oz. •90250 9 0-4 26-237 78 16575-0 128-21 •903Y5 9 0-6 25-865 77 16362-5 129-87 •90500 9 0.8 25-493 76 16150-0 131-58 •90625 9 1-0 25-123 75 15937-5 133-33 •90750 9 1-2 24-754 74 16725-0 135-13 •90876 9 1-4 24-386 73 16612-5 136-98 •91000 9 1-6 24-019 72 15300-0 138-99 •91125 9 1-8 23-653 71 15087-5 140-85 •91250 9 2-0 23-288 70 14875-0 142-86 •91376 9 2-2 22-924 69 14662-6 144-93 •91500 9 2*4 22-561 68 14450-0 147-06 •91625 9 2-6 22-198 67 14237-5 149-25 •91750 9 2-8 21-837 . 66 14025-0 151-51 •91875 9 3.0 21-477 65 13812-5 163-85 •92000 9 3-2 21-118 64 13600-0 156-25 •92125 9 3-4 20-760 63 13387-5 158-73 •92250 9 3-6 20-403 62 13175-0 161-29 •92375 9 3-8 20-046 61 12962-5 163-93 •92500 9 4-0 19-691 60 12750-0 166-67 •92626 9 4-2 19-337 69 12537-5 169-49 •92750 9 4-4 18-983 68 12325-0 172-41 •92875 9 4-6 18-631 67 12112-5 175-44 •93000 9 4-8 18-280 66 11900-0 178-57 •93125 9 5-0 17-929 66 11687-5 181-82 •93250 9 6-2 17-579 64 11475-0 185-18 •93376 9 6-4 17-231 63 11262-6 188-68 •93500 9 5-6 16-883 62 11050-0 192-31 •93625 9 6-8 16-536 61 10837.5 196-08 •93750 9 6-0 16-190 50 10625-0 200-00 •93875 9 6-2 15-846 49 10412-6 204-08 •94000 9 6-4 •16-502 48 10200-0 208-33 •94125 9 6-6 15-168 47 9987-5 212-77 •94250 9 6-8 14-816 46 9775-0 217-39 •94375 9 7-0 14-475 46 9562-5 222-22 •94500 9 7-2 14-135 44 9350-0 227-27 •94625 9 7-4 13-796 43 9137-6 232-66 •94760 9 7-6 13-466 42 8925-0 238-09 •94875 9 7-8 13-119 41 8712-5 243-90 •95000 9 8-0 12-782 . 40 8500-0 250-00 •95125 9 8-2 12-446 39 8287-5 256-41 •95250 9 8-4 12-111 38 8076-0 ' 263-16 •96376 9 8-6 11-777 37 7862-5 270-27 •95500 9 8-8 11-444 36 7650-0 277-78 •95625 9 9-0 11-111 35 ■ 7437-6 285-71 •95750 9 9-2 10-780 34 7225-0 294-12 •95875 9 9-4 10-4490 33 7012-5 303-03 •96000 9 9-6 10-1190 32 6800-0 312-50 •96125 9 9-8 9-7901 31 6587-6 322-58 •96250 9 10-0 9-4620 30 6376-0 333.33 •96375 9 10-2 9-1347 29 6162-6 344-83 •96500 9 10-4 8-8083 28 5950-0 357-14 •96626 9 10-6 8-4827 27 5737-5 370-37 •96750 9 10-8 8-1580 26 6525-0 384-62 •96875 9 11-0 7-8341 25 5312-5 400-00 •97000 9 11-2 7-5111 24 6100-0 416-67 •97125 9 11-4 7-1888 23 4887-5 434-78 •97250 9 11-6 6-8674 22 4675-0 454-54 •97375 9 11-8 6-5469 21 4462-6 476-19 •97500 9 12-0 6-2271 20 4260-0 600-00 •97625 9 12-2 5-9082 19 4037-6 626-32 AMMONIA. r ' 83 Table of Liquid Ammonia, (continued.) Specific Gravity of the Liquid Ammonia. Weight of an Imperial Gallon in Avoirdupois lbs. and ozs. Percentage of Ammonia by Weight. Test-atoms of Ammonia in one Gallon. Grains of Ammonia in one Gallon. Septems containing one Test-atom of Ammonia. lb. oz. •97750 9 12-4 5-6901 18 3825-0 555-56 •97875 9 12-6 5-2728 17 3612-5 688-24 •98000 9 12-8 4-9563 16 3400-0 625-00 •98125 9 13-0 4-6406 15 3187-6 666-67 •98250 9 13-2 4-3255 14 2975-0 714-29 •98375 9 13-4 4-0111 13 2762-5 769-23 •98500 9 13-6 3-6983 12 2550-0 833-33 •98625 9 13-8 3-3858 11 2337-5 909-09 •98750 9 14-0 3-0741 10 2125-0 1000-00 •98875 9 14-2 2-7632 9 1912-5 1111-10 •99000 9 14-4 2-4531 8 1700-0 1250-00 •99125 9 14-6 2-1438 7 1487-5 1428-60 •99250 9 14-8 1-8352 6 1275-0 1666-70 •99375 9 15-0 1-5274 6 1062-5 2000-00 •99500 9 15-2 1-2204 4 850-0 2500-00 •99625 9 15-4 0-9141 3 637-5 3333-30 •99750 9 15-6 0-6087 2 425-0 5000-00 •99875 9 15-8 0-3040 1 212-5 10000-00 1-0000 10 lbs. Water. 0 Ammoniacal gas combines directly with hydrated acids, forming a series of salts, the constitution of which is peculiar, and must be here briefly discussed, that the formula here- after employed in describing them may be understood. These compounds may be viewed as direct combinations of the ammonia with the hydrated acids ; thus, the compound with Hydrochloric acid as the Hydrosulphuric acid “ Sulphuric acid “ Nitric acid “ Carbonic acid “ Hydrochlorate, (NH^ HCl.) Hydrosulphate, (NH", HS.) Hydrated sulphate, (NH^ ; HO, SO^) Hydrated nitrate, (NH® ; HO, NO®.) Hydrated carbonate, (NH® ; HO, CO^). But the close analogy of these compounds, in all their properties, to the corresponding salts of potash and soda has led chemists to the assumption of the existence of a group of elements possessing the characters of a metal, of a basyl or hypothetical metallic radical, called ammonium, (NH'‘,) in these salts ; which theory of their constitution brings out the resemblance to the potash and soda salts more clearly, thus : — The chloride of potassium contains — sulphide “ — sulphate of potassa“ — nitrate “ “ — carbonate “ “ And the chloride KCl. of ammonium contains KS. — sulphide KO, SO®. — sulphate of ammonia KO, NO®. — nitrate “ KO, CO®. —carbonate “ NH'Cl. NH^S. NH'O, SO®. NH'O, NO®. NH^O, CO®. Although it may be objected to this view that the metal ammonium is not known, yet a curious metallic compound of this metal with mercury has been obtained ; and, after all, it is by no means necessary that the metal should be isolated, for already the existence of numerous basic radicals has been assumed in organic chemistry which have never been isolated. It is true, also, that the oxide of ammonium is unknown, but substitution- products of it have been produced, which are solid bodies, soluble in water, exhibiting all the characters of potash solution, being as powerfully caustic and alkaline. In fact, ammonia is in reality but the type of a vast number of compounds. It is capable of having its hydrogen replaced by metals, (as copper, mercury, calcium, &c.,) as well as by metallic or basic com- pound radicals, producing the endless number of artificial organic bases, which are primary, secondary, or tertiary nitrides, according as one, two, or three equivalents of the ammonia are replaced. When the substitution of the hydrogen in ammonia is effected by acid radi- cals, the compounds are called amides. Freparaiion of Ammonia . — Ammonia is obtained by the decomposition of one of the 84 AMMONIA, CARBONATE OF. salts of ammonia, either the chloride of ammonium, NH^CI, (sal ammoniac,) or the sul- phate, by a metallic oxide, e. g. lime. NH^Cl + CaO, HO = CaCl -j- NH^ 2HO. On the small scale in the laboratory the powdered ammoniacal salt is mixed with slaked lime, in a Florence flask or a small iron retort, and gently heated ; the ammoniacal gas being dried by passing it through a bottle containing lime. Chloride of calcium must not be employed in the desiccation of ammonia, since the ammonia is absorbed by this salt, producing a curious compound, the chloride of caliammonium, N | Cl, being, in fact, one of those substitution -compounds before alluded to. The gaseous ammonia must be collected over mercury, on account of its solubility in water. This operation is carried out on the large scale for the purpose of making the aqueous solution of ammonia, {liquor ammonia^ or spirits of hartshorn,) Solution of Ammonia. Preparation. — In preparing the aqueous solution, the gas is passed into water contained in Woolfe’s bottles, which on the small scale are of glass, whilst on the large scale they are made of earthenware. A sufficiently capacious retort of iron or lead should be employed, which is provided with a movable neck ; and it is desirable to pass the gas through a worm, to cool it, before it enters the first Woolfe’s bottle. Each of the series of Woolfe’s bottles should be fur- nished with a safety-funnel in the third neck, to avoid accidents by absorption. The whole of the condensing arrangements should be kept cool by ice or cold water. Properties. — In the London and in the Edinburgh “ Pharmacopoeia ” two solutions of ammonia are directed to be prepared, the stronger having the specific gravity 0’882, and containing about 30 per cent, of ammonia ; the weaker of specific gravity 0*960, contain- ing, therefore, about 10 per cent, of the gas. Sometimes the commercial solution of ammonia is made by treating impure ammoniacal salts with lime, and it then contains empyreumatic oils ; in fact, the various volatile prod- ucts of the distillation of coal which are soluble in or miscible with water. Pyrrol may be detected in ammonia by the purple color which it strikes with an excess of nitric or sulphuric acid. If the residue of its distillation be mixed with potash, Picoline is detected by its peculiar odor. Naphthaline is discovered not only by its odor, but may also be separated by sublimation or heating, after converting the ammonia in the solution into a salt by sulphuric or hydrochloric acid. — Dr. Maclogan. We imported into England of sulphate and liquor of ammonia as follows : — Ammonia, sulphate of, - - - - 1856, = - lbs. 23,904 “ “ .... 1855, - - 343,609 Ammonia, liquor, ... - 1855, - , 22,400 Since, for the purpose of purification on the large scale, ammonia is invariably con- verted into chloride or sulphate, the details of the manufacture of the ammoniacal salts will be given under those heads. For the determination of ammonia, see Nitrogen. — H. M. W. AMMONIA, CARBONATE OF. {The sesquicarhonate of commerce, 2NH®, 3CO^, 2HO=NH^O, CO^; HO, CO^-[~^^H^CO^, eqv. 118.) This salt was probably known to Raymond Lully and Basil Valentine, as the chief constituent of putrid urine. The real distinction between ammonia and [‘as carbonate was pointed out by Dr. Black. 25 AMMONIA, CAEBONATE OF. 85 Carbonate of ammonia is formed during the putrefaction of animal substances, and by their destructive distillation. Its presence in rain water has been before alluded to. The carbonate of ammonia of commerce is obtained by submitting to sublimation a mixture either of sal ammoniac or sulphate of ammonia with chalk. This is generally carried out in cast-iron retorts, similar in size and shape to those used in the manufacture of coal gas. The retorts are charged through a door at one end, and at the other they communicate with large square leaden chambers, supported by a wooden frame, in which .the sublimed salt is condensed. Fig. 25. The product of this first process is impure, being especially discolored by the presence of carbonaceous matter, and has to be submitted to resublimation. This is carried out in iron pots surmounted by movable leaden caps. These tops are either set in brickwork, and 26 heated by the flue of the retort furnace, or are placed in a water-bath, as shown in fig. 26. In fact, a temperature not exceeding 150° F. is found sufficient. The charge of a retort consists usually of about 65 lbs. of sulphate of ammonia (or an equivalent quantity of the chloride) to 100 lbs. of chalk, which yield about 40 lbs. of crude carbonate of ammonia. Modifications of the Process. — Mr. Laming has suggested to bring ammonia and car- bonic acid gases into mutual contact in a leaden chamber having at the lower part a layer of water, and then to crystallize the salt by evaporating this aqueous solution. He also proposes to prepare carbonate of ammonia from the sulphide of ammonium of gas liquors, by passing carbonic acid gas into the liquor, which carbonic gas is generated by heating a mixture of oxide of copper and charcoal, in the proportion of twelve parts of the former to one of the latter. Mr. Hill has described his mode of obtaining sesquicarbonate of ammonia from guano. To effect this, the guano is first mixed with charcoal or powdered coke ; the mixture is then heated, and the sesquicarbonate of ammonia obtained by sublimation. The process does not appear to be much employed. Manufacture of Ammonia from Peat and Shale. — Mr. Hills, in his patent of August 11th, 1846, specified the following method of obtaining ammonia from peat : — The peat is placed in an upright furnace and ignited ; the air passes through the bars as usual, and the ammonia is collected by passing the products of combustion through a suitable arrange- ment of apparatus to effect its condensation. This plan of obtaining ammonia from peat appears to be precisely similar to that patented by Mr. Rees Reece, (January 23d, 1849,) and made to form an important feature in the operations of the British and Irish Peat Com- pany. The first part of Mr. Reece’s patent is for an invention for causing peat to be burned in a furnace by the aid of a blast, so as to obtain inflammable gases and tarry and other products from peat. For this purpose, a blast furnace with suitable condensing apparatus is used. The gases, on their exit from the condensing apparatus, may be collected for use as fuel or otherwise ; and the tarry and other products pass into a suitable receiver. The tarry products may be employed to obtain paraffine and oils for lubricating machinery, &c. ; and the other products may be made available for evolving ammonia, wood spirit, and other matters by any of the existing processes. Dr. Hodges, of Belfast, states that in his experi- ments he obtained nearly 22 1 lbs. of sulphate of ammonia from a ton of peat. Sir Robert Kane, who was employed by Government to institute a series of experimental researches on the products obtainable from peat, states that he obtained sulphate of ammonia at the rate of 247io lbs. per ton of peat. Messrs. Drew and Stockton patented, in 1846, the obtaining ammonia from peat by distillation in close vessels, as practised in the carbonization of wood. 86 AMMONIA, NITRATE OF. It will thus be seen that the peat is a source of ammonia, but that this source is a profitable or economical one, in a commercial point of view, is a problem in process of solution. Ammonia from Schist. — Another source of ammonia is bituminous schist, which, when submitted to destructive distillation, gives off an ammoniacal liquor which may be employed in the manufacture of ammoniacal salts by any of the usual processes. The obtaining of ammonia from schist forms part of a patent granted to Count de Hompesch, September 4, 1841. Chemical Composition and Constitution. — The true neqtral carbonate of ammonia (NH^O, CO^) does not appear to exist. The sesquicarbonate of ammonia of the shops was found by Rose to have the composition assigned to it by Mr. Phillips, i. e. it contains 2NH^, 3CO^, 2HO ; and it may therefore be viewed as a compound of the true bicar- bonate, {i. e. the double carbonate of ammonia and water,) NH^O, CO^ ; HO, C0“, with a peculiar compound of anhydrous carbonic acid with ammonia itself, (NH®, CO*.) The equation representing its method of preparation will then be, 3NH'0, SO*-f 3CaO, C0*=(NH'0, CO* ; HO, CO*-l-NH*, C0*)-|-HN'0-f-3Ca0, SO*, or 3NH'Cl-l-3CaO, C0*=(NH'0, CO*, HO, CO*-fNH*, CO*-|-NH^O)-|-3CaCl ; for it is invariably found that a certain quantity of water and ammonia is liberated during the distillation, and hence the anomalous character of the compound. In fact, in operating upon 3 equivalents of the sulphate or chloride of the 3 equivalents of the true carbonate of ammonia (NH^O, CO*) which may be supposed to be generated, two are decomposed, one losing an equivalent of ammonia, the other an equivalent of water ; of course, the ammonia thus liberated is not lost ; it is passed into water to be saturated with acid, and thus again converted into sulphate or chloride. Properties. — Sesquicarbonate of ammonia (as it is commonly called) is met with in commerce in the form of fibrous white translucent cakes, about two inches thick. When exposed to the air the constituents of the less stable compound NH*, CO* are volatilized, and a white opaque mass of the true bicarbonate remains. Hence the odor of ammonia always emitted by the commercial carbonate. Mr. Seanlan has also shown that, by treatment with a small quantity of water, the carbonate is dissolved, leaving the bicar- bonate. It is soluble in four times its weight of cold water, but boiling water decom- poses it. Impurities. — The commercial salt is sometimes contaminated with empyreumatic oil, which is recognized by its yielding a brownish-colored solution on treatment with water. It may contain sulphate and chloride of ammonium. For the recognition of the pres- ence of these acids, see Sulphuric Acid. Sulphide and hyposulphite of ammonia are sometimes present, and likewise lead, from the chambers into which the salt has been sublimed. Other Carbonates of Ammonia. — Besides the neutral or monocarbonate of ammonia before alluded to, the true bicarbonate (NH^O, CO* ; HO, CO*) and the sesquicarbonate of the shops. Rose has described about a dozen other definite compounds ; but, for their de- scription, we must refer to lire’s “ Dictionary of Chemistry.” AMMONIA, NITRATE OF. This salt crystallizes in six-sided prisms, being isomor- phous with nitrate of potash. Its composition is NH^O, NO*. It is incapable of existing without the presence of an equivalent of water, in addition to NH* and NO*. If heat be applied, the salt is entirely decomposed into protoxide of nitrogen and water ; thus — NH^O, NO* = 2NO-|-4HO. Besides its use in the laboratory for making protoxide of nitrogen, it is a constituent of frigorific mixtures, on account of the cold which it produces on dissolving in water. Lastly, it is very convenient for promoting the deflagration of organic bodies, both its constituents being volatile on heating. AMMONIA, SULPHATE OF. (NH^O, SO*.) This salt is found native in fissures near volcanoes, under the name of mossagnine.^ associated with sal ammoniac. It also forms in ignited coal-beds — as at Bradley, in Staffordshire — with chloride of ammonium. This salt is prepared by saturating the solution of ammonia, obtained by any of the processes before described, (either from animal refuse, from coal, in the manufacture of coal-gas, from guano, or from any other source,) with sulphuric acid, and then evaporating the solution till the salt crystallizes out. Frequently, instead of adding the acid to the ammoniacal liquor, the crude ammoniacal liquor is distilled in a boiler, either alone or with lime, and the evolved ammonia is passed into the sulphuric acid, contained in a large tun or in a series of Woolfe’s bottles ; or a modification of Coffey’s still may be used with advantage, as in the case of the saturation of hydrochloric acid by ammonia. If Coffey’s still be employed, a considerable concentration of the liquor is effected during the process of saturation, which is subsequently completed generally in iron pans ; AMMONIA, SULPHATE OF. - 87 but great care has to be taken not to carry the evaporation too far, to avoid decomposition of the sulphate by the organic matter invariably present, which reduces it to the state of sulphite, hyposulphite, and even to sulphide, of ammonium. The salt obtained by this first crystallization is much purer than the chloride produced under similar circumstances, and one or two recrystallizations effect its purification suffi- ciently for all commercial purposes. It is on account of the greater facility of purification which the sulphate affords by crys- tallization than the chloride of ammonium, that the former is often produced as a prelimi- nary stage in the manufacture of the latter compound, the purified sulphate being then con- verted into sal ammoniac by sublimation with common salt. The acid mother-liquor left in the first crystallization is returned to be again treated, together with some additional acid, with a fresh quantity of ammonia. Preparation. Modifications in details and patents . — Since it is in the production of the sulphate of ammonia that the modification of Coffey’s still, called the ammonia stilly is generally employed, it may be well to introduce here a detailed account of its arrangement. This apparatus is an upright vessel, divided by horizontal diaphragms or partitions into a number of chambers. It is proposed to construct the vessel of wood, lined with lead, and the diaphragms of sheet iron. Each diaphragm is perforated with many small holes, so regulated, both with regard to number and size, as to afford, under some pressure, passage for the elastic vapors which ascend, during the use of the apparatus, to make their exit by a pipe opening from the upper chamber. Fitted to each diaphragm are several small valves, so weighted as to rise whenever elastic vapors accumulate under them in such quan- tity as to exert more than a certain amount of pressure on the diaphragm. A pipe also is attached to each diaphragm, passing from about an inch above its upper surface to near the bottom of a cup or small reservoir, fixed to the upper surface of the diaphragms next underneath. This pipe is sufficiently large to transmit freely downwards the whole of the liquid, which enters for distillation at the upper part of the upright vessel ; and the cup or reservoir, into which the pipe dips, forms, when full of liquid, a trap by which the upward passage of elastic vapors by the pipe is prevented. The vessel may rest on a close cistern, contrived to receive the descending liquid as it leaves the lowest chamber, and from this cistern it may be run off, by a valve or cock, whenever expedient. The cistern, or in its absence the lowest chamber, contains the orifice of a pipe which supplies the steam for working the apparatus. The exact number of chambers into which the upright vessel is divided is not of essential importance ; but the quantity of liquid and the surface of each diaphragm being given, the distillation, within certain limits, will be more complete the greater the number of chambers used in the process. The liquid undergoing distillation in this apparatus necessarily covers the upper surface of each diaphragm to the depth of about an inch, being prevented from passing downward through the small perforations by the up- ward pressure of the rising steam and other elastic vapors ; and, on the other hand, the steam being prevented, by the traps, from passing upwards by the pipes, is forced to ascend * by the perforations in the diaphragms ; so that the liquid lying on them becomes heated, and in consequence gives off its volatile matters. When the ammoniacal liquor accumu- lates on one of the diaphragms to the depth of an inch, it flows over one of the short pipes into the trap below, and overflows into the next diaphragm, and so on. See Distillation. The management of the apparatus varies in some measure with the form in which it is desirable to obtain the ammonia. When the ammonia is required to leave the upper cham- ber in the form of gas, either pure or impure, it is necessary that the steam which ascends and the current of ammoniacal liquid which descends, should be in such relative propor- tions that the latter remain at or near the atmospheric temperature during its passage through some of the upper chambers, becoming progressively hotter as it descends, until it reaches the boiling temperature ; in which state it passes through the lower chambers, either to make its escape, or to enter a cistern provided to receive it, and in which it may for some time be maintained at a boiling heat. On the contrary, if the ammonia, either pure or impure, be required to leave the upper chamber in combination with the vapor of water, the supply of steam entering below must bear such proportion to that of the ammoniacal liquid supplied above, that the latter may be at a boiling temperature in the upper part of the apparatus.* The use of this apparatus has been patented in the name of Mr. W. E. Newton, Nov. 9, 1841. Mr. Hill’s process, patented Oct. 19, 1848, for concentrating ammoniacal solutions, by causing them to descend through a tower of coke through which steam is ascending, is, in fact, nothing more than a rough mode of carrying out the same principle which is more effectually and elegantly performed by the modification of Coffey’s still above described. The concentrated ammonia liquor is then treated with acid and evaporated in the usual way. Mr. Wilson has patented, Dec. 7, 1850, another method of saturating the ammonia with ♦ Pharm. Journal, xiii. 64. AMMONIUM. 88 the acid by passing the crude ammonia vapor, obtained by heating the ammoniacal liquor of the gas-works, in at the bottom of a high tower filled with coke, whilst the sulphuric acid descends in a continuous current from the top ; in this manner the acid and ammonia are exposed to each other over a greatly extended surface. Dr. Richardson (patent, Jan. 26, 1850) mixes the crude ammonia liquors with sulphate of magnesia, then evaporates the solution, and submits the double sulphate of magnesia and ammonia, which separates, to sublimation ; but it would not appear that any great advantage is derived from proceeding in this way, either pecuniary or otherwise. ^ Mr. Laming passes sulphurous acid through the gas liquor, and finally oxidizes the sul- phite thus obtained to the state of sulphate, by exposure to the air. (Patent, Aug. 12, Michiel’s mode of obtaining sulphate of ammonia, patented April 80, 1850, is as fol- lows The ammoniacal liquors of the gas-works are combined with sulphate and oxide of lead, which is obtained and prepared in the following way : — Sulphuret of lead in its natu- ral state is taken and reduced to small fragments by any convenient crushing apparatus. It is then submitted to a roasting process, in a suitably arranged reverberatory furnace of the following construction : — The furnace is formed of two shelves, or rather the bottom of the furnace and one shelf, and there is a communication from the lower to the upper. The galena or sulphuret of lead, previously ground, is then spread over the surface of the upper shelf, to a thickness of about 2 or 2^ inches, and there it is submitted to the heat of the furnace. It remains thus for about two hours, at which time it is drawn off the upper shelf and spread over the lower shelf or bottom of the furnace, where it is exposed to a greater heat for a certain time, during which it is well stirred, for the purpose of exposing all the parts equally to the action of the heat, and at the same time the fusion of any portion of it is prevented. By this process the sulphuret of lead becomes converted partly into sulphate and partly into oxide of lead. This product of sulphate and oxide of lead is to be crushed by any ordinary means, and reduced to about the same degree of fineness as coarse sand. It is now to be combined with the ammoniacal liquors, when sulphate of ammonia and sul- phuret and carbonate of lead will be produced. The sulphate of ammonia is separated by treatment with water, and the residuary mix- ture of sulphide and carbonate of lead is used for the manufacture of lead compounds. Properties . — The sulphate of ammonia obtained by either of the methods above de- scribed is a colorless salt, containing, according to Mitscherlich, one equivalent of water of crystallization. It is isomorphous with sulphate of potash. It deliquesces by exposure to the air ; 1 part dissolves in 2 parts of cold water, and 1 of boiling water. It fuses at 140° C., (284° F.,) but at 280° C. (536° F.) it is decomposed, being volatilized in the form of free ammonia, sulphite, water, and nitrogen. For the other sulphates — the sulphites and those salts which are but little used in the arts and manufactures — we refer to the “ Dictionary of Chemistry.” Uses . — The chief consumption of ammoniacal salts in the arts is in the form of sal ammoniac, the sulphate of ammonia being principally used as a matei-ial for the manufac- ture of the chloride of ammonium. It may, however, be employed directly in making ammonia-alum, or in the production of free ammonia by treatment with lime. AMMONIUM. (NH^) The radical supposed to exist in the various salts of ammonia. Thus NH^O is the oxide, NH^Cl the chloride, of ammonium. Ammonium constitutes one of the best established chemical types. See Formula, Chemical. — C. G. W. AMMONIUM, CHLORIDE OF. This salt is formed in the solid state by bringing in contact its two gaseous constituents, hydrochloric acid and ammonia. The gases combine with such force as to generate, not only heat, but sometimes even light. It may also be prepared by mixing the aqueous solutions of these gases, and evaporating till crystallization takes place. When ammoniacal gas is brought into contact with dry chlorine, a violent reaction ensues, attended by the evolution of heat and even light. The chlorine combines with the hydrogen to produce hydrochloric acid, Avhich unites with the remainder of the ammonia, forming chloride of ammonium, the nitrogen being liberated. The same reaction takes place on passing chlorine gas into the saturated aqueous solution of ammonia. Manufacture of Sal Ammoniac from Gas Liquor . — By far the largest quantity of the ammoniacal salts now met with in commerce is prepared from “ gas liquor,” the quantity of which annually produced in the metropolis alone is quite extraordinary — one of the London gas works producing in one year 224,800 gallons of gas liquor, by the distillation of 51,100 tons of coal ; and the total consumption of coal in London for gas making is estimated at about 840,000 tons. The principle of the conversion of the nitrogen of coal into ammonia by destructive distillation, as in the manufacture of coal gas, will be found described in connection with the processes of gas manufacture and the products produced by the destructive distillation of coal. In the purification of the coal gas, the bodies soluble in water are all contained in the AMMONIUM, CHLORIDE OF. 89 “ gas liquor,” (see Coal Gas,) together with a certain quantity of tarry matter. The am- monia is chiefly present in the form of carbonate, together with certain quantities of chlo- ride sulphide, cyanide, and sulphocyanide of ammonium, as well as the salts of the com- pound ammonias. For the purpose of preparing the chloride, if hydrochloric acid be not too costly, the liquor is saturated with hydrochloric acid — the solution evaporated to cause the salt to crystallize, and then, finally, the crude sal ammoniac is purified by sublimation. Before treatment with-the acid, the liquor is frequently distilled. This is generally effected in a Avrought-iron boiler, the liquors passing into a modification of the Coffey’s still, by which the solution of ammonia is obtained freer from tar and more concentrated. The Saturation of the Ammoniacal Liquor with the acid is generally effected by allow- ing the acid to floAV, from a large leaden vessel in which it is held, into an underground 27 Or, in other works, the gas liquor is put into large tuns, and the acid lifted in gutta- percha carboys by cranes, thrown into the liquor and stirred with it by means of an agi- tator ; the offensive gases being in this case made to traverse the fire of the steam-engine. Sometimes the vapors produced in the distillation of the crude gas liquor are passed in at the lower extremity of a column filled with coke, down which the acid trickles. The Evaporation of the crude Saline Sohdion is generally performed in square or rec- tangular cast-iron vats, capable of holding from 800 to 1,500 gallons. They are encased in brickwork, the heat being applied by a fire, the flue of which takes a sinuous course beneath the lining of brickwork on which the pan rests, as shown in fig. 28. When the liquor is evaporated to a specific gravity of 1*25, it is transferred to the crys- tallizing pans; but during the processes of concentration a considerable quantity of tar separates on the surface, which must be removed, from time to time, by skimming, since it seriously impedes evaporation. The crystallization., which takes place on cooling, is performed in circular tubs, from 7 to 8 feet wide, and 2 to 3 deep, which are generally imbedded entirely or partially in the ground. To prevent the formation of large crystals, which would be inconvenient in the subsequent process of sublimation, the liquor is agitated from time to time. The crude mass obtained, which is contaminated with tarry matter, free acid and water, is next dried, by gently heating it on a cast-iron plate under a dome. The grayish-white mass remaining is now ready to be transferred to the sublimers. The method of sublimation generally adopted in this country consists in beating down into the metal pots, shown in fig. 29, the charge of dry coarsely crystallized sal am- moniac. These pots are heated from below and by flues round the sides. The body of the subliming vessel is of cast-iron, and the lid usually of lead, or, less frequently, iron. There is a small hole at the top, to permit the escape of steam ; and great attention is requisite in the management of the heat, for if it be applied too rapidly a large quantity of sal ammoniac 90 AMMONIUM, CHLOKIDE OF. is carried off with the steam, or even the whole apparatus may be blown up ; whilst, if the temperature be too low, the cake of sal ammoniac is apt to be soft and yellow. 28 The sublimation is never continued until the whole of the salt has been volatilized, since the heat required would decompose the carbonaceous impurities, and they, emitting volatile oily hydrocarbons, diminish the purity of the product. In consequence of this incomplete sublimation, a conical mass (shown in Jig. 29) is left behind, called the “ yolk.” After cooling, the dome of the pot is taken olF, and the attached cake carefully removed. This cake, which is from 3 td 5 inches thick, is nearly pure, only requiring a little scraping, where it was in contact with the dome, to fit it for the market. Modifications of the Process. — If, as is often the case, sulphuric acid is cheaper or more accessible than hydrochloric, the gas liquor is neutralized with sulphuric acid, and then the sulphate of ammonia thus obtained is sublimed with common salt, {chloride of sodium^) and thus converted into sal ammoniac. NH^O SO^ + NaCl = NH'Cl+NaOSO^ Mr. Croll has taken out a patent for converting crude ammonia into the chloride, by passing the vapors evolved^in the first distillation through the crude chloride of manganese, obtained, as a bye product in the preparation of chlorine, for the manufacture of chloride of lime : crude chloride of iron may be used in the same way. AMMONIUM, CHLOKIDE OF. 91 Mr. Laming patented in July, 1843, the substitution of a solution of chloride of calcium for treating the crude gas liquor, instead of the mineral acids. Mr. Hills, August, 1846, proposed chloride of magnesium for use in the same way ; and several other patents have been taken out by both these gentlemen, for the use of various salts in this way. Manufacture of Sal Ammoniac from Guano. — Mr. Young took out a patent, November 11th, 1841, in which he describes his method of obtaining ammonia and its salts from guano. He fills a retort, placed vertically, with a mixture of two parts by weight of guano, and one part by weight of hydrate of lime. These substances are thoroughly mixed by giving a reciprocating motion to the agitator placed in the retort ; a moderate degree of heat is then applied, which is gradually increased until the bottom of the retort becomes red-hot. The ammoniacal gas thus given off is absorbed by water in a condenser, whilst other gases, which are given off at the same time, being insoluble in water, pass off. Solutions of carbonate, bicarbonate, or sesquicarbonate of ammonia are produced, by filling the condenser with a solution of ammonia, and passing carbonic acid through it. A solution of chloride of am- monium or sulphate of ammonia, is obtained by filling the condenser with diluted hydro- chloric or sulphuric acid, and passing the ammonia through it as it issues from the retort. Dr. Wilton Turner obtained a patent, March 11th, 1844, for obtaining salts of ammonia from guano. The following is his method of obtaining chloride of ammonium in conjunction with cyanogen compounds : — The guano is subjected to destructive distillation in close ves- sels, at a low red heat during the greater part of the operation ; but this temperature is in- creased towards the end. The products of distillation are collected in a series of Woolfe’s bottles, by means of which the gases evolved during the operation may be made to pass two or three times through water, before escaping into the air. These products consist of car- bonate of ammonia, hydrocyanic acid, and carburetted hydrogen, the first two of which are rapidly absorbed by the water, with the formation of a strong solution of cyanide of am- monium and carbonate of ammonia. After the ammoniacal solution has been removed from the Woolfe’s apparatus, a solution of protochloride of iron is added to it, in such quantities as will yield sufficient iron to convert the latter into Prussian blue, which is formed on the addition of hydrochloric acid in sufficient quantity to neutralize the free ammonia ; the precipitate thus formed is now allowed to subside, and is carefully separated from the solu- tion, and by being boiled with a solution of potash or soda, will yield the ferrocyanide of the alkali, which is obtained by crystallizing in the usual way. The solution (after the removal of the precipitate) should be freed from any excess of iron it may contain, by the careful addition of a fresh portion of the ammoniacal liquor, by which means the oxide of iron will be precipitated,,and a neutral solution of ammonia obtained. When the precipi- tated oxide and cyanide of iron have subsided, the solution of chloride of ammonium is drawn off by a syphon, and the sal ammoniac obtained from it by the usual processes ; the oxide of iron is added to the ammoniacal solution next operated upon. If sulphate of iron and sulphuric acid are used, sulphate of ammonia is the ammoniacal salt produced, the chemical changes and operations being similar to the above. Since the greater part of the nitrogen present in guano exists in the state of ammoniacal salts, which are decomposed at a red heat, nearly the whole of the ammonia which it is capable of yielding is obtained by this method ; still there cannot be a doubt that the con- version of the urea, uric acid, and other nitrogenized organic bodies into ammonia, is greatly facilitated by mixing the guano with lime before heating it, as in Mr. Young’s process. Manufacture of Sal Ammoniac from Urine. — The urea in the urine of man and other animals is extremely liable to undergo a fermentative decomposition in the presence of the putrefiable nitrogenous matters always present in this excrement, by which it is converted into carbonate of ammonia. By treating stale urine with hyhrochloric acid, sal ammoniac separates on evaporation. Properties. — Chloride of ammonium (or sal ammoniac) usually occurs in commerce in fibrous masses of the form of large hemispherical cakes with a round hole in the centre, having, in fact, the shape of the domes in which it has been sublimed. By slowly evaporat- ing its aqueous solution, the salt may occasionally be obtained in cakes nearly an inch in height ; but it generally forms feathery crystals, which are composed of rows of minute oc- tahedra, attached by their extremities. Its specific gravity is ' 1-45, and by heating it sublimes without undergoing fusion. It has a sharp and acrid taste, and one part dissolves in 2*72 parts of hot, or in an equal weight of cold water. It is recognized by its being completely volatile on heating, giving a white curdy preci- pitate of chloride of silver on the addition of nitrate of silver to its aqueous solution, and by the copious evolution of ammonia on mixing it with lime, as well as the production of the yellow precipitate of the double chloride of ammonium and patinum (NH''C., PaCP) on the addition of bichloride of platinum. Impurities. — In the manufacture of chloride of ammonium, if the purification of the liquor be not effected before crystallizing the salt, some traces of protochloride of iron are generally present, and frequently a considerable proportion. Even when the salt is 92 AMMONIUM, SULPHIDES OF. sublimed, the chloride of iron is volatilized together with the chloride of ammonium, and appears to exist in the salt in the form of a double compound (probably of Fe, Cl NH^Cl, analogous to the compounds which chloride of ammonium forms with zinc and tin) 140 ; and this not only in the brown seams of the cake, but likewise in the colorless portion. This accounts for the observation so often made in the laboratory, that a solution of sal ammoniac, which, when recently prepared, was perfectly transparent and colorless, becomes gradually red from the peroxidation of the iron and its precipitation in the form of sesqui- oxide. It is in consequence of the existence of the iron in the state of this double salt, that Wurtz found that chloride of ammonium containing iron in this form gave no indications of its presence by the usual re-agents until after the addition of nitric acid ; and it is curious that there likewise exists a red compound of this class in which the iron exists in the state of perchloride similarly marked, in fact as NIU Cl Fe^CF. A very simple method of removing the iron, suggested by Mr. Brewer, consists in pass- ing a few bubbles of chlorine gas through the hot concentrated solution of the salt, by which the protochloride of iron is converted into the perchloride. 2Fe Cl -f Cl = Fe"CP. The free ammonia always present in the solution decomposes this perchloride with pre- cipitation of sesquioxide, and formation of an additional quantity of sal ammoniac. Fe^CF -f 3NH'0 = Fe^O" -h SNH'Cl. The sesquioxide of iron, which is of course present in the form of a brown hydrate, is filtered off or separated by decantation, and a perfectly pure solution is obtained. The only precaution necessary is to avoid passing more chlorine than is requisite to peroxidize the iron, since the ammonia salt itself will be decomposed with evolution of nitrogen, and the dangerously explosive body, chloride of nitrogen, may result from the union of the liberated nitrogen with chlorine. Uses . — The most important use of sal ammoniac in the arts is in joining iron and other metals, in tinning, &c. It is also extensively used in the manufacture of ammonia- alum, which is now largely employed in the manufacture of mordants instead of potash- alum. A considerable quantity is also consumed in pharmacy. Sal ammoniac is one of those salts which possess, in a high degree, the property of producing cold whilst dissolving in water ; it is, therefore, a common constituent of frigorific mixtures. See Freezing. AMMONIUM, SULPHIDES OF. When sulphuretted hydrogen gas is passed into a solu- tion of ammonia in excess, it is converted into the double sulphide of ammonium and hy- drogen — or, as it is frequently called, the hydrosulphate of sulphide of ammonium — NH^S, HS. This solution is extensively employed as a re-agent in the chemical laboratory, for the separation of those metals the sulphides of which are soluble in acids — viz., nickel, cobalt, manganese, zinc, and iron, which are precipitated by this re-agent in alkaline solutions. By exposure to the air, the hydrosulphuric acid which it contains is decomposed, the hydrogen being oxidized and converted into water, whilst the liberated sulphur is dissolved by the sulphide of ammonium, forming the bisulphide, or even higher sulphide. This solution of the polysulphide of ammonium is a valuable re-agent for dissolving the sulphides of certain metals, such as tin, antimony, and arsenic, the sulphides of which play the part of acids and form salts with- the sulphide of ammonium. By this deportment with sulphide of ammonium, these metals are separated both on the small scale in the laboratory and also on the large scale, from the sulphides of those metals — such as lead, copper, mercury, &c. — the sulphides of which are insoluble in sulphide of ammonium. The higher sulphides, viz., the tersulphidc, NH^S^, and the pentasulphide, NH^S®, — are bodies of purely scientific interest. They are obtained by distilling the corresponding sulphides of potassium with sal ammoniac. All the sulphides of ammonium are soluble in water without decomposition. Ammonia combines with all the other inorganic and organic acids, the name of which is “ legion ; ” but for an account of these bodies we must refer to the “ Dictionary of Chemistry,” as they have but few applications in the arts and manufactures. AMORPHOUS. This term may be regarded as the opposite of crystalline. Some elements exist in both the crystalline and the amorphous states, as carbon, which is amor- phous in charcoal, but crystalline in the diamond. The peculiarities which give rise to these conditions — evidently depending upon mole- cular forces which have not yet been defined — present one of the most fertile fields for study in the range of modern science. AMYGDALINE. IP'^ NO”® -{- 6HO.) A peculiar substance, existing ready formed in bitter almonds, the leaves of the cherry laurel, the kernels of the plum, cherry, peach, ANCHOR. 93 and the leaves and bark of Prunus padus^ and in the young sprouts of the P. domesfica. It is also found in the sprouts of several species of Sorbus, such as S. aucuparia, S. tormi- nalis, and others of the same order. To prepare it, the bitter almonds are subjected to strong pressure between hot plates of metal. This has the effect of removing the bland oil known in commerce as almond oil. The residue, when powdered, forms almond meal. To obtain amygdaline from the meal, the latter is extracted with boiling alcohol of 90 or 95 per cent. The tincture is to be passed through a cloth, and the residue pressed, to obtain the fluid mechanically adherent to it. The liquids will be milky, owing to the presence of some of the oil. On keeping the fluid for a few hours, it may be separated by pouring off, or by means of a funnel, and so obtained clear. The alcohol is now to be removed by dis- tillation, the latter being continued until five-sixths have come over. The fluid in the retort, when cold, is to have the amygdaline precipitated from it by the addition of half its volume of ether. The crystals are to be pressed between folds of filtering paper, and re- crystallized from concentrated boiling alcohol. As thus prepared it forms pearly scales very soluble in hot alcohol, but sparingly when cold ; it is insoluble in ether, but water dissolves it readily and in large quantity. The crystals contain six atoms of water of crystallization. Most persons engaged in chemical operations have noticed, when using almond meal for the purpose of luting, that, before being moistened with water, it has little odor, and what it has is of an oily kind ; but, after moistening, it soon acquires the powerful and pleasant perfume of bitter almond oil. This arises from a singular reaction taking place between the amygdaline and the vegetable albumen or emulsine. The latter merely acts as a ferment, and its elements in no way enter into the products formed. The decomposition, in fact, takes place between one equivalent of amygdaline and four equivalents of water, the prod- uct being one equivalent of bitter almond oil, two equivalents of grape sugar, and one of prussic acid. Or, represented in symbols : — (.40 JJ27 4JJO = W 0" 4- C- HN -}- O'l Amygdaline. Bitter-almond Prussic Grape sugar. oil. acid. In preparing amygdaline, some chemists add water to the residue of the distillation of the tincture, and then yeast, in order to remove the sugar present, by fermentation, previous to precipitating with ether ; the process thus becomes much more complex, because it is necessary to filter the fermented liquid, and concentrate it again by evaporation, before precipitating out the amygdaline. The proof that the decomposition which is experienced by the bitter almond cake, when digested with water, is owing to the presence of the two principles mentioned, rests upon the following considerations : If the marc, or pj’essed residue of the bitter almond, be treated with boiling water, the emulsine — or vegetable albumen — will become coagulated, and incapable of inducing the decomposition of the amygdaline. Moreover, if the latter be removed from the marc with hot alcohol previous to operating in the usual manner for the extraction of the essential oil, not a trace will be obtained. It is only the bitter almond which contains amygdaline ; the sweet variety is, therefore, incapable of yielding the essence by fermentation. But sweet almonds resemble the bitter in containing emulsine ; and it is exceedingly interesting — as illustrating the truth of the explanation given above — that if a little amygdaline be added to an emulsion of sweet almonds, the bitter almond essence is immediately formed. The largest proportion of essential oil is obtained when the marc is digested, previous to distillation, with twenty times its weight of water, for a day and a night. A temperature of 100° is the most favorable for the digestion. — C. G. W. ANCHOR. The metal employed for anchors of wrought-iron is known as “ scrap iron,” and for the best anchors, such as Lenox’s, they also use good “ Welsh mine iron.” It is not practicable, without occupying more space than can be afforded, to describe in detail the manufacture f an anchor. It does not, indeed, appear desirable that we should do so, since it is so special a form of mechanical industry, that few will consult this volume for the sake of learning to make anchors. The following will therefore suffice : The an- chor smith’s forge consists of a hearth of brickwork, raised about 9 inches above the ground, and generally about V feet square. In the centre of this is a cavity for containing the fire. A vertical brick wall is built on one side of the hearth, which supports the dome, and a low chirnney to carry off the smoke. Behind this wall are placed the bellows, with which the fire is urged ; the bellows being so placed that they blow to the centre of the fire. The an- vil and the crane by which the heavy masses of metal are moved from and to the fire are adjusted near the hearth. The Hercules, a kind of stamping machine, or the steam ham- mer, need not be described in this place. To make the anchor, bars of good iron are brought together to be fagoted ; the num- ber varying^ with the size of the anchor. The fagot is kept together by hoops of iron, and the^ whole is placed upon the properly arranged hearth, and covered up by small coals, which are thrown upon a kind of oven made of cinders. Great care and good management are required to keep this temporary oven sound during the combustion ; — a smith strictly ANCHOK. 94 attends to this. When all is arranged, the bellows are set to work, and a blast urged on the fire ; this is continued for about an hour, when a good welding heat is obtained. The mass is now brought from the fire to the anvil, and the iron welded by the hammers. One por- tion having been welded, the iron is returned to fire, and the operation is repeated until the whole is welded into one mass. 30 This will be understood by referring to the annexed figures, {Jig. 80,) in which the bars for the shanks, a a, and the arms, b b, are shown, in plan and sections, as bound together, and their shapes after being welded before union ; and c c represents the palm. The different parts of the anchor being made, the arms are united to the end of the shank. This must be done with great care, as the goodness of the anchor depends entirely upon this process being effectively performed. The arms being welded on, the ring has to be formed and welded. The ring consists of several bars welded together, drawn out into a round rod, passed through a hole in the shank, bent into a circle, and the ends welded together. When all the parts are adjusted, the whole anchor is brought to a red heat, and hammered with lighter hammers than tjiose used for welding, the object being to give a finish and evenness to the surface. The toughest iron which can be procured should be used in the manufacture of an anchor, upon the strength of which both the security of valuable lives and much property depend. The following drawings {Jig. 31) show an anchor on the old plan, and the dissected parts of which it is composed : — ANCHOR. 95 and the annexed, {fig. 32,) the patent anchor as invented by Mr. Perring, with its several parts dissected as before : — Previously to the introduction of Lieutenant Rodger’s small-palmed anchor, ships were supplied with heavy, cumbersome contrivances with long shanks, and broad palms extending half way up the flukes. So badly were they proportioned, that it was no uncommon thing for them to break in falling on the bottom, particularly if the ground was rocky. But, if once firmly imbedded in stiff holding ground, there was considerable difiiculty in breaking them out. The introduction of the small palm, therefore, forms an important era in the history of anchors. The next important introduction was Porter’s anchor, with movable flukes or ai’ms. One grand object sought to be attained here, was the prevention of fouling by the cable. It was considered, also, that as great injury was frequently occasioned by a ship grounding on her anchor, the closed upper arm would remedy the evil. It was found, however, that the anchor would not take the ground properly as at first constructed, and hence the “ shark’s fins ” upon the outside of each fluke. Rodger’s invention was for some time viewed with distrust ; but, from time to time, im- provements were introduced, until the patent, which gained the Exhibition prize, was brought out. On this the jurors reported as follows : — “ Many remarkable improvements have been recently made by Lieutenant Rodger, R.N., insuring a better distribution of the metal in the direction of the greatest strains. The palm of the anchor, instead of being flat, presents two inclined planes, calculated for cutting the sand or mud instead of resisting perpendicularly ; and the consequence is, that these new anchors hold much better in the ground. The committee of Lloyd’s — so compe- tent to judge of every contrivance likely to preserve ships — have resolved to allow for the anchors of the ships they insure a sixth ‘ less weight if made according to the plan of Lieu- tenant Rodger.” The original Porter’s anchor has also undergone considerable modification ; and, under the name of “ Trotman’s anchor,” has now a conspicuous place. Another invention is that of Mitcheson’s, which, in form and proportions, strongly re- sembles Rodger’s ; but the palm is that adopted in Trotman’s, or Porter’s anchor. It is a trifle longer in the shank than Rodger’s, and has a peculiar stock, which — although original in its form — lacks originality in its design, since Rodger had previously introduced a plan for an iron stock to obviate the weakness caused by making a hole for the stock to pass through. Mr. Lenox was the inventor of an anchor which differed somewhat frcrfn the Admiralty’s anchor — a modification of Rodger’s, — in being shorter in the shank and thicker in the flukes, the palms being spade-shaped. Mr. J. Aylen, the Master- Attendant of Sheer- ness Dockyard, modified the Admiralty's anchor. Instead of the inner part of the fluke, from the crown to the pea, being rounded, as in the Admiralty plan, or squared, as in Rodger’s and Mitcheson’s, it is hollowed. An American anchor known as Isaac’s, has a flat bar of iron from palm to palm, passing the shank elliptically on both sides ; and from the end of the stock to the centre of the shank two other bars are fixed to prevent its fouling. With the anchors thus briefly described the Admiralty ordered trials to be made at Wool- wich, and at the Nore. The results of those trials — the particulars of which need not be given here — were, that Mitcheson’s, Trotman’s, Lenox’s, and Rodger’s, were selected as the best. 96 ANCHOR. A competent authority, writing in the United Service Gazette, says : — “ The general opinion deduced from the series of experiments is, that although Mitcheson’s has been so successful, the stock is not at present seaworthy. Trotman’s has come out of the trial very successfully, but the construction is too complicated to render it a good working anchor. When once in the ground, its holding properties are very superior ; in fact, a glance at its grasp will show that it has the capabilities of an anchor of another construction one-fifth larger. There are, however, drawbacks not easily to be overcome. Its taking the ground is more precarious than with other anchors ; and if a ship should part her cable, it would scarcely be possible to sweep the anchor. It is also an awkward anchor to fish and to stow. Yet there are other merits which render it, upon the whole, a most valuable invention, and no ship should go to sea without one. Of Lenox's, it is sufficient to say that it has been found equal to, and that it has gained an advantage over, Lodger's ; but so strong is the professional feeling in favor of the latter, that it will ever remain a favorite. Our recom- mendation would be thus : — Lenox and Rodger for bower anchors, Mitcheson for a sheet, and Trotman for a spare anchor.” The following table gives at one view the results of the experiments made by the Ad- miralty upon breaking the trial anchors, and the time occupied upon each experiment : — Anchors. "Weight. Proof- strain. First Crack. Broke. Time in Breaking. Cwts. qrs. lbs. Tons. Tons. Tons. Minutes. Lieut. Rodger’s - 19 0 8 19| 45 '73i 21 Brown and Lenox’s - - 20 3 14 2H 44i 47 7 Isaac’s - - 21 0 14 21| 58 C3 10 Trotman’s - 21 1 10 2U 51 53-|- 18 Honiball’s - 20 3 1 21i 54 75i 42 Admiralty’s - 20 2 G 21i 40 66^ 2G Aylen’s - - - - 21 1 0 21f 44 47i 6 Y/ 83 The history of the introduction of Lenox’s anchors to the British navy was as follows : — After sundry attempts to induce the Admiralty to give up entirely the use of hempen cable anchors, in consequence of their breaking when applied to chain cables, Mr. Lenox, in 1832, was permitted to alter some of the old anchors to such proportions and shape as would enable them to stand a proof-strain upon the machine in Woolwich Dockyard. It was found, as previously apprehended and asserted, that, from the inequality of material in the old anchors, not above one in three was successfully altered, and Mr. Lenox was ordered to supply new anchors, which were proved, and then approved of. This state of things continued until 1838, when Mr. Lenox was requested to reconsider and complete the shape and proportions of anchors for the navy, with a view to a contract being given out for the supply of such anchors to the service. Then was constructed the shape called the “ Admiralty,” or “ Sir William Parker’s Anchor,” (Sir William being then Store Lord.) Mr. Lenox suggested to Sir William the doing away with every sharp edge and line in an anchor, and adopting the smooth long- oval (in the section) for the general shape of shank and arm. This was approved of by Sir William, and he brought it out as his anchor. An entire table of pro- portions was furnished ; but that it might meet with no opposition from the influence of dockyard authority, it was sent to the officers of Portsmouth Yard for their approval. They returned it, after a few months, with some slight alterations in the proportions of some of the sizes, and recommended the construction to be on “ Perring’s principle” of the cushioned, or made-up crown. It was so adopted, and continued to be made by Brown and Lenox for about a year or two, when the great and unnecessary expense incurred by the plan was pointed out. It was contended it was without any good ; because, if the crown of the anchor, or any shut or weld, was made sound and perfect, the amalgamation of the grain of the iron would be complete, and assume its full power or strength, whatever way it might be put together ; and the strongest form was that which exposed the least surface of iron to the welding heat, and consequently to injury. About the latter end of 1839, the subject was again opened. Mr. Lenox renewed his objections, by letter, to Sir William Parker, to “ Perring’s plan ” of shutting-up, and the consequence was — a contract with specification, &c. &c., appeared, and an improved or modified plan of shutting-up (as it ANCHOE. 98 TrotmarCs A nchor is represented in Jig. 84, under its various positions. Although for convenience Trotman’s anchor is, as we have already stated, largely used by the merchant steamers, we cannot but feel that the separation of the fluke from the shaft, although it may be in many cases unobjectionable, is attended with the risk that when, in an emergency, the anchor is required, the means of connection may be at fault. Captain Hall’s anchor is a very valuable one, from the circumstance that it is capable of division, as shown in Jig. 35, so that it can be taken out in boats. There are various other shapes of anchors ; but attention has been confined to those generally employed. We are not in a position to offer any opinion upon the value of the several anchors which have been named. Having described their peculiarities, there remains but little to be said. The solidity of Lenox’s anchors — as shown in Jig. 36, and again in their more recent modifications, in plan and section, with the new form of iron stock. Jig. 3Y — has recommended them strongly, and hence their general use. The weight of anchors for different vessels is proportioned to the tonnage. The follow- ing table shows the number of anchors now carried, and the weights of each anchor, by merchant vessels by the regulation of Lloyd’s. Lloyd's Regulation for the Number and Weights of Anchors for Merchant Vessels. Ship’s Tonnage. Bower. Stream. Kedge. Bower, Wood Stock. Bower, Iron Stock. Stream. Kedge. Second Kedge. Tons. Cwt. Cwt. Cwt. Cwt. Cwt. 50 2 1 1 3 4 H 75 2 1 1 4 5 If 100 2 1 1 5 7 2i u 150 2 1 1 8 10 Si u 200 3 1 1 10 12 H 2i 250 3 1 2 13 15 5 2i 300 3 1 2 15 17 6 8 850 3 1 2 17 20 6^ Si 400 3 1 2 19 22 7i Si 500 3 1 2 23 26 9 4J 600 3 1 2 26 80 10 5 24 700 3 1 2 29 34 11 64 2f 800 3 1 2 81 86 12 6 3 900 3 1 2 33 39 12 64 34 1,000 3 1 2 35 41 12 6f 84 1,100 3 1 2 37 44 12 7 84 1,200 8 1 2 39 46 12 74 84 1,400 3 1 2 41 48 12 7f 4 1,600 3 1 2 43 50 14 84 4 1,800 3 1 2 45 52 14 84 44 2,000 4 1 2 47 64 14 9 44 ANGORA WOOL. 99 ANCHOVY. {Anchois^ Fr. ; Acciughe^ It. ; Anschove, Germ.) The Clupea encrasi- colus of LinnjEus, a small fish, resembling the sprat, common in the Mediterranean Sea. The Gorgona anchovy is considered the best. Sardines {which see) are sometimes substi- tuted for anchovies. ANDIRONS, or HAND-IRONS, also called Firedogs. Before the introduction of raised and close fireplaces these articles were in general use. Strutt, in 1VV5, says : “ These awnd- irons are used at this day, and are called ‘ cob-irons ’ ; they stand on the hearth, where they burn wood, to lay it upon ; their fronts are usually carved, with a round knob at the top ; some of them are kept polished and bright ; anciently many of them were embellished with a variety of ornaments.” ANEMOMETER, (avegos, wind ; jaerpeo), to measure.) An instrument or machine to measure the wind, its direction and force. Three descriptions of anemometers are now usually employed : — 1, Dr. Whe well’s; 2, Mr. Follett Osier’s ; 3, Dr. Robinson’s. This is not the place to describe either of those most ingenious instruments, a full account of which will be found in the “ Transactions of the British Association,” and of the “ Royal Irish Academy.” ANEROID BAROMETER. This instrument was invented by M. Vidi, of Paris. In its latest form it consists of a cylindrical case, about 4 or 6 inches in diameter, and 2^ inches deep, in which lies a thin metal box, near to, and parallel with, the curved boundary of the case, its two ends being distant about half an inch from each other. From this box the air has been partially exhausted, and the pressure of the external atmosphere on it causes it to alter its form. The accompanying figure (38) shows a section of this box. It is made -of thin corrugated plates of metal, so that its elas- ticity is great. By means of the tube f, the ^ air is partially exhausted, when the box takes the form shown by the dotted lines. A small quantity of gas is introduced after exhaustion, the object of which is to compensate for the varying elasticity of the metal at different temperatures. The pressure of the air on the box in ordinary instruments is between 40 and 50 lbs., and it will be easily understood that any variation in this pressure will occasion the distances between the two plates to vary, and consequently the stalk will have a free motion in or out. This is, by an ingenious contriv- ance, changed from a vertical motion to a motion parallel to the face of the dial, and this is converted into a rotatory one by the application of a watch-chain to a small cylinder or drum. The original very slight motion is augmented by the aid of levers. This is so effec- tually done, that when the corrugated surfaces move through only the 250th part of an inch, the index hand on the face turns over a space of three inches. The extreme portabil- ity of this little instrument, and its comparative freedom from risk of injury, render it ex- ceedingly useful to the traveller. Its accuracy is proved by the experiments of Professor Lloyd, who placed one under the receiver of an air-pump, and found that its indications corresponded with those of the mercurial gauge to less than 0-01 of an inch ; and within ordinary variations of atmospheric pressure the coincidences are very remarkable. — Lloyd^ JVichol, Drew. ANGELICA. {Ang'dique.^ Fr. ; Angelika., Germ.) The archangelica officinalis. The dried angelica root is imported from Hamburg in casks. The tender stems, stalks, and the midribs of the leaves are made, with sugar, into a sweetmeat, (candied angelica.) The an- gelica root and seeds are used by rectifiers and compounders in the preparation of gin, and as an aromatic flavoring for “’bitters.” It is cultivated in some moist places in this country. In 1856 we imported 231 tons of angelica root. ANGORA WOOL. {Foil de chevron dAngora., Fr.) Called 2 X ^0 angola and angona. The wool of the Angora goat, {Capra Angorensis^) employed in the manufacture of the shawls of Cashmere, &c. This is obtained from the long-haired goat of Angora, to which province this animal is peculiar. Lieutenant Conolly has given an account of this goat and some other varieties : — “ The country where it is found was thus described to us — ‘ Take Angora as a centre, then Kizzil Ermak (or Haly’s) Chomgere, and from 8 to 10 hours’ march (say 30 miles) beyond ; Beybazar, and the same distance beyond, to near Nalaban ; Sevree, Hissar, Yoorrook, Tosiah, Costambool, Geredeh, and Cherkesh, from the whole of which tract the common bristly goat is excluded, and the white-haired goat alone is found.’ The fleece of the white Angora goat is called tiftik., (the Turkish for goats’ hair,) in distinction to yun., or yapak., sheep’s wool. After the goats have completed their first year, they are clipped annually, in April or May, and yield progressively, until they attain full growth, from 150 drachms to 1^ oke of tiftik., (from 1 lb. to 4 lbs. English.) ” The hair of the tiftik goat is exported from its native districts raw, in yarn, and woven in the delicate stuffs for which An- gora has been long celebrated. The last are chiefly consumed in Turkey, while the yarn 38 ANILINE. 100 , and raw material are sent to France and England. It appears that the first parcels of An- gora wool were shipped from Constantinople for England in 1820, and was so little appre- ciated that it fetched only lOd the pound. The exports from Constantinople then increased as follows : — 1836 3,841 bales 1837 2,261 “ 1838 - - 6,528 “ “ Within the last two or three years, a new texture made of goats’ wool has, however, been introduced both into France and this country, which calls for particular attention. This texture consists of stripes and checks expressly manufactured for ladies’ dresses, and having a soft feel and silky appearance. The wool of which this article is made is chiefly the wool of the Angora goat. This wool reaches us through the Mediterranean, and is chiefly shipped at Smyrna and Constantinople. In color it is the whitest known in the trade, and now more generally used in the manufacture of fine goods than any other. There are, however, other parts of Asiatic Turkey from which limited supplies are received ; but in quality not so good as that produced in Angora. After the manufacture of shawls with goats’ wool declined in France, this raw material remained neglected for a long while. About two or three years ago (1852) however, the French made another attempt, and brought out a texture for ladies’ dresses in checks and stripes, which they call ‘ poil de chevre.'' The warp is a fine spun silk, colored, and the weft Angora or Syrian white wool, which was thus thrown on the surface. This article has a soft feel, and looks pretty, but in wearing is apt to cut. The price of a dress of French manufacture has been from 2Z. 10s. to ?>l . ; but by adopting a cotton warp, the same article is now made in England and sold for 15s. ; and it is found that the cotton warp, as a mixture, suits the goats’ hair best.” — Southep on Colonial Sheep and Wool^ London, 1862. Angora goats’ wool is used for the manufacture of plush, and for coach and decorative laces. It is also used extensively for buttons, button-holes, and the braidings of gentle- men’s coats. It is equally made up into a light and fashionable cloth, suited for paletots and overcoats, possessing the advantage of repelling wet. In France this article is now applied to the ma.nufacture of a new kind of lace which in a great measure supersedes the costly fabrics of Valenciennes and Chantilly. The Angora wool lace is more brilliant than that made from silk, and costing only half the price, it has come into very general wear among the middle classes. The same material is also manufactured into shawls, which sell from 4^. to 16/. each. There is much difficulty in ascertaining the quantity of Angora wool used in France, as in the returns it is mixed up with the wool of goats of Thibet, all being entered as poil de Cachemire. See Mohair. ANILINE. H’ N. Syn. Phenylamine^ Cyanol^ Benzidam^ Crystalline.) This organic base having recently met with an important application in the arts in the production of a beautiful dye-color, by Mr. William H. Perkin, a short description of the methods of preparing it, and of some of its characters, becomes necessary ; though for details of its most interesting relations in scientific chemistry, we must refer to the “ Dictionary of Chemistry.” Preparation. — There are few bodies which admit of being prepared in a greater variety of ways — all of them interesting in tracing the chemical history of this most curious body ; but we will only here describe that one which might be most advantageously carried out on a manufacturing scale. Probably the most abundant source of aniline is the basic oil of coal tar. The oil is agitated with hydrochloric acid, which seizes upon the basic oils ; after decant- ing the clear liquor, which contains the hydrochlorates of these oils, it is evaporated over an open fire until it begins to disengage acrid fumes, which indicate a commencement of de- composition, and then filtered to separate any adhering neutral compounds. The clear liquor is then decomposed with potash or milk of lime, which liberates the bases themselves in the form of a brown oil, consisting chiefly of a mixture of aniline IP N) and leucol or quinoleine, (O’® H** N.) This mixture is submitted to distillation, and the aniline is chiefly found in that portion which passes over at or about 360° F., (182° C. :) repeated rectification and collection of the product distilling at this temperature purify the aniline ; but to complete the purification, it is well to treat the partially purified aniline once more with hydrochloric acid, to separate the bases again by an alkali, and then to rectify carefully. The violet reaction of aniline with solution of bleaching powder enables the operator to test the distillate from time to time, to ascertain when aniline ceases to pass over, since leucol does not possess this property. — Hofmann. Aniline may also be obtained in quantity from indigo. When indigo-blue (see Indigo) is dissolved by the aid of heat in a strong solution of potash, and the mass, after evaporation to dryness, submitted to destructive distillation, it intumesces considerably, and aniline is liberated, which condenses in the receiver in the form of a brown oil, together with a little water and ammonia disengaged with it. The ANILINE. 101 aniline is purified by rectification, as in the method before described. By this process the quantity of aniline obtained is about 18 to 20 per cent, of the indigo used. — Fritzche. By treatment with potash, the indigo-blue (C^® H® NO^) is converted into chrysanilio acid and anthranilic acid, (C‘^ H’ NO* ;) and it is this latter body which, by destructive dis-> tillation, yields carbonic acid and aniline. CM ir NO* = N + 2CO^ Nitrobenzole {which see) may be converted into aniline, either by the action of sulphu- retted hydrogen — * IP NO* 4- 6HS = C*" N + 4HO + 6S ; Nitrobenzole. Aniline. or, more conveniently, as has been recently shown by M. Bechamp, by the action of a basic acetate of iron. For this purpose the following proportions have been found convenient by the writer : mix in a retort ^ lb. of iron filings, with about 2 ounces of acetic acid, then add about an equal volume of nitrobenzole. After a few minutes a brisk effervescence sets in, and the aniline distils over together with water. The reaction may require to be aided by the application of very gentle heat ; but it takes place with the greatest ease, and a very tol- erably sufficient condensing arrangement should be employed. The aniline having so nearly the density of water, does not readily separate on the surfaee, but the addition of a few drops of ether, which dissolves in the aniline, brings it to "the surface. It may then be decanted off, dried by standing for a short time over chloride of calcium, and then purified by rectification, as before described. Properties. — Aniline is one of the organic basic derivatives of ammonia. In fact, it may be viewed as ammonia in which one equivalent of hydrogen is replaced by the compound radical Phenyl H®) thus : — ( H® N \ II ( H Just as phenyl is one of a series of homologous radicals, so aniline is the first of a series of homologous bases, in which the one equivalent of hydrogen is replaced by these radicals, respectively, thus : Homologous Eadicals. Homologous Bases. Phenyl - - H® — Aniline - N ^ f C13 H5 j Toluyl - C'*H^ — Toluidine - - N C* H’ H® Xylyl - - H® — Xylidine - N • Q16 29 H® Cumyl . C'® H“ — Cumidine - N ■ Q18 gll H® Cymyl - C®® H*® — Cymidine - N ■ C20 013 When pure, it is a colorless liquid of a high refractive power ; density 1*028, and of an aromatic odor. It is slightly soluble in water, and mixes in all proportions with alcohol and ether. It boils at 360° F., (182° C.) It dissolves sulphur and phosphorus when cold, and coagulates albumen. It has no action on litmus-paper, but turns delicate vegetable colors, such as dahlia-petal infusion, blue. Its basic characters are well developed thus : — it precipitates the oxides from the salts of iron, zinc, and alumina, just like ammonia, and yields, with bichloride of platinum, a double salt similar to ammonia, the platino-chloride of aniline, (C*‘^ H’ N, HCl, PtCP,) which on ignition is entirely decomposed, leaving only a residue of platinum. These characters, together with the beautiful blue color which it strikes with solution of bleaching powder, or the alkaline hypochlorites generally, are sufficient for the recognition and distinction of this body. Salts of Aniline. — Aniline combines with acids forming a long series of salts which are in every respect analogous to the corresponding salts of ammonia. They are nearly all soluble and crystallizable, and are decomposed by the mineral alkalies with liberation of ani- line. They are generally colorless, but become red by exposure to the air. *Sulphate qf Aniline. H’' N ; HO, SO®.) — This salt is employed in the manufacture of Mr. Perkin’s aniline colors. It is prepared by treating aniline with dilute sulphuric acid, and evaporating gently till the salt separates. It crystallizes from boiling alcohol in the form of beautiful colorless plates of a silvery lustre, for the salt is scarcely at all soluble in cold alcohol. It is very soluble in water, but insoluble in ether. The crystals redden by exposure to the air ; they can be heated to the boiling point of ANISEED. 102 water without change, but when ignited they are charred with disengagement of aniline and sulphurous acid. Oxalate of Aniline. (C'* H’ N ; HO, C* 0^) — This is one of the best-defined salts of aniline : it separates as a crystalline mass on treating an alcoholic solution of oxalic acid with aniline. It is very soluble in hot water, much less so in cold, only slightly soluble in alcohol, and insoluble in ether. A large number of other salts are known. The hydrochlorate, hydrobromate, hydrio- date, nitrate, several phosphates, citrate, tartrate, &c. &c. ; but they are of purely scientific interest. The same remark applies to the various products of the decomposition of aniline, which have been so ably investigated by Fritzche, Zinin, Hofmann, Gerhardt, and other chemists. Application. — Several most beautiful colors for dyeing silk have been prepared by Mr. William H. Perkin, of Greenford Green, near Harrow, from certain salts of aniline, which are of different shades of violet, some more approaching purple, others more pink. They are now being extensively employed in dyeing silk, and are found to be far finer in tint, and more permanent, than any other known dyes of a similar color. The processes for their manufacture have been patented by Mr. Perkin. For the following short description of the method of preparing them, we are indebted to that gentleman : — “ Take equivalent proportions of sulphate of aniline and bichromate of potash, dissolve them in water, mix, and allow the mixture to stand for several hours. The’ whole is then thrown upon a filter, and a black precipitate which has formed is washed and dried. It is then digested with coal-tar naphtha, to extract a brown resinous substance, and finally digested with alcohol to dissolve out the coloring matter, which is left behind on distilling off the spirit, as a coppery friable mass.” — II. M. W. ANISEED. {Anis^ Fr. ; Anis^ Germ.) The fruit or seed of the pimpinella anisum., largely cultivated in Malta, Spain, and Germany ; used in the preparation of the oil of anise, {oleum anisi,) the spirit of anise, {spiritus anisi^) and anise water, {aqua anisi.) It is also used imcordials. In 1855, 963 cwts. were imported. The oleum hadiani., or the oil of star anise, {illicium anisatum,) has the color and taste of the oil of anise ; but it preserves its fluidity at 35-6° F. It is sometimes fraudulently substituted for oleum anisi. — Pereira. ANTHRACITE. (&v0/>o|, coal.) A variety of coal containing a larger proportion of carbon and less bituminous matter than common coal. — De la Beche. Anthracite coal is obtained in this country, at Bideford, in Devonshire, in the Western divisions of the South Wales coal-field, and in Ireland. It is found abundantly in America. Professor H. D. Roger’s “ Transactions of American Geologists ” states that in the great Appalachian coal-field, extending 720 miles, with a chief breadth of 180 miles, the coal is bituminous towards the western limit, where it is level and unbroken, becoming anthracitic towards the south-west, where it is disturbed. Anthracitic coal is also found in the coal- fields of France, especially in the departments of Isere, the High Alps, Gard, Mayenne, and « of Sarth ; about 42,271,000 kilogrammes (of 2‘2046 avoirdupois pounds each) are produced annually. Anthracite is also raised in Belgium. Anthracite is not an original variety of coal, but a modification of the same beds which remain bituminous in other parts of the region. Anthracite beds, therefore, are not sepa- rate deposits in another sea, nor coal measures in another area, nor interpolations among bituminous coals, but the bituminous beds themselves,’ altered into a natural coke, from which the volatile bituminous oils and gases have been driven off. — J. P. Lesley, on Coal. Anthracite — now extensively used for iron-making, steam-engines, and for domestic pur- poses, in the United States — was, some 60 years since, regarded as incombustible refuse, and thrown away. This peculiar and valuable fossil fuel is found in various parts of the old and new con- tinent, as shown by the following lists, for which we are mainly indebted to the American publication. Statistics of Coal, by Taylor. Localities of Anthracite and Anthracitous Coal. EUROPE. Specific Gravity. Weight of a cubic yard in 11 South Wales : — Swansea . U263 - - 2,131 Cyfarthfa - 1-337 - - 2,256 Yniscedwin - 1.354 - - 2,284 Average - 1-446 - - 2,278 Ireland, mean - 1-445 - - 2,376 - 2,207 France : — Allier - - 1-380 - Tantal - - 1-390 - - 2,283 Brassac - 1-430 - - 2,413 Belgium : — Mons - - 1-307 - - 2,105 Westphalia - - 1.305 - - 2,278 Prussian Saxony - - 1-466 - - 2,474 Saxony ... - 1-300 - - 2,193 Average of Europe - ANTHRACITE. 103 Localities of Anthracite and Anthracitous Coal^ (continued.) AMERICA. Pennsylvania : — Lykens Valley - Lebanon co., gray vein Schuylkill co., Lorberry Creek Pottsville, Sharp Mountain “ Peach - “ Salem Vein Tamaqua, north vein Mauch Chunk Nesquehoning Wilkesbarre, best West Mahoney Beaver Meadow Girardville - ' Hazelton Broad Mountain j Lackawanna Massachusetts : — Mansfield Rhode Island : — Portsmouth Average in United States - The calorific value of anthracite coal is well shown by the following results from Dr. Fyfe’s experiments to compare Scotch and English bituminous coals with anthracite, in re- gard to their evaporative power, in a high-pressure boiler of a 4-horse engine, having a grate with 8’15 square feet of surface ; also in a wagon-shaped copper boiler, open to the air, surface 18 feet, grate 1*55. Specific Gravity. 1-327 - Weight of a cubic yard in 11 - 2,240 1-379 - - - 2,327 1-472 - - 2,484 1-412 - - 2,382 1-446 - - 2,440 1-574 - . 2,649 1-600 - - 2,700 1-550 - - 2,615 1-558 - - 2,646 1-472 - - 2,884 1-371 - - 2,313 1-600 - - 2,700 1-600 - - 2,700 1-550 - - 2,615 1-700 - - 2,869 2,715 1-609 - - 1-710 - - 2,882 1-810 - - 3,054 - - 2,601 Kind of Fuel employed. Poundi burnt per Hour on the Grate. Duration of the Trial in Hours. Temperature of the Water. Pounds of Water eva- j porated from the initial Temperature 1 by 1 lb. of Coal. Pounds of Water at 212* from 1 lb. of Coal. Coal per Hour on 1 Square Foot of Grate. Time in Seconds of consuming 1 lb. of Coal. Pounds evaporated per Hour from each Square F oot of Surface. Remarks. Middlerig Scotch coal. 81-33 1 9 45’ 6 '66 * 7-74 10-00 44-27 . Pressure 17 lbs. per sq. inch. Scotch coal, dif- ferent variety from preceding. 108 5 170 6 62 6-89 13-25 83-33 Ditto. Anthracite - 4794 81 45 8-73 10-10 5-88 7509 - Ditto. Scotch coal, from near Edinburgh 3-24 81 50 5-38 6-90 5-31 436-89 8-15 Low pressure, open English bitumi- nous coal. 6-07 8-4 50 7-84 9-07 8-91 503-08 3-06 copper boiler. Ditto. Space will not admit of our entering fully into the question of the evaporative power of anthracite ; but its advantages under certain conditions are fully established. In this country anthracite coal is used in the manufacture of iron in the following fur- naces : — Blast Furnaces making Iron from Anthracite. No. Names of Works. Owners. Furnaces built. Furnaces in blast. Furnaces in blast in Dis- trict. Glamorganshire. 1 Aberdare, Abernant, and Llwydcoed Aberdare Iron Company 3 3 2 Banwen - Out of blast - - . 2 0 3 Onllwyn or Brin - L. Llewellyn - 2 1 4 Venalt - Aberdare Iron Company - 2 0 5 Ystalyfera - Ystalyfera Iron Company 7 11 BRECKNOCKSmRE. 1 Abercrave - T. Walters - 1 1 2 Yniscedwin - Yniscedwin Iron Company 7 4 5 Caermarthenshire. 1 Bryn Ammon L. Llewellyn - 2 2 2 Gwendraeth T. Watney & Co. 2 1 3 Trim Saren - E. H. Thomas - 2 0 3 Pembrokeshire. 1 Sandersfoot - Pembroke Iron and Coal Co. 1 0 0 Total furnaces in blast in anthracite districts in 1857 • • 19 ANTELOPE HOKN. 104 Professor W. R. Johnson, of Pennsylvania College, informs us that fourteen furnaces using anthracite for the production of iron were in use in the United States. In the anthracite districts of South Wales, the produce was, in — 1855 . - - 997,500 tons. 1856 - - - 965,500 “ 1857 - - - 1,485,000 “ The following table shows the progress of production in America of anthracite from 1840 to 1857, inclusive, from Schuylkill, Lehigh, and Wyoming: — Year. Tons. Increase per Year. Tons. 1840 864,384 45,982 1841 950,973 86,689 1842 1,108,418 167,445 1843 1,263,598 155,180 1844 1,630,850 367,262 1845 2,013,013 382,163 1846 2,344,005 330,992 1847 2,882,300 638,596 1848 3,089,238 206,938 1849 8,217,641 128,403 1850 3,321,136 103,495 1851 4,329,530 1,008,394 1852 4,899,975 670,445 1853 6,097,144 197,169 1854 6,831,834 734,690 1855 6,486,097 654,263 1856 6,751,542 265,445 1857 6,431,379 320,163 decrease. Pottsville Miners' Journal. A steady increase is thus shown in the production of American anthracite, excepting during the last year. This decrease may be readily accounted for by the general depression of the iron and other manufactures. The annual consumption of anthracite in the Um'ted States was thus stated in the Science of New York Exhibition : — 1820 about 330 tons. 1825 “ 35,000 “ 1830 “ 176,000 “ 1835 “ 561,000 “ 1840 “ 865,000 “ 1845 “ 2,023,000 “ 1850 “ 3,357,000 “ 1853 “ 5,195,000 “ The quantity consumed in 1856 is stated to have been 7,900,000 tons. ANTELOPE HORN is used occasionally for ornamental knife handles. See Horn. ANTICHLORE. A term employed by bleachers to the means of obviating the perni- cious after-effects of chlorine upon the pulp of paper, or stuffs, which have been bleached therewith. Manufacturers have been in the habit of using sulphite of soda, whose action upon the adhering bleaching salt, which cannot be removed by washing, gives rise to the formation of sulphate and hydrosulphate of soda and chloride of sodium. Chloride of tin has been recommended by some chemists for this purpose. ANTI- ATTRITION, or, ANTI-FRICTION COMPOSITION. Various preparations have been, from time to time, introduced for the purpose of removing, as much as possible, the friction of machinery. Black lead, or plumbago, mixed with a tenacious grease, has been much employed. Peroxide of iron, finely divided heematite, &c., have also been used. A composition employed at Munich is reported to have been used with success and economy to diminish friction of machinery. It consists of ten and a half parts of pure hogs’ lard, fused with two parts of finely pulverized and sifted plumbago. The lard is first to be melted over a moderate fire, then a handful of the plumbago thrown in, and the materials stirred with a wooden spoon until the mixture is perfect ; the rest of the plumbago is then to be added, and again to be stirred until the substance is of uniform composition ; the ves- sel is then to be removed from the fire, the motion being continued until the mixture is ANTIMONY. 105 quite cold. The composition, in its cold state, was applied to the pivots, the teeth of wheels, &c., by a brush, and seldom more than once in 24 hours.* It was found that this composition replaced the oil, tallow, and tar, in certain iron works with economy, saving about % of the cost of these articles. ANTI-FRICTION METAL. Tin and pewter are commonly employed as anti-friction metals for the bearings of locomotive engines. Rabbet’s metal is prepared by taking about fifty parts of tin, five of antimony, and one of copper. Tin or pewter, used alone, owing to its softness, spreads out and escapes under the superincumbent weight of the locomotive, or other heavy machinery. It is usual, there- fore, to add antimony, for the purpose of giving these metals hardness. Fenton’s Anti-friction metal, which is much employed, is a mixture of tin, copper, and spelter. Its advantages are stated to be cheapness in first cost, low specific gravity, being 20 per cent, lighter than gun metal ; and being of a more unctuous or soapy character than gun metal, less grease or oil is required. The softer metal is often supported by brasses cast of the required form, the tin alloy being cast upon them. The brasses, or bearings, being properly tinned, and an exact modd of the axle having been turned, the parts are heated, put together in their relative positions, luted with plastic clay, and the fluid anti-friction metal poured in, which then becomes of the required form, and effectually solders the brass. The following compositions are recommended to railway engineers as having been em- ployed for several years in Belgium ; — In those cases where the objects are much exposed to friction, 20 parts of copper, 4 of tin, 0*5 of antimony, and 0’25 of lead. For objects which are intended to resist violent shocks, 20 parts of copper, 6 of zinc, and 1 of tin. For those which are exposed to heat, 17 parts of copper, 1 of zinc, 0‘5 of tin, and 0*25 of lead. The copper is added to the fused mass containing the other metals. ANTIMONY occurs with numerous ores of lead and silver, of nickel, &c., but the most important ore of antimony is the sulphuret, (Stibnite, or Gray Antimony,) which forms the chief and most common source of the antimony of commerce, and of the greater number of the pharmaceutical preparations of that metal. Antimony is not at present produced in this country, but in the last century it was mined extensively. The most celebrated localities of this ore are Falsobanya, Schemnitz, and Kremnitz, in Hungary, where it occurs in diverging prisms several inches long. It is also found in the Hartz, at Andreasberg, in Hungary, in Cornwall, at the old Trewetha mine, and abundantly in Borneo. This ore was called by the ancients TrKaTv6^Qa\iiov — ttXotus, broad, ocpOaXixhs, eye — from the use to which it was applied in increasing the apparent size of the eye, as is still prac- tised among oriental nations, by staining the upper and under edges of the eyelids. It was also used as a hair-dye and to color the eyebrows. It was the Lupus Metallorum of the alchemists. Crude antimony is obtained from it by simple fusion, and from this product the pure metal is extracted. The other principal ores of antimony are the following : — Native Antimony is a mineral of a tin-white color and streak and a metallic lustre, and sometimes contains silver, iron, and arsenic, with which last it is commonly associated. It is brittle, and possesses a specific gravity of 6 ‘62 to 6*72. It is generally lamellar, some- times botryoidal, or reniform. Before the blowpipe it soon melts, and continues to burn after the heat is removed ; but if the heat be continued, it evaporates in white fumes, and is redeposited round the globule. Native antimony occurs at Sahlburg in Sweden, Andreasberg in the Hartz, Allemont in Dauphiny, in Mexico, &c. Arsenical Antimony also occurs at Allemont, in the Hartz, and elsewhere, in reniform and amorphous masses, with a finely granular or a curved lamellar structure. It is com- posed of arsenic 62T5, antimony 67'85. It possesses a metallic lustre, and a reddish-gray or tin-white lustre. Its specific gravity is 6*2. Oxide of Antimony {Cervantite) occurs, associated with gray antimony, (of which it is an altered form,) at Cervantes, in Spain, in Hungary, and the Auvergne. It is found in octahedral crystals, and in radiating fibrous crystals in the province of Constantina, in Alge- ria, {Senarmontite,) also at Perneck, in Hungary. It occurs as a crust or powder, or in acicular crystals, with a greasy or earthy lustre, and of a pale yellow or nearly white color. Specific gravity = 40’8. It is composed of antimony 80T, oxygen 19"9 ; but frequently it contains an admixture of iron, carbonate of lime, &c. It is soluble in muriatic acid. ^ White Antimony ( Valentinite) is the result of the alteration of gray antimony, native antimony, and other ores of that metal. It possesses a shining pearly lustre and a snow- white color, but is sometimes pinkish, or ash-gray, or brownish. It affords a white streak. It is composed of antimony 84*32, oxygen 15*68. Specific gravity = 5*56. It is found in tabular crystals in veins traversing the primary rocks at Prizbram in Bohemia, near Frey- berg in Saxony, Allemont in Dauphiny, &c. * Ann. des Mines, xi. 79. 106 Al^TIMONY, GLASS OF. Red Antimony {Kermesite) is a compound of oxide of antimony 30-2, and sulphide of antimony 69-8, or antimony V4-45, oxygen 5-29, and sulphur 20*49. It occurs generally in capillary six-sided prismatic crystals of a cherry-red color, afford- ing a brownish-red streak. It has a specific gravity of from 4*5 to 4*6. It is feebly translucent, and possesses an adamantine lustre. It occurs at Walaczka in Hungary, Braunsdorf in Saxony, and at Allemont in Dauphiny. At Malboac, in the department of Ar- deche, in France, the separation of the sulphide of antimony from its associated gangue is effected by means of a peculiar apparatus, {Jig. 39.) The mineral is placed in large retorts, R R, of which four are set in each furnace. An aperture is left at the bottom of each of these cylinders, which corresponds with a sim- ilar opening by which they are supported. Beneath these, in the chambers c c, are placed earthen pots, p p, in which is received the melted sulphide as it descends through the openings in the cylinders. The fuel consumed on the grate consists of fir wood ; and the sul- phide obtained is converted into metallic anti- mony by roasting in a reverberatory furnace, and subsequent reduction by a mixture of 20 per cent, of powdered charcoal which has been saturated with a strong solution of the carbonate of soda. Melted with tin, antimony has of late been used as an anti-friction alloy for railway axles, and other bearings ; in metallic rings, or collars, for machinery. As this alloy is not so much heated by friction as the harder metals, less grease is consumed. ANTIMONY, GLASS OF. This substance, according to M. Soubeiran, contains — Protoxide of antimony 91*5 Silica 4*5 Peroxide of iron 3*2 Sulphuret of antimony 1*9 101*1 APPLE WINE. Cider. Winckler finds that the wine from apples is distinguished from the wine from grapes by the absence of bitartrate of potash and of aenanthic acid, by its containing a smaller amount of alcohol and more tannin, but especially by the presence of a characteristic acid, which he regards as lactic acid, notwithstanding that this opinion is not confirmed by the degree of solubility of its salts with oxide of zinc, lime, and magnesia. See Cider, vol. i., p. 561. AQUAFORTIS. This acid has usually been obtained by mixing common nitre with green vitriol or sulphate of iron, and distilling, or by mixing nitre and clay or siliceous matter, and distilling over the nitric acid, leaving the alkali to unite with the earthy base. It may, however, be usefully borne in mind, that this term of aquafortis., or strong water of the old chemist, w*as also applied to solutions which answered their special pur- poses. Thus Salmon, in 1685, gives the composition of aquafortis from certain mixtures of acids, not nitric, and salts, and distinctly refers to the Pharmacopoeia for the other kind. This may be of service when applying old recipes for processes in the arts. Aquafortis did not always mean nitric acid. See Nitric Acid. AQUAMARINE is the name given to those varieties of beryl which are of clear shades of sky-blue or greenish-blue, like the sky. It occurs in longitudinally-striated hexagonal crys- tals, sometimes a foot long, and is found in the Brazils, Hindustan, and Siberia. See Beryl. AQUA REGIA. Royal water. Now called nitro-muriatic acid., or nitro-chlorohydric acid, or hypochloro-nitric acid. Prepared under different conditions, it appears to give different results. Gay-Lussac observed that aqua regia, wdien heated in a water-bath, evolves a gaseous body which, dried and exposed to a frigorific mixture, separates into chlorine and a dark lemon-yellow liquid, boiling at 70° F. This yellow liquid was found to contain 69*4 per cent, of chlorine, the calculated quantity for the formula, NO'^CP, being 70*2. Gay-Lussac refutes the assertion of E. Davy and Baudrimont, that the properties of aqua regia are due to its containing a compound of chlorine, nitrogen, and oxygen, and confirms the, generally received view, that its action depends upon free chlorine. From the vapor evolved in the action of aqua regia upon gold, a liquid may be condensed which is nearly of the composition NO^CP, contain- ing, however, no free chlorine. ARABIC, GUM. Chemists have been disposed to divide gums into three varieties,, to which they have given the names of Arahine, cerasine, and dextrine. AKCHI'L. 107 Arabine, or gum Arabic, exudes from several species of acacia and prunus; it is also found in the roots of the mallow, comfrey, and some other plants. Gum Arabic never crys- tallizes, is transparent, and has a vitreous fracture. It dissolves in water in all proportions, forming mucilage. Its chemical composition is expressed by the formula, ARCH. As this dictionary is not intended to include articles connected with engineering or with architecture, it would be out of place to describe the conditions required to ensure the stability of the arch', which is manifestly one of great importance to the practical builder. (For the theory of the equilibrium of the arch, Gwilt’s treatise on the subject should be con- sulted, or the article Arch, “ Encyclopaedia Britannica.”) ARCHIL, {Orseille^ Fr. ; Orseiile, Germ. ; Oricdlo., Ital.) The name of archil is given to a coloring matter obtained, by the simultaneous action of the air, moisture, and an ammoniacal liquor, from many of the lichens^ the most esteemed being the lichen roccella. It appears in commerce in three forms : 1, As a pasty matter called archil ; 2, as a mass of a drier character, named perais ; and 3, as a reddish powder called cudbear. The lichen from which archil is prepared is known also as the canary weed or orchilla weed. It grows in great abundance on some of the islands near the African coast, particu- larly in the Canaries and several of the Islands of the Archipelago. Its color is sometimes a light and sometimes a dark gray. The chemical constitution of archil was first investigated by M. Cocq, “ Annales de Chimie,” vol. Ixxxi. ; and subsequently, yet more extensively, by Robiquet, “Annales de Chimie,” vol. xlii., 2d series. From the Variolaria, Robiquet obtained Orcine^ by digesting the lichen in alcohol, evaporating to dryness, dissolving the extract in water, concentrating the solution to the thickness of a syrup, and setting it aside to crystallize. It forms, when quite pure, color- less prisms, of a nauseous sweet taste, which fuse easily, and may be sublimed unaltered. Its formula is C'^H'D* -j- 3Aq. when sublimed ; when crystallized from its aqueous solution it contains 5 Aq. If orcine be exposed to the combined action of air and ammonia, it is converted into a crimson powder orceine^ which is the most important ingredient in the archil of commerce. Orceine may be obtained by digesting dried archil in strong alcohol, evaporating the solu- tion in a water-bath to dryness, and treating it with ether as long as any thing is dissolved ; it remains as a dark blood-red powder, being sparingly soluble in water or ether, but abun- dantly in alcohol. Its formula is C'^H^NO’. Orceine dissolves in alkaline liquors with a magnificent purple color ; with metallic oxides it forms lakes, also of rich purple of various shades. In contact with deoxidizing agents, it combines with hydrogen, as indigo does, and forms leuc-orceine, C^'^H^NO^ -(- H. When bleached by chlorine, a yellow substance is formed, cA^or-orceine, the formula of which is C^®H®NO^ -j- Cl analogous to the other. — Kane. Dr. Schunk, by an examination of several species of Lecanora, has proved that, although under the influence of ammonia and of air, they ultimately produce orceine, these lichens do not contain orcine ready formed, but another body, Lecanorine^ which, under the influ- ence of bases, acts as an acid, and is decomposed into orcine, and carbonic acid. If lecanoric acid be dissolved in boiling alcohol, it unites with ether, forming lecanoric ether, which crystallizes beautifully in pearly scales. In the roccella tinctoria and the evernia prunadri. erytheric acid is found. By the oxidation of this acid amarythrine or erythrine bitter is formed. These substances have been carefully examined by Schunk, Stenhouse, and Kane. The chemical history of these and some other compounds is of great interest ; but as they do not bear directly upon the manufacture of archil, or its use in dyeing, fur- ther space cannot be devoted to their consideration. Kane found archil and litmus of commerce to contain two classes of coloring matters, as already stated, orcine and orceine^ derived from it. Beyond these there were two bodies, one containing nitrogen, azoerythrine^ and the other destitute of nitrogen, erythroleic acid. This latter acid is separated from the other bodies present in archil by means of ether, in which it dissolves abundantly, forming a rich crimson solution. It gives with alkalies purple liquors, and with earthy and metallic salts colored lakes. Beyond those already named there are several other species of lichen which might be employed in producing an analogous dye, were they prepared, like the preceding, into the substance called archil. Hellot gives the following method for discovering if they possess this property : — A little of the plant is to be put into a glass vessel ; it is to be moistened with ammonia and lime-water in equal parts ; a little muriate of ammonia (sal ammoniac) is added, and the small vessel is corked. If the plant be of a nature to afford a red dye, after three or four days the small portion of liquid which will run off on inclining the vessel, now opened, will be tinged of a crimson red, and the plant itself will have assumed this color. If the liquor or the plant does not take this color, nothing need be hoped for ; and it is useless to attempt its preparation on the great scale. Lewis says, however, that he has tested in this way a great many mosses, and that most of them afforded him a yellow or reddish-brown color ; but that he obtained from only a small number a liquor of a deep red, which communicated to cloth merely a yellowish-red color. AEEOMETEK. 108 To prepare archil, the lichens employed are ground up with water to a uniform pulp, and this is then mixed with as much water as will make the whole fluid ; ammoniacal liquors from gas or from ivory-black works, or stale urine, are from time to time added, and the mass frequently stirred so as to promote the action of the air. The orcine or erythrine which exists in the lichen absorbs oxygen and nitrogen, and forms orceine. The roccelline absorbs oxygen and forms erythroleic acid ; these being kept in solution by the ammonia, the whole liquid becomes of an intense purple, and constitutes ordinary^ archil. — Kane. The herb archil, just named, called especially orceille de ierre^ is found upon the vol- canic rocks of the Auvergne, on the Alps, and the Pyrenees. These lichens are gathered by men whose whole time is thus occupied ; they scrape them from the rocks with a peculiarly shaped knife. They prefer collecting the orceille in rainy weather, when they are more easily detached from the rocks. They gather about 2 kilo- grammes a day, or about 4^ pounds. When they take their lichens to the makers of archil or litmus for the purpose of selling them, they submit a sample to a test, for the purpose of estimating their quality. To this end they put a little in a glass containing some urine, with a small quantity of lime. As the lichens very rapidly pass into fermentation if kept in a damp state, and thus lose much of their tinctorial power, great care is taken in drying them ; when dry they may be preserved without injury for some time. AREOMETER. An instrument to measure the densities of liquids. (See Alcoholom- ETRY.) The principle will be well understood by remembering that any solid body will sink further in a light liquid than in a heavy one. The areometer is usually a glass tube, having a small glass bulb loaded with either shot or quicksilver, so as to set the tube upright in any fluid in which it will swim. Within the tube is placed a graduated scale : we will suppose the tube placed in distilled water, and the line cut by the surface of the fluid to be marked ; that it is then removed and placed in strong alcohol — the tube will sink much lower in this, and consequently we shall have two extremities of an arbitrary scale, on which we can mark any intermediate degrees. ARNATTO, or ARNOTTO. See Annotto, vol. i. Arnatto was considered to contain two distinct coloring matters, a yellow and red, till it was shown by M. Pressier that one is the oxide of the other, and that they may be obtained by adding a salt of lead to a solution of arnatto, which precipitates the coloring matter. The lead is separated by sulphuretted hydrogen ; and the substance being filtered and evaporated, the coloring matter is deposited in small crystals of a yellow-white color. These crystals consist of bixine ; they become yellow by exposure to the air, but if they are dissolved in water they undergo no change. When ammonia is added to bixine., with free contact of air, there is formed a fine deep red color, like arnatto, and a new substance, called bixeine, is produced, which does not crys- tallize, but may be obtained as a red powder ; this is colored blue by sulphuric acid, and combines with alkalies, and is bixine with addition of oxygen. When arnatto, in the form of paste, is mixed from time to time with stale urine, it appears probable that the improve- ment consists in the formation of bixeine from the bixine by the ammonia of the urine. It has hence been suggested that, to improve the color of arnatto, it might be mixed with a little ammonia, and subsequently exposed to the air, previously to its being used for dyeing. A solution of arnatto and potash in water is sold under the name of Scott's Nankeen Dye, ARROBA (of wine). A Spanish measure, equal to 3 'SSI 7 gallons. ARROW ROOT. In commerce, the term arrow root is frequently used generically to indicate a starch or fecula, as Portland arrow root., a white amylaceous powder, prepared in the Isle of Portland, from the Arum vulgare., the common Cuckoo-pint., called also Wake- robin and Lords and Ladies. East India ar, ow root, prepared from the Curcuma angustifolia. Brazilian arrow root, the fecula of Jatropha manihot. English arrow root, tlie starch of the potato. Tahiti arrow root, the fecula of Tacca oceanica, which is imported into London and sold as “ arrow root prepared by the native converts at the missionary stations in the South Sea Islands.” ARSENIC, derived from the Greek apa^viKbv, masculine, applied to orpiments on ac- count of its potent powers. This metal occurs native in veins, in crystalline rocks, and the older schists ; it is found in the state of oxide, and also combined with sulphur under the improper name of yellow and red arsenic, or orpiment and realgar. Arsenic is associated with a great many metallic ores ; but it is chiefly extracted in this country from those of tin, by roasting, in which case the white oxide of arsenic, or, more correctly, the arsenious acid is obtained. On the Continent, arsenical cobalt is the chief source of arsenic. The following are the principal ores of arsenic : — Native Arsenic. — The most common form of native arsenic is reniform and stalactitic masses, often mammillated, and splitting off in thin successive layers like those of a shell. It possesses a somewhat metallic lustre, and a tin-white color and streak, which soon tar- nishes to a dark gray. Its specific gravity is 5*93. Before the blow-pipe it gives out an ARSENIOUS ACID. 109 alliaceous odor, and volatilizes in white fumes. It is found in the Hartz, in Andreasberg, at the silver mines of Freiberg, in Chili, the Asturias, &c. White Arsenic^ or Arsenious Acid^ {Arsenolite^) is often formed by the decomposition of other arsenical ores, anil is composed of arsenic 65 -76 and oxygen 24*24. It occurs either in minute radiating capillary crystals and crusts investing other substances, or in a stalactitic or botryoidal form. Before the blow-pipe it volatilizes in white fumes ; in the inner flame it blackens and gives out an alliaceous odor ; its specific gravity is 3*69. It is white, some- times with a yellowish or reddish tinge, and has a silky or vitreous lustre. It possesses an astringent, sweetish taste. — H. W. B. Realgar^ (ancienty called Sandaraca,) red orpiment, or ruby sulphur, is a sulphide of arsenic, having a composition, sulphur 29*91, arsenic 70*09. It occurs in Hungary, Saxony, and Switzerland. Orpiment, (a corruption of its Latin name, aurigmentum — golden paint,) yellow sulphide of arsenic: its composition is, sulphur 39, arsenic 61. Burns with a blue flame on char- coal, and emits fumes of sulphur and arsenic. Dissolves in nitromuriatic acid and am- monia. Both realgar and orpiment are artificially prepared and used as pigments. See those articles. Arsenic is a brittle metal, of an iron-gray color, with a good deal of brilliancy. It may be prepared by triturating arsenious acid, or the white arsenic of commerce, with black flux, (charcoal and carbonate of potash,) and subliming in a tube. If arsenical pyrites are ignited in close tubes, metallie arsenic sublimes, and sulphuret of iron remains. This metal, when exposed in the air, gradually absorbs oxygen, and falls into a gray powder, (suboxide.) This is sold on the Continent as fly powder. To prepare arsenic on a larger scale, mispickel, or the other ores employed, are pounded; some pieces of old iron are mixed with the ore, to retain the combined sulphur, and the mixture placed in retorts between four and five feet in length, to which receivers are adapted. The retorts are moderately heated by a fire placed beneath them ; the ores are decomposed, and metallic arsenic is sublimed and condensed in the receivers. T4ie arsenic obtained in this way is purified by a second distillation with a little charcoal. Arsenic is used in small quantities in the preparation of several alloys ; it is employed in the manufacture of opal glass ; also is much used in the manufacture of shot, to which it imparts a certain degree of hardness ; and, by preventing the distortion of the falling drops of metal, and thus securing regular globules, the manufacture is greatly facilitated. ARSENIOUS ACID, White Arsenic, Flowers of Arsenic. — This is the white arsenic of commerce, usually called Arsenic. It is obtained in this country from the arsenical ores of iron, tin, &c., and on the Continent from those of cobalt and nickel. It is prepared by heating the ores containing arsenic on the sole of a reverberatory furnace, through which a current of air, after passing through the grate, is allowed to play. The following ores are the more remarkable of this class, — the quantity, of arsenic in 100 grains is given in each case *. — Mispickel, or arsenical iron 42*88 Lolingite, arsenical pyrites 65*88 Kupfernickel, arsenical nickel - . . . 51*73 Rammelshergite, white arsenical nickel - - - 72*64 Synaltine, tin-white cobalt 74*22 Saffiorite, arsenical cobalt 70*37 In the roasting of tin ores, a considerable quantity of arsenious acid is collected in the flues leading from the furnaces in which this process is effected. White arsenic is extensively used in the preparation of various pigments, as the himl- phide, or realgar, the tersulphide, or orpiment, and also in the mineral greens used by paper-stainers. It is employed in glass and porcelain manufacture. Considerable discus- sion has arisen from a statement made by Mr. A. S. Taylor, that the arsenic employed in paper-hangings was removed at the ordinary temperatures of our rooms, and that many injurious effects had resulted from the use of such paper. Although, under some circum- stances, it is possible that portions of the arsenic may escape as dust from the wall of a room, experience appears against its exerting any injurious effects. Even the men employed in burning-houses, where they are necessarily exposed to the escaping oxide, do not appear to suffer in health. The following letter, published by Mr. Alfred E. Fletcher, is much to the point : — “ The color principally referred to is the aceto-arsenite of copper, commercially known as emerald green. The chief advantage which this color possesses over other of a similar tint is that, besides having greater brilliancy, it is quite permanent. The color, when ex- posed to the air for any length of time, does not fade in tint nor lessen in intensity, which would necessarily be the case did any evaporation of its constituent parts take place, though in the smallest degree, especially as the layer of color exposed is often extremely thin. 110 ARSENIOUS ACID. ■Were it true that such evaporation or dissemination went on, it would indeed afford just cause of alarm, when we reflect that on the walls of houses in this country are displayed some hundred millions of square yards of paper, most of which carries on its surface a por- tion of arsenical coloring matter ; our books are bound with paper and cloth so colored, cottons and silks, woollen fabrics and leather, are alike loaded with it. Now, it is stated that in a medical work an instance is noted in which injury has been received by those liv- ing in rooms decorated with these colors : surely, were the proximity of such materials inju- rious, it would not be necessary to search in recondite books for the registry of isolated cases. The fact of the large extent to which such materials have alwa 5 ^s been employed is a sufficient proof that there is no danger attending their use ; moreover, workmen who have been daily employed for many years in manufacturing large quantities of these colors, under the necessity of constantly handling them, are in the regular enjoyment of perfect health, though exposed also to the general influences of a chemical factory. Let blame be laid at the right door, and let the public be assured that it is not the looking at cheerful walls, the fingering of brightly ornamented books, nor the wearing of tastefully colored clothing, that will hurt them, but the dwelling in ill-ventilated rooms.” Arsenic, Poisoning by. — This poisoning is so commonly the cause of death, by acci- dent and by design, that it is important to name an antidote which has been employed with very great success. This is the hydrated peroxide of iron. This preparation has no action on the system, and it may therefore be administered as largely and as quickly as possible. The following statement will render the action of this hydrated salt intelligible. "When hydrated peroxide of iron is mixed in a thin paste with the solution of arsenious acid, this disappears, being changed into arsenic acid, (a far less active oxide,) and the iron into protoxide 2 Fe'^O^ and AsO®, producing 4 FeO -f- A^O^ The hydrated peroxide of iron may be made in a few min- utes by adding carbonate of soda to any salt of the red oxide of iron, (permuriate, muriate, acetate, &c.) It need not be washed, as the liquor contains only a salt of soda, which would be, if not beneficial, certainly not injurious. — Kane. Detection of Arsenic in Cases of Poisoning. Arsenious acid, which is almost always the form in which the arsenic has entered the system, possesses the power of preventing the putrefaction of animal substances ; and hence the bodies of persons that have been poisoned by it do not readily putrefy. The arsenious acid combines with the fatty and albuminous tissues to form solid compounds, which are not susceptible of alteration under ordinary circumstances. It hence has fre- quently occurred that the bodies of persons poisoned by arsenic have been found, long after death, scarcely at all decomposed ; and even where the general mass of the body had com- pletely disappeared, the stomach and intestines had remained preserved by the arsenious acid which had combined with them, and by its detection the crimes committed many years before have been brought to light and punished. — Kane. The presence of arsenic may be determined by one of the following methods : — 1. Portions of the contents of the stomach or bowels being gently heated in a glass tube, open at both ends, the arsenic, if in any* quantity, will be sublimed, and collected as minute brilliant octahedrons. 2. Or by the presence of organic matter ; if the ignition is effected in a tube closed at one end, metallic arsenic sublimes, forming a steel-gray coat, and emitting a strong smell of garlic. 3. Ammonia Nitrate of Silver produces a canary-yellow precipitate from a solution of arsenious acid, {arsenite of silver.) The phosphate of soda produces a yellow preeipitate of tribasic phosphate of silver, which exactly resembles the arsenite. The phosphate is, however, the more soluble in ammonia, and when heated gives no volatile product ; while the arsenite is decomposed with white arsenic and oxygen, leaving metallic silver behind. 4. Ammonia Sulphate of Copper produces a fine apple-green precipitate, which is dis- solved in an excess of either acid or ammonia. It is, however, uncertain, unless the pre- cipitate be dried and reduced. 5. The Reduction Test. — Any portion of the suspected matter, being dried, is mixed with equal parts of cyanide of potassium and carbonate of potash, both dry. This mixture is to be introduced into a tube terminating in a bulb, to which heat is applied, when metallic arsenic sublimes. 6. Marsh's Test. — This is one of the most delicate and useful of tests for this poison, and when performed with due care there is little liability to error. The liquid contents of the stomach, or any solution obtained by boiling the contents, is freed as much as possible from animal matter by any of the well-known methods for doing so. This fluid is then ren- dered moderately acid by sulphuric acid, and introduced into a bottle properly arranged. Fig. 40 is the best form for Marsh’s apparatus ; — a is a bottle capable of holding half, or, at most, a pint. Both necks are fitted With new perforated corks, which must be per- fectly tight. Through one of these the funnel tube, 6, is passed air-tight, and through the AESENIOUS ACID. Ill other the bent tube, c, which is expanded at / into a bulb about an inch in diameter. This bulb serves to collect the particles of liquid which are thrown up from the contents of the 40 if arsenic is present, in even the smallest quantity, it combines with the hydrogen, and {gaseous arseniuretted hydrogen) escapes. If the gas as it issues from the jet is set on fire, no product but water is generated if the hydrogen is pure ; and by holding against the flame a cold white porcelain basin, or piece of glass, or of mica, no steam is produced, and a dew is formed upon the cold surface. If arsenic be present, a deposit is obtained, which, according to the part of the flame in which the substance to receive it is placed, will be either a brown stain of metallic arsenic, or a white one of arsenious acid. If the quantity of arsenic is too small to be detected in this way, it will be well to ignite the horizontal part of the tube. All the arseniuretted hydrogen will, in passing that point, become decom- posed, and deposit its arsenic. The heat will drive this forward, and a little beyond the heated portion metallic arsenic will be condensed. Several precautions are necessary to be observed ; but for the details of those we must refer to works especially directed to the consideration of this subject. One source of error must, however, be alluded to. A com- pound of antimony and hydrogen is formed under similar circumstances ; and this gas in many respects resembles the compound of arsenic and hydrogen. If the stain formed by the flame is arsenic, it will dissolve, when heated, in a drop or two of sulpho-hydride of ammonia, and a lemon-yellow spot is left ; if antimony is present, it leaves a yellow stain. — Wohler. Y. Fleitmann^s Test. — If a solution containing arsenic be mixed with a large exeess of coneentrated solution of potassa, and boiled with fragments of granulated zinc, arseniu- retted hydrogen is evolved, and may be easily reorganized by allowing it to pass on to a piece of filter paper spotted over with solution of nitrate of silver. These spots assume a purplish-black color, even when a small quantity of arsenic is present. This experiment may be performed in a small flask, furnished with a perforated cork carrying a piece of glass tube of about ^ inch diameter. It will be observed that this test serves to distinguish arsenic from antimony. The following remarks on the Toxicological Discovery of Arsenic deserve attention : — This active and easily administered poison is fortunately one of those most easily and certainly discovered ; but the processes require great precaution to prevent mistaken infer- ences : if due care is taken, arsenic can be found after any lapse of time, as well as after the most complete putrefaction of the animal remains. The longest time after which it has been discovered by myself is eight years, which was the case of an infant ; nothing but the bones of the skeleton remained, the coffin was full of earth, and large roots of a tree had grown through it. The metal was obtained from the bones, and in the earth immediately below where the stomach had existed. Many cases have occurred in my experience, where one, two, three, four, and five years have elapsed ; in one case after fourteen months, where the body of a boy had been floating in a coffin full of water. The poison is given in one of three states, white arsenious acid, yellow sulphuret (“orpiment”) or “realgar,” red sulphuret of arsenic ; and it is worthy of notice, that putrefaction will turn either white or red into yellow, but will never turn yellow into either white or red ; this is owing to the hydrosulphuret of ammonia disengaged during decomposition. Modern toxicologists have abandoned all the old processes for the detection of this poi- son, and have adopted one of two, which have been found more expeditious, as well as more certain. The first was proposed by Marsh, of Woolwich : it is founded upon the principle that nascent hydrogen will absorb and carry off any arsenic which may be pres- ent, as arseniuretted hydrogen ; but as I prefer the principle first proposed by Reinsch, and bottle, and which drop again into the latter from the end of the tube. The other end of the tube is connected, by means of a cork, with tube d, about six inches long, which is filled with fused chloride of calcium, free from powder, destined to retain the moisture. In the opposite end of the tube d is fixed, air-tight, another tube, e, made of glass free from lead, 12 inches long, and, at most, V 12 of an inch in internal diameter. It must be observed that the funnel tube h is indispensably necessary to introduce the fluid to the pieces of perfectly pure metallic zinc already placed in the bottle. Hy- drogen gas is at once formed, and 112 ARSENIOUS ACID. have always acted upon it, I shall confine my description to the processes founded upon it. The principle is this : arsenic mixed or combined with any organic matter will, if boiled with pure hydrochloric acid and metallic copper, be deposited upon the copper ; but as this depositing property is also possessed by mercury, antimony, bismuth, lead, and tellurium, subsequent operations are required to discriminate between the deposits. I take pieces of copper wire, about No. 13 size, and 2^ inches long ; these I hammer on a polished plane with a polished hammer, for half their length, {fg. 41,) and having brought the suspected .. matters to a state of dryness, and boiled the copper blade in the pure hydrochloric ^cid, to prove that it contains no metal ca- ■■-I — .11 ^ pable of depositing, I introduce a portion of the suspected matter and continue the boiling ; if the copper becomes now either steel- gray, blue, or black, I remove it, and wash it free of grease in another vessel in which there is hot diluted hydrochloric acid ; I now dry it, and, with a scraper with a fine edge, take off the deposit with some of the adhering copper, and repeat the boiling, washing, and scraping, so as to have four or five specimens on copper ; one of these is sealed up her- metically in a tube for future production. I now take a piece of glass tube, and having heated it in the middle, draw it out, as in fg. 42, dividing it at 42 A, each section being about 2 inches long, the wide orifices being A about %o of an inch in diameter, and an inch long, the capil- lary part Vs of an inch in diameter, and 1| inch long ; now, by putting one portion of the scrapings into one of the tubes at b, and holding it upwards over a very small flame, so that the vola- tile products may slowly ascend into the narrow portion of the tube, we prove the nature of the deposit : if mercury, it condenses in minute white shining globules ; if lead or bis- muth, it does not rise, but melts into a yellowish glass, which adheres to the copper ; if tellurium, it would fall as a white amorphous powder ; if antimony, it would not rise at that low temperature ; but arsenious acid condenses as minute octahedral crystals, looking with the microscope like very transparent grains of sand. I make three such sublimates, one of which is sealed up like the arsenic for future production. I now cut the capillary part of another of the tubes in pieces, and boil it in a few drops (say 10) of distilled w'ater, and when cold drop three or four drops on a plate of white porcelain, and with a glass rod drop one drop of ammoniacal sulphate of copper in it : and now to make the colors from this and the next test more conspicuous, I keep a chalk stone, planed and cleaned, in readi- ness, and placing on it a bit of clean white filtering paper, I conduct the drops of copper test upon the paper, which permits the excess of copper solution to pass through into the chalk, but retains the smallest proportion of Scheele’s green ; tho other few drops of the solution are treated the same way with the ammoniacal nitrate of silver. When I get the yellow precipitate of arsenite of silver, the papers, with these two spots, are now dried and sealed up in a tube as before, and that with the silver must be kept in the dark, or it will become black. I have still one of the tubes with the arsenical sublimate remaining ; through this I direct a stream of hydrosulphuric acid gas for a few seconds, which converts the sublimate into yellow orpiment. I have now all five tests : the metal, the acid, arsenite of copper, arsenite of silver, and yellow sulphuret; and the Viooooo of a grain of arsenic is sufficient in adroit hands to produce the whole ; but all five must be present, or there is no positive proof, for many matters will cause a darkness of the copper in the absence of arsenic, — sulphurets even from putrefaction ; — but there is no sublimate in the second operation, because the sulphur burns into sulphurous add and passes off upwards. Corn, grasses, and earth slightly darken it from some unknown cause, but produce no sublimate ; so, if the solution of suspected arsenious acid is tested with the copper test while hot, it will produce a greenish deposit of oxide of copper, through the heat dissipating a little ammonia, or if the copper blade has not been deprived of grease by the diluted hydro- chloric acid, the sublimed acid from the grease will precipitate copper from that test ; but as much of the sulphuric acid of commerce, and nearly all such hydrochloric acid and some commercial zinc contain arsenic, nothing can excuse a toxicologist who attempts to try for arsenic if he has not previously experimented with all his reagents before he introduces the suspected matters. I should also mention that this metal is to be found in all parts of the body, but longest, and in greatest quantity, in the liver, where it is frequently found many days after it has disappeared from the intestines. — W. Herapath. Arsenious acid of commerce is frequently adulterated with chalk or plaster of Paris. These impurities are very easily detected, and their proportions estimated. Arsenious acid is entirely volatilized by heat, consequently it is sufficient to expose a weighed quantity of the substance to a temperature of about 400° F. in a capsule or crucible. The whole of the arsenic will pass off in fumes, while the impurities will be left behind as a fixed residuum, which can, upon cooling, be weighed. It is scarcely necessary to state that, the fumes of arsenic being very poisonous, the volatilization should be carried on under a chimney having a good draught. AETESIAN WELLS. 113 Our Imports of Arsenic were as follows : — 1855 - - - - 'ZS cwts. 1856 - 163 “ ARTESIAN WELLS. The most remarkable example of an Artesian well is that at the abattoir of Grenelle, a suburb of the southwest of Paris, where there was a great want of water. It cost eight years of difficult labor to perforate. The geological strata round the French capital are all of the tertiary class, and constitute a basin similar, in most re- spects, to that upon which London stands. The surface at Grenelle consists of gravel, pebbles, and fragments of rocks, which have been deposited by the waters at some period anterior to any historical record. Below this layer of detritus, it was known to the engi- neer that marl and clay would be found. Underneath the marl and the clay, the boring rods had to perforate pure gravel, plastic clay, and finally chalk. No calculation from geo- logical data could determine the thickness of this stratum of chalk, which, from its powers of resistance, might present an almost insuperable obstacle. The experience acquired in boring the wells of Elbeuf, Rouen, and Tours, was in this respect but a very imperfect guide. But, supposing this obstacle to be overcome, was the engineer sure of finding a supply of water below this mass of chalk ? In the first place, the strata below the chalk possessed all the necessary conditions for producing Artesian springs, namely, successive layers of clay and gravel, or of pervious and impervious beds. M. Mulot, however, relied on his former experience of the borings of the wells at Rouen, Elbeuf, and Tours, where abundant supplies of water had been found below the chalk, between similar strata of clay and gravel, and he was not disappointed. The strata traversed in forming this celebrated well were as follows : — Drift-sand and gravel, 83 feet. Lower tertiary strata, 115“ Chalk vVith flints, Ditto, lower, 246 f Calcareous sandstone, clays, and sands ending in a bed of green- colored sand, 256“ 1,798 “ The surface of the ground at the well is 102 feet above the level of the sea, and the water is capable of being carried above this to a height of 120 feet. The French geologists consider that the sands from which the supply is obtained are either subordinate beds of the gault^ or as belonging to the lower greensand. They crop out in a zone of country about 100 miles eastward of Paris, and range along the segment of a circle, of which Paris is the centre, from between Sancerre and Auxerre, passing near to Troyes, thence by St. Dizier to St. Menehould. The outcrop of this formation is con- tinued some distance further north ; it is also prolonged beyond Sancerre, southwestward towards Bourges, Chatellerault, and then northwest to Saumur, Le Mans, and Alengon. But the superficial area which it occupies in these latter districts does not appear to contribute to the water supply of Paris, for the axis of elevation of Mellerault must intercept the sub- terranean passage of the water from the district south of that line, whilst, on the north of Paris, the anticlinal line of the “ Pays de Bray,” and some smaller faults in the Aisne, pro- duce probably a similar stoppage with respect to the northern districts. The superficial area, therefore, from which the strata at the well of Grenelle draw their supplies of water, forms on the east of Paris a belt stretching from near Auxerre to St. Menehould. The exposed surface of the water-bearing beds which supply the well of Grenelle is about 117 square miles; the subterranean area in connection with these lines of outcrop may possibly be about 20,000 square miles, and the average thickness of the sands of the gres verts., serving in their underground range as a reservoir for the water, does not proba- bly exceed 30 or 40 feet. — Prestwick on the Water-hearing Strata of London. As the cost of these wells is an important consideration, the following statement from the “ Water-bearing Strata of London ” is of much value : — “ M. Degoussee has recently informed me of his having contracted to bore an Artesian well at Rouen to the depth of 1,080 feet, (through the lower cretaceous and oolitic series,) for £1,600, expenses of every kind to be defrayed by him. M. Degoussee has constructed three Artesian wells in different parts of France, of about 820 to 830 feet each, at an ex- pense, including tubes and all expenses, of from £600 to £1,000. The Calais well offers a very near counterpart of the deposits which occur beneath London, but the difficulties of the first 240 feet much exceeded those which would be met with here, and the chalk is probably 100 to 200 feet thicker. Here and at Paris the first 1,000 feet cost less than £3,000, and at Doncherry apparently not much more than £2,000.” The following Table shows the cost of several of the Artesian wells of France : — VoL. IIL— 8 ARTILLERY. 114 Crenelle, Dept. Seine, 1,798 feet - - £14,500 Calais, u Pas de Calais, - 1,138 44 3,560 Donchery, “ Ardennes, 1,215 44 3,045 St. Fargeau, “ Yonne, - 666 44 1,216 Lille, u Nord, 592 44 320 Crosne, (( Seine and Oise, 333 44 190 Brou, u Marne, 246 44 200 Ardres, (( Nord, 155 44 64 Claye, t( Seine and Marne, 108 44 78 Chaville, u Oise, 65 44 15 It appears that, in England, the cost of boring is about 5s. for the first 10 feet, £2 10s. for forty feet, £5 5s. for 60 feet, £13 15s. for 100 feet, and so on in proportion. (See Sir Charles Lyell’s “ Principles of Geology,” where the geological question is fully treated.) ARTILLERY. One of the first inquiries of importance in connection with the con- struction of pieces of artillery is that of the liability to fracture in the metal. Upon this point the researches of Mr. Mallet furnish much important matter. He tells us, as the result of his investigation, that it is a law of the molecular aggregation of crystalline solids, that when their particles consolidate under the influence of heat in motion, their crystals arrange and group themselves with their principal axes in lines perpendicular to the cooling or heating surfaces of the solid: that is, in the lines of the direction of the heat-wave in motion, which is the direction of least pressure within the mass. And this is true, whether in the case of heat passing from a previously fused solid in the act of cool- ing and crystallizing in consolidation, or of a solid not having a crystalline structure, but capable of assuming one upon its temperature being sufiiciently raised, by heat applied to its external surfaces, and so passing into it. Cast-iron is one of those crystallizing bodies which, in consolidating, obeys, more or less perfectly according to conditions, the above law. In castings of iron the planes of crystallization group themselves perpendicularly to the surfaces of external contour. Mr.. Mallet, after examining the experiments of Mr. Fairbairn — who states (“ Trans. Brit. Ass.,” 1853) that the grain of the metal and the physical qualities of the casting improve by some function of the number of meltings ; and he fixes on the thirteenth melting as that of greatest strength — shows that the size of crystals, or coarseness of grain in castings of iron, depends, for any given “ make ” of iron and given mass of casting, upon the hi<^ tempera- ture of the fluid iron above that just necessary to its fusion, which influences the time that the molten mass takes to cool down and assume the solid state. The very lowest temperature at which iron remains liquid enough fully to fill every cav- ity of the mould without risk of defect is that at which a large casting, such as a heavy gun, ought to be “ poured.” Since the cooling of any mass depends upon the thickness of the casting, it is important that sudden changes of form or of dimensions in the parts of cast- iron guns should be avoided. In the sea and land service 13-inch mortars, where, at the chamber, the thickness of metal suddenly approaches twice that of the chase, is a malcon- struction full of evils. The following statements of experiments made to determine the effect produced on the quality of the iron in guns, by slow or rapid cooling of the casting, are from the report of Major W. Wade, of the South Boston Foundry, to Colonel George Bomford, of the Ord- nance Department of the United States. Three six-pounder cannon were cast at the same time from the same melting of iron. The moulds were similar, and prepared in the usual manner. That in which No. 1 was cast was heated before casting, and kept heated after- wards by a fire which surrounded it, so that the flask and mould were nearly red-hot at the time of casting ; and it was kept up for three days. Nos. 2 and 3 were cast and cooled in the usual way. At the end of the fourth day, the gun No. 1 and flask were withdrawn from the heating cylinder while all parts were yet hot. Nos. 1 and 2 were bored for 6-pounders in the usual way ; No. 3 for a 12-pounder howitzer, with a 6-pounder chamber. The firing of the guns was in every respect the same. Nos. 1 and 2 were fired the same number of times with similar charges. No. 1 burst at the 27th fire, and No. 2 at the 25th. It appears, from these results, that no material effect is produced on the quality of the iron by these differ- ent modes of cooling the castings. A very extensive series of experiments were made by the order of the United States Government, on the strength of guns cast solid or hollow. In these it was confirmed that the guns cast hollow endured a much more severe strain than those cast solid. Consider- able differences were also observed, whether the casting was cooled from within or without ; and Lieutenant Rodman’s method of cooling from the interior is regarded as tending to prevent injurious strains in cooling. Major Wade informs us that time and repose have a surprising effect in removing strains caused by the unequal coolings of iron castings. Great improvements have been made in improving the quality of iron guns. Guns cast ARTILLERY. 115 prior to 1841 had a density of Y-US, with a tenacity of 23,638. Guns cast in 1851 had a density of V'289, with a tenacity of 37,774. The following Table gives the results of all the trials made for the United States Gov- ernment, showing the various qualities of different metals : — Torsion, Com- Metals. Density. Tenacity. Transverse Strength. At Half Degree. Ultimate. pressive Strength. Hardness. Cast-iron : — 4-57 Least - 6-900 9,000 5,000 3,861 5,605 84,592 Greatest 7-400 45,970 11,500 7,812 10,467 174,120 33-51 Wrought iron : — 3,197 10-45 Least - 7-704 38,027 6,500 - 40,000 Greatest 7-858 74,592 - 4,298 7,700 127,720 12-14 Bronze : — 4-57 Least - 7-978 17,698 - 2,021 5,511 - Greatest 8-953 56,786 - - - - 6-94 Cast-steel : — Least - 7-729 - - - - 198,944 Greatest 7-862 128,000 23,000 “ ■ ■ 391,985 The following analyses of the metal of iron guns of three qualities are important. Influence of Single Ingredients. Classes. Mechanical Tests. Chemical Constituents. Specific Gravity. Tensile Strength. Combined Carbon. Graphite. Silicium. Slag. Phos- phorus. Sulphur. Earthy Metals. 1 7-204 28,865 -0977 -0507 -0417 -0215 .0239 -0017 -0117 2 7-140 24,767 -0819 -0576 -0538 -0200 -0300 -0021 -0094 3 7-088 20,176 -0726 -0560 -0531 -0219 -0321 -0021 -0144 Influence of two or more Ingredients. Classes. Mechanical Tests. Chemical Constituents. Specific Gravity. Tensile Strength. Silicium and Carbon. Silicium and Slag. Graphite and Slag. Graphite, Silicium, and Slag. Graphite, Slag, Sili- cium, and Phosphorus. Total Carbon. 1 7-204 28,865 -1394 -0632 -0722 •1139 •1378 •1484 2 7-140 24,767 -1357 •0738 •0776 •1314 •1614 •1395 3 7-088 20,176 -1257 -0750 80 •1311 •1632 •1286 An inspection of the first of the foregoing tables, representing the average amount of each foreign ingredient in gun-metal deduced from all the analyses, shows a considerable difference in the proportions of those ingredients in each of the three classes into which guns are divided. It will be observed, that while the proportion of combined carbon diminishes from the 1st to the 3d class, that of silicium similarly increases, so that their united amounts are nearly the same. In other words, it appears that silicium can replace the carbon to a certain extent ; but that the quality of the metal is injured where the amount of the silicium approaches that of the carbon. KarvSten made a similar observation in determining the limits between cast-iron and steel, but did not notice the influence of that substitution. But the differences become more striking by combining the ingredients variously to- gether, as in the second of those tables ; and especially by comparing the extremes, which are each derived from a larger number of observations than the mean. After showing the total amount of carbon, (both combined and uncombined,) silicium and combined carbon are thrown together, w’hich indicates the replacement by silicium of that portion of carbon set free in the form of graphite. The column “ silicium and slag ” shows the general depreciation of the metal as the silicious metal increases. — From the Report of Campbell Morflt and James C. Booth to the Ordnance Office, United States Army. 116 AETILLERY. The following analyses, (rejecting those substances of which only a mere trace has been discovered,) from the same chemists, are selected as showing striking peculiarities : — Class . d o Graphitic Carbon. Combined Carbon. Silicium. So Phosphorus. i i bs g 53 Magnesium, Calcium. Aluminium. Sodium and Potassium. 1. 32-pdr., which endured 1 the extreme proof •93520 •02000 •02200 •00776 •00250 •00036 •02100 . - •00028 •C0106 2. 32-pdr., which endured the extreme proof. Hot blast iron - •88480 •02800 •00200 •02000 •00400 •00666 •05212 •00072 •00043 . •00034 24-pdr.,which endured the extreme proof. Hot blast iron - •92400 •03000 •01200 •01790 •00200 •00626 •02244 •00080 •00028 •00234 3. 42-pounder 92155 •03200 •00700 •01130 •00100 •00800 •01448 •00074 •00086 ! -00316 •00220 82-pounder •92540 •02800 •00150 •00730 ■00200 •00738 •02317 •00061 •00057 ! -00170 32-pounder •93450 •02900 •00900 •00900 •00200 •01290 •01810 i ? •00158 •00026 Comparison of Weighty Strength, Extensibility, and Stiffness ; Cast-iron being unity within practical limits to static forces only. Material. Weight for = Volume. Strength. Extensibility. Stiffness. Torsion. Cast-iron - 1-00 1-00 100 1-00 1-00 Gun-metal 1-18 0-65 1-27 0*63 0-55 Wrought iron - 1-07 3-00 0-45 2-20 1*11 Steel 1-07 4-75 0*32 3-16 2-11 We find that wrought-iron guns are more than five-fold as durable as those of gun- metal, and twenty-two times as durable as those of cast-iron. And taking first cost and durability together, gun-metal cannon are about seventy-seven times, and cast-iron guns about thirty times, as dear as wrought-iron artillery. Again : the cost of horse-labor, or other means of transport for equal strength, (and, of course, therefore, for equal effective artillery power,) is about five times as great for gun-metal, and nearly three times as great for cast-iron as for wrought-iron guns. In every respect in which we have submitted them to a comparison, searching and rigid, and that seems to have omitted no important point of inquiry, wrought iron stands pre-eminently superior to every other material for the fabrica- tion of ordnance. — United States Report. The advantages possessed by rolled bars for the construction of artillery are thus summed up by Mr. Mallet, in his “ Memoir on Artillery ” : — 1. The iron constituting the integrant parts is all in moderate-sized, straight, prismatic pieces, formed of rolled bars only ; hence, with its fibre all longitudinal, perfectly uniform, and its extensibility the greatest possible, and in the same direction in which it is to b^ strained — it is, therefore, a better material than any forged iron can, by possibility, be made. 2. The limitation of manufacture of the iron, thus, to rolling, and the dispensing with all massive forgings, insure absolute soundness and uniformity of properties in the material. 3. The limited size of each integrant part, and the mode of preparation and combina- tion, afford unavoidable tests of soundness and of perfect workmanship, step by step, for every portion of the whole : unknown or wilfully concealed defects are impossible. 4. Facility of execution by ordinary tools, and under easily obtained conditions, and without the necessity of either for peculiarly skilled labor on the part of “ heavy forge- men,” or for steam and other hammers, &c., of unusual power, and very doubtful utility ; and hence very considerable reduction in cost as compared with wrought-iron artillery forged in mass. 5. Facility of transport by reduction of weight, as compared with solid guns of the same or of any other known material. 6. A better material than massive forged iron, rolled bars are much more scientifically and advantageously applied ; the same section of iron doing much more resisting work, as applied in the gun built-up in compressed and extended plies, than in any solid gun. 7. The introduction thus into cannon of a principle of elasticity, or rather of elastic range, (as in a carriage-spring divided into a number of superimposed leaves,) greater than that due to the modulus of elasticity of the material itself ; and so acting, by distribution of the maximum effort of the explosion, upon the rings successively recipient of the strain during the time of the ball’s traject through the chase, as materidly to relieve its effects upon the gun. ARTILLERY. 117 Considerable attention has been given, of late years, to the construction of very power- ful pieces of ordnance. Cast-iron cannon are usually employed, but these very soon be- come useless when exposed to the sudden shocks of rapid firing. Cast-iron is, compara- tively speaking, a weak substance for resisting extension, or for withstanding the explosive energy of gunpowder, compared with that of wrought-iron, the proportion being as 1 is to 5 ; consequently, many attempts have been made to substitute wrought-iron cannon for cast. A gun, exhibited in 1861 by the Belgian Government, made of cast-iron ‘‘''prepared with coke and wood,'" was said to have stood 2,116 rounds, and another, 3,647 rounds, with- out much injury to the touch hole or vent. Another is said to have been twice “ rebouched,” and has stood 6,002 rounds without injury. As few guns of cast-iron will stand more than 800 rounds without becoming unserviceable, this mode of preparing the iron appears to be a great improvement. At St. Sebastian, 2,700 rounds were fired from the English bat- teries, but, as was observed by an eye-witness, “ you could put your fist into the touch- holes.” — Colonel James, R. E. In Prussia they have for some time made cannon of “ forged cast-steel.” To get over the difficulty of forging the gun with the trunnions on, the gun has been made without them, and a hollow casting with trunnions afterwards slipped over the breech, and secured in its proper position by screening in the cascable. The tenacity of this metal must be very great. Casting op Guns. — Guns have long been cast in a vertical position, and with a certain amount of “ head of metal ” above the topmost part of the gun itself. One object gained by this (of great value) is to afford a gathering-place for all scoria, or other foreign matter ; an end that i»ight be much more effectually accomplished were the metal always run into the cavity of the mould by “ gaits ” leading to the bottom, or lowest point, in place of the metal being thrown in at the top, with a fall, at first, of several feet, as is now the common practice, by which much air and scoria are carried down and mixed with the metal, some of which never rises up again, or escapes as “ air-bubbles.” (See “ Mallet on the Physical Conditions involved in the Construction of Artillery.” Table showing the Increase of Density in Castings of large Size, due to their Solidification under a Head of Metal, varying from two to fourteen Feet : — No. of Experiment. Calder Cast-iron, Hot Blast. No. 1. Blaenavon, No. 1. Cold Blast. Apedale, No. 2. Hot Blast. Quam prox. Pressure ■when fluid in lbs. per square inch. Depth of Cast- ing in Inches. Specific Gravity. First Difference. Depth of Cast- ing in Inches. Specific 1 Gravity. First Difference. Depth of Cast- ing in Inches. Specific Gravity. First Difference. 1 0 6*9551 0 7-0479 0 7-0328 •0 2 24 6*9633 •0082 24 7-0576 •0097 24 7-0417 •0089 6-4 . 3 48 7*0145 *0512 . 48 7-0777 •0201 48 7-0558 •0141 12-8 4 72 7*0506 *0361 72 7-0890 •0113 72 7-0669 •0111 19-2 6 96 7*0642 •0136 96 7-1012 •0122 96 7-0789 •0120 25*6 6 120 7*0776 •0134 120 7-1148 •0136 120 7-0915 •0126 32-0 7 144 7*0907 •0131 144 7*1288 •0140 144 7-1046 •0131 38*4 8 168 7*1035 •0128 168 7-1430 •0142 168 7-1183 •0137 44-8 The experiments were made upon cylindrical shafts of cast-iron, cast vertically in dry sand-mould, under heads gradually increasing up to fourteen feet in depth, and all poured from “ gaits ” at the bottom. These experiments show an increase of density due to fourteen feet head, about equal to a pressure of ^'4-8 lbs. per square inch on the casting ; from 6*9551 to 7*1035 for Scotch cast-iron. In the foregoing paper frequent referenee has been made to the investigations of Mr. Mallet. His monster mortar promises such results that an especial account of it appears to be required. About the latter end of 1854, the attention of Mr. Robert Mallet, C. E., was directed to the mathematical consideration of the relative powers of shells in proportion to their in- crease of size or of diameter. His inquiries resulted in a memoir presented by him to Government, in which he investigated the increase of power in shells with increase of diam- eter, under the heads of : — 1, Their penetrative power ; 2, Their increased range and greater accuracy of fire ; 3, Their explosive power ; 4, Their power of demolition, or of levelling earthworks, buildings, &c. ; 6, Their fragmentary missile power ; 6, and lastly, their moral effect, — in every case viewing the shell, not as a weapon against troops, but as n 118 ARTILLERY. an instrament of destruction to an enemy’s works. The result so convinced Mr. Mallet of the rapid rate at which the destructive powers of a shell increase with increase of size, that he was induced to propose to Government the employment of shells of a magnitude never before imagined by any one, namely, of a yard in diameter, and weighing, when in flight, about a ton and a quarter each ; and to prepare designs, in several respects novel and pecu- liar, for the construction of mortars capable of projecting these enormous globes. Such a mortar was made, and on the 19th of October, 1857, the first of those colossal mortars con- structed from Mr. Mallet’s design was fired on Woolwich Marshes, with charges (of projec- tion) gradually increasing up to 70 lbs. ; and Avith the latter charge a shell weighing 2,550 lbs. was thrown a horizontal range of upwards of a mile and a half to a height of probably three-quarters of a mile, and falling, penetrated the compact and then hard dry earth of the Woolwich range to a depth of more than 18 feet, throwing about cart-loads of earth and stones by the mere splash of the fall of the empty shell. What would have been the crater blown out, if the bursting charge of 400 lbs. of powder had been within ! It would be out of place here to attempt to follow Mr. Mallet’s mathematical results as to the relative powers of small and large shells ; some popular notion, however, of the sub- ject may be given in a few words. Say we have a 13-inch shell and a 36-inch shell, and, for simplicity, that each has the same proportion of iron and powder in relation to their bulks, or the same density. Roughly, the large shell may be said to be three times the diameter of the small one. Then, a ring or circle through which the larger one will just pass will have nine times the area of that through which the smaller one will just pass, and the weight of the large shell will be 27 times that of the small one. If the two shells, then, be thrown at the same angle of elevation and at the same ve- locity, the larger shell will range greatly further th^an the small one, for their relative resistances in the air are about as 1 to 9, while their relative energy of motion or momen- tum is as 1 to 27. A 13-inch shell, weighing about 180 lbs., is thrown, by a charge of 30 lbs. of powder, barely 4,700 yards. While, with not much more than double this amount of powder, the 36-inch shell, of more than 14 times its weight, can be thrown 2,660 yards, or much more than half the distance. The explosive power, it is obvious, is approximately proportionate to the weight of pow- der ; but, by calculations, of which the result only can here be given, Mr. Mallet has shown that the total power of demolition — that is to say, the absolute amount of damage done in throwing down buildings, walls, &c., &c. — by one 36-inch shell, is 1,600 times that possible to be done by one 13-inch shell ; and that an object which a 13-inch shell could just over- turn at one yard from its centre, will be overthrown by the 36-inch shell at 40 yards’ distance. A 13-inch shell penetrates, on falling upon compact earth, about feet. The Antwerp shell penetrated 7 feet. The 36-inch shell penetrated 16 to 18 feet. The funnel-shaped cavity, or “ crater,” of earth blown out by the explosion of a buried shell, is always a simi- lar figure, called a “ paraboloid its diameter at the surface, produced by the 13-inch shell, is about 7 feet, and by the 36-inch shell about 40 feet. Shells. — The hollow explosive projectiles that we call shells or bombs are a very old invention. Under the name of “ coininges,” they consisted of rudely formed globes of plate iron soldered together, filled with gunpowder and .all sorts of miscellaneous “ mitraille.” These were thrown to short distances both from “ pierriers ” (a sort of mortar) and from catapult®, as early as 1495 at Naples, 1590 at Padua, 1520 at Heilsberg, 1522 at Rhodes, and 1642 at Boulogne, Lieges. About the middle of the 16th century, bombs of cast-iron seem to have come into use ; an Englishman, named Malthus, learned the art of throwing them from the Dutch, and perfected the system for the French armies — being the first to throw shells in France, at the siege of La Mothe, in 1643. The diameter of the bomb seems at that time to have become fixed at 13 inches — the old Paris foot ; and at this it remains (with very few exceptional cases) down to the present day. A few attempts to increase the size and power of these projectiles have been made at different periods, but never with the practical skill necessary to success ; for example, 18- inch shells were thrown by the French, at the siege of Tournay, in 1745 ; whereas, just a century before, the Swedes threw shells of 462 lbs. weight, and holding 40 lbs. of powder. The French, when they occupied Algiers in 1830, found numbers of old shells of nearly 900 lbs. in weight ; and in almost every arsenal and fortress in Europe ofie or two old 16-inch and 18-inch shells are to be found. No attempt was made in modern days to realize the vast accession of power that such large shells confer, until the year 1832, when the “ mon- ster mortar,” as it was then called, of 24 inches’ calibre, designed by Colonel Paixhans, (the author of the Paixhans gun,) was constructed by order of Baron Evain, the Belgian minis- ter of war, and attempted to be used by the French at the siege of the citadel at Antwerp, but with the worst possible success. The mortar, a crude cylindrical mass of cast-iron, sunk in a bed of timber weighing about 8 tons, and provided neither with adequate means ARTILLERY. 119 for “ laying” it, nor for charging it — the heavy shells weighing, when filled with 99 lbs. of powder, 1,015 lbs. each — could with difficulty be fired three rounds in two hours, while the shells themselves were very badly proportioned. One of these shells fell nearly close to the powder magazine, but did not explode ; had it fallen upon the presumed bomb-proof arch of the magazine, containing 300,000 lbs. of powder, it would have pierced it, according to the opinion of all the military engineers present at the siege ; and so closed the enterprise at a blow. The ill success of this mortar prevented for several years any attempt to develop bombs into their legitimate office — as the means of suddenly transferring mines into the body of fortified places — of a power adequate to act with decisive effect upon their works ; although some years afterwards a 20- inch mortar was made in England for the Pacha of Egypt, and proved at Woolwich. But another circumstance still more tended to the neglect of large shells thrown by ver- tical fire. After repeated trials and many failures, it was found practicable to throw 10- inch (and since that even 13-inch) shells from cannon, or “ shell-guns,” by projecting them nearly horizontally, or at such low angles that they should “ ricochet” and roll along the ground before they burst ; and, thus fired, it was soon seen that their destructive power as against troops was greater than if fired at angles approaching 45° of elevation from mor- tars. Paixhans and his school had pushed a good and useful invention beyond its proper limits, and had lost sight wholly of the all-important fact, that horizontal shell-fire, powerful as it is against troops or shipping, is all but useless ks an instrument of destruction to the works (the earthwork and masonry, &c.) of fortified places ; for this end, weight and the penetrative power due to the velocity of descent in falling from a great height are indis- pensable. No bomb-proof arch (so called) now exists in Europe capable of resisting the tremen- dous fall of such masses, and the terrible powers of their explosion when 480 lbs. of pow- der, fired to the very best advantage, put in motion the fragments of more than a ton of iron. No precautions are possible in a fortress ; no splinter-proof, no ordinary vaulting, perhaps no casemate, exists capable of resisting their fall and explosion. Such a shell would sink the largest ship or floating battery. A single 36-inch shell in flight costs £25, and a single 13-inch £2 2s., yet the former is the cheaper projectile ; for, according to Mr. Mallet’s calculations, to transfer to the point of effect the same weight of bursting powder, we must give — 55 shells of 13 inches, at £2 2s. - - - - - - £115 10 0 Against 1 shell of 36 inches 25 00 Showing a saving in favor of the large shell of - - £90 10 0 And this assumes that 55 small shells, or any number of them, could do the work of the single great one. We must briefly notice the mortars from which these projectiles are proposed to be shot, and of which fig. 46 gives an elevation, with section of bore and chambers and lines of separation in dotted lines. 46 ASBESTUS. 120 These mortars are, with the exception of one part, (the base,) and the elm timber ends, formed wholly of wrought iron, in concentric rings, and each entire mortar is separable at pleasure into thirteen separate pieces, the heaviest of which weighs about 11 tons, so that the immense weight when all put together (about 62 tons) is susceptible of easy transport, on ordinary artillery carriages, over rough country, or can be conveniently shipped, stowed, or landed. Special mortar rafts for the use of these mortars at sea have been designed by their inventor, and novel and more precise methods of pointing, especially at night, than hitherto practised. It has been for some time the practice in Turkey to make field-pieces like the twisted barrel of a rifle. One of the greatest improvements in modern artillery is the manufacture, by Mr. G. W. Armstrong, of Newcastle-on-Tyne, of field-pieces of this character, which are breech-loading, and have several peculiarities which give them decided advantages over any other piece of artillery. For a further description, see Kifles. Exportatio7i of arms and ammunition : — 1852. 1853. 1854. 1855. 1856. Guns - - - No. 181,121 238,'76Y 226,952 181, 740 219,636 Gunpowder - - lbs. 7,140,133 9,410,891 8,715,213 8,576,430 10,600,018 Foreign and Colomal. 1856. Gun stocks in the rough of wood cwts. 235 ASBESTUS, from unconsnmable. {Asbesfe, Fr. ; Asbeat, Germ.) When the fibres of the fibrous varieties of amphibole are so slender as to be flexible, it is called asbes- tos, or amianthus. It is found in Piedmont, Savoy, Salzburg, the Tyrol, Dauphine, Hun- gary, Silesia ; also in Corsica so abundantly as to have been made use of by Dolomieu for packing minerals ; in the United States, St. Kevern in Cornwall, in Aberdeenshire, in some of the islands north of Scotland, and Greenland. Asbestos was manufactured into cloth by the ancients, who were well acquainted with its incombustibility. This cloth was used for napkins, which could be cleansed by throwing them into the tire ; it was also used as the wick for lamps in the ancient temples ; and it is now used for the same purpose by the na- tives of Greenland. It has been proposed to make paper of this fibrous substance, for the preservation of important matters. An Italian, Chevalier Aldini, constructed pieces of dress which are incombustible. Those for the body, arms, and legs, were formed out of strong cloth steeped in a solution of alum ; while those for the head, hands, and feet, were made of cloth of asbestus. A piece of ancient asbestus cloth, preserved in the Vatican, appears to have been formed by mixing asbestus with other fibrous substances ; but M. Aldini has executed a piece of nearly the same size, which is superior to it, as it contains no foreign substance. The fibres were prevented from breaking by the action of steam. The cloth is made loose in its fabric, and the threads are about the fiftieth of an inch in diameter. The Society of Encouragement, of Paris, has proposed a prize for the improve- ment of asbestus cloth. The use of it is now (1858) being exhibited in London. ASHES. In commerce, the word ashes is applied to the ashes of vegetable substances from which the alkalies are obtained, as Kelp, Barilla, &c., {which see.) It is the popular name of the vegetable alkali, potash, in an impure state, as procured from the ashes of plants by lixiviation and evaporation. The plants which yield the great- est quantity of potash are wormwood -and furmitory. See Potash, Pearlash, and for the mode of determining the value of ashes. Alkalimetry. Our Importations of the various kinds of Ashes were — 1855. Soap ashes, cwts. 268 Wood ashes, “ 26 Weed ashes, “ - - Unenumerated ditto, value £5,302 and of pearl and pot ashes as follows : — 1856. cwts. 1,073 {vedasse^ Fr. ; waidasche^ Germ.) “ 380 £7,131 ; Countries from which imported. 1853. 1854. 1855. 1 1856. Cwts. Cwts. Cwts. Cwts. Russia ------ Holland 87,604 6,881 906 • 3,671 Tuscany - - - - - 1,854 3,604 - 2,224 87,246 British North America - - - 98,774 86,080 71,344 United States - 10,398 18,334 6,473 11,673 Prize cargoes - - - 109 Other parts 228 867 207 1,127 155,739 109,791 78,133 105,941 ASPHALTUM. 121 ASHES OF PLANTS. The ashes of all species of woods and weeds are found to con- tain some alkali, hence it is that the residuary matter, after the combustion of any vege- table matter, is found to act as a stimulant to vegetable growth. The following analyses of the ashes of plants have been selected from the tables which have been published, by Messrs. Thomas Way and G. Ogston, in the “ Journal of the Agri- cultural Society”: — Peas. Beans. Red Clover. Sain- foin. Wheat Grain. j straw. j Barley. Oats. Turnip Root. Turnip Leaves. Beet Root. Carrot Root. Potassa 42-43 30-72 18-44 31-90 29-76 10-51 1 20-07 17-70 23-70 11-56 21-68 37-55 Soda - - - 3-27 0-14 2-79 . . 5-26 1-03 4-56 3-84 14-75 12-43 313 12-63 Lime 5-73 12-00 35-02 24-30 2-88 5-91 1-48 8-54 11-82 28-49 1-90 9-76 Magnesia - 5-92 0-00 11-91 5-03 11-06 1-25 7-45 7-33 3-28 2-62 1-79 3 78 Sesqiiioxide of iron 0-44 0-05 0-98 0-01 0-23 0-07 0-51 0 49 0-47 3-02 0-52 6-74 Sulphuric acid - 6-23 4-23 8-91 3-28 0-11 214 0-79 ’1-10 16-13 10-36 3-14 6-34 Silica 1-74 1-52 4-03 3-22 2-23 73 57 32-73 38-43 2-69 8-04 1-40 0-76 Carbonic acid - 4-38 1-03 12-92 15-20 0-22 10-47 6-18 15-23 15-15 Phosphoric acid Chloride of potas- 29-92 33-74 5-82 9-35 48-21 5-51 31-69 26-46 9-31 ^4-85 1-65 8-37 sium 0-24 0-92 Chloride of sodium - - 3-20 4-13 0-78 7-05 12-41 49-51 4-91 Total amount - Percentage of ash 99-90 100-00 99-95 99-90 99-96 99-99 99-98 99-96 99-93 99-96 99 96 99-99 in the dry sub- stance - 2 -00 2-90 7-87 0-37 2-05 - . 2-50 2-50 6.00 16-40 11-32 512 Percentage of ash in the fresh sub- stance - 2-24 2-54 6-77 5-65 1-Sl - - 2-25 2-27 0-75 1-97 1-02 0-77 ASPHALTIC MASTIC, used in Paris for large works, is brought down the Rhone from Pyrimont, near Lyssell. It is composed of nearly pure carbonate of lime, and about 9 or 10 per cent, of bitumen. When in a state of powder it is mixed with about 7 per cent, of bitumen or mineral pitch, found near the same spot. The powdered asphalt is mixed with the bitumen in a melted state along with clean gravel, and consistency is given to pour it into moulds. Sul- phur added to about 1 per cent, makes it very brittle. The asphalt is ductile, and has elas- ticity to enable it, with the small stones sifted upon it, to resist ordinary wear. Walls having cracked, and parts having fallen, the asphalte has been seen to stretch and not crack. It has been regarded as a sort of mineral leather. The sun and rain do not appear to affect it ; and it answers for abattoirs and barracks, keeps vermin down, and is uninjured by the kicking of horses. A large roof has been formed in Paris for a store for the Government food, entirely of earthenware tiles, and without timber, the tiles being 9 inches long and 5 wide. The arch is covered with a concrete of lime, sand, and gravel ; then with a thin coat of hydraulic mortar ; over this, when dry, canvas was tightly stretched ; asphaltic mastic was poured in a semi-fluid state, and this formed the finished surface of the roof. The strength of the roof has been purposely tested to bear six tons without yielding, and has borne the acci- dental fall of a stack of chimneys, with the only effect of bruising the mastic, readily repaired. ASPHALTUM. {Bitume or Asphalte^ Fr. ; Asphalt Germ.) Mineral Pitch ; so called from the lake Asphaltites ; a variety of bitumen, arising from one of the many pcv.a- liar changes of vegetable matter. Asphaltum, in common with other varieties of bitumen, is a form of hydrocarbon produced in the interior of the earth by the transformation of carbonaceous matter, like all combustible bodies of the same class. Composition, C®H^ It is a solid black or brownish-black substance, possessing a bright conchoidal fracture. It fuses at 212° F., burning with a brilliant flame, and emitting a bituminous odor. Specific gra*rity = 1 to 1’2. Asphaltum is insoluble in alcohol, but soluble in about five times its weight of naphtha. See Bitumen. This solid shining bitumen, of a deep black color when broken, is found in many parts of Egypt. A thin piece appears of a reddish color when held to the light ; when cold, it has no odor ; by a moderate heat or by friction, the odor is slight ; fully heated, it lique- fies, swells, and burns with a thick smoke ; the odor given is acrid, strong’, and dis- agreeable. Spirits of wine dissolves pitch, but only takes a pale color with asphaltum. It is readily procured at Mocha. In the arts, asphaltum is used as a component of japan varnish. It is likewise em- pioy^d as a cement for lining cisterns, and for pavements, as a substitute for flag-stones. — The following quantities of Asphaltum, or Bitumen Judaicum^ were imported into Great Britain: — in 1855, 1,674 tons; in 1856, 2,707 tons, of which 2,573 tons were from France. . 122 ASSAY AND ASSAYING. ASSAY and ASSAYING. The process employed in assaying gold bullion, by the pres- ent assayers to the Mint and Bank of England, is similar to that practised at the Paris Mint. The quantity operated on is half a gramme. This quantity, having been accurately weighed, is wrapped in paper with a portion of pure silver, about equal to three times that of the gold the alloy is supposed to contain, and submitted to cupellation with lead in the manner described in vol. i. The button is then hammered into a flattened dish, about the size of a sixpence, and afterwards annealed and passed through laminating rolls until it is reduced to a riband from 2^ to 3 inches in length ; after which it is again annealed, and coiled into a spiral by rolling between the Anger and thumb. The cornet is next placed in a small flask containing about an ounce of pure nitric acid of 22 B., (= 1’180 speciflc gravity,) and boiled for 10 minutes. The acid is carefully poured off, and the cornet again boiled with nitric acid of 32 B. (1-280 specific gravity) for 20 minutes; and this second boiling with the stronger acid is repeated and continued about 10 minutes. In the second and third boilings a small piece of charcoal should be introduced into the flask, as recommended by Gay-Lussac, in order to prevent the ebullition taking place irregularly and with sudden bursts, which would be liable to break the cornet, and eject a portion of the liquid from the flask. The cornet is then washed and annealed as above. The return is made to the Mint in decimals or thousandths, and the assayer’s weights are so subdivided as to give him the value in thousandths of the original ^ gramme taken. To the Bank the return is made to the of a carat grain better or worse than standard. The late Master of the Mint caused Tables to be prepared for the conversion of the reports of assays expressed in carats into decimals, and conversely, which are in general use for this purpose. In order to ascertain the amount of error due to the surcharge, a number of proofs are passed through the process simultaneously with the alloys. These proofs con- sist of weighed portions of absolutely pure gold, to which is added a proportion of cop- per equal to that estimated to exist in the alloy to be assayed. The excess of weight in these proofs gives the amount to be deducted. It generally varies from 0*2 to 0*5 parts in 1,000. The last traces of silver may be removed from the cornet by treating it before the final annealing with fusing bisulphate of potash in a porcelain crucible. When sufficiently cool, the whole is heated with hot water containing a little sulphuric acid, and the cornet dried and ignited. By this means gold may be obtained of almost absolute purity, or ^®“%ooo, as it is termed. The following examples will show the difference in the results, and the degree of accu- racy attainable, by the various methods described : — Ten grains of pure gold, alloyed with three times its weight of silver, cupelled and boiled with acid at 22° B., and 32° B., once weighed 10-016. Ten grains of a half-sovereign, with silver, &c., and acid at 22°, and twice at 32° B., gave 915-4 again, 915-6 With acid, as before, and bisulphate of potash, 915-2 again, 915-2 Pure gold alloyed with copper, to bring it to standard, cupelled with silver and lead, and treated with acids and bisulphate, gave in one case precisely the same as was taken originally, or *“°7iooo, and in another 999-98. In accurate assaying of gold bullion, it is of course absolutely necessary that - 47 the acids should be pure, and that the silver used should be most carefully freed from the traces of gold which it usually contains. Instead of charcoal or coke, which are generally used for cupellation, much advantage has been found in employing the best anthracite : reduced to the prop- er size, it contains very little ash, is free from slag or clinker, and allows the heat to be maintained at one steady temperature for many hours, which is a matter of \ great importance to the assayer.* ASTRAGAL. An ornamental moulding, generally used to conceal a junction in either wood or stone. ASTRAGAL PLANES. Planes fitted with cutters for forming astragal mould- ings. They are commonly known as moulding planes. ASTRAGAL TOOL, for turning. By using a tool shaped as in fig. 47, the process of forming a moulding or ring is greatly facilitated, as one member of the moulding is completed at one sweep, and we are enabled to repeat it any number of times with exact uniformity. * The most useful works on this subject are Chaudet, “ L’ A.rt de I’Essayeur ; ” the work of Gay- Lussac mentioned in the text ; “Manuel complet de TEssayeur,” par Yauquelin and D’Arcet, edited by Versnaud. Paris, 1836, (a most useful little work;) Bodemann, “Anleitung zur Berg- und Iluttenman- nischen Probierkunst,” Clansthal, 1845; and (perhaps the best of them all) the “Scheikundig Handbook Voor Essaijeurs Goud und Zilversmeden” by Stratingh, Groningen, 1821. ATOMIC THEORY. 123 ATOMIC THEORY. Dr. Dalton suggested the happy idea, which has been most fruit- ful in its results, of accounting for the constancy of chemical combinations by assuming that they were composed of one or more atoms of the several elements, the weight of which atoms is represented by the combining proportions ; that carbonic oxide, for instance, con- tains single atoms of carbon and oxygen, whilst carbonic acid is composed of one atom of carbon and two of oxygen. It must always be remembered that the combining proportions are purely the results of experiment, and, therefore, incontestable, whatever may be the fate of this theory, which, however, has now stood its ground for many years, and done excellent service to science. This theory offers a most satisfactory explanation of the different laws of chemical com- bination. The fact of bodies uniting only in certain proportions, or multiples of those proportions, is a necessary consequence of the assumption that the weight of the elementary atoms is represented by the combining proportions ; for, if they united in any other ratio, it would involve the splitting up of these atoms, which are assumed to be indivisible. And, of course, the combining proportion of a compound must be the sum of the com- bining proportions of the constituents, since it contains within itself one or more atoms of the several constituents. The term atom is, therefore, very often used instead of combining proportion or equiva- lent, a body being said to contain so many atoms of its elements. All that is assumed in this theory is, that the atoms are of constant value hy weight ; the same atoms may be arranged in a different way, and hence, although any particular compound contains always the same elements in the atomic ratios, yet the same atoms may, by difference in arrangement, give rise to bodies agreeing in composition by weight, but differing essentially in properties. M. Dumas has suggested the subdivision of the combining numbers of certain elements, but this idea is quite subversive of the atomic theory, as it is at present understood. The atomic theory is further confirmed by the observation, that if the specific beat of the elements be compared, it is found that in a large number of cases the specific heat of quantities of the bodies represented by the atomic weights coincides with each other in a remarkable manner. The Atomic Theory of Dalton is thus set forth by the author : — “ When any body exists in the elastic state, its ultimate particles are separated from each other to a much greater distance than in any other state ; each particle occupies the centre of a comparatively large sphere, and supports its dignity by keeping all the rest — which, by their gravity, or otherwise, are disposed to encroach on it — at a respectful dis- tance. When we attempt to conceive the number of particles in an atmosphere, it is some- what like attempting to conceive the number of stars in the universe — we are confounded with the thought. But if we limit the subject, by taking a given volume of any gas, we seem persuaded that, be the divisions ever so minute, the number of particles must be finite ; just as in a given space of the universe, the number of stars and planets cannot be infinite. “ Chemical analysis and synthesis go no further than to the separation of particles one from another, and to their reunion. No new creation or destruction of matter is within the reach of chemical agency. We might as well attempt to introduce a new planet into the solar system, or to annihilate one already in existence, as to create or destroy a par- ticle of hydrogen. All the changes we can produce consist in separating particles that are in a state of cohesion or combination, and joining those that were previously at a dis- tance. “ In all chemical investigations it has justly been considered an important object to ascertain the relative weights of the simples which constitute a compound. But, unfortu- nately, the inquiry has terminated there ; whereas, from the relative weights in the mass, the relative weights of the ultimate particles or atoms of the bodies might have been inferred, from which their number and weights in various other compounds would appear, in order to assist and to guide future investigations, and to correct their results. Now it is one great object of this work (‘ A New System of Chemieal Philosophy ’) to show the im- portance and advantage of ascertaining the relative weights of the ultimate particles^ both of simple and compound bodies^ the number of simple elementary particles which constitute one compound particle^ and the number of less compound particles which enter into the formation of each more compound particle''’ For a full examination of this subject, consult “ An Introduction to the Atomic Theory,” by Charles Daubeny, M.D. ; and “ Memoirs of John Dalton and History of the Atomic Theory,” by Robert Angus Smith, Ph. D. The following Table will show the quantity of precipitate that may be expeeted to result from the addition of nitrate of silver to 100 grains of a salt of sodium, according to the proportion of chloride and of bromide present : — 124 ATOMIC WEIGHTS. Quantity of Salt. Quantity of Precipitate. Quantity of Salt. Quantity of Pre, into kier, c, — this operation occupies one hour, — where they are boiled for twelve hours in lime. They are then withdrawn by the same washing machine, washed, and passed into second kier, 5, (operation occupying one hour,) where they are boiled for twelve hours in ashes and resin ; again withdrawn by the same machine, washed, squeezed, (see plan at u,) and passed over winch e, and piled at A, (this operation occupies one hour. ) They are then taken from pile. A, and threaded through sour-machine, e, soured, passed over winch, e", and piled at A, (operation, one hour,) where it remains in the pile for three hours. It is then squeezed at u, and washed through machine, (an hour’s operation,) delivered into third kier, «, boiled for six hours, washed at g, squeezed at u, (an hour’s operation,) and passed through chemick machine^ (an hour’s operation,) and piled for one hour ; after which it is soured again, (an hour’s operation,) squeezed, and washed at g^ (an hour’s operation,) squeezed again at/, (an hour’s operation,) and dried by machine at », I fig. 63.) There are several advantages in using the squeezing process so often in the above arrangement : — Firstly, The bowls of the washing machine are not so much damaged by the heavy pressure which is required to be applied, if no squeezers are used, in order to prepare the pieces for the sour and chemick machines : Secondly, A drier state of the cloth than can possibly be produced by the washing machine alone, thus fitting it to become better satu- rated with the chemick or sour : Thirdly, The piece passing from the souring to the washing machine, in this arrangement, carries with it less of the acid, and thus ensures a better washing with less water. It may be observed, that the velocity of the above-mentioned machines is much higher than usual, experience having shown that the various operations are thus better performed 156 BLEACHING. 68 BLEACHING. 157 than when running slower. The reason of this appears to be, firstly, that the piece, running at such velocity, carries with it, by reason of capillary attraction, a greater quantity of liquid to the nip of the bowls ; secondly, the great velocity of the bowls, together with the greater quantity of water carried up, produces a more powerful current at the nip and down the ascending piece, thus penetrating to every fibre of it. It may also be remarked, that the above-mentioned machines are not adapted to the bleaching of linen ; for the latter cloth, not having the same elasticity as cotton, if it should become tight, would either be pulled narrow or torn. In illustration of the continuous process as at present used, the plan of proceeding at Messrs. McNaughten, Barton, and Thom’s, at Chorley, may be described : 1. In order that there may be no interruption in the process, the pieces are united in one continuous piece — each piece being about 30 yards, the whole varying with the weight of cloth — about 300 yards long. Each piece is marked with the name of the printer. This is sometimes done in marking ink of silver, and sometimes in coal tar, at the extremity of the piece. The pieces are rapidly tacked together by girls, who use in some establishments a very simple sewing machine. (See Sewing Machine.) The whole amount to be bleached at a time is united in one piece, and is drawn from place to place like a rope. To give them this rope form, the goods are drawn through an aperture whose surface is exceedingly smooth, being generally of glass or earthenware. Of these many are used in transferring the cloth from place to place. They serve instead of pulleys. The cloth when laid in a vessel is not thrown in at random, but laid down in a carefully made coil. The rope form enables the water to penetrate it more easily. 2. The pieces are singed. 3. They are boiled in the first kier. In this, 3,500 lbs. of cloth have added to them 250 lbs. of caustic lime, 1 lb. of lime to 14 of cloth. The kier is cylindrical, 7 feet deep and 8 feet in diameter ; as much water is added as will cover the cloth, about 500 gallons. This boiling lasts thirteen hours. 4. They are washed in the washing machine. Robinson and Young’s machine is used. 5. They are soured in a similar machine with hydrochloric acid of specific gravity 1010*, or 2° of Twaddle. 6. The same amount of cloth being supposed to be used, it is bucked in a solution of soda-ash and resin, 170 lbs. of soda-ash to 30 lbs. of resin. The boiling lasts sixteen hours, the same amount of water being used. 7. Washed as before. 8. Passed through chloride of lime, or chemicked. The cloth is laid in a stone or wooden cistern, and a solution of bleaching powder is passed through it, by being poured over it and allowed to run into a vessel below ; this is managed by continued pumping. This solution is about half a degree Twaddle, or specific gravity 1002*5. The cloth lies in it from one to two hours. 9. Washed. 10. Boiled again in a kier for five hours with 100 lbs. of carbonate of soda crystals. 11. Washed. 12. Put in chloride of lime as before. 13. Soured, in hydrochloric acid of 1012*5 specific gravity, or 2^° Twaddle. 14. Lies six hours on stillages. — A stillage is a kind of low stool used to protect the cloth from the floor. 15. Washed till clean. 16. Squeezed in rollers. 17. Dried over tin cylinders heated by steam. This is the process for calico generally ; some light goods must be more carefully handled. The usual time occupied by all these processes is five days. They are sometimes dried in a hydro-extractor ; after singeing, laid twenty-four hours to steep, then washed before being put into the lime kier. High-pressure Steam Kier, — This is designed still further to hasten the process of bleaching, and at the same time to improve it. Fig. 65 is an elevation showing the arrangement of these kiers, (which are recommended to be made of strong boiler-plate iron.) One of these is shown in section, a and h are the kiers ; c is a perforated platform, on which the goods to be bowked are laid ; k k is the pipe connecting^ the bottom of the kier h with the top of the adjoining kier, a ; and /, /, the corresponding pipe connecting the opposite ends of the kiers a and h \ m m are draw-off cocks, connected with the pipes k and /, by which the kiers can be emptied of spent liquor, water, &c. ; n and o are ordinary two-way taps, by which the steam is admitted into the respective kiers from the main pipe, />, and the reversing of which shuts off the steam com- munication, and admits the bowking liquor as it becomes expelled from the adjoining kier ; is a blowing-off valve or tap ; r, the pipe through which the bowking liquor enters into the kier ; s, manhole, (closed by two cross bars, secured by bolts and nuts,) through which BLEACHING. 158 65 the goods are introduced and removed ; 1 1 are gauges, by which it is ascertained when the liquor has passed from one kier and has entered the other. The process adopted for bleaching is as follows ; it is the shortest and simplest in use : 1. The box or water trough of the washing machine is then half filled with milk of lime of considerable consistence, and the goods are run through it, being carried forward by the winches and deposited in the kiers. The whole of the cloth in a kier is in one length, and a boy enters the vessel to lay it in regular folds until the kier is filled. All the cloth before entering the kier must pass through the lime. 2. When the kiers are filled, a grid of movable bars is laid on the top of the cloth, and the manhole of the kiers is closed. High-pressure steam is then admitted at the top ; this presses down the goods and removes the lime water, which is drawn off at the bottom. At the same time the air is also removed from the goods and replaced by steam. When this is driven off, and nothing but steam issues from the tap at the bottom, 40 lbs. of lime, which have been previously mixed with 600 gallons of water, are introduced into the first kier in a boiling state. High-pressure steam is again admitted, which forces the lime liquor through the goods to the bottom of the vessel, then up the tube /, and on to the goods in the second kier. The tap is then closed which admits steam into the first kier, and the steam is now sent into the second. The same process occurs, only in this case the liquid is sent again on to the top of the goods in the first kier. This process is continued about eight hours. In this method each 7,000 lbs. of cloth take into the kiers 2 cwts. of lime, which is equally distributed. The clear lime-water which is blown out of the steam at the com- mencement contains only 3 to 4 lbs. of lime in solution. At the close of the operation the liquor has a specific gravity of 3^ to 4° Twaddle, (1017’6 to 1020,) instead of half that amount, or 1^ to 2° Twad., (1007’6 to 1010,) as is usual. 3. When the liming is completed the steam pressure in the kiers is removed, the man- way opened, the grid lying above the cloth removed, and the cloth in the kier attached to the washing machine, which draws the goods out of the kiers and washes them. 4. The pieces are then passed by the winches through the soui’ing machine, or soured BLEAGHING. 159 by having muriatic acid of 2° Twaddle pumped upon them, (1010.) They must remain with the acid two or three hours, either steeped in it, or after having passed through it. 5. Again attach the cloth to the washing machine, and wash it well, passing it on by winches, as before, into the kier. 6. Introduce steam and drive off the air and the cold water ; these are let out by the tap at the bottom: add then 224 lbs. of soda-ash and 150 lbs. of resin, boiled in 600 gallons of water, for Y,000 lbs. of cloth. Work the kiers by driving the liquid from one to the other as before ; about eight hours is a sufficient time. These proportions of soda may be varied. If the cloth is very strong, a little more may be used, (or if the cloth has been printed upon in the gray state, from having been used to cover the blanket of the calico- printing machine.) 7. After this the cloth is passed through the washing machine, and then submitted to chloride of lime. This may be done either by the machine or by pumping. In either case it is an advantage to warm the bleaching liquid up to 80° or 9b° F. The strength of the solution when the machine is used may be about -J° Twaddle, or 1002-5 specific gravity ; but if the pump is used it must be much weaker. When the bleaching is for finishing white, milk of lime is added to the chloride, in order to retard the operation ; the goods are also washed from the bleaching liquor before souring them. This causes a similar escape of chlorine, and is a more careful method ; it tends to preserve the headings, or the colored threads, which are often put into the ends of pieces of cloth in order to see if the bleaching has been performed roughly or not. The original use of this has almost been forgotten, but these headings are still carefully preserved. This method preserves also the cloth, which is also less apt to be attacked by the chlorine. If the cloth has been well managed, it will be almost white when it leaves the second kier containing the resinate of soda ; it will therefore require very little decolorizing. If the. goods have been printed on, more chloride will be needed. The cloth should lie from two to eight hours in the liquor, or after saturation with it. The action is quickened if warmth is used. They are soured then, as before, in muriatic and sulphuric acid, at 2° Tw., for three or four hours ; then wash for drying. This method of Mr. Barlow’s is an undoubted shortening of the process of bleaching ; eight hours only of bucking are found to be enough, and the whole may be performed, by the help of the continuous system, in two days. It will be seen that the steam drives the solution through the cloth ; and this is equal to the process of stirring, which is a continual c’.iange of surface and of liquid, but it is more effectual than any stirring could possibly be. The goods are laid in a firm, compact mass, and held down by an iron grid, so that the liquid cannot run through ruts and crevices, but must run through the cloth itself. From what has been said, it will be seen that the operations of the bleacher are not so numerous as at first sight appears, when we call every washing a separate process ; and although it really is so, it is managed so rapidly that it can scarcely be said to occupy time, and as it is carried on at the same time as the other processes, it scarcely can be said to give trouble. The work may be divided into : — 1. Singeing. 2. Bowking with lime. 3. Washing, souring, and washing. 4. Bowking with resinate of soda. 5. Washing and chlorinating. 6. Souring, washing, and drying. This process has been tried with success on linen, although not yet in active operation. Bleaching op Linen. Old Method . — What is called the old method, or that used from about the introduction of bleaching powder, at the beginning of the century, till within ten or fifteen years, re- quired bleaching on the grass ; and the mode in which it was managed in Ireland and Scot- land, where it held its ground longest, is as follows : — 1. They were rot-steeped in a weak solution of potash, at about 130° F., for two days, until the dressing used in manufacturing the cloth was removed. 2. Washed. 3. Boiled or bowked in potash lye, at ^° Twaddle, for ten hours. 4. Washed, and the ends turned so that the whole might be equally exposed to the lye. 5. Boiled or bowked in a similar lye to the above for twelve hours. 6. Washed well. Y. Exposed on the grass for three days, and watered. 8. Taken up and soured with sulphuric acid, at 2° Tw., for four hours. 9. Taken up and washed well. 10. Boiled again for eight hours in potash lye, at 1° Tw., to which had been added black or soft soap, about 20 lbs. to a kier of about 300 gallons. 11. Washed. . 160 BLEACHING. 12. Crofted, or exposed on the grass, as before. 13. Treated with chloride of lime at 1^° Tw., for four hours. 14. Washed. 15. Soured in sulphuric acid, at 2° Tw., for four hours. 16. Washed. 17. Boiled for six or seven hours with soap and lye, using in this case more soap and one-third less lye than in the former bowkings. 18. Drawn out and put through rub-boards. This is a kind of washing machine, made of blocks of wood, with hard-wood teeth. The goods are washed by it in a soapy liquid. The teeth, moving rapidly, drive the soap into the cloth. 19. Boiled in the lye alone for six hours. 20. Washed. 21. Crofted, keeping them very clean, as this is the last exposure. 22. Treated with chloride of lime. 23. They are then starched, blued, and beetled, to finish them for the market. These operations last six weeks. A'ew System^ as practised hi Scotland and Ireland. — Directions given hy an extensive Bleacher. 1. Wash. 2. Boil in lime-water ten or twelve hours. 3. Sour in muriatic acid, of 2° Tw., for three, four, or five hours. 4. Wash well. 5. Boil with resin and soda-ash twelve hours. 6. Turn the goods, so that those at the top shall be at the botom, and boil again as at No. 5. 7. Wash well. 8. Chemick, at Tw., or 1002'5, four hours. 9. Sour, at 2° Tw., or lOlO’ specific gravity. 10. Wash. 11. Boil in soda-ash ten hours. 12. Chemick again. 13. Wash and dry. This is the system chiefly adopted when the goods are to be printed. The following is the system practised in the neighborhood of Perth, where the chief trade is in plain sheetings : — 1. Before putting them into operation, they are put up into parcels of about 35 cwts. 2. They are then steeped in lye for twenty-four hours. 3. Then washed and spread on the grass for about two days. 4. Boiled in lime-water. 5. Turned, and boiled again in lime-water, those at the top being put at the bottom. 60 lbs. of lime are used at a time, and about 600 gallons of water. 6. Washed, then soured in sulphuric acid of 2° Tw., or 1010* sp. gr., for four hours, then washed again. 7. Boiled with soda-ash for ten hours ; 110 lbs. used. 8. Washed and spread out on the green, or crofted. 9. Boiled again in soda as before. 10. Crofted for three days. 11. They are then examined : the white ones are taken out ; those that are not finished are boiled and crofted again. 12. Next, they are scalded in water containing 80 lbs of soda-ash, and washed. 13. The chloride of lime is then used at Tw., or 1002-5 specific gravity. 14. Washed and scalded. 15. Washed and treated with chloride of lime. 16. Soured, for four hours, with sulphuric acid, at 2° Tw., or lOlO' specific gravity. 17. Washed. If cloths lighter than sheetings are used, the washing liquids are used weaker. The great point is to observe them carefully during the process, in order to see what treatment will suit them best. It will be seen that the process of bleaching linen is still very tedious ; and although it may be managed in a fortnight, it is seldom that this occurs regularly for a great length of time. The action of the light introduces at once an uncertain element, as this varies so much in our climate. If, again, linen be long exposed to the air in a moist condition, it is apt to become injured in strength. To shorten the process, therefore, is important ; and if no injurious agents are introduced, a shortening promises also to give increased strength to the fibre. It has not been found possible to introduce chlorine into linen bleaching at an early stage, as in the case of cotton ; and the processes for purifying it without any chlorine render it so white that unskilled persons would call it as white as snow. The chlorine is BLEACHING. 161 . introduced nearly at the end of the operation, after a series of boilings with alkalies, sour- ings, and exposures on the grass. If introduced at an earlier stage, the color of the raw cloth becomes fixed, and cannot be removed. The technical term for this condition is “ seV Mr. F. M. Jennings, of Cork, has just patented a method which promises to obviate the difficulty. The peculiarity consists in using the alkali and the chloride of alkali at the same moment, thus giving the alkali opportunity to seize on the coloring matter as soon as the chloride has acted, and thereby preventing the formation of an insoluble compound. He prefers the chlorides of potash or soda. His plan is as follows : — 1. He soaks the linen in water for about twelve hours, or boils it in lime or alkali, or alkali with lime, and then soaks it in acid, as he uses soaps of resin in other mixtures — the alkalies being from 3° to 6° Tw., 1015 -1025' specific gravity. 2. Boils in a similar alkaline solution. 3. Washes. 4. Puts it into a solution of soda, of 5° Tw., 1025* specific gravity, adding chloride of soda until it rises up to from 6°-'7° Tw. It is allowed to remain in this solution for some hours, and it is better if subjected to heating or squeezing between rollers, as in the wash- ing machine. 5. He then soaks, sours, and washes. 6. He then puts it a second time into the solution of alkali and chloride. 7. Then washes, and boils again with soda. These operations, 6 and 7, may be repeated until the cloth becomes almost white. The amount of exposure on the grass by this proeess is said to be not more than from one-half to one-fourth that required by the usual method, or it may be managed so as en- tirely to supersede crofting. Chevalier Clausen has opened up the filaments of flax by the evolution of gas from a carbonate in which the plant is steeped, and at the same time bleached by chloride of mag- nesia. Bleaching op Materials for Paper. The bleaching of paper is conducted on the same principle as the bleaching of cotton. Paper is made principally of two materials, cotton and flax, generally mixed. The cotton waste of the mills, which is that inferior portion which has become too impure for spinning, or otherwise deteriorated, and cotton rags, are the principal, if not the only, sources of the cotton used by paper-makers. The waste is sorted by hand, the hard and soft being sepa- rated, and all accidental mixtures which occur in it are removed. This is done at first roughly on a large lattice, which is a frame of wire cloth, having squares of about three- quarters of an inch through which impurities may fall. It is then put into a duster, which is a long rectangular box, it may be ten feet long, lying horizontally, the inside diameter about two feet, and covered with wire gratings running horizontally, leaving openings of half an inch in width. As this revolves, the waste is thrown from one angle to the other, and throws out whatever dust or other material falls into the holes or spaces. The fibrous matter has little tendency to separate from the mass, which is somewhat agglutinated by being damp, chiefly from the oil obtained during the processes in the cotton mill. A second duster, however, is used to retain whatever may be of value ; it is a kind of riddle. It is then transferred to the lattices, which are a series of boxes covered with wire gauze, the meshes of which are about half an inch square, and so arranged as to form a series of sort- ing tables. The sorting generally is done by young women. Each table has a large box or basket beside it, into which the sorted material is thrown ; this is removed when filled, by being pushed along a railroad or tramway. Pieces of stone, clay, leather, wood, nails, and other articles, are taken out. The cotton is then put into a devil similar to that which is used in cotton machinery, but having larger, stronger teeth, which tear it up into small fragments. The rags are sorted according to quality, woollen carefully removed, and all the unavail- able material sent back to the buyer. They are then chopped up by a knife, on the circum- ference of a heavy wheel, into pieces of an inch wide, devilled, and dusted. The rags and the cotton waste are bleached in a similar manner. The cotton is put into kiers of about ten feet in diameter, of a kind similar to those described, and boiled with lime. The amount of lime used is about 6 lbs. to a cwt. of cotton or rags, but this varies according 'to the impurity. The lime removes a great amount of impure organic matter, and, as in bleaching, cotton cloth lays hold of the fatty matter, of which there is a great deal in the waste. When taken out, it is allowed to lie from two to three hours. The ap- pearance is not much altered ; it appears as impure as ever. It is then put into the rag-engine and washed clean. This is a combined washing ma- chine and filter, the invention of Mr. Wrigley, near Bury. The washing may last an hour and a half, or more. The cotton has now a bright gray color, and looks moderately clean. It is full of water, which is removed by a hydraulic press, the cotton being put into an iron cylindrical box with perforated sides. It is then boiled in kiers or puffing boilers, where soda-ash is used, at the VOL. III.— 11 L BLEAK. 162 rate of 4 to 5 lbs. a cwt. Only as much water is used as will moisten the goods thoroughly. Much water would weaken the solution and render more soda necessary. It is then washed again in the rag-engine ; afterwards put into chloride of lime, acidified as in cotton bleach- ing, and washed again in the rag-engine. The cotton rags are treated in a similar manner. The colored rags are treated sepa- rately, requiring a different treatment according to the amount of color ; this consists chiefly in a greater use of chloride of lime. Some points relating to bleaching are necessarily treated of under Calico Printing. BLEAK. {Cyprinus Alburnus.) The scales of this fish are used for making the essence of pearl, or essence d' orient, with which artificial pearls are manufactured. In the scales of the fish the optical effect is produced in the same manner as in the real pearl, the grooves of the latter being represented by the inequalities formed by the margins of the concentric laminae of which the scales are composed. These fish are caught in the Seine, the Loire, the Saone, the Rhine, and several other rivers. They are about four inches in length, and are sold very cheap after the scales are washed off. It is said that 4,000 fish are necessary for the production of a pound of scales, for which the fishermen of the Cha- lonnois get from 18 to 25 livres. The pearl essence is obtained merely by well washing the scales which have been scraped from the fish in water, so as to free them from the blood and mucilaginous matter of the fish. BLENDE (sulphide or sulphuret of zinc, “Black Jack”) is a common ore of zinc, com- posed of zinc 6Y, sulphur 33 ; but it usually contains a certain proportion of the sulphide of iron, which imparts to it a dark color, whence the name of “ Black Jack,” applied to it by the Cornish miner. The ore of this country generally consists of zinc 61*5, iron 4'0, sulphur 33*0. Blende occurs either in a botryoidal form or in crystals, (often of very com- plex forms,) belonging to the tetrahedal division of the monometric system. H = 3'5 to 4. Specific gravity = 3*9 to 4. — H. W. B. In some districts the presence of the sulphide of zinc is regarded by the miners as a favorable indication, hence we have the phrase, '■'■Black Jack rides a good horsed In other localities it is thought to be equally unfavorable, and the miners say, “ Black Jack cuts out the ore."'^ For many years the English zinc ores were of little value, the immense quantity of zinc manufactured by the Vieille Montague Company, and sent into this country, being quite sufficient to meet the demand. Beyond this, there was some difficulty in obtaining zinc which would roll into sheets, from the English sulphides. Although this has been to some extent overcome, most of the zinc obtained from blende is used in the manufacture of brass. Dana has given the following analyses of varieties of blende : — Sulphur. Zinc. Iron. Cadmium. Carinthia , 32*10 64*22 1*32 trace New Hampshire - 32* 6 52*00 10*0 3*2 New Jersey - - 32*22 67*46 - trace Tuscany ■ 32*12 48*11 11*44 1*23 BLIND COAL, a name given to Anthracite. BLOCK TIN. Metallic tin cast into a block, the weight of which is now about 3^ cwts. Formerly, when it was the custom to carry the blocks of tin on the backs of mules, the block was regulated by what was then considered to be a load for the mule, at 2^ cwts. Subsequently, the block of tin was increased in size, and made as much as two men could lift, or 3 cwts. It was the custom to order so many blocks of tin, and the smelter, being desirous of selling as much tin as possible, continued to increase the size of the block, so that, although 3| cwts. is the usual weight, many blocks are sold weighing 3f cwts. BLOOD. Mr. Pillans, in 1854, took out a patent for the separation of the coloring matter of blood, and also for drying the prepared serous matters. He recommends the blood (which must be received warm) to be caught in shallow vessels containing from 14 lbs. to 20 lbs. of blood, to stand at rest from two to six hours according to the weather and the nature of the blood ; then the clot is separated by a strainer from the serous fluid, and by means of cutting-knives, or rollers, the clot is divided into small pieces ; a considerable quantity of coloring matter flows with the serum, which is to be set aside to deposit ; the clot is placed on strainers until the serum has all drained away. By these operations there are obtained readily from the blood — 1st, the clot, in a comparatively dry state, comprising hematosine, with a portion of serum and all the fibrine ; 2d, a portion of serum, highly colored with hematosine ; 3d, the clear serum. The blood, in small fragments, is dried on wirework or trays, at a less temperature than will coagulate the hematosine, so that, when dry, it may be soluble in water ; 110° to 115° BLOWPIPE. 163 is the temperature recommended. The second or highly-colored serum can be dried by itself or mixed with the serum, and may be used for sugar refining and in dyeing. The clear serum is dried and ground and in a fit state to be used as albumen, and may be employed by the printers of textile fabrics for fixing ultramarine blue and other colors, or as a substitute for egg albumen, both in printing colors and in refining liquids. Instead of drying at once the clear serum, it may be mixed with ^ per cent, of oil of turpentine. Other vegetable, and, particularly, volatile oils, are also suitable, preferring those that have been exposed to the air ; from 10 to 20 per cent, of water, ultramarine, suitable colors, or thickening, may be added, taking care that under no circumstance is it to be exposed to a heat high enough to coagulate it while in the drying-room. BLOODSTONE. A very hard, compact variety of haematite iron ore, which, when reduced to a suitable form, fixed into a handle, and well polished, forms the best descrip- tion of burnisher for producing a high lustre on gilt coat-blittons. The gold on china is burnished by the same means. — Knight. Bloodstone is a name also applied to the jaspery variety of quartz known as the helio- trope^ colored deep-green, with interspersed blood-red spots like drops of blood — Dana. BLOWPIPE. The blowpipe is so extremely useful to the manufacturer and to the miner that an exact description of the instrument is required. When we propel a flame by means of a current of air blown into or upon it, the flame thus produced may be divided into two parts, as possessing different properties — that of reducing under one condition and of oxidizing under another. The reducing flame is produced by blowing the ordinary flame of a lamp or candle simply aside by a weak current of air impinging on its outer surface ; it is therefore unchanged except in its direction. Unconsumed carbon, at a white heat, giving the yellow color to the flame, coming in contact with the substance, aids in its reduction. The oxidizing flame is formed by pouring a strong blast of air into the interior of the flame ; combustion is thus thoroughly established, and if a small fragment of an oxidizable body is held just beyond the point of the flame, it becomes intensely heated, and, being exposed freely to the action of the surrounding air, it is rapidly oxidized. The best form of blowpipe is the annexed, {flg. 66,) which, with the description, is copied from Blandford’s excellent transla- tion of Dr. Theodore Scheerer’s “ Introduction to the Use of the Mouth Blowpipe.” The tube and nozzle of the instrument are usually made of German silver, or silver with a platinum point, and a trumpet- shaped mouth-piece of horn or ivory. Many blowpipes have no mouth-pieces of this form, but are simply tipped with ivory, or some similar material. The air-chamber a serves in some degree to regulate the blast and receives the stem, b, and the nozzle, «, which are made separately, and accurately ground into it, so that they may be put together, or taken apart at pleasure. The point h is best made of platinum, to allow of its being readily cleaned, and is of the form shown in the wood-cut. When the in- strument is used, the mouth-piece is pressed against the lips, or, if this is wanting, the end of the stem must be held between the lips of the operator. The former mode is far less wearying than the latter ; and whereas, with the trumpet mouth-piece, it is easy to maintain a continued blast for five or ten minutes, without it it is almost impossible to sustain an unbroken blast of more than two or three minutes’ duration. While blowing, the operator breathes through his nostrils only, and, using the epiglottis as a valve, forces the air through the blowpipe by means of the cheek muscles. Some years since, Mr. John Prideaux, of Plymouth, printed some valuable “ Sugges- tions” for the use of the blowpipe by working miners. Some portions of this paper appear so useful, especially under circumstances which may preclude the use of superior instru- ments, &c., that it is thought advisable to transfer them to these pages. For ordinary metallurgic assays, the common blowpipe does very well. A mere taper- ing tube, 10 inches long, | inch diameter at one end, and the opening at the other scarcely equal to admit a pin of the smallest kind, the smaller end curved off for inch to a right angle. A bulb at the bend, to contain the vapor condensed from the breath, is useful in long operations, but may generally be dispensed with. In selecting the blowpipe, the small 164 BLOWPIPE. aperture should be chosen perfectly round and smooth, otherwise it will not command a good flame. A common candle, such as the miner employs under ground, answers very well for the flame. To support the subject of assay, or “ the assay,” as it has been happily denominated by Mr. Children, two different materials are requisite, according as we wish to calcine or re- duce it. For the latter purpose, nothing is so good as charcoal ; but that from oak is less eligible, both from its inferior combustibility and from its containing iron, than that from alder, willow, or other light woods. For calcination, a very convenient support, where platinum wire is difficult to procure, is white-baked pipe-clay or china clay, selecting such as will not fuse nor become colored by roasting with borax. These supports are conveniently formed by a process of Mr. Tennant. The clay is to be beaten to a smooth stiff" body ; then a thin cake of it, being placed between a fold of writing paper, it is to be beaten out with a mallet to the thickness of a wafer, and cut, paper and all, into squares of f inch diameter, or triangles about the same size. These are to be put in the bowl of a tobacco-pipe, and heated gently till dry, then baked till the paper is burnt away, and the clay left perfectly white. They should be baked in a clear Are, to keep out coal-dust and smoke as much as possible, as either of these adhering to the clay plates would color the borax in roasting. A small fragment of the bowl of a new tobacco-pipe will serve instead in the absence of a more convenient material. A simple pair of forceps, (Jig. e'Z), to move and to take up the hot assay, may be made of a slip of stiff tin plate, 8 inches long, ^ inch wide in the middle, and Vie inch at the ends. The tin being rubbed off the points on a rough 67 whetstone, the slip is to be bent until they approach each ^ other within ^ an inch, and the two sides are parallel ; thus there will be spring enough in the forceps to open ^ and let go the assay when not compressed upon it by the finger and thumb. A magnetic needle, very desirable to ascertain the presence of iron, is easily made of the requisite delicacy where a magnet is accessible. A bit of thin steel wire, or a long fine stocking-needle, having \ inch cut off at the point, is to be heated in the middle that it may be slightly bent there, {Jg. 68.) While hot, a bit of sealing-wax is to be attached to the centre, and the point which had been cut off, being heated 68 at the thick end, is to be fixed in the sealing-wax, so that the sharp end may serve as a pivot, descending about ^ inch below the centre, taking care that the ends of the needle fall enough below the pivot, to prevent it overturning. It must be mag- netized, by sliding one end of a magnet half a dozen or more times from the centre to one end of the needle, and the other end a similar number of times from the centre of the needle to its other end. A small brass thimble (not capped with iron) will do for the support, the point of the pivot being placed in one of the indentations near the centre of the tap, when, if well balanced, it will turn until it settles north and south. If one side preponderate, it must be nipped until the balance be restored. A black gun-flint is also occasionally used to rub the* metallic globules, (first attached, whilst warm, to a bit of sealing-wax,) and ascertain the color of the streak which they give. Thus minute particles of gold, copper, silver, &c., are readily discriminated. A little refined borax and carbonate of soda, both in powder, will complete the requisites. Having collected these materials, the next object for the operator is to acquire the faculty of keeping up an unintermitted blast through the pipe whilst breathing freely through the nose. A very sensitive, and, for most purposes, sufficiently delicate balance, {Jig. 69,) was also devised by Mr. Prideaux, of which the following is a description : — 69 Iiio 100 90 80 10 fiO 50 40 30 20 lU ! 10 20 30 40 50 GO 70 UO 90 100 I The common marsh reed, growing generally in damp places throughout the kingdom, will yield straight joints, from 8 to 12, or more, inches long ; an 8-inch joint will serve, but the longer the better. This joint is to be split down its whole length, so as to form a BLUE COPPERAS, or BLUE STONE. 165 • trough, say inch wide in the middle, narrowed away to ^ inch at the ends. A narrow slip of writing paper, the thinner the better, (bank post is very convenient for the purpose,) and as long as the reed trough, is to be stuck with common paste on the face of a carpen- ter’s rule, or, in preference, that of an exciseman, — as the inches are divided into tenths instead of eighths ; — in either case observing that the divisions of the inch on the rule be left uncovered by the paper. When it is dry, lines must be drawn the whole length of it, 4 inch apart, to mark out a stripe ^ inch wide. Upon this stripe the divisions of the inch are to be ruled off by means of a small square. The centre division being marked 0, it is to be numbered at every fourth line to the ends. Thus the fourth from the centre on each side will be 10 ; the eighth, 20 ; the twelfth, 30 ; the sixteenth, 40, &c. ; and a slip of 10 inches long, graduated into tenths of an inch, will have on each arm 50 lines, or 125 degrees, divided by these lines into quar- ters. While the lines and numbers are drying, the exact centre of the reed-trough may be ascertained, and marked right across, by spots on the two edges. A line of gum water, full ^ inch wide, is then laid with a camel-hair pencil along the hollow, and the paper being stripped from the rule, (which it leaves easily,) the graduated stripe is cut out with scissoi’s, and laid in the trough, with the line 0 exactly in the centre. Being pressed to the gummed reed, by passing the round end of a quill along it, it graduates the trough from the centre to each end. This graduation is very true, if well managed, as the paper does not stretch with the gum water after being laid on the rule with the paste. A very fine needle is next to be procured, (those called 6eao?-needles are the finest,) and passed through a slip of cork the width of the centre of the trough, about ^ inch square, ^ thick. It should be passed through with care, so as to be quite straight. The cork should then be cut until one end of it fits into the trough, so that the needle shall bear on the edges exactly in the spots that mark the centre, as it is of importance that the needle and the trough be exactly at right angles with each other. The cork is now to be fixed in its place with gum water, and, when fast dry, to be soldered down on each side with a small portion of any soft resinous cement, on the point of a wire or knitting-needle ; a little cement being also applied in the same manner to the edges of the cork where the needle goes through, to give it firmness, the beam is finished. It may be balanced by paring the edges on the heaviest side : but accurate adjustment is needless, as it is subject to vary with the dampness or the dryness of the air. The support on which it plays is a bit of tin plate, (or, in preference, brass plate,) If inch long, and 1 inch wide. The two ends are turned up square f of an inch, giving a base of f of an inch wide, and two upright sides f high. The upper edges are then rubbed down smooth and square upon a Turkey stone, letting both edges bear on the stone to- gether, that they may exactly correspond. For use, the beam is placed evenly in the sup- port, with the needle resting across the edges. Being brought to an exact balance by a bit of writing paper, or any other substance, placed on the lighter side, and moved toward the end until the equilibrium is produced, it will turn with extreme delicacy, a bit of horsehair, f inch long, being sufficient to bring it down freely. It must not be supposed that any such instrument as this is recommended as in any way substituting the beautiful balances which are constructed for the chemist, and others requir- ing to weigh with great accuracy. The object is merely to show the miner a method by which he may construct for himself a balance which shall be sufficiently accurate for such blowpipe investigations as it may be important for him to learn to perform for himself. If the suggestions of the chemist who devised the above balance had been carried out, much valuable mineral matter which has been lost might have been turned to profitable account. The blowpipe is largely used in manufactures, as in soldering, in hardening and temper- ing small tools, in glass-blowing, and in enamelling. In many cases the blowpipes are used in the mouth, but frequently they are supplied with air from a bellows moved by the foot, by vessels in which air is condensed, or by means of pneumatic apparatus. Many blowpipes have been invented for the employment of oxygen and hydrogen, by the combustion of which the most intense heat which we can produce is obtained. Pro- fessor Hare, of Philadelphia, was the first to employ this kind of blowpipe, when he was speedily followed by Clark, Gurney, Leeson, and others. The blowpipe, fed with hydro- gen, is employed in many soldering processes with much advantage. The general form of the “ workshop blowpipe ” is that of a tube open at one end, and supported on trunnions in a wooden pedestal, so that it may be pointed vertically, horizon- tally, or at any angle as desired. Common street gas is supplied through one hollow trun- nion, and it escapes through an annular opening, while cqmmon air is admitted through the other trunnion, which is also hollow, and is discharged in the centre of the hydrogen through a ceiitral conical tube ; the magnitude and intensity of the flame being determined by the relative quantities of gas and air, and by the greater or less protrusion of the inner cone, by which the annular space for the hydrogen is contracted in any required degree. — Holtz- apffel. BLUE COPPERAS, or BLUE STONE. The commercial or common names of the sulphate of copper. See Copper. BLUE VITKIOL. 166 BLUE VITRIOL. Sulphate of copper. When found in nature, it is due entirely to the decomposition of the sulphides of copper, especially of the yellow copper pyrites, which are liable to this change when placed under the influence of moist air, or of water contain- ing air. BOGHEAD COAL, and other Brown Cannel Coals. The brown cannels are chiefly confined to Scotland, and have been wrought, with the exception of the celebrated Bog- head, for the last thirty years. They are found at Boghead, near Bathgate ; Rocksoles, near Airdrie ; Pirnie, or Methill ; Capeldrea, Kirkness, and Wemyss, in Fife. The first- named coal, about which there has been so much dispute as to its nature, has only been in the market eight years. It is considered the most valuable coal hitherto discovered for gas and oil-making purposes ; but, strange to say, the middle portion of the Pirnie, or Met- hill seam, which has been unnoticed for thirty years, is nearly as valuable for both pur- poses. Boghead. Amorphous ; fracture subconchoidal, compact, containing impressions of the stems of Sigillaria^ and its roots, {Stigmarice^) with rootlets traversing the mass. Color, clove-brown, streak yellow, without lustre ; a non-electric ; takes fire easily, splits, but does not fuse, and burns with an empyreumatic odor, giving out much smoke, and leaving a considerable amount of white ash. H. 25. Specific gravity, P200. According to Dr. Stenhouse, F. R. S., its composition is : — Carbon 65*72 Hydrogen 9-03 Nitrogen 0*72 Oxygen 4*78 Ash 19-75 100-00 Dr. Stenhouse’s analysis of the ash of Boghead coal, from three analyses, was as fol- 's : — Silica 58-31 Alumina 33-65 Sesquioxide of iron 7*00 Potash 0-84 Soda 0-41 Lime and sulphuric acid traces. Dr. Andrew Fyfe, F. R. S. E., on analysis, found that the coal yielded, from a picked specimen, 70 per cent, of volatile matter, and 30 per cent, of coke and ash. From a ton he obtained 14-880 cubic feet of gas, the illuminating power of which was determined by the use of the Bunsen photometer, the gas being consumed by argands burning from 2^^ to 3^ feet per hour, according to circumstances. The candle referred to was a spermaceti candle, burning 140 grains per hour. Cubic Feet of Gas per Ton of Coal. Specific Gravity. Condensation by Chlorine in 100 Parts. Durability 1 foot burns. Illuminating Power 1 foot = Light of Candles. Pounds of Coke per Ton of Coal. 14-880 •802 27 Min. Sec. 88 25 7-72 760 The Pirnie or Methill brown cannel, on analysis, gives the following results : — Specific gravity 1-126 Gas per ton 13,500 feet. Illuminating power 28 candles. Coke and ash 36 per cent. Hydro-carbons condensed by bromine ... - 20 “ Sulphuretted hydrogen Carbonic acid 4f“ Carbonic oxide 7f“ Volatile matter in coal 65“ Specific gravity of gas *700 “ The Boghead coal occurs in the higher part of the Scotch coal field ; in about the posi- tion of the “ slaty band ” of ironstone, its range is not more than 3 or 4 miles in the lands of Torbane, Inchcross, Boghead, Capper’s, and Bathvale, near Bathgate, in the county of Linlithgow. In thickness it varies from 1 to 30 inches, and at the present consumption, say from 80,000 to 100,000 tons per annum, it cannot last many years. BOG IRON ORE. 167 measures, and under circumstances common to beds of coal : — Ft. In. Boghead house coal 27 Arenaceous shale 60 Slaty sandstone 07 Shale and ironstone, containing remains of plants and shells - 0 10 Cement stone (impure ironstone) 04 Boghead cannel 19 Fire clay, full of 8tigmarice - ------05 Coal (common) 0 6 Black shale OOf Coal 0 1 Shale 0 Of Coal . . . 0 Oi Fire clay Olf Hard shale 0 3 Thin laminae of coal and shale - 0 3^ Common coal ..--.-.---0 6 Fire clay 00 One of the chief characters of this cannel is its indestructibility under atmospheric agencies ; for whether it is taken from the mine at a depth of fifty fathoms, or at the out- crop, its gas and oil-yielding properties are the same. Even a piece of the mineral taken out of the drift deposits, where it had most probably lain for thousands of years, appears to be just the same in quality as if it had been but lately raised from the mine. In the earth the seam lies parallel to its roof and floor, like other beds of coal ; and it is traversed by the usual vertical joints, dividing it into the irregular cubes which so generally characterize beds of cannel. The roof lying above the cement stone contains remains of Catamites ; and the ironstone nodules, fossil shells of the genus Unio. The floor of the mine contains Stigmarice ; and the coal itself affords more upright stems of Sigillarice^ and its roots {Stigmarice) and their radicles, running through the seam to a considerable dis- tance, than the majority of coals show. In these respects it entirely resembles the Pirnie or Methill seam. Most cannels afford remains of fish ; but in Boghead no traces of these fossils have yet been met with, although they have been diligently sought after. The roots in the floors, and the upright stems of trees in the seam itself, appear to show that the vegetable matter now forming the coal grew on the spot where it is found. If the mangroves and other aquatic plants, at the present day found growing in the black vegetable mud of the marine swamps of Brass town, on the west coast of Africa, were quietly sub- merged and covered up with clay and silt, we should have a good illustration of the forma- tion of a bed of carbonaceous matter showing no structure, mingled with stems and roots of trees showing structure, which is the case of Boghead coal, the structure being only de- tected in those parts showing evidence of stems and roots, and not in the matrix in which those fossils are contained. The chemical changes by which vegetable matter has been converted into Boghead can- nel will not be here dwelt on ; but the chief peculiarity about the seam is its close and compact roof, composed of cement stone and shale. This is perfectly water and air-tight, so much so that, although the mine is troubled with a great quantity of water, it all comes through the floor, and not the roof. This tight covering of the coal has doubtless exercised considerable influence on the decomposing vegetable matter after the latter had been sub- merged. It is worthy of remark, that, above the Pirnie or Methill seam, — the coal nearest approaching Boghead, — a similar bed of impure ironstone occurs. Away from whin dykes which traverse the coal field, there are no appearances of the action of an elevated temperature, either upon the coal or its adjoining strata, to give any sanction to the hypothesis that the cannel has resulted from the partial decomposition of a substratum of coal by the heat of underlying trap, the volatile matters having been retained in what has probably been a bed of shale. First, it must be understood that Boghead can- nel, even when treated with boiling naphtha, affords scarcely a trace of bitumen ; and, secondly, when the seam of coal is examined in the neighborhood of a whin dyke, where heat has evidently acted on it, it is found nothing like cannel, but as a soft sticky substance, of a brown color, resembling burnt Indian-rubber. Besides these facts, the seams of coal and their accompanying strata, both above and below the cannel, show no signs of the ac- tion of heat, but, on the contrary, exhibit every appearance of having been deposited in the usual way, and of remaining without undergoing any particular altei’ation. — E. W. B. BOGHEAD NAPHTHA, {syn. Bathgate naphtha,) naphtha from the Boghead coal. See Naphtha, Boghead. BOG IRON ORE is an example of the recent formation of an ore of iron, arising from the decomposition of rocks, containing iron, by the action of water charged with carbonic BOILER. 168 acid. The production of this ore of iron in the present epoch, explains to us many of the conditions under which some of the more ancient beds of iron ore have been produced. Bog iron ore is common in the peat bogs of Ireland and other places. The iron manufactured from bog iron ore is what is called “ cold short,” from the pres- ence of phosphorus ; it cannot, therefore, be employed in the manufacture of wire, or of sheet iron ; but, from the fluidity of the metal, it is valuable for casting. It varies much in composition, some specimens giving 20 and others 70 per cent, of the peroxide of iron. Protoxide of iron and oxide of manganese are often present ; and as much as 10 per cent, of phosphorus and organic matter have been detected. See Iron. BOILER. See Boilers, vol. i. BOLE. A kind of clay, often highly colored by iron. It usually consists of silica, alu- mina, iron, lime, and magnesia. It is not a well-defined mineral, and, consequently, many substances are described by mineralogists as bole. Armenian hole is of a bright red color. This is frequently employed as a dentifrice, and in some cases it is administered medicinally. Bole of Blois is yellow, contains carbonate of lime, and efiervesces with acids. Bohemian hole is a yellowish red. French hole is of a pale red, with frequent streaks of yellow. Lemnian hole and Silisean hole are, in most respects, similar to the above-named va- rieties. The following analysis are by C. Van Hauer: — ’ Capo di Bove — Silica, 45*64 ; alumina, 29*33 ; peroxide of iron, 8*88 ; lime, 0'60 ; magnesia, a trace ; water, 14-27 = 98-72. New Holland — Silica, 38*22; alumina, 31*00; peroxide of iron, 11*00; lime, a trace; magnesia, a trace ; water, 18*81 = 99*03. BOLOGNIAN STONE. A sulphate of barytes, found in roundish masses, which phos- phoresces when, after calcination, it is exposed to the solar rays. BOMBAZINE. A worsted stuff mixed with silk ; it is a twilled fabric, of which the warp is silk and the weft worsted. BOMBYX MORI. The moth to which the silkworm turns. This species was originally brought from China. In this country the eggs of this moth are hatched early in May. The caterpillar (silkworm) is at first of a dark color ; but gradually, as with all other caterpillars, it becomes lighter colored. This worm is about eight weeks in arriving at maturity, during which time it frequently changes its color. When full grown, the silkworm commences spinning its web in some convenient place. The silkworm continues drawing its thread from various points, and attaching it to others ; it follows, therefore, that, after a time, the body becomes, in a great measure, enclosed in the thread. The work is then continued from one thread to another, the silkworm moving its head and spinning in a zigzag way, bending the fore part of the body back to spin in all directions within reach, and shifting the body only to cover with silk the part which was beneath it. As the silkworm spins its web by thus bending the fore part of the body back, and moves the hinder part of the body in such a way only as to enable it to reach the farther back with the fore part, it follows that it encloses itself in a cocoon much shorter than its own body ; for soon after the begin- ning, the whole is continued with the body in a bent position. During the time of spinning the cocoon, the silkworm decreases in length very considerably ; and after it is completed it is not half its original length ; at this time it becomes quite torpid, soon changes its skin, and appears in the form of a chrysalis. The time required to complete the cocoon is five days. In the chrysalis state the animal remains from a fortnight to three weeks; it then bursts its case, and comes forth in the imago state, the moth having previously dissolved a portion of the cocoon by means of a fluid which it ejects. — Penny Magazine. BON-BONS. Comfits and other sweetmeats of various descriptions pass under this name. A large quantity is regularly imported from France into this country, and, from its usually superior quality, it is much in request. The manufacture of sweetmeats, confectionary, &c., does not enter so far into the plan of this work as to warrant our giving any special detail of the various processes employed. Liqueur Bon-hons are made in the following manner : — A syrup evaporated to the proper consistence is made, and some alcoholic liqueur is added to it. Plaster of Paris models of the required form are made ; and these are employed, several being fastened to a rod, for the purpose of making moulds in powdered starch, filling shallow trays. The syrup is then, by means of a funnel, poured into these moulds, and there being a powerful repulsion be- tween the starch and the alcoholic syrup, the upper portion of the fluid assumes a spherical form ; then some starch is sifted over the surface, and the mould is placed in a warm closet. Crystallization commences on the outside of the bon-bon, forming a crust inclosing the syrup, which constantly gives up sugar to the crystallizing crust until it becomes sufficiently firm to admit of being removed. A man and two boys will make three hundredweights of bon-bons in a day. BONES. 169 Crystallized Bon-bons are prepared by putting them with a strong syrup contained in shallow dishes, placed on shelves in the drying chamber, pieces of linen being stretched over the surface, to prevent the formation of a crust upon the surface of the fluid. In two or three days the bon-bons are covered with crystals of sugar ; the syrup is then drained off, and the comfits dried. Painted Bon-bons. — Bon-bons are painted by being first covered with a layer of glazing ; they are then painted in body colors, mixed with mucilage and sugar. The French have some excellent regulations, carried out under the “ Prefet de Police,” as to the cotors which may be employed in confectionary. These are to the following effect : — • “ Considering that the coloring matter given to sweets, bon-bons, liqueurs, lozenges, &c., is generally imparted by mineral substances of a poisonous nature, which imprudence has been the cause of serious accidents ; and, that the same character of accidents have been produced by chewing or sucking the wrapping paper of such sweets, it being glazed and colored with substances which are poisonous ; it is expressly forbidden to make use of any mineral substance for coloring liqueurs, bon-bons, sugar-plums, lozenges, or any kind of sweetmeats or pastry. No other coloring matter than such as is of a vegetable character shall be employed for such a purpose. It is forbidden to wrap sweetmeats in paper glazed or colored with mineral substances. It is ordered that all confectioners, grocers, dealers in liqueurs, bon-bons, sweetmeats, lozenges, &c., shall have their name, address, and trade printed upon the paper in which the above articles shall be enclosed. All manufacturers and dealers are personally responsible for the accidents which shall be traced to the liqueurs, bon-bons, and other sweetmeats manufactured or sold by them.” If similar provisions were in force in this country, it would prevent the use, to an alarm- ing extent, in our cheap confectionary, of such poisonous substances as Arsenite of copper. Acetate of copper. Chromate of lead. Sulphide of arsenic, Oxide of lead. Sulphide of mercury, &c. The coloring matters allowed to be used in France are indigo, Prussian blue, saffron, Turkey yellow, quercitron, cochineal, Brazil wood, madder, &c. BONES. Heintz found that the fixed bases in the bones were sufficient to saturate completely the acids contained in them, so that the phosphate of lime, as well as the phos- phate of magnesia, which the bones contain, is composed, accoi’ding to the formula 3RO, PO®. Bone phosphate of lime was considered by Berzelius to be 8CaO, 3PO^. True bony struc- ture is perfectly free from chlorides, from sulphates, and from iron, these salts being only found when the liquid pervading the bones has not been completely removed. The bones in youth contain less earthy constituents than those of adults ; and, in advanced age, the proportion of mineral matters increases. Von Biria found more bone earth in the bones of birds than in those of mammals ; he found also the ratio of the carbonate of lime to the phosphate to be generally greater. In the bones of amphibia., he found less inorganic mat- ter than in those of mammals and birds ; and, in the bones of fishes., the earthy matters vary from 21 to 5Y per cent. The scales of fishes have a composition somewhat similar to that of bone, but they contain phosphate of lime in small quantity only. In certain diseases, (the craniotabes in children,) the earthy salts fall in the spongy por- tion of the bone as low as 28-16 per cent, of the dry bone ; and in several cases the propor- tion of earthy matter was found by Schlossberger as low as 50 per cent. At the age of 21 years, the weight of the skeleton is to that of the whole body in the ratio of 10*5 : 100 in man, and in that of 8*5 : 100 in woman, the weight of the body being about 125 or 130 lbs. The quantity of organic matter in fossil bones varies very considerably : in some cases it is found in as large a quantity as in fresh bones, while in others it is altogether wanting. Carbonate of lime generally occurs in far larger quantity in fossil than in recent bones, which may arise from infiltration of that salt from without, or from a decomposition of a portion of the phosphate of lime by carbonic acid or carbonates. Magnesia often occurs in larger quantities in the fossil remains of vertebrated animals than in the fresh bones of the present animal world. Liebig found in the cranial bones excavated at Pompeii a larger proportion of fluoride of calcium than in recent bones ; while, on the other hand, Girar- din and Preisser found that this salt had greatly diminished in bones which bad lain long in the earth, and, in some cases, had even wholly disappeared. The gelatinous tissue of bones was found by Von Biria to consist of Carbon Ox bones. - 60-401 - . Fossil bones. - 50-130 Hydrogen - - - - 7-111 - - - - 7-073 Nitrogen - - - 18-154 - . - - 18-449 Oxygen - . - 24-119 - . . - 24-348 Sulphur - 0-216 the same composition as that of the gelatinous tissues. BONES. 170 In the arts, bones are employed by turners, cutlers, manufacturers of animal charcoal, and, when calcined, by assayers, for making cupels. In agriculture, they are employed as a manure. Laid on in the form of dust, at the rate of 30 to 35 cwts. per acre, they have been known to increase the value of old pastures from 10s. or 15s. to 30s. or 40s. per acre ; and after the lapse of 20 years, though sensibly becoming less valuable, land has remained still worth two or three times the rent it paid before the bones were laid on. In the large dyeing establishments in Manchester, the bones are boiled in open pans for 24 hours, the fat skimmed off and sold to the candle makers, and the size afterwards boiled down in an- other vessel till it is of sufficient strength for stiffening the thick goods for which it is in- tended. The size liquor, when exhausted or no longer of sufficient strength, is applied with much benefit as a manure to the adjacent pasture and artificial grass lands, and the ex- hausted bones are readily bought up by the Lancashire and Cheshire farmers. When burned bones are digested in sulphuric acid diluted with twice its weight of water, a mixture of gypsum and acid phosphate of lime is obtained, which, when largely diluted with water, forms a most valuable liquid manure for grass land and for crops of rising corn ; or, to the acid solution, pearl ashes may be added, and the whole then dried up, by the addition of charcoal powder or vegetable mould, till it is sufficiently dry to be scattered with the hand as a top dressing, or buried in the land by means of a drill. In France, soup is extensively made by dissolving bones in a steam heat of two or three days’ continuance. Respecting the nutritive property of such soup, Liebig has expressed the following strong opinion : — “ Gelatine, even when accompanied by the savory constitu- ents of flesh, is not capable of supporting the vital process ; on the contrary, it diminishes the nutritive value of food, which it renders insufficient in quantity and inferior in quality, and it overloads the blood with nitrogenous products, the presence of which disturbs and impedes the organic processes.” The erroneous notion that gelatine is the active principle of soup, arose from the observation that soup made, by boiling, from meat, when concen- trated to a certain point, gelatinizes. The jelly was taken to be the true soup until it was found that the best meats did not yield the finest gelatine tablets, which were obtained most beautiful and transparent from tendons, feet, cartilage, bones, &c. This led to an investiga- tion on nutrition generally, the results of which proved that gelatine, which by itself is tasteless, and when eaten excites nausea, possesses no nutritive value whatever. The following table exhibits the relation between the combustible animal matter and the mineral substances of bones, as found by different observers : — Organic Portion. Inorganic Portion. Observers. Ox bones - . i ( 1 1 2-0 2-1 Berzelius. Marchand. 1 2-0 Berzelius. Human bones - 1 1 1- 8 to 2-3 ) 2- 0 in mean ) Frerichs. 1 1-6 to 2*2 ) 1 1*9 in mean Von Biria. Bird bones - 1 2-3 to 2-6 ) Prior to the use of bones by the turner or carver, they require the oil with which they are largely impregnated, to be extracted, by boiling them in water, and bleaching them in the sun or otherwise. This process of boiling, in place of softening, robs them of part of their gelatine, and therefore of part of their elasticity and contractibility likewise, and they become more brittle. The forms of the bones are altogether unfavorable to their extensive or ornamental employment : most of them are very thin and curved, contain large cellular cavities for marrow, and are interspersed with vessels that are visible after they are worked up into spoons, brushes, and articles of common turnery. The buttock and shin bones of the ox and calf are almost the only kinds used. To whiten the finished works, they are soaked in turpentine for a day, boiled in water for about an hour, and then polished with whitening and water. Iloltzapffel also informs us, that after the turning tool, or scraper, has been used, bone is polished, 1st, with glass paper ; 2d, with Trent sand, or Flanders brick, with water on flan- nel ; 3d, with whiting and water on a woollen rag ; 4th, a small quantity of white wax is rubbed on the work with a quick motion ; the wax fills the minute pores, but only a very minute portion should be allowed to remain on the work. Common bone articles, such as nail and tooth brushes, are frequently polished with slaked lime used wet on flannel or woollen cloth. See “ On Bone and its Uses,” by Arthur Aitkin, Trans, of Society of Arts., 1832 and 1839. The importance of the trade in bones will be seen from the following statement of Im- ports, in 1856, of the bones of animals and fish — not whalebone. BONE BLACK. m Tons. Computed real Value. Russia 13,383 £68,588 Norway 878 4,500 Denmark 2,636 13,609 Prussia 826 4,233 Hanover 551 2,824 Hanse Towns 4,073 20,874 Holland 4,453 22,822 France 881 4,515 Spain - 777 3,982 Tuscany 787 4,033 Two Sicilies 901 4,618 Austrian Italy 1,968 10,086 Turkey Proper 857 4,392 United States 589 3,019 Brazil - - - 7,812 40,036 Uruguay 15,457 79,217 Buenos Ayres 9,936 50,922 Australia 837 4,289 Other parts 3,347 17,154 - 70,949 £363,613 In 1857, of bones, whether burnt or not, or as animal charcoal, 63,951 tons. — H. M. N. BONE BLACK. The composition of perfectly dry bone black of average quality is as follows : — Phosphate of lime, with carbonate of lime, and a little sulphuret of iron, or oxide of iron, 88 parts ; iron in the state of silicated carburet, 2 parts ; charcoal containing about Vi 5 of nitrogen, 10 parts. None of the substances present, except the charcoal, possess separately any decolorizing power. It was formerly supposed that the peculiar absorbing and decoloring power of animal charcoal was only exerted towards bodies of organic origin ; but it was found, by Graham, that inorganic substances are equally subject to this action ; and later experiments have demonstrated that there are few, if any, chemical compounds which altogether resist the absorbing power of charcoal. The action is of a mechanical nature, and in some cases it is sufficiently powerful to overcome chemical affinities of considerable power. It is not con- fined to charcoal, though pre-eminent in this substance, in consequence of the immense ex- tent of surface which its porous structure presents. The action of charcoal in sugar refining has been particularly studied by Llldersdorf. When the defecated saccharine juice is allowed to flow upon a moist and firmly compressed charcoal filter, pure water is the first product that passes through ; but a considerably larger quantity is obtained than was em- ployed for moistening the charcoal. Water is then obtained of a decidedly saline character, which increases in strength, and after this has passed through for some time, a sweet taste becomes perceptible, which gradually increases, and at last entirely masks the saline. This purely sweet fluid continues to flow for some time ; after which, the liquid acquires an alkaline reaction from the presence of caustic lime ; it then becomes colored, the liquor getting gradually darker, till the action of the charcoal ceases. Lime is completely abstracted from lime water by bone charcoal ; and, according to the experiments of Cheval- lier, lead salts are likewise entirely absorbed, the acetate the most readily. It has also been shown by Graham, that iodine even is separated from iodine of potassium. The commercial value of animal charcoal has usually been estimated by its decoloring power on sulphate of indigo ; its absorbent power, which is a property of equal, perhaps of greater importance, may, according to M. Corenwinder, be determined, approximatively, by the quantity of lime which a given weight will absorb. For this purpose he employs a solution of saccharate of lime of known strength. An acid liquor is first prepared, composed of 20 grammes of pure oil of vitriol diluted with water to exactly 1 litre. A solution of saccharate of lime is then prepared, by dissolving 125 to 130 grammes of white sugar in water, adding thereto 15 to 20 grammes of quick-lime, boiling the liquid, and then filtering to separate the undissolved lime. This solution is prepared of such a nature, that it will be exactly saturated by the same volume of the dilute sulphuric acid. By adding the latter to 50 cubic centimetres of the liquid filtered from the animal charcoal, it is easy to see how many degrees of the burette are required to complete the saturation of the lime. Suppose 35 are required for this purpose, 100 — 35 = 65, which represent the proportion of lime absorbed by the char- coal : this is, therefore, the number representing the standard. By operating with a burette graduated from the bottom, the degree of the charcoal experimented upon may be read directly. BOOKBINDING. 172 BOOKBINDING. The process of sewing together the sheets of a book, and securing them with a back and side boards. Books are said to be either stitched^ or in hoards^ or half -bounds or hound. The first consists simply of stitching the sheets together. The second, of placing the sheets, after they have been stitched, between millboard sides, which are covered with paper or cloth, and with the backs lettered and ornamented. The third is a process of more perfectly se- curing the leaves, and of placing them between boards with a back of leather, the side-boards being covered with marble paper. Books are whole bound when the sides as well as the back are covered with leather. Bookbinding is performed in the following manner : — The sheets are first folded into a certain number of leaves, according to the form in which the book is to appear, as follows : — The folio consists of - 2 leaves “ quarto of 4“ “ octavo of - - - - - - - 8“ “ duodecimo of - - - - - - 12 “ When the leaves are thus folded and arranged in proper order, they are, if the books have been long printed., usually beaten upon a stone with a heavy hammer, to make them solid and smooth, and are then subjected to severe pressure in a powerful press ; but in the case of newly-printed books, pressure alone is considered sufficient. Beating, or severe pressure, would spoil the book ; because the ink, not being well dried, would “ set off” on the opposite pages. The employment in bookbinding of a rolling-press for smoothing and condensing the leaves, instead of the hammering which books have usually received, is an improvement introduced several years ago in the trade by Mr. W. Burn. His press consists of two iron cylinders about a foot in diameter, adjustable in the usual way by means of a screw, and put in motion by the power of one man, or of two if need be, applied to one or two winch- handles. In front of the press sits a boy who gathers the sheets into packets, by placing two, three, or four upon a piece of tin plate of the same size, and covering them with an- other piece of tin plate, and thus proceeding by alternating tin plates and bundles of sheets till a sufficient quantity has been put together, which will depend on the stiffness and thickness of the paper. The packet is then passed between the rollers and received by the man who turns the winch, and who has time to lay the sheets on one side and to hand over the tin plates by the time that the boy has prepared a second packet. A minion Bible may be passed through the press in one minute, whereas the time necessary to beat it would be twenty minutes. It is not, however, merely a saving of time that is gained by the use of the rolling-press ; the paper is made smoother than it would have been by beating ; and the compression is so much greater, that a rolled book will be reduced to about five-sixths of the thickness of the same book if beaten. A shelf, therefore, that will hold fifty books bound in the usual way, would hold nearly sixty of those bound in this manner — a circum- stance of no small importance, when it is considered how large a space even a moderate library occupies, and that book-cases are expensive articles of furniture. The rolling-press is now substituted for the hammer by our principal bookbinders. After the sheets have been thus prepared, they are sewed ; for which purpose the sew- ing press is employed. See Bookbindery, Vol. I. BORACIC ACID. {Acide Borique., Fr. BO^ ; chemical equivalent, 84*9 ; specific grav- ity, 1-83.) Supposed to be the chrysocolla of Pliny. In the seventh century, Geber mentions borax ; and it was described by Geoffroy and by Baron in the early part of the eighteenth century. Boracic acid was formerly called Homherg's s^edative salt. This acid occurs in several minerals, particularly as tincal, or crude biborate of soda, which is found in the form of incrustations in the beds of small lakes in Thibet, where it is dug up during the hot season. Sassolin, so called from its having been first obtained from one of the localities in Tuscany named Sasso, is native boracic acid. It is found abundantly in the crater of Vulcano, one of the Lipari Islands, forming a layer on the sulphur and around the fumaroles, or exits, of the sulphurous exhalations. The native stalactitic salt, according to Klaproth, contains mechanically mixed sulphate of magnesia and iron, sulphate of lime, silica, carbonate of lime, and alumina. Erdmann has stated that sassolin contains 3-18 per cent, by weight of ammonia, and, instead of being pure boracic acid, that it is a bo- rate of ammonia. Native boracic acid is composed of boracic acid, 66-4 ; water, 43 '6. — Dana. Professor Graham, in his “ Report on the Chemical Products of the Great Exhibition of 1851,” thus speaks of Larderel’s discovery : — “ The preparation of boracic acid by Count F. de Larderel, of Tuscany, was rewarded by a Council medal. Although this well-known manufacture is not recent, having attained its full development at least ten years, still the bold originality of its first conception, the per- severance and extraordinary resources displayed in the successful establishment, and the value of the product which it supplies, will always place the operations of Count de Larderel BORACIO ACID. 173 among the highest achievements of the useful arts, and demand the most honorable mention at this epoch. The vapor issuing from a volcanic soil is condensed, and the minute pro- portion of boracic acid which it contains (not exceeding 0*3 per cent.) is recovered by evaporation, in a district without fuel, by the application of volcanic vapor itself as a source of heat. The boracic acid thus obtained greatly exceeds in quantity the old and limited supply of borax from the upper districts of India, and has greatly extended the use of that salt in the glazes of porcelain, and recently in the making of the most brilliant crystal, when combined with the oxide of zinc instead of oxide of lead.” — Reports of the Jurors of the Great Exhibition 0 / 1851. The violence with which the scalding vapors escape from the suffioni gives rise to muddy explosions when a lake has been drained by turning its waters into another lake. The mud is then thrown out, as solid matters are ejected from volcanoes, and there is formed in the bottom of the lake a crowd of little cones of eruption, whose temperatures when in activity and play are generally from 120 ° to 145° C., and the clouds which they form in the lagoons constitute true natural barometers, whose greater or less density rarely disappoints the predictions that they announce to the inhabitants of those lagoons. The boracic acid of the Tuscan lagoons is obtained from nine different works belonging to Count Larderel, the produce of which is on the average as follows : — Sasso 36,000 lbs. per month. Larderello 32,700 “ Lervazauo 20,270 “ Monte Cerboli 19,125 “ Castel Nuovo 16,870 “ Monte Rotondo 16,850 “ San Frederigo 9,000 “ Lustignano 7,640 “ Lago 5,400 “ 163,855 avoirdupois pounds. M. Payen has given the following as the composition of this crude boracic acid for 100 kilogrammes : — Pure crystallized boracic acid 74 to 84 Sulphate of ammonia I “ of magnesia “ of lime 14 to 8 Chloride of iron - Alumina - J Sand, &c. ) _ 2*5 to 1*25 Sulphur ) Hygroscopic water disengaged at 35° C. ... 7 to 5*75 Azotic organic matter ~ } Hydrochlorate of ammonia - f “ ‘ - 2*5 to 1 Hydrochloric and hydrosulphuric acid } * The processes of chemical alteration taking place beneath the crater of Vulcano, already spoken of, may, according to the statement of Hoffmann, depend upon conditions very similar to those existing in Tuscany. There, likewise, sulphuretted hydrogen is associated with the boracic acid, and, it would appear, in much greater quantity, since the fissures through which the vapor issues are thickly lined with sulphur, which is in sufl5cient quantity to be collected for sale. A profitable factory is established at the place, which yields daily, besides boracic acid and chloride of ammonium, about 1,700 lbs. of refined sulphur, and about 600 lbs. of pure alum. — Bischof. In 1855 our Imports were : — Cwts. Computed real Yalue. Boracic acid from Sardinia - - 85 - - - £383 “ “ Tuscany - 26,777 - - - 121,163 “ “ Gibraltar - • 947 - - - 4,285 27,809 £125,831 And in 1856 : — Cwts. Computed real Value. Boracic acid from Sardinia - - 313- - - £1,377 “ “ Tuscany - 25,063 - - - 110,264 “ “ Peru - - 1,453 - - - 6,394 “ “ other parts . 1 - . - 4 26,830 £118,039 174 BORAX. BORAX. {Borax, Fr. ; Borar, Germ.) Anhydrous Borax is composed of- 1 equivalent of boracic acid 872 or 69*0 1 soda - 390 “ 31*0 1262 for 100*0 Octahedral Borax — 1 equivalent of 1 boracic acid 872 or 47*7 soda - 390 “ 21*3 6 “ water 562*5 “ 31*0 1824*5 for 100*0 Prismatic Borax — 1 equivalent of boracic acid 872 or 36*65 1 soda - 390 “ 16*35 10 “ water • 1*125 “ 47*1 2*387 for 100*00 Tincal was originally brought from a salt lake in Thibet ; the borax was dug in masses from the edges and shallow parts of the lake ; and in the course of a short time the holes thus made were again filled. The borate of soda has been found at Potosi, in Peru ; and it has been discovered by Mr. T. Sterry Hunt, of the Geological Survey, in Canada, from whose report the following extract is made : — “In the township of Joly there occurs a very interesting spring on the banks of the Ruisseau Magnenat, a branch of the Riviere Souci, about five miles from the mills of Methot at Saint Croix. The spring furnishes three or four gallons a minute of a water which is sulphurous to the taste and smell, and deposits a white matter along its channel, which exhibits the purple vegetation generally met with in sulphur springs. The tem- perature of this spring in the evening of one 7th of July was 46° F., the air being 62° F. The water is not strongly saline, but when concentrated is very alkaline and salt to the taste. It contains, besides chlorides, sulphates, and carbonates, a considerable propor- tion of boracic acid, which is made evident by its power of reddening paper colored by turmeric, after being supersaturated with hydrochloric acid. . . . The analysis of 1,000 parts of the water gave as follows: — Chloride of sodium 0*3818 “ potassium 0*0067 Sulphate of soda 0*0215 Carbonate and borate of do. 0.2301 “ of lime 0*0620 “ magnesia 0*0257 Silica 0*0245 Alumina a trace 0*7523 “The amount of boracic acid estimated was found to be equal to 0*0279.” * Professor Bechi has analyzed a borate occurring as an incrustation at the Tuscan lagoons, which afforded boracic acid 43*56, soda 19*25, and water 37*19. Lagonite is a mineral of an earthy yellow color, which appears to be boracic acid and iron ; while Lar- dcrellite^ also from Tuscany, is a compound of boracic acid and soda. See Dana^ and “American Journal of Science.” BORING. The importance of boring, as a means of searching for coal and for water, renders it necessary that some special attention should be given to the subject in a work * devoted to manufactures and mining. Boring for water appears to have been in use from the earliest periods, in Egypt and in Asia. In many of the desert tracts there are remains of borings, which served, evi- dently, at one period, to supply the wants of extensive populations which once inhabited those now deserted regions. In the “ Guide du Sondeur,” by M. J. Degousee, we find it stated, with reference to China, “ There exists in the canton of Ou-Tong-Kiao many thousand wells in a space of ten leagues long by five broad. These wells cost a thousand and some hundred taels, (the tael being of the value of 6s. 6c?.,) and are from 1,500 to 1,800 feet deep, and about 6 inches in diameter. To bore these wells, the Chinese com- mence by placing in the earth a wooden tube of 3 or 4 inches diameter, surmounted by a stone edge, pierced by an orifice of 5 or 6 inches ; in the tube a trepan is allowed to play, weighing 300 or 400 lbs. A man, mounted on a scaffold, swings a block, which raises the trepan 2 feet high, and lets it fall by its own weight. The trepan is secured to the swing-lever by a cord made of reeds, to which is attached a triangle of wood ; a man BORING. 175 sits close to the cord, and at each rise of the swing seizes the triangle and gives it a half turn, so that the trepan may take in falling another direction. A change of workmen goes on day and night, and with this continuous labor they are sometimes three years in boring wells to the requisite depth.” Boring appears to have been practised in England during the last century, but to a very limited extent; it has, however, for a considerable period been employed in seeking for coal, and in the formation of wells. The ordinary practice of boring is usually carried out, by first sinking a well of such a depth that the boring apparatus can be fixed in it; and thus a stage, raised from the surface of the ground, is dispensed with. A stout plank floor, well braced together by planks nailed transversely and resting on putlocks, forms the stage. In the centre of the floor is a square hole, through which the boring-rods pass. The boring-rods are of many different forms. A few are represented in the following figure, (70.) 1, 2, 3 are an elevation, plan, and section of an auger; the tapped socket is for the purpose of allowing the rods to be screwed into it. 4, 5 are two views of a small auger, with a longitudinal slit, and no valve, which is used for boring through clay and loam. In very stiff clay the slit is generally made larger ; in moist ground the slit is objectionable. 6, 7, 8 are different views of a shell, a a are valves opening upwards, to admit the material. These tools are used for boring through sand, or through ground which has been loosened by other tools. 9, 10, 11 show an S chisel, for cutting through rocks, flints, and the like. Such are the principal tools employed. The boring-rods are turned round by the leverage of two handles moved by man, or, where the work is heavy, by horse, or, some- times, even steam power is applied. Besides the circular motion of the tool, a vertical percussive action of the same is required in certain cases, such as rock or hard sand ; indeed, always, where the position of the auger or chisel requires a fresh place to act upon during its revolution. This motion is most readily got by suspending the boring- rods to a windlass, through the intervention of a rope coiled two or three times round the latter, and adjusting it so that if the workman holds one end of the coil tight, suffi- 70 176 BORING. cient will be the friction to raise the rods on putting the windlass in motion. Should the end of the rope the workman holds now be slackened, the coil becomes loose, and the rods descend with a force equivalent to their weight and the distance through which they have fallen. A regular percussive action is thus gained by keeping the windlass contin- ually in motion in one direction, the attendant w'orkman alternately allowing the rods to be drawn up a certain distance, and then, by relaxing his hold, allowing them to fall. — — Swindell^ on Boring. The following list of the prices of boring, in different localities, may prove useful: — In the North of England, the prices for boring, in the ordinary strata of the district or of that coal field, are as follows : — s. d. First 5 fathoms - - - - - 5 6 per fathom. Seconds “ 11 0 “ Third 5 “ 16 6 “ Fourth 5 “ 22 0 “ and so increasing 5s. 6cf. per fathom on each succeeding depth of 5 fathoms. When any unusually hard strata are met with, the borer is paid by special arrangement, unless a binding contract has been previously made. It is sometimes usual for the borer to take all risk of hard strata, when the prices are as follows, the borer finding the tools : — s. d. First 5 fathoms 7 6 per fathom. Seconds “ 15 0 Third 6 “ ..... 22 6 “ Fourth 5 “ 30 0 “ and so increasing 7s. 6c?. per fathom on each succeeding depth of 5 fathoms. In the Midland Counties, where the strata are more inclined than in the north of Eng- land, the prices for ordinary strata are as follows : — s. d. First 20 yards 3 6 per yard. Next 10 “ 5 0 “ “ 10 “ 6 6 “ “ 10 “ 8 0 “ “ 10 “ 9 6“ and so advancing Is. 6c?. per yard upon each 10 yards. In some localities, where the boring is still more favorable, the prices are as follows, — the bore hole being 2^ to 2| inches diameter : — s. d. First 20 yards 36 per yard. Next 10 “ 4 6“ “ 10 “ - - - - - 5 6 “ “ 10 “ 6 6“ “ 10 “ 7 6“ In boring strata of unusual hardness, a special arrangement is made, as before stated, and the borer is allowed some payment for filling up and for removing tackling. In Scotland the general prices for boring are as follows : — s. d. First 5 fathoms 5 0 per fathom Second 5 “ 10 0 “ Third 5 “ 15 0 “ Fourth 5 “ 20 0 and so advancing 5s. per fathom for each succeeding 5 fathoms. In boring through very hard strata, the work is done either by shaft-work, or at the following rates, the bore hole being 2f inches diameter : — s. d. First 5 fathoms 10 0 per fathom. Second 5 “ 20 0 “ Third 5 “ 80 0 “ The borer usually specifies to have his tackle laid down ready for erecting at the cost of the employer. ■ As the boring proceeds, it is often necessary to lower pipes into the hole made, to pre- vent the falling of fragments from the sides of the cylinder. There are many ingenious contrivances for effecting this, which need not be described in this place. See Pit Coal, vol. i. BKASS. 177 BORON. One of the non-metallic elements ; it exists in nature in the form of boracic acid, and as borax, tincal, &c. Homberg is said to have obtained boron from borax in 1702 ; if so, his discovery appears to have been forgotten, since it was unknown, except hypothetically, to the more modern chemists until, in 1808, it was obtained by Gay-Lussac and Thenard, and by Davy in 1808, who decomposed boracic acid into boron and oxygen. Boron is best obtained by preparing the double fluoride of boron and potassium, (3KF 2BF^,) by saturating hydrofluoric acid with boracic acid, and then gradually adding fluoride of potassium. The difficultly soluble double compound thus produced is collected and dried at a temperature nearly approaching to redness. This compound is then powdered and introduced into an iron tube closed at one end, together with an equal weight of potas- sium, whereupon heat is applied sufficient to melt the latter, and the mixture of the two substances is effected by stirring with an iron wire. Upon the mass being exposed to a red heat, the potassium abstracts the fluorine. The fluoride of potassium may afterwards be removed by heating the mass with a solution of chloride of ammonium, which converts the free potassa into chloride of potassium, and thus prevents the oxidation of the boron, which takes place in the presence of fixed alkali ; the chloride of ammonium adhering to the boron may be afterwards removed by treatment with alcohol. Boron is a dark greenish- brown powder, tasteless, and inodorous ; its chemical equivalent is 10*9, or, according to Laurent, 1 1 ’0. BOTTLE MANUFACTURE. See Glass and Pottery. BOULDERING STONE. A name given by the Sheffield cutlers to the smooth flint pebbles with which they smooth down the faces of buff* and wooden wheels. As these stones are usually taken from gravel pits, the name is, no doubt, used in the same sense as the geologist uses the word boulder. BOX WOOD. {Buis., Fr. ; Buchshaum^ Germ. ;) Buxus sempervirens. — Two varieties of box wood are imported into this country. The European is brought from Leghorn, Por- tugal, &c. ; and the Turkey box wood from Constantinople, Smyrna, and the Black Sea. English box wood grows plentifully at Box Hill, in Surrey, and in Gloucestershire. The English box wood is used for common turnery, and is preferred by brass finishers for their lathe-chucks, as it is tougher than the foreign box, and bears rougher usage. It is of very slow growth, as in the space of 25 years it will only attain a diameter of to 2 inches. — Holtzapffel. Box wood is used for making clarionets and flutes, carpenters’ rules, and drawing scales. As the wood is peculiarly free from gritty matter, its sawdust is used for cleaning jewellery. Box wood is exclusively employed by the wood engraver. See Engraving on Wood. . A similar wood was imported from America by the name of Tugmutton., which was used for making ladies’ fans ; but we cannot learn that it is now employed. BRASS. The table on the following page, for the compilation of which we are indebted to Mr. Robert Mallet, C. E., presents, in a very intelligible form, the chemical and physical conditions of the various kinds of brass : — Brass Color, for staining glass, is prepared by exposing for several days thin plates of brass upon tiles in the leer., or annealing arch of the glass house, till they are oxidized into a black powder, aggregated in lumps. This being pulverized and sifted, is to be again well calcined for several days more, till no particles remain in the metallic state, when it will form a fine powder of a russet-brown color. A third calcination must now be given with a carefully regulated heat, its quality being tested from time to time by fusion with some glass. If it makes the glass swell and intumesce, it is properly prepared ; if not, it must be still further calcined. Such a powder communicates to glass greens of various tints, passing into turquoise. When thin narrow strips of brass are stratified with sulphur in a crucible and calcined at a red heat, they become friable and may be reduced to powder. This being sifted and exposed upon tiles in a reverberatory furnace for 10 or 12 days, becomes fit for use, and is capable of imparting a chalcedony — red or yellow — tinge to glass by fusion, according to the mode and proportion of using it. The glassmakers’ red color may be prepared by exposing small plates of brass to a mode- rate heat in a reverberatory furnace till they are thoroughly calcined, when the substance becomes pulverulent, and assumes a red color. It is then ready for immediate use. Mr. Holtzapffel, in his “ Mechanical Manipulation,” has given some very important descriptions of alloys. From his long experience in manufacture, no one was more capable than Mr. Holtzapffel to speak with authority on the alloys of copper and zinc. From his work the following particulars have been obtained : — The red color of copper slides into that of yellow brass at about 4 or 5 ounces of zinc to the pound of copper, and remains little altered unto about 8 or 10 ounces ; after this it becomes whiter, and when 32 ounces of zinc are added to 16 of copper, the mixture has the brilliant silvery color of speculum metal, but with a bluish tint. These alloys — from about 8 to 16 ounces to the pound of copper — are extensively used VoL. III.— 12 178 BRASS. BRAZIL WOOD. 179 for dipping, a process adopted for giving a fine color to an enormous variety of furniture work. The alloys with zinc retain their malleability and ductility well unto about 8 or 10 ounces to the pound ; after this the crystalline character slowly begins to prevail. The alloy of 2 zinc and 1 copper may be crumbled in a mortar when cold. In the following list, the quantity of zinc employed to 1 lb. of copper is given : — 1 to H oz. gilding metal for common jewellery. 3 to 4 oz. Bath metal, pinchbeck, Mannheim gold, Similor ; and alloys bearing various names, and resembling inferior jewellers’ gold. 8 oz. Emerson’s patent brass. lOVs oz. Muntz’s metal, or 40 zinc and 60 copper. “ Any proportion,” says the patentee, “ between the extremes, 60 zinc and 50 copper and 37 zinc and 63 copper, will roll and work well at a red heat.” 16 oz. soft spelter solder, suitable for ordinary brass work. 1 6^ oz. Hamilton and Parker’s patent mosaic gold. Brass is extensively employed for the bearings of machinery. Several patents have been taken out for compositions varying but slightly. The following, for improvements in cast- ing the bearings and brasses of machinery, appears important : — Mr. W. Hewitson, of Leeds, directs, in his patent, that the proper mixture of alloy, copper, tin, and zinc, should be run into metal or “ chill ” moulds, in place of the ordinary mould. In large castings, it is found more especially that the metals do not mix intimately in cooling, or, rather, they ar- range themselves into groups when cast in sand, and the bearings are found to wear out more quickly ; but if the bearings are cast so that the alloy comes in contact with metal, the mixture is more intimate, and the bearings last longer than if cast in dry or green sand moulds. Mr. Hewitson generally only applies these chill-metal surfaces of the moulds to those parts of a brass, or bearing, that are to receive the shaft or bear the axis of a machine. The chills are preferred of iron, perforated with holes (Vte to Vs inch) for the passage of air or vapors ; the surface should be thinly coated with loam, and heated to about 200°. Fenton’s patent metal consists of copper, spelter, and tin ; it has less specific gravity than gun metal, and is described as being “ of a more soapy nature,” by which, conse- quently, the consumption of oil or grease is lessened. Many of the patentees of bearing-metals assure us that the metals they now use differ very considerably from the statement in their specifications. Surely this requires a careful examination. We exported of our brass manufactures, in 1856, 19,198 cwts., the declared real value of which was £121,206. BRASSING IRON. Iron ornaments are covered with copper or brass by properly preparing the surface, so as to remove all organic matter, which would prevent adhesion, and then plunging them into melted brass. A thin coating is thus spread over the iron, and it admits of being polished or burnished. The electro-magnetic process is now employed for the purpose of precipitating brass on iron. This process was first mentioned in Shaw’s “ Metallurgy,” in 1844, where he remarks, “ In depositing copper upon iron, a solution of the cyanide or acetate of copper should be employed. The only value of these salts is, that a die or surface of iron may be immersed in their solutions without receiving injury by the corrosion consequent upon the deposition of a film of metal by chemical action.” The fol- lowing solutions are recommended by Dr. Woods, in the “ Scientific American,” for coat- ing iron with copper, iron, or brass, by the electrotype process ; — To make a Solution of Copper or Zinc. — Dissolve 8 ounces (troy) cyanide of potassium and 3 ounces of cyanide of copper or zinc in 1 gallon of rain or distilled water. These solu- tions to be used at about 160° F. with a compound battery of from 3 to 12 cells. To prepare a Solution of Brass. — Dissolve 1 lb. (troy) cyanide of potassium, 2 ounces of cyanide of copper, and 1 ounce of cyanide of zinc, in 1 gallon of rain or distilled water ; then add 2 ounces of muriate of ammonia. This solution is to be used at 160° F. for smooth work, and from 90° to 120°, with a compound battery of from 3 to 12 cells. See Electro-Metallurgy. BRAZIL WOOD. The ibiripitanga., or Brazil wood, called, in Pernambuco, pao da rainha, (Queen’s wood,) on account of its being a Government monopoly, is now rarely to be seen within many leagues of the coast, owing to the improvident manner in which it has been cut down by the Government agents, without any regard being paid to the size of the tree or its cultivation. It is not a lofty tree. At a short distance from the ground, innu- merable branches spring forth and extend in every direction in a straggling, irregular, and unpleasing manner. The leaves are small and not luxuriant ; the wood is very hard and heavy, takes a high polish, and sinks in water : the only valuable portion of it is the heart, as the outward coat of wood has not any peculiarity. The name of this wood is derived from hrasas, a glowing fire or coal ; its botanical name is Ccesalpinia Brasileto. The leaves are pinnated, the flower white and papilionaceous, growing in a pyramidal spike ; one spe- 180 BEE AD. cies has flowers variegated with red. The branches are slender and full of small prickles. There are nine species. See Bell’s “ Geography.” The species BrasiletOy which is inferior to the crista^ grows in great abundance in the West Indies. The demand for the Brasileto^ a few years ago, was so great, owing to its being a little cheaper than the crista^ that nearly the whole trees in the British possessions were cut down and sent home, which Mr. Bell very justly terms improvidence. It is not now so much used, and is consequently scarcer in the English market. The wood known in commerce as Pernambuco is most esteemed, and has the greatest quantity of coloring matter. It is hard, has a yellow color when newly cut, but turns red by exposure to the air. That kind termed Lima wood is the same in quality. Sapan wood grows in Japan, and in quality is next the two named above. . It is not plentiful, but is much valued in the dyehouse for red of a certain tint ; it gives a very clear and superior color. The quantity of ash that these two qualities of wood contain is worthy of remark. Lima wood, as imported, gives the average of 2'7 per cent., while Sapan wood gives 1‘5 per cent. ; in both, the prevailing earth is lime. The quantity of moisture in the wood averages about 10 per cent. ; that in the ground wood in the market about 20 per cent. Peach wood, or Nicaragua, and sometimes termed Santa Martha wood, is inferior to the other two named, but is much used in the dyehouse, and, for many shades of red, is pre- ferred, although the coloring matter is not so great. It gives a bright dye. The means of testing the quality of these woods by the dyer is similar to that describey for logwood, with the same recommendations and precautions. — Napier on Dyeing. BREAD. One of the most important, if not altogether the most important, article of food, unquestionably, is bread ; and although rye, barley, oats, and other cereals are some- times used by the baker, wheat is the grain which is best fitted for the manufacture of that article, not only on account of the larger amount of gluten, or nitrogenous matter, which it contains, and than can be found in other edible grains, but also on account of the almost exact balance in which the nitrogenous and non-nitrogenous constituents exist in that cereal, and owing to which it is capable of ministering to all the requirements of the human frame, and of being assimilated at once and without effort by our organs, whence the name of “ staff of life,” which is often given to it, wheat being, like milk, a perfect food. Although gluten is one of the most important constituents of wheat, the nutritive power of its flour, and its value as a bread-making material, should not be altogether considered as dependent upon the quantity of gluten it may contain, even though it be of the best quality. Doubtless a high percentage of this material is desirable, b^ut there are other considerations which must be taken into account ; for, in order to become available for making good bread, flour, in addition to being sound and genuine, must possess other qualities beyond containing merely a large amount of gluten. Thus, for example, the ble rouge glace d"' Auvergne, which contains hardly 45 per cent, of starch, and as much as 36 per cent, of gluten, though admirably adapted for the manufacture of macaroni, vermicelli, semolina, and other pates dPtalie, is totally unfit for making good bread ; the flour used for making best white loaves containing only from 10 to 18 per cent, of gluten, and from 60 to 70 per cent, of starch. Bread is obtained by baking a dough, previously fermented either by an admixture of yeast or leaven, or it is artificially rendered spongy by causing an acid, muriatic or tartaric, to react upon carbonate or bicarbonate of soda, or of ammonia, mixed in the doughy mass ; or, as in Dr. Dauglish’s process, which will be described further on, by mixing the flour which has to be converted into dough, not with ordinary water, but with water strongly im- pregnated with carbonic acid. The conversion of flour into bread includes two distinct operations — namely, the prepa- ration of the dough, and the baking. The preparation of the dough, however, though reckoned as one, consists, in fact, of three operations — namely, hydrating, kneading, and fermenting. When the baker intends to make a batch of bread, his first care is, in technical lan- guage, to stir a ferment. This is done, in London, by boiling a few potatoes, in the pro- portion of 5 lbs. or 6 lbs. of potatoes per sack of flour, (which is the quantity we shall assume it is desired to convert into bread,) peeling them, mashing and straining them through a cullender, and adding thereto about three-quarters of a pailful of water, 2 or 8 lbs. of flour, and one quart of yeast. The water employed need not be warmed beforehand, for the heat of the potatoes is sufficient to impart a proper temperature (from 70° to 90° F.) to the liquid mass, which should be well stirred up with the hand into a smooth, thin, and homo- geneous paste, and then left at rest. In the course of an hour or two, the mass is seen to rise and fall, which swelling and heaving up is due to carbonic acid, generated by the fermentation induced in the mass, which may be thus left until wanted. In about three hours, this fermenting action will appear to be at an end, and when it has arrived at that stage, it is fit to be used. The fer- ment, however, may be left for six or seven hours and be still very good at the end of that time, but the common practice is to use it within four or five hours aJter its preparation. ^ BREAD. 181 The next operation consists in “ setting the sponged This consists in stirring the fer- ment well, adding thereto about two gallons of lukewarm water, and as much flour as will make, with the ferment, a rather stiff dough. This constitutes “ the sponged It is kept in a warm situation, and in the course of about an hour, fermentation again begins to make its appearance, the mass becomes distended or is heaved up by the carbonic acid produced, the escape of which is impeded by the toughness of the mass. This carbonic acid is the result of the fermentation induced under the influence of water, by the action of the gluten upon the starch, a portion of which is converted thereby into sugar, and then into alcohol. A time, however, soon comes when the quantity of carbonic acid thus pent up becomes so great that it bursts through, and the sponge collapses or drops down. This is called the first sponge ; but as the fermentation is still going on, the carbonic acid soon causes the sponge to rise again as before to nearly twice its volume, when the carbonic acid, bursting through the mass, causes it to fall a second time ; and this constitutes what the bakers call the second sponge. The rising and falling might then go on for twenty-four hours ; but as the alco- holic would pass into the acetous fermentation soon after the second rising, the baker always interferes after the second, and very frequently after the first sponge. The bread made from the first sponge is generally sweeter ; but, unless the best flour is used, and even then, the loaf that is made from it is smaller in size and more compact than that which is made with the second sponge. In hot weather, however, as there would be much danger of the bread turning sour, if the sponge were allowed to “ take a second fallfi the first sponge is frequently used. The next process consists in breaking the sponge^ which is done by adding to it the necessary quantity of water and of salt, — the quantity of the latter substance vary- ing from \ lb. to f of a pound per bushel of flour ; that is, from 2^ lbs. to 3f lbs. per sack of flour, (new flour, or flour of inferior quality, always requires, at the very least, 3^ lbs. per sack, to hind it., that is to say, to render the dough sufficiently firm to support itself while fermenting.) Salt acts, to a great extent, like alum, though not so powerfully. As to the quantity of water to be used, it depends also a great deal on the quality of the flour, the best quality absorbing most ; though, as we shall have occasion to remark, the baker too often contrives to force and keep into bread made from inferior flour, by a process called under-baking, the same amount of water as is normally taken up by that of the best quality. Generally speaking, and with flour of good average quality, the amount of water is such that the diluted sponge forms about 14 gallons of liquid. The whole mass is then torn to pieces by the hand, so as to break any lumps that there may be, and mix it up thoroughly with the water. This being done, the rest of the sack of flour is gradually added and kneaded into a dough of the proper consistency. This kneading of the dough may be said to be one of the most important processes of the manufacture, since it not only produces a more com- plete hydration of the flour, but, by imprisoning a certain quantity of air within the dough, and forcibly bringing into closer contact the molecules of the yeast or leaven with the sugar of the flour, and also with a portion of the starch, the fermentation or rising of the whole mass, on which the sponginess of the loaf and its digestibility subsequently depend, is se- cured. When, by forcing the hand into the dough, the baker sees that, on withdrawing it, none of the dough adheres to it, he knows that the kneading is completed. The dough is then allowed to remain in the trough for about an hour and a half or two hours, if brewers' or German yeast have been employed in making the sponge ; if, on the contrary, patent yeast or hop yeast have been used, three or even four hours may be required for the dough to rise up, or, as in technical language, to give proof. When the dough is sufficiently proof edfi it is weighed off into lumps, shaped into the proper forms, of 4 lbs. 4 oz. each, and exposed for about one hour in an oven to a temperature of about 570° F., the heat gradually falling to 430 or 420° F. The yield after baking is 94 quartern (not 4-lb.) loaves, or from 90 to 92 really 4-lb. loaves, as large again as they were when put into the oven in the shape of dough. The manner in which yeast acts upon the flour is, as yet, an unsolved mystery, or, at any rate an, as yet, unsatisfactorily explained action ; for the term “ catalysis,” which has sometimes been applied to it, explains absolutely nothing. A yeast, or fermenting material, may be prepared in various ways ; but only three kinds of yeast are used by bakers ; namely, brewers’ yeast, or barm, — German yeast, and patent, or hop yeast. The most active of these ferments is the first, or brewers’ yeast ; it is, as is well known, a frothy, thickish material, of a brownish or drab color, which, when recent, is in a state of slight effervescence, exhales a sour characteristic odor, and has an acid reaction. When viewed through the microscope, it is seen to consist of small globules of various size, generally egg-shaped. They were first described by M. Desmayieres. The best, and in fact the only brewers’ yeast used in bread-making, is that from the ale breweries ; porter yeast is unavailable for the purpose, because it imparts to the bread a dis- agreeable bitter taste. German yeast is very extensively used by bakers. It is a pasty but easily crumbled mass, of an agreeable fruity odor, and of a dingy white color. German yeast will remain 182 BEEAD. good for a few weeks, if kept in a cool place. When in good condition, it is an excellent article ; but samples of it are occasionally seized on bakers’ premises, of a darker color, vis- cid, and emitting an offensive cheesy odor : such German yeast, being in a putrefied state, is, of course, objectionable. The so-called ^'‘patent yeasV is the cheapest and at the same time the weakest of these ferments ; very good bread, however, is made with it, and it is most extensively used by bakers. It is made either with or without hops : when with hops, it is called hop yeasty and is nothing more than a decoction of hops to which malt is added while in a scalding hot state ; when the liquor has fallen to a blood heat, a certain quantity of brewers’ or German yeast is thoroughly mixed with it, and the whole is left at rest. The use of the hops is in- tended to diminish the tendency of this solution to become acid. Potato yeast is a kind of '‘'‘patent yeast ” in general use. The theory of panification is not difficult of comprehension. “ The flour,” says Dr. Ure, “ owes this valuable quality to the gluten, which it contains in greater abundance than any of the other cerealia, (kinds of corn.) This substance does not constitute, as has been here- tofore imagined, the membranes of the tissue of the perisperm 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 situation analogous to that of the starch, and of most of the im- mediate principles of the vegetables. The other immediate principles 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 com- pleting these reactions through a more intimate union, favors also the fermentation of the sugar, by bringing its particles into close contact with those of the leaven or yeast ; and the drawing out and laminating the dough softens and stratifies it, introducing at the same time oxygen to aid the fermentation. 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 pro- pitious to the development of their volume by fermentation. The dimensions of all the lumps of dough now gradually enlarge, from the disengagement of carbonic acid in the de- composition of the sugar, which gas is imprisoned by the glutinous paste. Were these phe- nomena to continue too long, the dough would become too vesicular ; they must, therefore, be stopped at the proper point of sponginess, by placing 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 the water. “ The fermentation of a small dose of sugar is, therefore, essential to true bread-making ; but the quantity actually fermented is so small as to be almost inappreciable. It seems probable that in well-made dough the whole carbonic acid that is generated remains in it, amounting to one-half the volume of the loaf itself at its baking temperature, or 212° F. It thence results that less than one-hundredth part of the weight of the flour is all the sugar requisite to produce well-raised bread. “ Although the rising of the dough is determined by the carbonic acid resulting from the decomposition of the sugar, produced by the reaction of the gluten on hydrated or moist flour, considering that the quantity of sugar necessary to produce fermentation does not amount, probably, to more than one-hundredth part of the weight of the flour employed, and perhaps to even considerably less than that, — the saving and economy which is said to accrue to the consumer from the use of unfermented bread (which is bread in which the ac- tion of yeast is replaced by an artificial evolution of carbonic acid, by decomposing bicar- bonate of soda with muriatic acid, as we said before) is therefore much below what it has been estimated (25 per cent. !) by some writers ; and it is certainly very far from compen- sating for the various and serious drawbacks which are peculiar to that kind of bread, one of which — and it is not the least — is its indigestibility, notwithstanding all that may have been said to the contrary. “ In a pamphlet entitled, ‘ Instructions for making Unfermented Bread, by a Physician,’ published in 1846, the formula recommended for bread made of wheat meal is as follows : Wheat meal - - - - 3 lbs. avoirdupois. 4^ drachms troy. 5 fluid drachms and 25 minims, or drops. 30 fluid ounces, f of an ounce troy. “ Bread made in this manner,” says the author, “ contains nothing but flour, common salt, and water. It has an agreeable, natural taste, keeps much longer than common bread, is much more digestible^ and much less disposed to turn acid,” &c. Liebig, in his “ Letters on Chemistry,” very judiciously remarks, “ that the intimate mixture of the saliva with the bread, whilst masticating it, is a condition which is favorable to the rapid digestion of the starch ; wherefore the porous state of the flour in fermented bread accelerates its digestion.” Now, it is a fact, which can readily be ascertained by any one, that unfermented bread Bicarbonate of soda Hydrochloric acid - Water - - - Salt . - - BREAD. 183 is permeated by fluids with difficulty. It will not absorb water, hence its heavy and clammy feel ; nor saliv^, hence its indigestibleness ; nor milk, nor butter. Unfermented bread will neither make soup, nor toast, nor poultice. When a slice of ordinary bread is held before a bright fire, a portion of the moisture of the bread, as the latter becomes scorched, is con- verted into steam, which penetrates the interior of the mass, and imparts to it the spongi- ness so well known in a toast properly made ; but if a piece of unfermented bread be treated in the same manner, the steam produced by the moisture, not being able to penetrate the unabsorbent mass, evaporates, and the result is an uninviting slice, toasted, but hard inside and out, and into which butter penetrates about to the same extent as it would a wooden slab of the same dimensions. “ Fermentation,” says Liebig, “ is not only the best and simplest, but likewise the most economical way of imparting porosity to bread ; and besides, chemists^ generally speaking^ should never recommend the use of chemicals for culinary preparations^ for chemicals are seldom met with in commerce in a state of purity. Thus, for example, the muriatic acid which it has been proposed to mix with carbonate of soda in bread is always very impure^ and very often contains arsenic. Chemists never employ such an acid in operations which are certainly less important than the one just mentioned, without having first purified it.” In order to remove this ground of objection, tartaric acid has been recommended instead of muriatic acid for the purpose of decomposing the carbonate of soda ; but in that way an- other unsafe compound is introduced, since the result of the reaction is tartrate of soda, a diuretic aperient, and consequently very objectionable salt, for it is impossible to say what mischief the continuous ingestion of such a substance may eventually produce ; and what- ever may be the divergence of opinion, — if there be such a divergence, — as to whether or not the constant use of an aperient, however mild, may be detrimental to health, it surely must be admitted that, at any rate, it is better to eschew such, to say the least of it, suspi- cious materials ; and that, at any rate, if deprecating their use be an error, it is an error on the safe side ; — after all, a bakehouse is not a chemical laboratory. Before leaving this question of unfermented bread, we must not omit to speak of a re- markable process invented by Dr. Dauglish, and which has lately excited some attention. Without discussing the value of the idea which is said to have led Dr. Dauglish to invent the process in question, we shall simply describe Dr. Dauglish’s method of making bread, and give his own version of its benefits : — “ Taking advantage of the well-known capacity of water for absorbing carbonic acid, whatever its density, in quantities equal to its own bulk, I first prepare the water which is to be used in forming the dough, by placing it in a strong vessel capable of bearing a high pressure, and forcing carbonic acid into it to the extent of say ten or twelve atmospheres,” (about 150 to 180 lbs. per square inch;) “this the water absorbs without any appreciable increase in its bulk. The water so prepared will of course retain the carbonic acid in solu- tion so long as it is retained in a close vessel under the same pressure. I therefore place the four and salt, of which the dough is to be formed, also in a close vessel capable of bear- ing a high pressure. Within this vessel, which is of a spheroidal form, a simply-constructed kneading apparatus is fitted, worked from without through a closely-packed stuffing box. Into this vessel I force an equal pressure to that which is maintained in the aerated water- vessel ; and then, by means of a pipe connecting the two vessels, I draw the water into the flour, and set the kneading apparatus to work at the same time. By this arrangement the water acts simply as limpid water among the flour, the flour and water are mixed and kneaded together into paste, and to such an extent as shall give it the necessary tenacity. After this is accomplished the pressure is released, the gas escapes from the water, and in doing so raises the dough in the most beautiful and expeditious manner. It will be quite unnecessary for me to point out how perfect must be the mechanical structure that results from this method of raising dough. In the first place, the mixing and kneading of the flour and water together, before any vesicular property is imparted to the mass, render the most complete incorporation of the flour and water a matter of very easy accomplishment ; and this being secured, it is evident that the gas which forms the vesicle, or sponge, when it is released, must be dispersed through the mass in a manner which no other method — fermen- tation not excepted — could accomplish. But besides the advantages of kneading the dough before the vesicle is formed, in the manner above mentioned, there is another, and perhaps a more important one, from what it is likely to effect by giving scope to the introduction of new materials into bread-making, — and that is, I find that powerful machine-kneading, continued for several minutes, has the effect of imparting to the dough tenacity or tough- ness. In Messrs. Carr and Co.’s machine, at Carlisle, we have kneaded some wheaten dough for half an hour, and the result has been that the dough has been so tough that it resembled birdlime, and it was with difficulty pulled to pieces with the hand. Other materials, such as rye, barley, &c., are affected in the same manner. So that by thus kneading, I am able to impart to dough made from materials which otherwise would not make light bread, from their wanting that quality in their gluten which is capable of holding or retaining, the same degree of lightness which no other method is capable of effecting. And I am sanguine of BREAD. 184 being able to make from rye, barley, oatmeal, and other wholesome and nutritious sub- stances, bread as light and sweet as the finest wheaten bread. One reason why my process makes a bread so different from all other processes where fermentation is not followed, is, that I am enabled to knead the bread to any extent without spoiling its vesicular property ; whilst all other unfermented breads are merely mixed^ not kneaded. The property thus imparted to my bread by kneading, renders it less dependent on being placed immediately in the oven. It certaintly cannot gain by being allowed to stand after the dough is formed, but it bears well the necessary standing and waiting required for preparing the loaves for baking. “ There is one point which requires care in my process, and that is, the baking, — as the dough is excessively cold ; first, because cold water is used in the process ; and next, be- cause of its sudden expansion on rising. It is thus placed in the oven some 40° Fahr. in temperature lower than the ordinary fermented bread. This, together with its slow spring- ing until it reaches the boiling point, renders it essential that the top crust shall not be formed until the very last moment. Thus, I have been obliged to have ovens constructed which are heated through the bottom, and are furnished with the means of regulating the heat of the top, so that the bread is cooked through the bottom ; and, just at the last, the top heat is put on and the top crust formed. “ With regard to the gain effected by saving the loss by fermentation, I may state what must be evident, that the weight of the dough is always exactly the sum of the weight of flour, water, and salt put into the mixing vessel ; and that, in all our experiments at Carlisle, we invariably made 118 loaves from the same weight of flour which by fermentation made only 105 and 106. Our advantage in gain over fermentation can only be equal to the loss by fermentation. As there has been considerable difference of opinion among men of science with respect to the amount of this loss, — some stating it to be as high as I'J-J per cent, and others so low as 1 per cent,, — I will here say a few words on the subject. Those who have stated the loss to be as high as I'Zi per cent, have, in support of their position, pointed to the extra yield from the same flour of bread when made by non-fermentation, compared with that made by fermentation. Whilst those who have opposed this assertion, and stated the loss to be but 1 per cent, or little more, have declared the gain in weight to be simply a gain of extra water, and have based their calculations of loss on the destruction of material caused by the generation of the necessary quantity of carbonic acid to render the bread light. Starting then with the assumption that light bread contains in bulk half solid matter and half aeriform, they have calculated that this quantity of aeriform matter is ob- tained by a destruction of but one per cent, of solid material. In this calculation the loss of carbonic acid, by its escape through the mass of dough during the process of fermenta- tion and manufacture, does not appear to have been taken into -account. All who have been in any way practically connected with bakeries, well know how large this loss is, and how important it is that it should be taken into account, that our calculations may be correct. “ One of the strongest proofs that the escape of gas through ordinary soft bread dough is very large, arises from the fact that when biscuit dough, in which there is a mixture of fatty matter, is prepared by my process, about half the quantity of gas only is needed to obtain an equal amount of lightness with dough that is made of flour and water only, the fatty matter acting to prevent the escape of gas from the dough. Other matters will ope- rate in a similar manner — boiled flour, for instance, added in small quantities. But the as- sumption that light bread is only half aeriform matter is altogether erroneous. Never before has there been so complete a method of testing what proportion the aeriform bears to the solid in light bread as that which my process affords. The mixing vessel at Messrs. Carr and Co.’s works, Carlisle, has an internal capacity of 10 bushels. When bushels of flour are put into this vessel, and formed into spongy bread dough, by my process, it is quite full. And when flour is mixed with water into paste, the paste measures rather less than half the bulk of the original dry flour. This will therefore represent about If bushels of solid mat- ter expanded into 10 bushels of spongy dough, showing in the dough nearly 5 pat precise temperature is uniformly retained. The BREAD. 189 smallest fluctuation in the heat of the water which circulates in the pipes instantly sets the levers in motion, and the expansion of one-thirty-sixth part of an inch is sutiicient to close the damper. It will be observed, that if the pipe be heated to 550° F., the brickwork will soon attain the same temperature, or nearly so, and accordingly the oven will thus possess double the amount of the heating surface of ordinary ovens applicable to baking. The baking temper- ature of the oven is from 420° to 450° F,, which is ascertained by a thermometer with which the oven is provided. With respect to Rolland’s oven. Messieurs Boussingault, Payen, and Poncelet, in their report to the Institute of France ; Gaultier de Glaubry, in a report made in the name of the Committee of Chemical Arts to the Societe d’Encouragement ; and the late M, Arago, represented that oven as successfully meeting all the conditions of salubrity, cleanliness, and hygiene. Wood, coals, and ashes, are likewise banished from it, and neither smoke nor the heated air of the furnace can find access to it. As in Perkins’, the furnace is placed at a distance from the mouth of the oven, but, instead of conveying the heat by pipes, as in the hot-water oven, it is the smoke and hot air of the furnace which, circulating through fan-shaped flues, ramifying under the floor, and spreading over the roof of the oven, impart to it the requisite temperature. The floor of the oven, on which the loaves are deposited, consists of glazed tiles, and it can thus be kept perfectly clean. The distinctive character of M. Rolland’s oven, however, is that the glazed tiles just spoken of rest upon a revolving platform, which the workman gradually, or from time to time, moves round by means of a small handle, and without effort. Figures V6 to 85 represent the construction and appearance of M. Rolland’s oven on a reduced scale. 76. Front elevation. 77. Vertical section through the axis of the fire-grate. 78. Ditto, ditto. 79. Elevation of one of the vertical flues. 80. Suspension of the floors. 76 When the oven has to be charged, the workman deposits the first loaves, by means of a short peel, upon that part of the revolving platform which lies before the mouth of the oven, and when that portion is filled, he gives a turn with the handle, and proceeds to put the loaves in the fresh space thus presented before him, and so on, until the whole is fitted up. The door is then closed through an opening covered with glass, and reserved in the wall of the oven, which is lighted up with a jet of gas, or by opening the door from time to time, the progress of the baking may be watched ; if it appears too rapid on one point, or too slow on another, the journeyman can, by means of the handle, bring the loaves successively to the hottest part of the oven, and vice versd^ as occasion may require. The oven is pro- vided with a thermometer, and, in an experiment witnessed, the temperature indicated 210° C. = 410° F., the baking of a full charge was completed in one hour and ten minutes, and the loaves of the same kind were so even in point of size and color that they could not be distinguished from each other. The top of the oven is provided with a pan for the purpose of heating the water neces- sary for the preparation of the dough, by means of the heat which in all other plans (Mou- chot’s excepted) is lost. The workman should take care to keep always some water in that 81. Plan of the first floor. 82. Plan of the sole. 83. Plan of the second floor. 84. Plan of the fire-grate and flues. 85. Plan of the portion under ground. BEEAD. 190 pan, for otherwise the leaden pipe would melt and occasion dangerous leaks. For this and other reasons, the safest plan, however, would be to replace this leaden pipe by an iron one. The said pan should be frequently scoured, for, if neglected, the water will become nn rusty, and spoil the color of the bread. Bread-baking may be considered as consisting of four operations— namely, heating the oven, putting the dough into the oven, baking, and 192 BREAD. taking the loaves out of the oven. The general directions given by M. Rolland for each of these operations are as follows : — In order to obtain a proper heat, and one that may be easily managed, it is necessary to charge the furnace moderately and often, and to keep it in a uniform state. When the fire is kindled, the door should be kept perfectly closed, in order to compel the current of air necessary to the combustion to pass through the grate, and thence through the flues under and the dome over the oven. If, cu the contrary, the furnace door were left ajar, the cold air from without would rapidly pass over the coals, without becoming 85 properly heated, and, passing in that condition into the flues, would fail in raising it to the proper, temperature. In order that the flame and heated products of the combustion may pass through all the flues, it is, of course, necessary to keep them clear by introducing into them once a month a brush made of wire, or whalebone, or those which are now generally used for sweeping the tubes of marine tubular boilers, and the best of which are those patented and manufactured by Messrs. Moriarty, of Greenwich, or How, of London. The vertical flues which are built in the masonry are cleared from without or from the pit, ac- cording to the nature of the plan adopted in building the oven. These flues need not be cleaned more often than about once in three months. 86 Sweeping between the floors should be performed about every fortnight. In case of accident or injury to the thermometers, the following directions, which, in- deed, apply to all ovens, may enable the baker to judge of the temperature of his oven : — If, on throwing a few pinches of flour on the tiles of the oven, it remains white after the lapse of a few seconds, the temperature is too low ; if, on the contrary, the flour assumes a deep brown color, the temperature is too high ; if the flour turns yellowish, or looks slightly scorched, the temperature is right. The baking in Rolland’s oven takes place at a temperature varying from 410° to 432° r., according to the nature and size of the articles intended to be baked. During the baking, the revolving floor is turned every ten or twelve minutes, so that, the loaves not remaining in the same place, the baking becomes equal throughout. BREAD. 193 As to the hot-whter oven, two establishments only have as yet adopted it in England ; one of them is the “ Hot-water Oven Biscuit-baking Company,” on whose premises fancy biscuits only are baked ; the second establishment is that of a baker of the name of Neville, carrying on his business in London. With respect to M. Mouchot’s system, it is not even known in this country, otherwise than by having been alluded to in one or two techno- logical publications or dictionaries. The quantity of bread which can be made from a sack of flour depends to a great extent upon the quantity of gluten that the flour of which it is made contains, but the wheat which contains a large proportion of nitrogenous matter, does not yield so white a flour as those which are poorer. From a great number of determinations, it is found that the amount of gluten contained in the flour to make best white bread ranges from 10 to 18 per cent., that of the starch being from 63 to 70 per cent., the ashes ranging from 0‘5 to 1‘9 per cent. This day, (17th of March, 1858,) the sack of genuine best household flour, weighing 280 lbs., delivered at the bakers’ shop, costs 42s., and the number of sacks of flour converted weekly into bread by the London bakers is nearly 30,000, which gives about 12 sacks of flour per week as the average trade of each of them. The average capital of a baker doing that amount of business may be computed at £300, which, at 5 per cent., gives £15 interest ; his rent may be estimated at about £55, and the rates, taxes, gas, and other expenses at about £25, in all £95, or very nearly £1 16s. 6|-d per week, which sum, divided by 12, would give 3s. 0\d. per sack. In the ordinary plan of bread-making, London bakers reckon that 1 sack of such a flour, weighing 280 lbs., will make 90 real 4-lb. loaves (not quartern) of pure, genuine bread, although a sack of such flour may yield him 94 or even 95 quartern (not 4-lb.) loaves.* From this account it may be easily imagined that if the baker could succeed in dispos- ing at once of all the loaves of his day’s baking either by sale at his shop, or, still better, by delivery at his customers’ residences, such a business would indeed be a profitable one, commercially speaking, for on that day he would sell from 28 to 34 lbs. of water at the price of bread, not to speak of the deficient weight ; but, on the one hand, so many people provokingly require to have their loaves weighed at the shop, and are so stingily particular about having their short weight made up ; and, on the other hand, the loaves, between the first, second, and third day, do so obstinately persist in letting their water evaporate, that the loss of weight thus sustained nearly balances the profit obtained upon the loaves sold on the first day at the shop, or to those customers who have their bread delivered at their own door, to those who the baker knows, from position or avocations, will never take the trouble to verify the weight of his loaves, and who, he says, are gentlefolks^ and no mistake about it. As to those bakers who, by underbaking, or by the use of alum, or by the use of both alum and underbaking, manage to obtain 96, 98, 100, or a still larger number of loaves from inferior flour, or materials, their profit is so reduced by the much lower price at which they are compelled to sell their sophisticated bread, that their tamperings avail them but little ; their emphatically hard labor yields them but a mere pittance, except their business be so extensive that the small profits swell up into a large sum, in which case they only jeopardize their name as fair and honest tradesmen. Looking now at the improved ovens, of which we have been speaking merely in an economical point of view, and abstractedly from all other considerations, the profits realized by their use appears to be well worth the baker’s attention. But as with the improved ovens the economy bears upon the wages and the fuel, the advantages are much less consider- able in a small concern than in a large one. Thus, the economy which, upon 12 sacks of flour per week, would scarcely exceed 20 shillings upon the whole, would, on the contrary, assume considerable proportions in establishments baking from 60 to 100 sacks per week. We give here the following comparative statements of converting flour into bread at the rate of 70 sacks per week, from documents which may be fully relied upon. 70 sacks of flour manufactured into genuine bread, in the ordinary way, would yield 6,300 real 4-lb. loaves, and the account would stand as follows, taking 90 loaves, weighing really 4 lbs., as the ultimate yield of 1 sack of good household flour, of the quality and price above alluded to : — By the Ordinary Process. RETURNS. £ s. d. 6,300 loaves (4 lbs.) at 7d 183 15 0 * It is absolutely necessary thus to establish a distinction between four-pounds and quartern loaves, because the latter very seldom indeed have that weight, and this deficiency is, in fact, one of the profits calculated upon; for, although the Act of Parliament (Will. IV. cap. xxxvii.) is very strict, and directs (sect, yii.) that bakers delivering bread by cart or carriage shall be provided with scales, weights, &c., for weighing bread, this requisition is seldom, if ever, complied Avith. There are, of course, a few bakers Avhose quartern loaves weigh exactly four pounds, but the immense majority are from four to six ounces short. VoL. III.— 13 194 BREAD. EXPENSES. £ VO sacks of household flour at SYs. 129 Coals, gas, potatoes, yeast, salt, wages, and other baking ex- penses, at 6s. per sack Rent, taxes, interest of capital, and general expenses - Ret profit on 1 week’s baking By Perkins's Process. 11 24 111 10 0 £12 6 0 RETURNS. 6,300 loaves (4 lbs.) at Id. £ 183 EXPENSES. 10 sacks of flour at 3 Vs. Yeast, potatoes, and salt, at Is. per sack Coals at 6c?. per sack - - . - Wages of a man per week - “ 1 workman - - . - “ 1 hand Wear and tear, and repairs - Rent, interest on capital, (£1,500,) taxes, gas, waste, and general expenses, per week £ 129 3 1 1 1 0 0 10 10 15 V 0 16 4 24 10 0 162 12 0 £21 13 0 In Rolland’s process the profits are very nearly the same as in that of Perkins’, except the amount of fuel consumed is still more reduced, and does not amount, it is stated, to more than 4^d. per sack, which, for VO sacks, is £1 Os. 3c?., instead of £1 15s., or 9s. differ- ence between the two methods for baking that quantity of flour. The richness or nutritive powers of sound flour, and also of bread, are proportional to the quantity of gluten they contain. It is of great importance to determine 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 the temperature of 16V° F., 1,000 grains of bread (or flour) with 1,000 grains of bruised barley malt, in 6,000 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 a soluble dextrine,) the gluten left un- changed may be collected on a filter cloth, washed, dried at a heat of 212° F., and weighed. The color, texture, and taste of the gluten ought also to be examined, in forming a judg- ment of good flour or bread. The question of the relative value of white and of brown bread, as nutritive agents, is one of very long standing, and the arguments on both sides may be thus resumed : — The advocates of brown bread hold — That the separation of the white from the brown parts of wheat grain, in making bread, is likely to be baneful to health ; That the general belief that bread made with the finest flour is the best, and that white- ness is a proof of its quality, is a popular error ; That whiteness may be, and generally is, communicated to bread by alum, to the injury of the consumer ; That the miller, in refining his flour, to please the public, removes some of the ingre- dients necessary to the composition and nourishment of the various organs of our bodies ; so that fine flour, instead of being better than the meal, is, on the contrary, less nourishing, and, to make the case worse, is also more difficult of digestion, not to speak of the enormous loss to the population of at least 25 per cent, of branny flour, containing from 60 to VO per cent, of the most nutritious part of the flour, a loss which, for London only, is equal to at least V,500 sacks of flour annually ; That the unwise preference given so universally to white bread, leads to the pernicious practice of mixing alum with the flour, and this again to all sorts of impositions and adul- terations ; for it enables the bakers who are so disposed, by adding alum, to make bread manufactured from the flour of inferior grain to look like the best and more costly, thus de- frauding the purchaser, and tampering with his health. On the other side, the partisans of white bread contend, of course^ that all these asser- tions are without foundation, and their reasons were summed up as follows in the Bakers' Gazette^ in 1849 : — BREAD. 195 “ The preference of the public for white bread is not likely to be an absurd prejudice, seeing that it was not until after years of experience that it was adopted by them. “ The adoption of white bread, in preference to any other sort, by the great body of the community, as a general article of food, is of itself a proof of its being the best and most nutritious. “ The finer and better the flour, the more bread can be made from it. Fifty-six pounds of fine flour from good wheat will make seventy-two pounds of good, sound, well-baked bread, the bread having retained sixteen pounds of water. But bran, either fine or coarse, absorbs little or no water, and adds no more to the bread than its weight.” And lastly, in confirmation of the opinion that white bread contains a greater quantity of nutriment than the same weight of brown bread, the writer of the article winds up the white bread defence with a portion of the Report of the Committee of the House of Com- mons, appointed in 1800, “ to consider means for rendering more effectual the provisions of 13 Geo. III., intituled ‘ An Act for the better regulating the assize and making of Bread.’ ” In considering the propriety of recommending the adoption of further regulations and restrictions, they understood a prejudice existed in some parts of the country against any coarser sort of bread than that which is at present known by the name of “ fine household bread,” on the ground that the former was less wholesome and nutritious than the latter. The opinions of respectable physicians examined on this point are, — that the change of any sort of food which forms so great a part of the sustenance of man, might, for a time, affect some constitutions ; that as soon as persons were habituated to it, the standard wheaten bread, or even bread of a coarser sort, would be equally wholesome with the fine wheaten bread which is now generally used in the metropolis ; but that, in their opinion, the fine wheaten bread would go farther with persons who have no other food than the same quan- tity of bread of a coarser sort. It was suggested to them, that if only one sort of flour was permitted to be made, and a different mode of dressing it adopted, so as to leave it in the fine pollards, 62 lbs. of flour might be extracted from a bushel of wheat weighing 60 lbs., instead of 47 lbs., which would afford a wholesome and nutritious food, and add to the quantity 5 lbs. in every bushel, or somewhat more than Vs- On this they remarked that there would be no saving in adopting this proposition ; and they begged leave to observe, if the physicians are well founded in their opinions, that bread of coarser quality will not go equally far with fine wheaten bread, an increased consumption of wheaten bread would be the consequence of the measure. From the bakers’ point of view, it is evident that all his sympathies must be in favor of the water-absorbing material, and therefore of the fine flour ; for each pound of water added and retained in the bread which he sells, represents this day so many twdpences ; but the purchaser’s interest lies in just the opposite direction. The question, however, is not, in the language of the Committee of the House of Com- mons of those days, or of the physicians whom they consulted, whether a given weight of wheaten bread toill go farther than an equal weight of bread of a coarser sort ; nor whether a given weight of pure flour is more nutritious than an equal weight of the meal from the same wheat used in making brown bread. The real question is, — Whether a given weight of wheat contains more nutriment than the flour obtained from that weight of wheat. The inquiry of the Committee of the House of Commons, and the defence of white bread versus brown bread, resting, as it does, in this respect, upon a false ground, is therefore perfectly valueless ; for whatever may have been the opinion of respectable physicians and of committees, either of those days or of the present times, one thing is certain — namely, that bran contains only 9 or 10 per cent, of woody fibre, that is, of matter devoid of nutri- tious property ; and that the remainder consists of a larger proportion of gluten and starch, fatty, and other highly nutritive constituents, with a few salts, and water, as proved by the following analysis by Millon ; — Composition of Wheat Bran. Starch 62*0 Gluten 14-9 Sugar 1-0 Fatty matter -..-.--.-3-6 Woody “ - - 9 -Y Salts 5-0 Water 13*8 100-0 And it is equally certain that wheat itself — I mean the whole grain — does not contain more than 2 per cent, of unnutritious, or woody matter, the bran being itself richer, weight for weight, in gluten, than the fine flour ; the whole meal contains, accordingly, more gluten than the fine flour obtained therefrom. The relative proportions of gluten BEEAD. 196 in the whole grain, in bran, and in flour of the same sample of wheat, were represented by the late Professor Johnston to be as follows : — Gluten of Wheat. Whole grain 12 per cent. Whole bran 14 to 18 “ Fine flour 10“ Now, whereas a bushel of wheat weighing 60 lbs. produces, according to the mode of manufacturing flour for London, 4*7 lbs. — that is, 78 per cent, of flour, the rest being bran and pollards ; if we deduct 2 per cent, of woody matter, and l^- per cent, for waste in grinding at the mill, the bushel of 60 lbs. of wheat would yield 58 lbs., or at least 96|- per cent, of nutritious matter. It is, therefore, as clear as any thing can possibly be, that by using the whole meal in- stead of only the fine flour of that wheat, there will be a difference of about Ve in the pro- duct obtained from equal weights of wheat. In a communication made to the Koyal Institute nearly four years ago, M. Mfege Mouries announced that he had found under the envelope of the grain, in the internal part of the perisperm, a peculiar nitrogenous substance capable of acting as a ferment, and to which he gave the name of “ cerealine.” This substance, which is found wholly, or almost so, in the bran, but not in the best white flour, has the property of liquefying starch, very much in the same manner as diastase : and the decreased firmness of the crumb of brown bread is re- ferred by him to this action. The coloration of bread made from meal containing bran is not, according to M. Mege Mouries, due, as has hitherto been thought, to the presence of bran, but to the peculiar action of cerealin ; this new substance, like vegetable casein and gluten, being, by a slight modification, due perhaps to the contact of the air, transformed into a ferment, under the influence of which the gluten undergoes a great alteration, yield- ing, among other products, ammonia, a brown-colored matter analogous to ulmine, and a nitrogenous product capable of transforming sugar into lactic acid. M. Mege Mouries having experimentally established, to the satisfaction of a committee consisting of MM. Chevreul, Dumas, Pelouze, and Peligot, that by paralyzing or destroying the action of cerealin, as described in the specification of his patent, bearing date the 14th of June, 1856, white bread, having all the characters of first quality bread, may be made, in tlie language of the said specification, “ with using either all the white or raw elements that constitute either corn or rye, or with such substances as could produce, to this day, but brown bread.” Cerealin, according to M, Mege Mouries, has two very distinct properties the first consists in converting the hydrated starch into glucose and dextrine ; the second, which is much more impcfrtant in its results, transforms the glucose into lactic, acetic, butyric, and formic acid, -which penetrate, swell up, and partly dissolve the gluten, rendering it pulpy and emulsive, like that of rye ; producing, in fact, a series of decompositions, yielding eventually a loaf having all the characteristics of bread made from inferior flour. In order to convert the whole of the farinaceous substance of -wheat into white bread, it is therefore necessary to destroy the cerealin ; and the process, or series of processes, by which this is accomplished, is thus described by M. Mege Mouries in his specification : — “ The following are the means I employ to obtain my new product : — “ 1st. The application of vinous fermentation, produced by alcoholic ferment or yeast, to destroy the ferment that I call ‘ cerealine,’ existing, together w.ith the fragments of bran, in the raw flour, and which, in some measure, produces the acidity of brown bread directly, whilst it destroys indirectly most part of the gluten, “ 2dly. The thorough purification of the said flour, either raw or mixed with bran, (after dilution and fermentation,) by the sifting and separating of the farinaceous liquid from the fragments of bran disseminated by the millstone into the inferior products of corn. “ 3dly. The employing that part of corn producing browm bread in the rough state, as issuing from the mill after a first grinding, in order to facilitate its purification by fermen- tation and wet sifting. “ 4thly. The employing acidulated water (by any acid or acid salt) in order to prevent the lactic fermentation, preserving the vinous fermentation, preventing the yellow color from turning into a brown color, (the ulmic acid,) and the good taste of corn from assuming that of brown bread. However, instead of acidulated water, pure water may be employed with an addition of yeast, as the acid only serves to facilitate the vinous fermentation. “ 5thly, The grinding of the corn by means of millstones that crush it thoroughly, in- creasing thereby the quantity of foul parts, a method which will prove very bad with the usual process, and very advantageous with mine. “ 6thly. The application of corn washed or stripped by any suitable means. “ 7thly. The application of all these contrivances to wheat of every description, to rye, and other grain used in the manufacture of bread. “ 8thly. The same means applied to the manufacture of biscuits. “ I will now describe the manner in which the said improvements are carried into effect. BREAD 197 “ First Instance. When flour of inferior quality is made use of — This description of flour, well known in trade, is bolted or sifted at 73, 75, or 80 per cent., (a mark termed Scipion mark in the French War Department,) and yields bread of middle quality. By applying to this sort of flour a liquid yeast, rather different from that which is applied to white flour, in order to quicken the work and remove the sour taste of bread, a very nice quality will be obtained, which result was quite unknown to everybody to this day, and which none ever attempted to know, as none before me were aware of the true causes that produce brown bread, &c. “ Now, to apply my process to the said flour, (of inferior mark or quality,) I take a part of the same — a fourth part, for instance — which I dilute with a suitable quantity of water, and add to the farinaceous liquid 1 portion of beer yeast for 200 portions of water, together with a small quantity of acid or acid salt, sufficient to impart to the said water the property of lightly staining or reddening the test-paper, known in France by the name of papier de tournesol. When the liquid is at full working, I mix the remaining portions of flour, which are kneaded, and then allowed to ferment in the usual way. The yeast applied, which is quite alcoholic, will yield perfectly white bread of a very nice taste ; and I declare that if similar yeast were ever commended before, it was certainly not for the purpose of prevent- ing the formation of brown bread, the character of which was believed to be inherent to the nature of the very flour, as the following result will sufficiently prove it, thus divesting such an application of its industrial appropriation. “ Second Instance. When raw flour is made use of — By raw flour, I mean the corn crushed only once, and from which 10 to 15 per cent, of rough bran have been separated. Such flour is still mixed with fragments of bran, and is employed in trade to the manufac- ture of so-called white flour and bran after a second and third grinding or crushing. In- stead of that, I only separate, and without submitting it to a fresh crushing, the rough flour in two parts, about 70 parts of white flour and 15 to 18 of rough or coarse flour, of which latter the yeast is made ; this I dilute with a suitable quantity of water, sufficient to reduce the whole flour into a dough, say 50 per cent, of the whole weight of raw flour. To this mixture have been previously added the yeast and acid, (whenever acid is applied, which is not indispensable, as before stated,) and the whole is allowed to work for 6 hours at a tem- perature of 77 ° F., for 12 hours at 68°, and for 20 hours at 59°, thus proportionally to the temperature. While this working or fermentation is going on, the various elements (cerea- line, &c.) which, by their peculiar action, are productive of brown bread, have undergone a modification ; the rough parts are separated, the gluten stripped from its pellicles and dis- aggregated, and the same flour which, by the usual process, could have only produced deep brown bread, will actually yield first-rate bread, far superior to that sold by bakers, chiefly if the fragments of bran are separated by the following process, which consists in pouring on the sieve, described hereafter, the liquid containing the rough parts of flour thus disag- gregated and modified by a well-regulated fermentation. “ The sieve alluded to, which may be of any form, consists of several tissues of different tightness, the closest being ever arranged underneath or the most forward, when the sieve is of cylindrical or vertical form, is intended to keep back the fragments of bran, which would, by their interposition, impair the whiteness of bread, and, by their weight, diminish its nutritive power. The sifted liquid is white, and constitutes the yeast with which the white flour is mixed after being separated, so as to make a dough at either a first or several workings, according to the baker’s practice. This dough works or ferments very quickly, and the bread resulting therefrom is unexceptionable. In case the whiteness or neatness of bread should be looked upon as a thing of little consequence, a broader sieve might be employed, or even no sieve used at all, and yet a very nice bread be obtained. “ The saving secured by the application of my process is as follows ; — By the common process, out of 100 parts of wheat, 70 or 75 parts of flour are extracted, which are fit to yield either white or middle bread ; whilst, by the improved process, out of 100 parts of wheat, 85 to 88 parts will be obtained, yielding bread of superior quality, of the best taste, neatness, and nutritious richness. “ In case new yeast cannot be easily provided, the same should be dried at a temper- ature of about 86° F., after being suitably separated by means of some inert dust, and pre- vious to being made use of, it should be dipped into 10 parts of water, lightly sweetened, for 8 to 10 hours, a fit time for the liquid being brought into a full fermentation, at which time the yeast has recovered its former power. The same process will hold good for manu- facturing rye bread, only 25 per cent., about, of course bran are to be extracted. For manufacturing biscuits, I use also the same process, only the dough is made very hard, and immediately taken into the oven, and the products thus obtained are far superior to the common biscuits, both for their good taste and preservation. Should, however, an old practice exclude all manner of fermentation, then I might dilute the rough parts of flour in either acidulated or non-acidulated water, there to be left to work for the same time as be- fore, then sift the water and decant it, after a proper settling of the farinaceous matters of which the dough is to be made ; thus the action of the acid, decantation, and sifting, would 198 BREAD. effectively remove all causes of alteration, which generally impair the biscuits made of in- ferior flour. “ The apparatus required for this process is very plain, and consists of a kneading- trough, in which the foul parts are mixed mechanically, or by manual labor, with the liquid above mentioned. From this trough, and through an opening made therein, the liquid mixture drops into the fermenting tub, deeper than wide, which must be kept tightly closed during the fermenting work. At the lower part of this tub a cock is fitted, which lets the liquid mixture down upon an inclined plane, on which the liquid spreads, so as to be equally distributed over the whole surface of the sieve. This sieve, of an oblong rectangular form, is laid just beneath, and its tissue ought to be so close as to prevent the least fragments of bran from passing through ; it is actuated by the hand, or rather by a crank. In all cases, that part of the sieve which is opposite to the cock must strike upon an unyielding body, for the purpose of shaking the pellicles remaining on the tissue, and driving them down towards an outlet on the lower part of the sieve, and thence into a trough purposely con- trived for receiving the waters issuing from the sieve, and discharging them into a tank. “ The next operation consists in diluting those pellicles, or rougher parts, which could not pass through the sieve, sifting them again, and using the white water resulting there- from to dilute the foul parts intended for subsequent operations. The sieve or sieves may sometimes happen to be obstructed by some parts of gluten adhering thereto, which I wash off with acidulated water for silk tissues, and with an alkali for metallic ones. This washing method I deem very important, as its non-application may hinder a rather large operation, and therefore I wish to secure it. This apparatus may be liable to some variations, and ad- mit of several sieves superposed, and with different tissues, the broadest, however, to be placed uppermost. “ Among the various descriptions and combinations of sieves that may be employed, the annexed figures show one that will give satisfactory results : 87 88 “ Fig. 87 is a longitudinal section, and Jig. 88 an end view, of the machine from which the bran is ejected. The apparatus rests upon a cast-iron framing, a, consisting of two cheeks, kept suitably apart by tie pieces, h ; a strong cross-bar on the upper part admits a wood cylinder c, circled round with iron, and provided with a wooden cock, d. The cylin- der, c, receives through its centre an arbor,/, provided with four arms, e, "which arbor is sup- ported by two cross-bars, g and A, secured by means of bolts to the uprights, i. Motion is imparted to the arbor, / by a crank, / by pulleys driven by the endless straps, A:, and by the toothed wheel, A, gearing into the wheel, m, which is keyed on the upper end of the ar- bor, f. Beneath the cylinder, c, two sieves, n and o, are borne into a frame, p, suspended on one end to two chains, and on the other resting on two guides or bearings, r, beneath which, and on the crank shaft, are cams, s, by which that end of the frame that carries the sieves is alternately raised and lowered. A strong spring, w, is set to a shaft borne by the framing, a, whilst a ratchet-wheel provided with a clink, allows the said spring, according to the requirements of the work, to give more or less impulse or shaking as the cams, s, are acting upon the frame-sieve carrying the sieve. Beneath the said frame a large hopper, BREAD. 199 is disposed, to receive and lead into a tank the liquid passing through the sieves. The filter sieve is worked as follows : — After withdrawing, by means of bolting hutches, 70 per cent., ^ about, of fine flour, I take out of the remaining 30 per cent, about 20 per cent, of groats, neglecting the remaining 10 per cent., from which, however, I could separate the little flour still adhering thereto, but I deem it more available to sell it off in this state. I submit the 20 per cent, of groats to a suitable vinous fermentation, and have the whole taken into the cylinder, c, there to be stirred by means of the arbor, /, and the arms, e ; after a suitable stirring, the cock, allow it to rise as the pieces become wound on, and the diameter consequently increases. If fewer pieces than 40 are to be printed in one pattern or coloring, it is usual to stitch a few yards of old cloth between two pieces where the change is intended to be made ; by this means the printer, on coming to the waste piece, stops his machine, and fits another pattern or changes the colors without damaging good cloth. The doctors used in cleaning off the superfluous color from the rollers, are generally thin blades of steel, of a thickness varying from Vsa of an inch to Vie of an inch, according to the sort of engraving on the roller ; but some colors, such as those containing saltsj of copper, would be too corrosive on a steel doctor, and in this case doctors of a composition like brass are used. They are filed to a bevelled edge, and require to be retouched with the file after printing from 10 to 30 pieces. The cylinder or drum, in contact with which revolve the copper rollers, is wrapped round with a cloth called “ lapping,” which is gen- erally a coarse strong woollen cloth of peculiar make, and is folded tight on the cylinder about an inch thick. The blanket is next put on and drawn tight : this blanket is a very important part of the machine ; it is a thick woollen web, about 40 yards long, and requires to be made with great care, so as to be uniform in texture, thickness, and elasticity. If the blanket is uneven, it has the effect of throwing the blanket into confusion at the un* even places. A good blanket will serve to print 10,000 pieces, being washed whenever loaded with color, and then is suitable for covering the tables of the block printer. In the year 1835 Messrs. Macintosh and Co. patented an Indian-rubber blanket, which con- sists of several thick cotton webs, cemented together with dissolved Indian-rubber. This blan- ket is very useful and economical for some purposes ; the surface being very smooth, great delicacy of impression is obtained, and, when soiled, it is not necessary to remove it from the machine, as it is easily washed with a brush whilst revolving on the machine. An Indian- rubber blanket will print 20,000 pieces, which is twice as much as a woollen one will do, the price per yard being also lower. Several descriptions of these blankets are made by Messrs. Macintosh, some of them having a coating of vulcanized Indian-rubber on the face that is printed from, thereby giving a still more elastic surface. A great improvement has been recently made in these Indian-rubber blankets by shrinking or preparing the cotton pre- vious to cementing, according to the patent process of Mr. John Mercer, viz. by soaking in strong alkali, and afterwards in dilute sulphuric acid ; this process contracts the fibre to a certain extent, and the cloth is found to possess a great increase of strength. When made into blankets, they are found to be more capable of resisting the severe strains of the print- ing process, and consequently many more pieces can be printed from them than from the old sort. They are made by Mr. Richard Kay, of Accrington, and are coming into general use. The woollen blanket, however, seems to be preferred for several styles. Several patents have been taken out for printing without blankets, but have never come into ^ CALICO PRINTING. 243 general use ; but recently a mc'«de of printing with gray or unbleached calico has come into use, which is very favorably sp«!pken of. In this method a roll of gray cloth is so disposed behind the machine that the fabric can be conducted five times through the machine before finally going away to be wound Ion a beam for removal. There are, therefore, 5 layers of cloth under the white calico whei\i printing, which give a sufficiently elastic bed for printing from ; and very delicate shapes ihan be got. Any given part of the gray cloth is 6 times uppermost on the pressure cylindcW, and consequently 1 piece of gray cloth is used to print 5 pieces of white. Gutta percha VDressure cylinders, or “ bowls,” have been suggested by Dalton, an Eaglish printer ; but,^^chough theoretically preferable to iron, they do not appear to be much used. The proper hygrometric ?‘itate of calico when printing should be attended to ; very dry calico does not take colors oJr mordant nearly so well as when containing a certain amount of hygrometric moisture. Practically this is attained by the bleached pieces being stored in the “ white room,” ger/erally several hundred pieces in advance, and they easily absorb sufficient moisture fro;m the air to be in a proper state for printing on. Pieces after prhating by either block or machine are rarely put through the next opera- tions at once, but;' are for the most part hung in spacious airy chambers in folds, from an arrangement of rails at the top of the room. These chambers are kept at an equable sum- mer temperature, and in proper hygroscopic conditions, due ventilation being also provided. These “ agei ng rooms,” as they are called, are in several print works of enormous dimen- sions, and a.ve generally separate buildings. Those of Messrs. Edmund Potter & Co., and Messrs. Thomas Hoyle & Co., in Lancashire, may be particularized as forming quite a feature in the works. The pieces stay in these chambers from 1 to 6 days, according to the style of work, during which time the color which was deposited on the outside of the fibre gradu- ally permeates it, and becomes more firmly attached, a portion of the base being deposited, and ace^cic acid given off in vapors. Where colors are required to absorb a certain amount of oxygen, such as iron mordant, catechu browns, &c., they find the necessary conditions here. On the proper ageing of printed goods depends in a great measure the success of many styles ; should the room be too hot or too dry, imperfect fixation of the color ensues, and. meagre and uneven tints are obtained in the subsequent operations. In countries where in summer the atmosphere is dry, great difficulty is found in ageing properly. In America catechu browns have been known to require weeks before being of the proper shade. These are of course exceptional cases ; the scientific printer knows how to combat th‘'se evils by the introduction of watery vapor, or even by erecting his ageing room over a reservoir of water, with rather open boarding for floor ; many colors also may have deli- quescent salts introduced. In England the process of ageing is of pretty uniform duration. Quite recently several printers have begun to adopt a method of “ ageing,” which prom- ises to revolutionize the old way of hanging for several days, and thus occupying a large space. In a patent of Mr. John Thom for sulphuring mousseline-de-laines, a claim is made for using the same apparatus, or a modification of it, for passing calico printed goods through a mixture of air and aqueous vapor. Pieces, after leaving the hot room in which they are dried after printing, are run over rollers arranged in a narrow room, above and below. A very small quantity of steam is allowed to escape into this room, which is kept slightly warm by the steam-pipes. The pieces, on issuing from the apparatus, should feel soft but not moist ; they are loosely folded together, and stay in this state one night and are taken to the dyehouse next day. It is even stated that this one night’s age may be dis- pensed with, and the pieces dunged off after five or six hours’ age. The thickening of mordants and colors is a subject of very great importance to the printer. It is obvious that a mere solution of salts or coloring matters, such as used in dyeing, cannot be used in printing a pattern ; capillary attraction speedilycauses such a solution to spread beyond the limits of the pattern, and nothing but confusion is the result. A proper degree of inspissation is then essential. To the capability of very thick color being printed by engraved plates or rollers under severe pressure is due the superior smartness of outline characteristic of goods produced by these means. Where color can be laid on the outside of the cloth, so as to penetrate as little as possible to the other side, much brighter shades are produced In order to obtain the most brilliant shades of color, it is necessary that the cloth act as a sort of mirror behind the color, which cannot be the case if the fibre is per- fectly saturated with color. Independent of this, a great economy of coloring material fol- lows from the proper application of the color or mordant to the face only. This is especial- ly noticeable in madder goods, where the mordant, if printed in excess, is apt to give up a portion from the cloth in the dyebeck, thereby consuming a certain quantity of madder in pure loss. The color-house should be a spacious apartment on the ground floor, with the roof ventilated in such a manner that the steam produced finds a speedy exit ; at one end, or down one side, is fixed a range of color-pans, varying in size, and supplied with steam and cold water. Color-pans are usually made to swing on pivots, whereby they are easily emptied and cleaned. A range of this sort, as manufactured by Messrs. Storey & Co., of CALICO PRINTING. 244 Manchester, is represented in jig. 120. This range consists c!)f 8 double-cased copper pans, containing from 1 to 28 gallons, riveted together at the top, ^ wired at the edges, and made perfectly steam-tight ; they are supported on cast-iron pillai^s, and are so arranged or fitted as to swivel or turn over when the color is required to emptied, by means of a brass stuffing box attached to pan, and working in the corresponiding part attached to pillar on the one side, and moving at the other on a plain brass noazle, supported by a pedestal pro- jecting from pillar, the nozzle having a blank end, thereby cutting off the communication of steam, which is carried to the following pan. They a-j^'^e also supplied with a condense tap to carry off the waste steam and water. Each pillar ‘.in the range, except the last, is supplied with a brass tap on the top, with 3 flanges, to correct the steam and cold water pipes, as more fully explained hereafter. ' 121 120 A,^^. 120, is a copper pipe, with one blank end, and open at the other with flange for the admission of steam, which passes through the downward-bent pipe marked b, in con- nection with the brass tap on top of pillar, the plug of this tap being open at bottom to admit the steam down the pillar as far as the stuffing box, marked e, through which it rushes into the casing of pans, and out. by the condense pipe d, when required, c is a cop- per pipe, with one blank end and open at the other, for the admission of cold water for cooling the color after boiling, and is likewise connected with the tap on top of pillar, as shown in jig. 121, marked/, the water passing through precisely in the same manner as the steam in a. d is the condense pipe, with one blank end and open at the other, with flange, qnderneath the pans, to , carry off the water or steam, and is supplied with ground brass pozzies, to fit the condense tap at bottom of pan, being accurately adjusted, so that in the swivelling of pan it leaves its seat and returns perfectly steam-tight. Fig. 121 represents an end view of range, showing more fully the position and connection of steam and cold water pipes to brass tap, the cold water pipe running along back of range, the steam pipe above, parallel with centre of pans, and the downward-bent pipe in front ; and likewise the stoppage in pillar, so far as is necessary there should be an aperture for the steam -or water to meet the brass stuffing box. In this jig. is also shown the copper pipe, with elbow swivel tap, for supplying pans with cold water, (one pipe to supply two pans,) and fixed on top of cold water pipe exactly opposite pillar, as further shown in jig. 122 marked g. Fig. 123 is an end view of range, with pillar cut, in order to show the position of condense tap at bottom of pan, and its connection with condense pipe, and where the point of separation takes place in swivelling, by the line marked h. It will be seen by the foregoing that the CALICO PRINTING. 245 process of boiling and cooling is rapid and certain, every thing being accurately adjusted and steam-tight throughout the’ whole apparatus. The colors are placed in theifse pans and stirred well all the time they are being boiled ; good stirring is very essential t(^> prod\ice smooth colors. This was formerly done by hand with a flat stick, but lately the biest print works have been fitted with machinery over the pans to stir mechanically. A \very effective plan of this sort is represented in figs. 124 and 125. It is that of Mes'^srs. Mather and Platt, of Manchester, the boilers in this drawing being not reversible, thoiugh the plan can be just as easily adapted to that descrip- / 124 tion of pans. Fig. 124 is a front elevation; fig. 125 is a transverse section, and^^. 126 is a sectional plan, the same letters referring to all. a is a horizontal shaft above the pans, fitted with a pair of mitre wheels, b b, for each pan. The vertical wheel b is not keyed on the shaft a, but is brought into connection with it when required by the catch box c, which slides on a key on the shaft, and revolves with it (see small cuts ) ; the catch box is worked by a lever handle c?, and thus motion is given to the vertical shaft e. The shafts a and e are both supported by the framework/, fastened to the wall; the shaft e is terminated by the frame g h g, the centre of which, A, is a continuation of the shaft e ; and the wings g are hollow to carry the shafts A, which are surmounted by the cog wheels i i, which gear into a cog wheel I on the shaft e. The agitatii'S n n are made of flat brass rod, and are curved to fit the bottom ; they are connected with the shafts A A by a hook joint, which is steadied by the conical sliding ring m ; the agitators thus hang from the shaft c, and nearly touch the bottom of the boiler. When the shaft e is put in motion, the agitators have two movements, one round each other, and also each on its own axis ; as they are set at right angles to each other, as shown in fig. 126, it follows that no part of the' pan can escape being stirred. When the color is made, the piece m is slid up on A, and the agitators un- hooked and taken out, the waste of color being very trifling, in consequence of the agita- tors being outlines only. The saving of labor effected in a color house by this machinery is very great, as, after turning on the steam, the pan may be left to itself till the color is finished. From the great variety of substances used in mordants and colors, of very different chemical properties, a variety of thickening substances is required. Chemical combination between the mordants or color and the thickening substance is to be avoided as much as possible, for such combination may be regarded as so much pure loss, the fibre of the fabric not being able to decompose and assimilate them. Several circumstances may Jr. \ 246 CALICO PRINTIN'O. 125 require the consistence of the thickening to be varied such as the nature of the mordant, its de^risity, and its acidity. A strong acid mordant cannot be easily thickened with starch ; but it may be by roasted starch, vulgarly called British gum, and by gum arabic or Senegal. Some mordants which seem sufficiently inspissated with starch, liquefy in the course of a few days ; and being apt to run in the px'inting-on make Wotted work. In France, this evil is readil}' obviated, by adding one ounce of spirits of wine to half a gallon of color. The very same mordant, when inspis- sated to different degrees, produces dif- ferent tints in the dye-copper ; thus, the same mordant, thickened with starch, fur- nishes a darker shade than when thick- ened with gum. Yet there are circum- stances in which the latter is preferrej^d, because it communicates more transpja- rerfdy to the dyes, and because, in spii|te of the washing, more or less of the starch 126 always sticks to the mordant. Gum has the inconvenience, however, of drying too speedily, and forming a hard crust on the cloth, which does not easily allow the necessary capillary attraction to take place, and the tints obtained are thin and meagre. The substances gen- erally employed in thickening are : — 1. Wheat flour. 2. “ starch. 3. Torrefied wheat starch, or British gum. 4. Torrefied potato farina. 6. Gum substitutes or soluble gums. 6. Gum Senegal. 7. Gum tragacanth. 8. Sa^ep. 9. Pipe-clay or china-clay mixed with gum Senegal. 10. Sulphate of lead. 11. Molasses. 12. Dextrine. 13. Albumen of eggs. 14. Lactarine. 15. Gluten. 16. Glue. CALICO FEINTING. 247 Those most used are the fiirst seven. The rest are only adapted for special styles or colors. The artificial gums pi^ Sduced by roasting starch or farina are very largely in use. The action of heat on starch c. i uses a modification in it. According to the degree of heat and its duration a greater or lei^ss modification ensues, the higher the heat, the more soluble in water the gum, but also the lorowner and of least thickening properties. The addition of various acids and alkalies to s tarch or farina before calcination, causes them to become soluble at lower temperatures tha^n without ; different acids also produce different results ; those most generally used are ni\tric, acetic, muriatic, oxalic, and recently lactic acid has been proposed by Pochin. Tht\. proportion of acid used is very small, and, though the effect is produced, the acid disa Appears during calcination. Small quantities of alkalies are also used for special modificat'ions of these gum substitutes. The making of these gums is a distinct branch of trade, aiiid finds employment for large capital and numerous hands. In giving the receipts for the/ various colors, care will be taken to specify the nature and pro- portion of thickening tio be employed for each color; a most important matter, often neglected by English -writers upon calico printing. It is often observed that goods printed upon the same day, and with the same mordant, exhibit inequalitie>3 in their tints. Sometimes the color is strong and decided in one part of the piece, w’hile it is dull and meagre in another. The latter has been printed in too dry an atcmosphere. In such circumstances a neutral mordant answers best, espe- cially if the 'goods be dried in a hot flue, through which humid vapors are in constant cir- culation. In padding, where the whole surface of the calico is imbued with mordant, the drying apartment or flue, in which a great many pieces are exposed at once, should be so con- structed a.s to afford a ready outlet to the aqueous and acid exhalations. The cloth ought to be int roduced into it in a distended state ; because the acetic acid may accumulate in the foldings., and dissolve out the earthy or metallic base of the mordant, causing white and gray spots in such parts of the printed goods. Fans may be employed with great advan- tage, combined with Hot Flues. See Ventilation. The mordant and thickening, or the dye decoction and thickening, being put in one of the copper pans, is stirred by hand or machinery and boiled till perfectly smooth ; the steam then being shut off, cold water is admitted to the double casing, and the color cooled. It is then emptied out of the pan into a straining cloth, stretched over a tub, and strained to remove all gritty particles, which would be very injurious to the copper rollers. A very ureful straining machine has been recently invented by Dollfus Mieg & Co., and patented in this country. This machine is shown in fig. 127. It consists of a case or cylinder, in which a piston is worked, either by hand or power, to press the color through a cloth made of cotton, linen, hair, or other suitable material at the bottom of the case or cylinder ; or, in- stead of the said cloth, a wire gauze may be used. The bottom of the piston may be made of wood, copper, brass, gutta percha, caoutchouc, or other suitable material. The manner of working the apparatus will be clearly understood by reference to the drawings, in which fig. 127 is a side elevation of the said machine or apparatus, Sia6.fig. 128 a front elevation of the same, a represents the case or cylinder, which is strengthened at its upper part by the iron band b, and also at its lower part by the ring a. The skeleton plate 6, which forms the bottom of the cylinder, is removable, and sustained by the four hooks c. To disengage the plate 6, springs are fitted on the ring c?, which act upon two of the hooks c, so as to throw them out from under the grid h. Upon the ring a the second ring d is laid, which supports the circular handle e. The upper parts of the four hooks c lay upon four inclined planes fitted on the ring d. The modus operandi is as follows : — If the ring d is turned right or left, the skeleton plate 6, on which one of the said cloths or wire gauze has pre- viously been placed, will be brought firmly up to the extremity of the cylinder a ; and if the said cylinder be filled with coloring matter, the piston m, being worked by the pulley e, the wheels p, g, h, i, k, and the rack l, will force it through the cloth or sieve, to be re- ceived in a vessel under it for the purpose ; and by a proper arrangement of the teeth of the said rack l, the piston can only descend to any required point in the cylinder. To facilitate the working of the apparatus and increase its general efficiency, the cylinder is fixed on pivots at n, so that it may be easily inclined or brought towards the operator for the purpose of introducing the coloring matter or cleaning the vessel. To the ring or band B are fixed the two handles f and the two catches h. The catches being raised from the notch k on the frame p, the cylinder may be pulled forward by means of the handles /, till the hooks, being acted upon by a spring, re-engage themselves at k on the lower part of the frame p, and vice versd. On the shaft x is placed a second wheel q, by which a reverse motion is obtained, and the piston m raised to its original position. Colors for printing by block are for the most part thickened in the same manner as those for machine, b^ut are made thinner, since very thick color cannot be applied by block. Some substances also can be used in block printing that are inapplicable to machine, such as pipe-clay and china-clay, which, however finely ground, still contain CALICO FEINTING. 248 gritty particles, which would speedily scratch and destroy the delicate engraving of the machine rollers. A spacious drug room is attached to the color-house where all the drugs used are kept away from the steam of the color-house. Near the color-house should be a well-appointed laboratory, where drugs can be tested and experiments made. Formerly, all the decoctions and mordants used in print-works were made on the spot, but the trade having very much extended, the manufacture of the various mordants and decoctions of dyewood is now a separate business, and printers can be supplied with these articles at the same or in some cases a lower rate than they could be produced for on the works, the quality also being uniform and good. The printer now only makes for himself a few unimportant artieles. The province of the foreman color maker, who is generally a well-paid and responsible servant, is to combine these primary materials so as to form the different colors required for the different styles of work ; as the taste of customers varies, he is required to be able to make any given variation of shade at will, and be able to judge of the quality of the various materials submitted to him. The ordinary decoctions that are kept in stock in the color department are : — Logwood liquor. Peachwood liquor. Sapan liquor. Quercitron bark liquor. Gall liquor. Persian berry liquor. Cochineal liquor. Fustic liquor Catechu liquor. Ammoniacal cochineal liquor. Extract of indigo. I CALICO PRINTING. 249 And the various mordants am'd solutions are : — Red liquor, or acetate of alumina. Iron liquor, or acetate of iron. Buff liquor, or pyrolig- nite of iron. Pernitrate of iron. Permuriate of iron. Protomuriate of iron. Protochloride of tin in so- \ lution. Oxymuriate of tin in solu- \ tion. kNitrate of copper in solu- I tion. Acetate of copper in solu- ^ tion. . Lime juice. * Ammonia liquor. Acetic acid. Pyroligneous acid. Nitric acid. Muriatic acid. Sulphuric acid. Caustic soda liquor. Caustic potash liquor. Many other dry acids ar.xd salts are also kept in stock. For the constitution of the vari- ous mordants and their p^:’eparation see Mordants. It would be impossPole to particularize all the styles of calico printing. The variety is infinite ; but they mary be broadly classed as follows : — I. Madder stylf^s, varieties of which are — a. The simple5!,’t form is a pattern printed in mordants on white ground, such as black and red ; black., red, and purple ; black and two reds, &c., chocolate being sometimes sub- stituted for b>ick, and brown from catechu being also introduced ; these are dyed,jvith mad- der, the ^ .and remaining white. b. An './or all of the above mordants, together with lime juice, technically termed acid^ printed, a^.d a fine pattern printed all over or covered in purple or light chocolate, then dyed madder. In this style the red is a peculiar one, termed resist red ; and the result when dyed is, that the acid and red have prevented the purple or chocolate fixing on those parts, the red remaining pure and the acid having formed a white, the rest of the ground being covered with the fine pattern or cover ; of this style large quantities are printed in black, purple, and acid, and covered in paler purple, the cover roller being any small full pattern, and t’nis not being required to fit to the other pattern, a great variety of effects may be pro- duced by varying the cover : often a still weaker purple is padded or blotched in a plain sha.de all over the piece, and in this case the only white in the pattern is that reserved by the acid. \ c. The French pink style, which is wholly various shades of reds or pinks, and is printed in, one or more shades of red and acid, then covered or blotched in pale red, then dyed m adder and subjected to a peculiar clearing with soap, whereby pink shades of very great delicacy are obtained. ‘ All these are what are termed fast colors, and having, after dyeing, undergone severe soaping, cannot be altered by the usual domestic washing process. II. The same styles are dyed with garancin instead of madder ; heavier and darker col- ors being employed. These goods are not soaped, garancin producing bright colors at once, but the shades, though stil classed as fast colors, do not possess the permanence of those dyed with madder. III. The first style is frequently relieved by lively colors, such as green, blue, yellow, &c., blocked in after dyeing and clearing ; these colors are generally what are termed steam- colors, being fixed by steaming the cloth, and afterwards washing in water only, or the printed or dyed pattern is covered with a resist paste blocked on, and various shades of drab, slate, buff, &c., printed with a small pattern all over; sometimes these colors are mordants, to be subsequently dyed with cochineal, quercitron bark, &c., or they may be colors composed of dyewood decoctions, mixed with mordants, and are fixed by passing through soda or other solutions. The result in either case being that the original pattern, generally a group of flowers, being protected by the paste which prevented the subsequent color fixing there, stand out pure, the rest of the ground being covered by the small pat- tern or cover. White may be also reserved by the paste, and frequently these white parts are blocked with blue, yellow, green, &c., as before. IV. Padded styles. — In these the cloth is first padded (as will be hereafter explained) all over with a liquid mordant, dried and printed in spots or figures with strong acid, or dis- charge as it is called, then put through the dyeing operations necessary for the shade re- quired ; the printed spots remaining white, and the rest of the piece one plain shade. The white portions are frequently relieved by steam-colors blocked in. V. Indigo-blue ; a style of considerable importance. In this, a resist paste, either alone or accompanied by resist yellow, or orange mordant, is printed on white calico, which is then dipped in the indigo vat, till the shade of blue wanted is obtained. If yellow or orange is present, these colors are raised with bichromate of potash liquor. The peculiar colors printed in this style have the property of preventing the indigo fixing on the printed parts, and the result is dark blue ground, with white, orange, or yellow spots, steam-colors being sometimes blocked in the whites. VI. China-blues, a modification of the indigo-blue style, but in this case the pattern is produced by indigo-colors, printed on white cloth : the pieces are next put through a pecu- \ I I _ ^ / 250 CALICO PEINTmC. j liar process fixing the indigo in the cloth, the result being ;|blue figures on white ground. All indigo styles are fast or permanent. I VII. Turkey-red and discharge. — On dyed Turkey-red clmth is printed an acid, or acid solutions mixed with pigments or salt of lead ; the printed [pieces are passed through chlo- ride of lime solution, when chlorine is eliminated by the acip colors, and discharges the red. The pigments or lead-salt being fixed in the cloth at tme same time, after washing and chroming where yellow has to be obtained, the piece presepts a pattern, bitten as it were in the Turkey-red ground. Black is also printed along* with i^he other colors. A modification of this style is the well-known Bandanna style used for h^indkerchiefs. Turkey-red cloth is folded in a hydraulic press on a lead plate perforated witfo a pattern. When a sufficient number of folds are made on this plate, a precisely similar pla.te is put on the top, so as to register accurately with the bottom one ; pressure being now apf>lied, the cloth is squeezed tightly between the two plates, a top being opened above the upp\er plate, solution of chlo- rine is forced through the perforations, and in its passage through ^the cloth, discharges the dye ; the chlorine liquor is followed by water, and the operation is^ finished : the pieces when removed from the press being discharged, according to the pattena of the lead plates. VIII. Sleam-colors. — In this style colors are formed from mixtures of dyewood extracts and mordants, together with various acids and salts, and being printed on calico which has been mordanted with peroxide of tin, the pieces are exposed to steam at 212° in close ves- sels, which causes an intimate union of the calico with the dyewood extract and mordant, so that subsequent washing with water removes only the thickening substance, and leaves the cloth dyed according to the pattern in various colors. Woollen fabrics and de -laines are always printed in this manner, and also often silk ; animal fabrics not being well adapted for mordanting and dyeing in the same manner as cotton fabrics, owing to the peculiar property of wool to absorb coloring matters, which renders the obtaining of whitCwS an im- possibility where the wool is steeped in a dye decoction. These steam-colors are very brilliant and tolerably permanent to light, but do not withstand hot-soap solution which alters their shades. IX. Spirit colors are made in somewhat the same manner as the steam-colors, but con- tain larger quantities of mordant and acid, and will not bear steaming, because the calico would be too much tendered by the acid, and are therefore only dried and hung up a day or two, and then washed in water. They are the most brilliant colors, but generally fugitive and are not much used. i X. Bronzes^ formerly a style in large demand, but now almost obsolete ; done by paili- ding the cloth in solution of protochloride of manganese, precipitating the oxide by meaps of alkali, peroxidizing this by chloride of lime, and then printing on colors composed of protochloride of tin and pigments or decoctions ; the protochloride of tin immediately de- oxidizes, bleaching the brown oxide of manganese, and, where mixed with decoctions or pig- ment, leaving a dyed pattern cutting through the ground. XI. Pigment-printing. — The colors in this class are the same pigments as used by painters, such as Scheele’s green, ultramarine blue, chrome yellow, &c., and, being quite insoluble in water, are, so to speak, cemented to the fibre. The vehicle used for fixing these is generally albumen, which coagulates when the cloth is steamed, and imprisons both cloth and fibre with the coagulum ; of course these colors, though not altered in shade by soap, are detached in part by severe treatment, such as rubbing, &c. First Style : Madders. Madder styles being the most important, demand the most detailed descriptions. The colors used are of the class termed mordants, which, not coloring matters themselves, act by combining with both cloth and coloring matter. They are generally the acetates or pyrolig- nites of iron and alumina. Red Liquor is the technical name of the pyrolignite of alumina used as mordant for red, &c. Iron Liquor is the pyrolignite of iron used as mordant for black, purple, &c. The preparation of these liquors on a large scale forms a separate business, and will be found described under the head Mordants. Fixing Liquor. — For a long time it has been customary to add to black and purple colors, or mordants, some substance which has a tendency to prevent the oxide of iron from passing to the state of peroxide. The oxide of iron necessary to produce the best results with madder is a mixture of protoxide and peroxide of iron, probably the black or magnetic oxide, though this point is not precisely determined. If the oxide should pass to the red oxide state, inferior shades are produced ; and the object of the printer introducing fixing liquor into his color is to prevent this injurious tendency. The earliest fixing liquor used was a solution of arsenious acid ; and though other fixers have from time to time been introduced, the preparations of arsenic still hold their ground. A very good fixing liquor, that has been much used in France and England, is made as follows : — ) CALICO PRINTING. 251 No. 1. Purple fixing Lxquof^ — gallons water, gallons acetic acid, 9 lbs. sal ammo- niac, 9 lbs. arsenious acid ; boi'l till the arsenic is dissolved, and let stand till quite clear. In 1844, Mr. John Mercer jpatented an assistant mordant liquor for the same purpose, which was made as follows ; — \ No. 2. To 100 lbs. potato st4rch, add 37| gallons water, 123 gallons nitric acid, specific gravity 1'3, and 4 oz. oxide of n manganese. The chemical action which takes place amongst these ingredients is allowed to p^jroceed till the nitric acid is destroyed. To the residuum thus produced are added 50 gallon.s of pyroligneous acid, and the compound is the assistant mordant liquor in a fit state to (hdd to the various mordants used in printing and dyeing. The intention in making this lio^iior is to carry on the decomposition of the nitric acid and starch as far as possible withfjut forming oxalic acid, and as little as possible of carbonic acid, which is gently aided ^oy the catalytic action of the oxide of nfanganese, preventing the formation of oxalic ac’/u. Apparently there is formed by this process saccharic acid, or an acid in a low state qfr oxidation, which is the active agent in preventing the peroxidize- ment of the iron whejx added to purple mordants. This liquor has been largely used, and is still preferred by s^ome printers. Of late, various fixing liquors have been made and sold by manufacturing cjnemists, pyroligneous acid and arsenious acid, or arsenite of soda, form- ing the staple of them ; some of these have chlorate of potash added, the object being the formation of /^rseniate of iron when the cloth is dried, whereby the acetic acid is more speedily dri,"^en off ; and since arseniate of iron does not pass beyond a certain degree of oxidizemen-.i in the air, the mordant is kept in a proper state for dyeing good colors. The following is. also a good purple fixing liquor : — No. 3., Purple fixing Liquor. — Boil together till dissolved 2 gallons water, 25 lbs. soda crystals, 22^ lbs. arsenious acid. When dissolved, add to 50 gallons wood acid, previously heated to 120° F. ; let stand for a day or two till the tar of the acid is settled, and add 3 quarts muriatic acid. The following madder colors are from some in practical use, and though almost every color- maker has different receipts for his colors, they may be taken to represent the general principles on which these colors are composed. In all these colors the thickening substance is first beaten up with a little of the liquid till quite fine and free from lumps, then the remainder of the liquid added, and the whole boiled and stirred in one of the double-cased steam-pans till quite smooth ; cooled, and str;ained. No. 4. Black for Machine., {Madder.) — 4 gallons iron liquor at 24° T., 4 gallons pyrolig- ne<.)us acid, 4 gallons water, 24 lbs. flour ; boil, and add 1 pint oil. ‘No. 5. Black for Garancin., {Machine.) — 7^ gallons water, 3 gallons iron liquor 4it 24° T., 1-J gallons purple fixing liquor, (No. 3,) 24 lbs. flour, 1 pint oil. No. 6. Dark-red for Madder., {Machine.) — 12 gallons red liquor at 18° T., 24 lbs. flour. No. V. Pale-reds for Madder {Machine) are made by reducing the standard liquor. No. 8, with gum water to the shade wanted : for instance. No. 3 pale-red is 1 of No. 8 and 3 of gum water. No. 9. No. 8. Standard red Liquor. — 10 gallons hot water, 40 lbs. alum, 25 lbs. white acetate of lead ; rake up till dissolved, let settle, and decant the clear. No. 9. 3 Ihs.-Gum-suhstitute Water. — 10 gallons water, 30 lbs. gum substitute. No. 5 in the list of thickeners. . No. 10. Dark resist-red Madder., {Machine^ see Mordants. — 12 gallons resist-red liquor, 18° T., 24 lbs. flour; boil, and when nearly cold add 12 lbs. of muriate of tin crystals. No. 11. Dark resist-red Machine. — Same as No. 10, but 6 lbs. of tin crystals only. Of these two last. No. 10 is used when it has to resist a chocolate cover, and No. 11 when it has to resist a purple cover. No. 12. Pale resist-reds Madder., {Machine.) — Made by reducing resist-red liquor with water, and thickening it. For instance. No. 5, pale-red: 12 gallons resist-red liquor at 5° T., 9 lbs. flour ; boil, and add, when cool, 2 lbs. tin crystals. No. 13. Chocolates are made from iron liquor and red liquor mixed, and the red liquor is a multiple of the iron ; as, for instance, 3 chocolate {madder) {inachine) : — 3 gallons iron liquor at 24° T., 9 gallons red liquor at 18° T., 24 lbs. flour, 1 pint oil. No. 6 Choco- late : — 1 gallon iron liquor at 24° T., 6 gallons red liquor at 18° T., 14 lbs. flour, ^ pint oil. No. 14. Strong red for Garancin., {Machine.) — 10 gallons red liquor at 18° T., 2 gallons water, 24 lbs. flour. No. 15. Resist-red for Garancin., {Machine.) — 12 gallons resist-red liquor at 14° T., 24 lbs. flour ; boil, cool, and add 9 lbs. tin crystals. This for resisting chocolate. No. 16. Resist-red for Garancin., {Machine.) — 12 gallons resist-red liquor at 14° T., 24 lbs. flour ; boil, cool, and add 4^ lbs. tin crystals. This for resisting purple. No. 17. Brown Standard for bladder. — 50 gallons water, 200 lbs. catechu; boil 6 hours, then add 4^ gallons acetic acid, and add water to make up to 50 gallons ; take out, and let stand 36 hours, and decant the clear; heat it to 130° F., and add 96 lbs. sal ammoniac, dis- solve, and leave to settle 48 hours ; decant the clear, and thicken it with 4 lbs. of gum Senegal per gallon. 252 CALICO PRINimO. No. 18. Brown Color for Madder^ {Machine .) — 4 galloris No. 17, 1 gallon acetate of copper, (No. 19,) 2 quarts acetic acid, 2 quarts gum Senegal water 4 lbs. per gallon. No. 19. Acetate of Copper. — 1 gallon hot water, 4 lbs. sBulphate of copper, 4 lbs. white acetate of lead; dissolve, let settle, decant the clear, and seJt at 16° T. No. 20. Brown for Madder, {Machine.) — 7 gallons of ]Wo. 17, 1^ gallons of No. 19, 1^ gallons gum-red, (No. 21.) No. 21. Gum red. — 3 gallons red liquor at 18° T., 12^1bs. gum substitute; boil. No. 22. Brown for Garancin, {Machine.) — 2 gallons 18, 1 gallon 4 lbs. -gum-substi- tute water. v No. 23. Brown for Garancin, {Machine.) — 2 gallons N^>, 17, 3|^ gallons 4 lbs. -gum-sub- stitute water, 3 quarts acetic acid, 3 quarts No. 19. No. 24. Drab for Madder, {Machine.) — 4 gallons No. 17, 1- gallon protomuriate of iron at 9° T., 3 gallons No. 19, 1 gjdlon 4 lbs. -gum-substitute water. ''•For garancin, add 4 gal- lons gum water instead of 1 gallon. No. 25. Drab for bladder, {Machine.) — 5 gallons No. 24, 1 quari/ muriate of iron at 9° T., 6 gallons 4 lbs. -gum-substitute water, 3 quarts No. 19. No. 26. Madder Fawns are made by adding to madder drab '’/la, of' so, of red liquor, according to the shade wanted. No. 27. Madder Purples. — Iron liquor, mixed with purple fixing liquor, is diluted with gum water according to the shade wanted. For instance. No. 4 purple\^^or madder {^machine): — 1 gallon of iron liquor at 24° T., 2 gallons No. 3, 4 gallons farina gum water No. 28. No. 12 purple : — 1 gallon iron liquor at 24° T., 2 gallons No. 3, .12 gallons No. 28. No. 28. Dark Farina Gum Water. — 10 gallons water, 60 lbs. dark calcined farina; boil. No. 29. Garancin Purples are reduced from iron liquor to the shade wanted with the following gum : — 20 lbs. light British gum, 8 gallons water, 1 gallon purple fixing liquor No. 3; boil well, then take out, and let stand 3 or 4 days before using. Color: 1 meas- ure iron liquor, 8, 10, 20, 30, &c., of the above gum, according to shade wanted. No. 30. Padding Purples. — Reduce to shade with the following gum: — 6f gallons water, 1 gallon No. 3, 1 quart logwood liquor at 8° T., 9 lbs. flour; boil, and add 5 quarts farina gum No. 28. For instance, ’lO-padding purple for machine : — 1 gallon iron liquofat 24° T., 70 gallons of the above gum. ( Block colors are made from any of the preceding receipts, by making them a little thinner. No. 31. Alkaline red Mordant. — In a vessel capable of holding 12 gallons, put 10 lbs. alum, and dissolve with 5 gallons boiling water, then add gradually 3 quarts caustic soda at 70° T., mixed with 1 gallon cold water, fill up with cold water; let settle, decant and repeat the washing till the clear liquor is tasteless; filter to a pulp, take off, and add to it 5 pints caustic acid at 70° T., boil down to 3 gallons, add 9 lbs. dark gum substitute, and boil again a short time. No. 32. Pale-red Alkaline Mordant. — 1 measure of the above color and 2 or 3 meas- ures of dark gum-substitute water. No. 33. 10 Acid. — 1 gallon lime juice at 10° T., 1 lb. starch; boil. No. 34. 20 Acid. — 1 gallon lime juice at 20° T., 1 lb. starch ; boil. No. 35. 30 Acid. — 1 gallon lime juice at 30° T., 1 lb. starch ; boil. No. 36. Acid Discharge. — 1 gallon lime juice at 22° T., 1 lb. bisulphate of potash; filter, and thicken the clear with 1 lb. starch. No. 37. Acid Discharge. — 1 gallon lime juice at 28° T., 2 lbs. bisulphate of potash; filter, and thicken the clear with 5 lbs. dark British gum. In the last two colors, the bisulphate throws down a quantity of flocculent matter, which has to be filtered out. No. 38. Reserve Paste. — 3^ gallons lime juice at 50° T., 2J gallons caustic soda at 70° T., heat to boil, then, in a separate vessel, beat up 56 lbs. pipe-clay with 3f gallons boiling water, and add 3:^ gallons 6 Ibs.-gum-Senegal water; add to the other solution, and boil 20 minutes. No. 39. Reserve Paste. — 4 gallons lime juice at 60° T., 3 gallons caustic soda at 70° T., boil, and add 48 lbs. pipe-clay beat up with 2 quarts boiling water, and 4 gallons 6 Ibs.-gum- Senegal water ; boil 20 minutes. The above two pastes are used for blocking on madder-work, to protect the pattern from the following covering shades, which are raised with quercitron bark, &c., &c. No. 38 is a paste used where there are only black and reds to preserve, and No. 39 is used where there is also purple. . Covering Shades. No. 40. 5 Drab. — 1 quart iron liquor at 24° T., 5 quarts water, 2^ lbs. light British gum. No. 41. 10 Drab. — 1 quart iron liquor at 24° T., 10 quarts water, 4|- lbs. light British 2 :um. I CALICO PPwINTING. 253 No. 42. 6 Drab. — 1 quart 'iron liquor at 24° T., 1 quart red liquor at 20° T., 6 quarts water, 2^ lbs. light British gum,\ No. 43. 10 Drab. — 1 quart ijjron liquor at 24° T., 1 quart red liquor at 20° T., 10 quarts water, 5 lbs. light British gum. No. 44. Olive. — 2 gallons re^d liquor at 12° T., 1 gallon iron liquor at 14° T., 6 lbs. light British gum. ^ No. 45. Olive. — 3 gallons reO liquor at 18° T., 2 gallons iron liquor at 8° T., 10 lbs. light British gum. ‘ No. 46. Sage. — 9 quarts red,fliquor at 9° T., 1 quart iron liquor at 12° T., 4 lbs. light British gum. No. 47. Sage. — 14 quarts r,>ed liquor at 3° T., 1 pint iron liquor at 12° T., 6^ lbs. light British gum. No. 48. Chocolate Bro^thn. — 6 gallons red liquor at 15° T., 1 gallon iron liquor at 24° T., 10| lbs. light British /gum, 3^ lbs. flour. No 49. Slate. — 3 o;darts logwood liquor at 8° T., 2 quarts iron liquor at 24° T., 1 quart red liquor at 18° T.,.l quart No. 50, Y gallons water, 18 lbs. light British gum ; boil. No. 50. Gall Vjiquor. — 28 lbs. 'ground galls, 2 gallons acetic acid, 12 gallons water ; stir occasionally I'or two days, and filter. No. 61. Hazel. — 4 quarts brown No. 18, 2 quarts bark liquor at 10° T., 1 pint logwood liquor at 12°/T., 1 quart cochineal liquor at 8° T., 16-oz. measure No. 62, 4^ quarts 6 Ibs.- gum-Senegf-11 water. No. 52.' — 1 quart nitrate of iron at 80° T., 1 pint nitrate of copper at 100° T. No. 53. Standard for Buffs. — 10 gallons water, 40 lbs. copperas, 20 lbs. brown acetate of lead ; .••'stir till dissolved, settle, and use the clear ; reduced to shade wanted with gum- Senegal water. No., 54. Chrome-oxide Standard. — 3 gallons water, 12 lbs. bichromate potash ; dissolve with h.eat, put in a mug of 12 gallons’ capacity, add 3J pints oil of vitriol diluted with 6 quart^ss cold water, add gradually 3 lbs. sugar ; when the effervescence has ceased, boil down to 3 gallons. No. 55. Drab. — 5 quarts gum-tragacanth water, (8 oz. per gallon,) 2^ quarts No. 55, f })int cochineal liquor at 4° T., f pint bark liquor at 8° T. No. 66. Fawn. — 1 gallon No. 55, 2 gallons 8 oz. -gum-tragacanth water, ^ gallon brown No. lY. , • No. 5Y. Slate. — 1 gallon No. 55, 1 gallon 8 oz. -gum-tragacanth water. ^ No. 68. Gum-tragacanth Water. — 10 gallons water, 5 lbs. gum tragacanth in powder ; stii occasionally for 3 days. No. 59. Fast Blue Standard. — 150 gallons water, 18 lbs. indigo in pulp, 24 lbs. cop- peras, 28 lbs. lime previously slaked ; stir occasionally for 2 days, let settle, and draw off the clear liquor, and to every 10 gallons add 1 pint muriate-of-tin liquor at 120° T. ; filter on flannel to a thick paste. No. 60. Fast Blue for Machine. — 1 quart No. 60, 6 oz. muriate-of-tin crystals, 3 quarts of water. Na 61. Fast Blue Standard. — 4 lbs. indigo ground to pulp, 3 quarts caustic soda at Y0° T., 3 quarts water, and granulated tin in excess ; boil in an iron pot till perfectly yel- low, when put on a piece of glass. No. 62, Fast Blue., {Block.) — 1 quart No. 62, 12 oz. muriate-of-tin crystals, 12 oz. lime juice at 60° T., 3 quarts 6 Ibs.-gum-Senegal water. No. 63. Fast Green. — 1| quarts No. 60, 2 quarts lead gum No. 64, lb. muriate-of-tin crystals. No. 64. Lead Gum. — 1 gallon hot water, 8 lbs. white acetate lead, 4 lbs. nitrate lead ; dissolve, and add 1 gallon 6 Ibs.-gum-Senegal water. The course of operation for the styles 1, 2, and 3 above, is to print in one or more of the madder colors ; after dyeing, the goods are hung in the ageing room for a day or two, then brought to the dye-house. The first operation is that termed dunging., which is the same in principle for all varieties of madder or garancin goods, and as it is an operation the careful performance of which is of vital importance to the success of the subsequent opera- tions, a somewhat detailed description of it will not be out of place. The process of dung- ing has for its object : — 1. Precipitating on the fibre, by double decomposition, that portion of the mordant which has escaped decomposition in the ageing room. 2. Rendering insoluble and inert those portions of the mordant which are not in direct contact with the fibre, and which, if allowed to diffuse in water only, would fix on and stain the white or unprinted parts of the cloth. 3. Softening and removal of the staining substances. 4. Neutralizing the acids which may have been added to the mordants, and which otherwise would dissolve in the water and weaken the colors. 6. The formation, in the case of iron mordants, of a compound of oxide of iron, and f \ 254 CALICO PEmilNG. j certain organic or inorganic acids which will not become Vperoxidized beyond a certain point. The use of cow’s dung, derived from India, has beeri continued down to the present time, though for several years printers have largely introduced various substitutes. No very exact analysis has been made of Cow dung. Morin’s, which is the most recent and elaborate, is as follows : > Water . '70*00 Vegetable fibre " 24’08 Green resin and fat acids 1,52 Undecomposed biliary matter - - - - - 0‘60 Peculiar extractive matter {buhuline) - - v . 1-00 Albumen - 0*40 Biliary resin - 8*80 According to M. Koechlin’s practical knowledge on the great s^eale, it consists of a moist fibrous vegetable substance, which is animalized, and forms about oine-tenth of its weight ; 2, of albumen ; 3, of animal mucus ; 4, of a substance similar to mle ; 5, of muriate of soda, muriate and acetate of ammonia, phosphate of lime, and other salii;s ; 6, of benzoin or musk. Probably the hot water in which the calico-printer diffuses the dung exer.ts a powerful solvent action, and in proportion as the uncombined mordant floats in the batfo it is precip-. itated by the albumen, the animal mucus, and the ammoniacal salts ; but there .is reason to think that the fibrous matter in part animalized or covered with animal matter, plays here the principal part ; for the great affinity of this substance for the aluminous sadts is well known. It would appear that the principal function of dunging is to hinder the uncombined mordant diffused in the dung bath from attaching itself to the unmordanted portion of the cloth, as already observed ; for if we merely wished to abstract the thickening stuffs, or to complete by the removal of acetic acid the combination of the aluminous base with the goods, dung would not be required, for hot water would suffice. In fact, we may obsdfve, that in such cases the first pieces passed through the boiler are fit for dyeing ; but when a certain number have been passed through, the mordant now dissolved in the water is tracted to the white portions of the cloth, while the free acid impoverishes the mordanted parts, so that they cannot afford good dyes, and the blank spaces are tarnished. 1 It seems to be ascertained that the mordant applied to the cloth does not combine entirely with it during the drying ; that this combination is more or less perfect according to the strength of the mordants, and the circumstances of the drying ; that the operation of dunging, or passing through hot water, completes the combination of the cloth with the aluminous base now insoluble in water ; that this base may still contain a very minute quantity of acetic acid or sulphate of alumina ; that a long ebullition in water impoverishes the mordant but a little ; and that even then the liquid does not contain any perceptible quantity of acetate or sulphate of alumina. A very able and learned memoir upon this subject, by M. Penot, Professor of Chem- istry, appeared in the Bulletin of the Society of Mulhausen, in October, 1834, with an inge- nious commentary upon it, under the title of a Report by M. Camille Koechlin, in March, 1835. 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 com- position. Fresh cow’s dung is commonly neutral when tested by litmus paper ; but some- times it is slightly alkaline, owing, probably, 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 potash, 0’05 ; sulphate of lime, 0‘25 ; carbonate of lime, 0’24 ; phosphate of lime, 0-46 ; carbonate of iron, 0*09 ; woody fibre, 26‘39 ; silica, 0*14 ; loss, 0'14. In dunging calicoes, the excess of uncombined mordant is in part attracted by the solu- ble matters of the cow’s dung, and forms an insoluble precipitate, which has no affinity for 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 dissolved by the water of the bath, and thus to render their reaction upon the cloth impossible. It is only in the deposit, therefore, that the matters carried off from the cloth by the dung are to be found. M. Camille Koechlin ascribes the action of cow dung chiefly to its albuminous constituent 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 become evident by the test of litmus paper, 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 deoxidating power on the iron mordant, and restores it to a state more fit to combine with coloring matter. See Dunging. 1 1 h r 1 CALICO PRINTING. 255 The use of cow dung is ope'W to some objections, amongst which are its giving a certain amount of greenish coloring nWtter to the white mordants, and its being apt to vary in its constituents from differences ir\ the food of the animals, their health, &c. ; the method of using substitutes for it being }|iow well known, and better colors and whites being more easily obtained from them than With dung, it is probable that cow dung will in a short time cease to be used in calico printirag processes. The dunging operation ought to be a definite chemical decomposition, which Icannot be the case with a variable substance like dung. The substitutions for dung in use,' are : — 1. Phosphate of soda and l^!me. I 4. Silicate of soda. 2. Arseniate of soda. , ' | 5. Silicate of lime. 3. Arsenite of soda. / j Each of these has its po^culiar virtues, and the printer determines for himself which is best adapted for his stylcjs. The first was patented by John Mercer, about 1842, and is made by calcining bond's, then decomposing them with sulphuric acid, filtering out the sul- phate of lime, and, ■'to the clear superphosphate of lime, adding carbonate of soda till slightly alkaline ; fne resulting mixture of phosphate^ of soda and phosphate of lime is dried down to a powde;r ; the use of arseniates formed part of the same patent. Arsenite of soda followed as a matter of course, though not so safe in use as phosphates and arseniates. Silicate of so da was suggested by Adolph Schlieper, of Elberfeld, and patented by J ager in 1852. It is„ the ordinary soluble glass dissolved in water. It is open to the objection of being too pJkaline, and requires care in the use. The silicate of lime was suggested by Higgin wi,th a view to remove this objection. The silicate of lime is formed in the dung cistern, by mixing silicate of soda and muriate of lime, when sparingly soluble silicate of lime is f ormed ; the quantity in solution at one time being never so much as to be danger- ous, and fresh portions being dissolved as wanted. Dunging salts, or liquors, are now made by the manufacturing chemist, containing various mixtures, arseniates, phosphates, arsen- ites, i&c., which are adapted for every variety of dunging. Great economy of time and material result from the use of these dung substitutes. In some of the largest print works, instead of, as with dung, running off the spent-dung cistern after passing through from 100 to '200 pieces, and having to fill again, and heat to the proper temperature, it is found pos- sible to run pieces through the same cistern charged with substitute, at the rate of a piece per minute half a day, and with light goods a whole day — before letting off, of course occa- sibnally adding some of the substitute, to make up for that saturated by the mordants. The du pging process is always performed twice : the first time in a cistern with rollers ; and the second, in a beck similar to a dye beck, washing Avell between. The first is called ing ; the other, second dunging. The manner of immersing the goods, or passing them through the dung bath, is an im- portant circumstance. They should be properly extended and free from folds, which is secured by a series of cylinders. The fly-dung cistern is from 10 to 12 feet long, 4^ feet wide, and 6 or 8 feet deep. The piece passes alternately over the upper rollers and under rollers near the bottom. There are two main squeezing rollers at one end, which draw the cloth through between them. The immersion should take place as fast as possible ; for the moment the hot water penetrates the mordanted cloth, the acetic acid quits it, and, therefore, if the immersion was made slowly, or one ply after another, the acid, as well as the uncombined mordant, become free, would spread their influence, and would have time to dissolve the aluminous subsalts now combined with the cloth, whence inequalities and impoverishment of the colors would ensue. The fly-dung cistern should be set with about 30 gallons of dung to 1,000 gallons of water ; or, to the same quantity, 3 or 4 gallons of dung-substitute liquor ; a little chalk is added, to make the cistern slightly milky. The heat varies for different styles — from 150° F. to boil. Where there is acid discharge or resist, and the colors are heavy, fly-dunging at boil is necessary, to enable the acid to cut properly through the color; the nearer to 150° F. that the bath will give good whites at, the better will be the subsequent dyed color. With cow dung, an excess of it is injurious, both to white and color; but with a tolerably neutral substitute, excess does no harm. The pieces should run at the rate of 60 to 60 per hour. On leaving the cistern, they are well winced in water, and washed, and are then second dunged, which is generally performed in a beck similar to a dye beck, which will be found described further on. This beck is set with about 1 quart of dung-substitute liquor, or 12 gallons of dung to 250 gallons. From 12 to 24 pieces are put in together, and made to revolve over a reel for about 20 minutes or half an hour, the heat being about 150° F. They are then well washed, and are ready for dyeing. This second dunging is principally for the purpose of removing the thickening substance from the cloth, and it should feel quite soft when well done. An improved method of dunging adopted by some extensive firms consists in arranging a fly-dung cistern, a wince pit, a machine similar to the bleacher’s washing machine, and containing the second dunging solution and one of the dye-house ■ ^ ^ If 256 CALICO PRINTING. washing machines all in a line ; the pieces, being then stitcheW end to end, are drawn through the series; first, extended and free from folds, through the .fly-dung cistern ; thence drop- ping into water in the pit ; from that being worked spirallyj! from end to end of the second dunging vessel, which runs at such a speed that one piece ia^ about 15 minutes in traversing it; from that into a water pit again, and finally, spirally,, through the washing machine, when they are ready for dyeing. By this arrangement the' process is a continuous one, and little labor is required. The drawing rollers on the ily-dui)ig cistern are worked by a strap from a shaft. On the thorough cleansing from loosely Vittached mordant, and especially thickening, depends a good deal of the success of the dyedng, and this process is one that requires to be carefully attended to. The washing processes in the dye house have undergone great modifications within the last few years. Formerly, in washing, the old dash wheels we.-e exclusively employed, but now are considered far too slow, and expensive in labor, and\^re nearly abolished, being substituted by various washing machines. A great number of machines have been invented, which all have their admirers. Three, which have been found v(^ry efficacious, are here given. Fig. 129 is a perspective view, and^^. 130 a section of the machine patented by Mather and Platt. The pieces, fastened end to end, are run spirally through the machine, being subjected to the action of the beams or beaters d d, wliilst lying in loose foLds on the large wooden roller c. CALICO PEINTIITG. 257 Fig. 131 is a machine patt^nted by Whitaker, and possesses the merit of great sim- plicity with comparatively smal'l first cost, together with great efficiency. The invention consists of a peculiar arrangement of the material to be washed, by which, instead of it moving in one continuous direction, it is made to cross in its traverse; and by one part being in constant contact with a,;nother part, a powerful rubbing action is continually kept up, thereby washing or cleansing^ the cloth or material more eftectually than can be done by the usual method of merely passjing it between presser rollers. Fig. 131 is an end view of this washing machine, and fig. 132 an end view with the frame side removed, to show the improved arrangement, a and b represent two stones, upon which the machine is fixed ; c is the frame, which forms sides for the water cistern, VoL. III.— 17 258 CALICO FEINTING. 1 and also the journals, or bearings, of the bowls d, e, /, wmich pass from one side to the other, as in ordinary washing machines ; ^ is a peg rail, wi^h the pegs A passing across the machine ; i is the outlet for spent water ; a wooden frain/e surrounding the whole of the water or liquor in the cistern A, which is open at the top emd, and communicates with the space for over water. The machine is put in motion by i^pur wheels, represented by the dotted circles I, m, and n, in Ji^. 131 ; the wheel m is putf upon the main shaft or shafts connecting with the moving power. The piece o is introd^iced into the machine at that end where the outlet for water is placed, and threads through i-the peg rail progressively to the other end of the machine, where the fresh water is introduced just upon the cloth or material as it leaves. When the machine is in motion, the clohh moves on progressively, and is caused to vibrate by the varying dimensions of the squake bowl, which motion rubs one part of the material against another part, by being crossed o'vUce on each side of the square bowl, and washes in the same manner as a woman would do in\ ordinary domestic washing. And it will be observed that when a corner of the square bowl is-xat the bottom, the material is then below the surface of the water, and when the side of the Si^uare bowl is at the bot- tom the cloth is above the surface ; thus, for each revolution of the bsquare bowl, the cloth is plunged four times, which action encloses air within the folded material, and opens it out between the peg rail and square bowls, sometimes as large as a mam’s hat. The water is preserved clean at that end of the machine where the material leavesx it, by its being brought in there, and allowed to escape where the dirty material enters, and the shallow- ness of the water cistern the water is constantly being renewed. Fig. 133 represents the maehine patented by Mr. David Crawford of the Earrowfield Printworks. It is said to answer well for all sorts of fabrics, the finest muslins not being torn by this, as is the case with most washing machines. This machine consists of a rec- tangular frame, fitted up with rollers, dashboards, a dashing frame and driving gearing. The frame is divided into a series of stories or flats, one above another, like the floors of a house, each flat having a dashboard or a fixed platform divided down the centre, towards which division-line each half inclines downwards. The goods in a continuous length-like form are passed first of all round a taking-in roller, which directs the cloth round a long horizontal roller of considerable diameter, which runs in bearings at one side or end of the lowest of the series ; the fabric passes round this roller, and there proceeds horizontally along and through the flat at that level, passing in its way through a vertical traversing frame, which works between the contiguous edges of the platforms or dashboards of all the flats where the boards are divided as before explained. In the centre, at the opposite end of the flat, there is a corresponding horizontal roller, round which the fabric passes, return- ing through the flat and through the vertical traversing frame to the first roller ; the fabric passes again round this roller and again through the flat, and so on until the required num- ber of crossings and re-crossings has been completed. The rollers are geared together so as to be driven simultaneously to carry the fabric along back and forward over these rollers and through the flats, whilst jets of water or other fluids are allowed to fall upon the fabric in its passage, and whilst the vertical traversing frame dashes the cloths with rapidity and severity upon the dashboards beneath ; the traversing frame being worked by an overhead crank, or by any other reciprocator. As the cleansing liquid falls down it is received upon the dashboards beneath, and until it pours off at the centre : the striking action causes the liquid to be well forced into the fabric. When the water falls away at the centre it is re- ceived by a bottom duct and conveyed away to a bottom side-chamber, into which chamber the fabric, as primarily washed in the bottom flat, is first of all delivered from its rollers to the next flat on the series, where it is treated in a precisely similar manner ; and this routine is continued throughout the whole of the flats until the fabric finally emerges from the top of one of the series in its completely cleansed condition. Each flat is supplied with jets of water, and it is obvious that as the fabric passes through and beneath these jets, and is vio- lently struck upon the dashboards, a most powerful washing and cleansing action is secured ; provision is made for varying the length of traverse of the vertical dashing frame and the rapidity of its traverses. Fig. 133 on the drawings is a sectional elevation, and fig. 134 is an end view correspond- ing, as looking on the driving gear, and the taking in and delivering movements. The two cast-iron side standards, a, form the main frame. These standards carry internal bracket flanges for supporting the four dashboard floors C. All the driving movements are actuated from a bottom horizontal shaft, carrying a bevel wheel q, in gear with a correspond- ing wheel R, fast on the lower end of a vertical shaft s. This shaft, by means of the two pairs of bevel wheels w, drives the two large end rollers n, carried in end bearings ex- ternal to the main framing. The lower end of the shaft rests in a footstep bearing on the floor, whilst the upper end is supported in a collar bearing, carried by a bracket t, bolted to the frame. At this part, a third pair of bevel wheels, u, forms the driving communica- tion between the shaft and the end conical roller pulley l, working the dashing movement. All the stories or dashboards of the machine are plentifully supplied with water by the pipe D, having a regulating stop-cock at its upper or lower branch. From this main pipe, cross CALICO PRINTING. 259 branches d, pass into and throiygh all the divisions discharging the water by the jets upon the goods passing through the i^nachine. A guide ring is attached to the ceiling of the workshop v, for the passing thi.’ough of the goods b. From this ring, the line of goods passes in the direction of the ar\row, down and round a guide roller arrangement, so as to be directed through the water in!, the small bottom chamber z. On leaving this chamber the fabric passes through a delpm eye in the end boarding of the machine, and thus reaches the lowest division of the series, j As it continues its course it passes between the lowest pair of rollers or bars e, of the vertical traversing frame f, which gives the necessary dashing action, then proceeds, gi^ided by the pin o round the bottom back roller n, corre- sponding to the lowest of the frpnt rollers n. On rounding this roller, the fabric repeats the circuit already described tl^ree or more times, as indicated by the turns upon the roller, in the view of fig. 2. After/the completion of this traverse, the line of fabric ascends, as shown by the arrow being jiJfrawn out between the nipping roller p and the bottom roller n. The fabric again ascends fior the last time and passes through the third and fourth divisions, being delivered in a ck;ansed condition at g. The dashing action, as already explained, is worked from the coniical pulley J, the spindle of which runs in pedestal bearings imme- diately above the c^entre of the machine. A sliding rod, with a double strap fork m, is fitted up for enab.Ving the attendant to set the drawing belt k, at any part of the conical pulley, so as to, vary the rate of revolution of the driving pulley j, that of l being constant. The spindle o,i the pulley j carries at each end an adjustable disc crank i, the face slots of these discs having crank stud-pins set in them for working the upper ends of the pendant connecting, rods h. The lower ends of^ these rods are similarly jointed to stud g upon the opposite c,dges of the traversing dashing frame f. These studs work through vertical slots in the madn standards, and as the disc crank i revolves at a rapid rate, it follows that the corresp(i*nding rapid traverse of the dashing frame energetically dashes the lines of fabric passing between its rollers upon the several dashboards of the machine. The cleansing water galling from the several jets, is conducted from flat to flat by conductors y, thoroughly washes the goods, whilst this is going on, and it finally falls through the central openings in the rdashboards, and is received into the bottom central trough, whence it flows away by the duct, and is delivered into the chamber z. The lever x in connection with pulley p is to emible the attendant to raise up pulley p in threading the machine. This machine is beau- tif ally adapted for bleaching purposes, as from the peculiarity of its action it answers as a 138 perfect Bleaching Machine in itself. The slots, grooves in the disc cranks, afford a ready means of varying the length of the traverse of the dashing frame ; and this adjustment, coupled with that of the rate of revolution of the central conical roller, affords the greatest possible nicety of adjustment of the powers of the machine, which the manufacturer, bleacher, or finisher can ever require, either for light or heavy goods. j ■ ■ — 1 CALICO PRINTING. ' 261 the stone foundation. The bec»;k is fixed Over a channel c, which communicates with the system of drains which carry a^‘^yay the waste liquors into the river. There are two holes in the curved bottom — one at efjach end — which, when the beck is in use, are stopped with movable plugs ; one of these hot,les communicates direct with the drain and the other with a trough d, which communicates ' with a pit out- side the dye-house, and where tht<^ spent madder can be run for the purpose of makfing into garan- ceux. E is a water pipe, with \ a bi’anch into each beck, with a screw tap attached ; f is a main steam pipe, which divides U.ito the branches G, furnished with valves at h ;^’the pipes g sub- divide in branches i, one of/ which goes down each end of the dye beck, tide perforated pipe k, which traverses the beck ^I’om end to end, con- necting them ; a perfor/ated iron diaphragm is placed across the beck/from end to end; above this is a strong rod m/, from end to end, carrying pieces n projectirag at right angles from it. Bolted on the ei\ds of the dye beck is the frame- work 0, whic’ii carries the bearings of the shaft Q of the wiihch reel; keyed on the shaft are three sets o f cast-iron arms r, which terminate in forks, i:ii which fit the spars s ; the reel is boarded between the spars, as at t. The frame- work o of the two dye becks is connected by the piece u, which carries the bearings of the short fthaft v, on which is keyed one of a pair of mitre wheels w w ; there are sliding catch boxes X X on this shaft, which revolve with it ; there are corresponding catch boxes keyed on the ’ends of the shaft q; the connecting piece u car des also the pillar p, which carries the bear- ingiS of the vertical shafts y, and also of the hor izontal shaft z ; keyed on the shafts y and z are ibevel wheels a a, and at the bottom of shaft y, the mitre wheel w. Permanent motion being given the shaft v y, by this gearing, either of the reels can be put in motion or stopped by the catch boxes x x, worked by lever handles, in or out of the catch boxes on the ends of the reels. In working the becks, two pieces are knotted end to end, and each length passed over the reel down between two of the studs n, under the steam pipe k, up behind the diaphragm l, being then knotted together so as to form an endless web, the bulk of which lies on the bottom of the beck. The drawing shows a beck adapted for 15 lengths of 2 pieces each, or 30 pieces. About 200 gallons of water are put in the beck before the pieces are put in ; and, after the pieces, the dye stuff is added, the reel set in motion, and the steam gently turned on ; from the steam going in at each end, the beck is uniformly heated ; the heat is then gradually raised to boil, generally in about two hours, the pieces continually revolving with the reel so as to bring each portion successively into the air, agi- tating the dyeing materials at the same time. When the dyeing is finished, the steam is shut off, the knots untied, and the pieces pulled over into a pit of water surrounded by a winch reel, which is always placed behind every dye beck. After wincing in this, the pieces are fastened together again, and put through the washing machine two or three times ; they then are ready for the subsequent operations. Maddered goods, on issuing from the dye beck, are far from possessing the beauty that they afterwards show, the colors are dull and heavy, and the white part stained with a reddish shade ; various clearings are required, in which soap plays a principal part. Garancined goods show pretty nearly the color they are intended to be ; but as the white is also stained, a peculiar clearing is given them which will be described further on. Madder goods are cleared with soap in a beck similar to a dye beck. They receive generally two soapings of about half an hour, with from i to lb. of soap per piece each time, washing between. If the white is not sufficiently good, the pieces are spread out on the grass for a day or two, and are afterwards winced in hot water to which a little solution of chloride of lime or soda is added. They are then washed and dried. Chintz work is dyed with from 1 lb. to 5 lbs. madder per piece of 30 yards, accord- ing to the pattern ; generally, a little chalk is added, and if there is no purple in the pat- tern, some sumac, which is found to economize madder, but will not do where there is pur- ple, the shade of which it deadens. Pieces of any style, after undergoing the final process, are passed through a pair of squeezing rollers, or put in the hydro-extractor, when the moist- ure is driven out by centrifugal force, (see Hydro-extractor ;) they are then dried on the cylinder drying machine. 136 CALICO FEINTING. 262 Plate Purple is a style composed of black and one or i|iore shades of purple only, and requires a little different treatment. Print in black No. 4 , dark purple to shade No. 2Y and acid, say No. 35, cover pad in pale purple. No. 30, age/. Fly dung at 170° F., second dung at 165° F. half an hour ; wash and dye with ground) Turkey madder root, giving 720 of its weight in chalk, and 3 quarts of bone size to the becik ; bring to 175° F. in 2 hours, and keep at 175° F. half an hour ; wash well and soap 15 / pieces, 30 yards, half an hour at boil with 5 lbs. soap to 15 pieces ; wash well and wiince 5 minutes at 140° F. with 2 quarts chloride of lime liquor at 8° F. to 300 gallons ; win ce and soap again at boil half an hour with 3 lbs. soap to 15 pieces ; wash and wince 5 miuutes in 4 quarts chloride of lime at 8° F. and 2 lbs. carbonate of soda crystals to 200 gallo?ns water ; at 160° F. well wash and dry. In this style, as in any where there is severe soaping, it is^iuecessary to give a slight ex- cess of madder in the dye, so as to ensure perfect saturation — -if this is not done, the color speedily degrades, and becomes impoverished. It may be observed here, that the style plates are such as formerly were printed by the plate or flat press, and are generally small patterns, with padded or well covered grounds, the colors being fe’w, and frequently only different shades of one color. Plate Pinks or Swiss Pinks — a style imported from Switzerland, cOJisisting of various shades of red and delicate pinks, produced as follows : — Print in No. 6 wit.h second or third shades, as No. 7 — acid No. 34 may be also printed, and a very pale shade of red covered, aged two or three days, dunged at 160° F. — if dung substitute is used, care muLst be taken to use one that is not caustic from free alkali ; the dyeing must be done with the finest quality of French or Turkey madder. The pieces must have sufficient madder allowed to overdye them, or dye a heavy brownish -red. For a full plate pink on cloth, from 4 to 6 lbs. of French madder will be required. About 5 per cent, of chalk may be added to the dye where the water is soft. The heat should be raised to 150° F. in 2 hours, and kept at that heat half an hour. It is necessary to keep the heat low in dyeing French pinks, to prevent the impurities from fixing on the mordants, as only the very finest portion of the coloring matter must be fixed — after dyeing, the pieces are well washed and soaped with about half a pound of soap per piece in a beck at 140° F. for half an hour, they are then well washed and entered in a beck with cold water, to which has been added sufficient oxymuri- ate of tin or sulphuric acid to make faintly sour, a little steam is turned on, and the heat raised to about 120° F. in half an hour; the colors which on entering the beck were full shades of red, gradually assume an orange tint, and when of a bright orange color, the pieces are taken out, and winced in water. This operation, termed cutting^ is the one that decides the depth of tint in the finished piece. The longer the pieces are kept in the beck, and the greater the heat, the paler and more delicate the shade of pink obtained. After this treatment they are put in a beck with soap, and boiled for an hour, taken out, washed well, and put in a strong pan charged with soap and water, the lid screwed down, and boiled at a pressure of two atmospheres, either by direct fire or high-pressure steam, for two or three hours, then taken out, washed, and put in a beck with water at 160° F., charged with a little hypochlorite of soda : they stay in this about ten minutes, and are then washed and dried. In some print works, after the high pressure boil, the pieces are spread out on the grass for a night or two, and then cleared in hypochlorite, &c. The use of the acid here is not very clear, it probably completely purifies the color from iron which may have been in the mordant, but it also seems to render the combination of alumina, tin, lime, coloring matter, and fat acid a definite one by removing a small quantity of the mordant. The French chemists assert, that, after the final process, a definite atomic compound of lime and alu- mina, coloring matter, and fat acid remains. The quality of the soap used by printers is of great importance. It is made for them specially from palm oil, and requires to be as neutral an oleo-stearate as possible ; an alka- line soap like domestic soap would impoverish and degrade the shades. The soaping process has a twofold action : — To clear the white by decomposing the compound of lime and coloring matter which forms the stain ; this it does by double decomposition, forming oleo-stearate of lime, which dissolves or forms an emulsion with the excess of soap ; and a compound of soda and color- ing matter, which dissolves. In its action on the dyed parts, it probably first removes resi- nous and other impurities which are loosely held by the mordant, and secondly gives up a portion of its fat acid to the dyed parts — the resinous acids or possibly phosphoric acid from the dyed parts, by combining with the soda, setting free fat acid for this purpose. Second Style : Garancin. Almost all the madder styles are imitated by dyeing with garancin; a concentrated prep- aration of madder (see Madder) which dyes fine brilliant colors at once, not requiring to be soaped to develop the shades, but not possessing the extreme solidity of madder color. Garancin dyeing is the most economical way of using madder, since more coloring matter is obtained in this way than by using madder direct, and consequently garancin is principally CALICO PRINTING. 263 used for full heavy colors, whjjich, if dyed with madder and soaped, would be, to a certain extent, abraded, and not stanod so finely on the surface of the cloth. Chocolate grounds, black, red, and chocolate, with t brown or drab, dark purple plates, black and scarlet ground, are thus dyed ; in short, where\i/er the pattern is very full, and cheapness essential, garancin is resorted to. The colors or ; mordants for garancin are usually about two-thirds of the strength of similar colors for nuadder, (see the list of colors,) the ageing and dunging, &c. are the same as for madder ; thile dyeing is performed in the same manner, using from one- fourth to one-third the quantity Uhat would be used of madder. A little chalk is also added where the water is soft ; and tihe dyeing is commenced at 110“ F., and carried to 185“ F., or 190° F. in two hours ; thepl got out and well washed and rinsed in water at 140° F., in a beck, for 10 minutes, then sc4ueezed and dried. The white is always stained a little, though not to the same extent as i/zh maddered goods, and this slight stain is removed by a process peculiar to garancin goof^s. In front of an ordinary cylinder drying machine, is placed a padding apparatus, and I6etween it and the drying machine is placed a chest provided with a few rollers at top andj-' bottom ; this chest is covered by a lid, which has at each end a slit, by which the piece emters and issues ; a perforated steam pipe at the bottom of the chest allows steam to bl»w freely in. The padding machine is charged with solution of hypo- chlorite of lime, . 'at from ^° to 2J° Twaddell’s hydrometer, according to the depth of the stain on the wfcnte ; the pieces are padded in this liquor, squeezed out by the bowls, and then run into the steaming chest, which is of such a size, that any given point on the piece is about 4- minute in passing through it ; on leaving this chest, the pieces pass through water, or; water is spirted on from a perforated pipe ; after again passing through squeezing rollers, t’ney proceed on to the cylinders of the drying machine, on leaving which the white is foundi to be perfectly bleached and the colors brightened. There are several varieties of garancin, each adapted to particular styles. For dark full black, chocolate, and red, with brown or drab, and where there is no purple, a garancin termed chocolate garancin, made from the commonest descriptions of madder, answers very weli, and this class of goods is usually dyed with chocolate garancin, assisted by small quan- tities of sumac, quercitron bark, and peach wood, which additions give full rich shades. W here there is purple, none of these adjuncts can be used, and the garancin requires to be n> ade from a superior description of madder. Within the last three or four years, great im- pi movements in the manufacture of purple garancins have been made. The Alizarin, patented bf PincofF and Schunck, has the property of dyeing at once purples as pure as the finest soaped madder shades ; it has the disadvantage of not dyeing good black and reds, and when these colors are freely introduced along with purple, an admixture of ordinary purple garancin is required, the general elfect being still very good, but the purple not quite so fine. The garancin patented by Higgin dyes very good purple, with black, chocolate, and red also. Both these improved garancins stain the white grounds very little, and produce considerably faster work than the ordinary garancins ; the goods may even be soaped to a considerable extent. A garancin that will bear as severe soaping as madder, or a method of so dyeing with garancin as to produce the same effect, is still a desideratum. When this can be accomplished, there will be an end of dyeing with madder, which will be considered a raw material, and be all manufactured into garancin. Garanceux. — In ordinary madder dyeing, the madder can never be made to give up all its coloring matter ; when all coloring matter soluble in water has been exhausted, there still remains about a quarter of the whole quantity, combined with lime, and mixed with the woody fibre. This madder is turned to account by converting it into garancin, or, as this preparation is called, garanceux. The spent madder is run off into a pit outside the dye- house, where it is mixed with a small quantity of sulphuric acid, to precipitate any coloring matter in solution. It is then allowed to drain dry ; removed from the pit, it is boiled in a leaden vessel, with more sulphuric acid, for several hours, then washed on a filter till free from acid, and, after draining, is ready for use. It dyes to about one-third the strength of ordinary chocolate garancin, and is principally used for the commoner garancin styles. Mr. John Lightfoot, of Accrington, has patented an improvement in the ordinary process of maliing garanceux. He recommends large vats to be provided, two or more in number, each sufficiently large to contain all the waste dyeing liquor produced in the dye-house in one day, and so arranged that the liquor runs from the dyebecks into them ; at a certain point in the trough that conducts the liquor to the vats, is placed a lead cistern with a valve and perforated bottom ; this cistern holds a regulated quantity of concentrated sulphuric acid, and whenever a dyebeck is let off and the liquor flowing down the trough, a quantity of acid, proportionate to the quantity of madder, is allowed to run down through the per- forated bottom and mix with the hot liquor ; the acidulated liquor then runs into the vat, a tightly fitting cover on which keeps the liquor hot. When the day’s dyeing is done, the vat is left covered up all night ; next day the lid is raised, and, by means of holes and pegs in the side of the vat, all the clear liquor is drained away, the vat filled anew with water, stirred up, and, when settled, the clear drawn off again ; this washing being repeated till all the acid is washed away, the garanceux is then run on a filter to drain for use. The advan- \ I / 264 CALICO PEIOTING. tages of this plan are, first, the saving of fuel, by economizio^ g the heat of the waste liquor, and, secondly, the production of one-fourth more coloring mrfatter. ’ Third Style : Reserved. I Maddered or garancined goods are often left with white nspots, as leaves, &c., and when dyed these spaces are filled with various bright colors, sujch as green, blue, yellow, &c. These colors are the ordinary steam colors, described hereihafter, and are fixed in the same manner. ’ Another way of combining madder or garancin colors Wiith steam colors, is by blocking on the dyed object, generally groups of flowers, a reserved j-xfiste, (No. 89,) and when this is dry, covering by machine in small patterns with various shade ^ of drab, olive, &c., (Nos. 5, 44, 46, &c.,) which then are dunged and dyed with quercitron b\ark, cochineal, madder, and bark, &c., &c. Where the paste has been applied, the colors undvfrneath, or the white spots reserved, are unaffected by the covering color, and stand out deaf surrounded by the cov- ering color. In the white spaces reserved are now blocked steam .r-olors, which are raised by steam, as described further on. Fourth Style : Padded. In this style the white cloth is mordanted all over by padding in red o':? iron liquor, or mixtures of them, drying in the padding flue ; then a pattern is printed on ib.acid, and the usual dunging and dyeing operations performed, the result being a dyed grojmd with a white pattern. Fig. 137 represents a section of the padding flue used in mordanting to this stjle. 137 It consists of a long vaulted chamber, about 35 yards long by 5 yards, and 4 yards high, cut in two at nearly half its length, by 6 small arches built in an opposite direction to that of the chamber, the object of which is to preserve the principal arch from the action of the heat, and to hinder the dried pieces from being exposed, on coming to the higher part, to moisture and acids, which are disengaged in great abundance, and might condense there, c c is a long furnace, the flue of which forms the bottom of the chamber ; the top of the flue is covered with plates of cast-iron fitting one into another, and which can be heated to near red heat by the flame of the furnace, r is an arched passage, by which the interior of this' store can be reached, h h are ventilating holes in the lateral wall, which can be opened and closed at will by means of the rod y, which is connected with sliding doors over the apertures, k k are cast-iron supports for turned copper rollers, which are fixed to the cross pieces y ?/, and serve to conduct the piece. 1 1 are bars of iron which carry the fans m w, which are covered by gratings, and make about 300 turns per minute. In front of this hot flue is placed all the apparatus necessary for padding the pieces, and moving them through the drying chambers. This movement is caused by pulleys n n driven from a prime mover. The mordant liquor being put in the box of the padding machine, the pieces wound on a beam and placed above the machine are conducted through the box, then between the two lowest rollers above the box, from them through the liquor again, passing next through the highest rollers, and so into the flue, their course being easily traced by the arrows ; on leav- ing the flue dry, they are wound on a beam, or plated down on the wooden platform behind the machine. The 3 rollers of the padding machine are made of brass, and are wrapped with a few folds of calico ; the iron journals of them work in slots, the lowest one being at f CALICO FEINTING. . 265 the bottom of the slot working)- in brass bearings ; a weighted lever presses the top roller in forcible contact with the others. \ Padded goods, after printin Sg in acid, are hung 2 or 3 days in the ageing room, dunged, and dyed. A few of these shad^es are here given : — a. Claret and white. — Pad '-in red liquor at 10° F., dry, cool, and pad again in same liquor, dry, cool, and print in alcid No. 37, age 3 nights. Fly dung at boil, wash, second dung at 160° F., k hour, wash,i/dry, and singe., wash and dye 12 pieces 7 ft. 8 in. 30 yards with 18 lbs. ground peachwood, lbs. of French madder, 6 lbs. sumac, 5 lbs. prepared log- wood, run the pieces in the birck cold for 20 minutes, and then bring to a boil in 1 hour and 10 minutes, boil 15 minutils, get out, rinse and wash, bran 10 minutes at boil in a beek with a few pounds of bran, rii^ise in a pit and bran again at boil, wash and dry. Prepared Logwood is th^s made. — Ground logwood is spread out on a floor, damped with water, and heaped ui^. It is then turned over once a day for a fortnight, and occa- sionally wetted, during w’nich time it changes from a dull red to a bright scarlet. It is then ready for use. Some ^^hange, probably oxidation, has taken place, and the wood dyes fur- ther after this process.^ h. Scarlet and vjohite. — Padded and dunged as for clarets ; then 10 pieces dyed with 15 lbs. French madder, 15 lbs. Dutch crop madder, 7 lbs. peachwood, 4 lbs. sumac, with 3 quarts bone si/jt ; bring to a boil in 2^ hours, and boil a quarter of an hour ; wash and bran, &c. c. Scarlet and yellow. — Proceed as for scarlet and white, but dye 10 pieces with 22^ lbs. crop Dutch madder, 22^ lbs. French madder, 7^ lbs. sumac, wash, bran, and dry ; then pad in re;d liquor at 10° T., age 2 nights, fly dung at 130° F. ; wash and warm water at 120° 10 ^minutes, dye 10 pieces with 20 lbs. quercitron bark, heat to 120° in 1 hour, keep at 120°/ 15 minutes, wash and dry. d. Burgundy and white. — Pad, &c., as for clarets; dye 10 pieces with 18 lbs. French maddrer, 18 lbs. peachwood, 1|- lbs. logwood, 5 lbs. sumac, 4 quarts glue. Heat to boil in If hours, boil a quarter of an hour, wash and bran at boil 10 minutes, wash and dry. e. Tyrian purple and white. — Pad, &c., as for clarets ; dye 10 pieces with 5 lbs. prepared log;wood, 5 lbs. Dutch crop madder, and 7 lbs. peachwood, 2 lbs. bran, and 3 quarts bone si 2 e. Bring to boil in If hours, boil a quarter of an hour, wash and brail at 150° 5 minutes with 1 lb. bran per piece, wash and dry. •■/. Puce and white. — Pad, &c., as for clarets; dye 12 pieces with 3 lbs. fine ground CO chineal, 1 lb. ground galls, 4 lbs. prepared logwood, 3 lbs. peachwood, heat to 170° in 1 hollir and 20 minutes, keep at 170° 10 minutes, wash, bran at 160° 10 minutes ; wash and dr/. g. Amber and white. — Pad, &c., as for clarets ; dye 10 pieees with 20 lbs. quercitron bark, 10 lbs. Dutch crop madder, 2 quarts bone size. Heat to 160° in 1 hour and 15 minutes, keep at 160° 15 minutes, wash, bran 10 minutes at 150° ; wash and dry. h. Peach and white. — Pad, &c., as for clarets ; dye 10 pieces with 2 lbs. ground cochi- neal, 2 lbs. peachwood, 6 oz. logwood, heat to 140° in If hours, wash, bran at 140° 10 minutes ; wash and dry. i. Black and white. — Pad in red liquor at 20° T. once ; print in No. 36, age 3 nights, fly dung at boil, second dung at 140° 20 minutes, wash, dry, and singe ; wash and dye 10 pieces with 60 lbs. prepared logwood, 4 gallons of bone size, and 6 oz^ carbonate of soda crystals, heat to boil in 1 hour and 10 minutes ; wash well and dry. k. Olive., drabs, ckc., with white. — A great variety of shades may be obtained by varying the mordants. For drabs, pad in iron liquor diluted about 10 times, according to the shade wanted, and dye in bark, or bark and logwood. For olives, pad in mixtures of red liquor and iron liquor, diluted, and dye in bark, or bark and logwood. The acid used may be No. 33. l. Bark dyeing. — Dye 10 pieces with 25 lbs. bark, and 3 quarts bone size ; heat to 190° in If hours, and keep at 190° 10 minutes, wash and bran at 160° 10 minutes; wash and dry. m. Bark and Logwood dyeing. — Dye 10 pieces with 20 lbs. bark, and 30 oz. prepared logwood, with 3 quarts bone size ; heat as in bark dyeing. Fifth Style : Indigo. The indigo dye-house is always on the ground floor of a building, and is fitted up with a number of stone vats let into the ground. There are generally several rows of these vats, about 3 feet apart. They are about 8 feet long by 4 feet wide, and 8 to 10 feet deep. Some of them have steam pipes inserted, which go to near the bottom, so that they can be heated when necessary. There are about 10 vats in a row. A. Blue and white. — The simplest form of blue styles is blue and white ; dark blue ground with white figures. The cloth is printed in one of the following reserve pastes : — No 65. Reserve paste for Block. — 3 lbs. sulphate of copper, dissolved in 1 gallon of water, 15 lbs pipe-elay, heat up with some of the liquor ; 1 gallon of thick gum Senegal so- lution, and 1 quart of nitrate of copper at 80° T. ( 266 . CALICO PRINTING. I No. 66. Reserve paste for Machine. — 2^ lbs. sulphate copper, 1 gallon of water, thickened with 9 lbs. flour, and 2 lbs. dark British gum. / No. 67. Reserve paste for Machine. — 5 lbs. sulphate of] copper, 2 lbs. white acetate of lead, 2 gallons water, dissolve and thicken the clear with 3 ^bs. flour and 2 lbs. pale British gum ; when cold, add half a pint of nitrate of copper at 80j T., to every 2 gallons of color. No. 68. Reserve paste for Machine. — 4 gallons boilinfg water, 16 lbs. of sulphate of copper, 8 lbs. white acetate of lead, let settle and pour ofF^ the clear liquor ; thicken 3 gal- lons of this with 8 lbs. of flour, and 4 lbs. pale British gur^n. When boiled, add 4 lbs. sul- phate of zinc, and dissolve. The foregoing are all to resifit deep shades of blue, for light shades of blue dipping any of the following : — \ No. 69. Mild paste for Block. — 25 lbs. dark British gum', 15 quarts of water, boil 10 minutes, and add 7^ lbs. soft soap ; stir well in, and, when mix^ed, add 20 lbs. sulphate of zinc, stir well in, and add 10 lbs. pipe-clay, beaten up into 7|- q'Ciarts of water, and 7i gills of nitrate of copper at 80'’ T. Mix all well together. No. 70. Mild paste for Machine. — 8 lbs. dark British gum ; 3f'''quarts water; boil and * add 2 lbs. soft soap, cool, and add 6 lbs. sulphate of zinc dissolved in 2 quarts of boiling * water and 1 quart of nitrate of copper at 80° T. After printing in one of these reserves, hang in a rather humid atmosphere for 2 days, and then dip blue. Indigo for use in the dye-house is ground with water to a fine pulp ; a series of cast-iron mills with curved bottoms, are arranged in a lino : one or two iron rollers are moved back- wards and forwards on the curved bottom in each mill by an upright rod, which is furnished with a roller at the bottom, and is connected with a horizontal rod 'worked by an eccentric. Indigo and a certain quantity of water are left in these mills several days, till the pulp is perfectly smooth. The method of blue dipping is as follows : — In a line of ten vats, the first one is set with lime ; as — (No. 1.) 1,000 gallons \vater, 250 lbs. of hydi’ate of lime, or lime slaked to a dry ^pow- der ; when used, it is well raked up. The indigo vats vary according to the style of work ; for deep blue and white, or blue and yellow, or orange, the following is a good one : — (No. 2.) 1,000 gallons -water, 50 lbs. indigo previously pulped, 140 lbs. copperas, apd 170 lbs. lime ; dissolve the copperas in the water, then add the indigo, stir well up, arid add the lime, previously riddled to separate small stones. Rake up every two hours for t-wo days, and let settle clear. The clear liquor, when taken up in a glass, must have a deep yellow color, be perfectly transparent, and be immediately covered with a pellicle of regen- erated indigo when exposed to the air. Eight or nine vats are all set alike. The pieces to be dipped are hooked backwards and forwards on a rectangular frame which just fits the vats, so that the cloth can be immersed, but still not so deep as to touch the sediment of the vats. The process is thus performed : — The lime vat No. 1 being stirred up, the frame which contains two pieces, is lowered down into it, so as to completely immerse the pieces ; a gentle up and down movement is given by hand. The frame is allowed to stay 10 minutes in, is then lifted out, and supported over the vat by rods put across. After draining here a few minutes, it is then removed and immersed in vat No. 2, or the first indigo vat. It stays here seven minutes, is lifted out, and drained as before over the vat 8 minutes, then removed to No. 3 vat, and so on, till it has gone through the whole series, or till the shade of blue is considered strong enough. After the last dip, the pieces are unhooked and winced in a pit of water, then winced about 10 minutes in a pit contain- ing sulphuric acid at 6° T., washed well in the wheel, squeezed, and dried. In large dye- houses, there is an arrangement for collecting all the waste indigo which is washed off the pieces, by running all the water used into a vaulted chamber under the dye-house, where it passes from one compartment to another, gradually depositing the suspended indigo, which is periodically removed. In heavy bodies of color, the paste sometimes slips, or the shapes become irregular ; this is counteracted by using the first indigo vat raked up instead of clear. The vats are used till nearly exhausted, and then the clear liquor pumped off, to be used instead of water for -setting fresh vats with. B. Blue and Yelknv. or Orange. — Print in one of the reserve pastes, and yellow or orange color made as follows : — No. 71. Chrome yellow for Machine. — 2 gallons w^ater, 20 lbs. sulphate copper, 20 lbs. nitrate of lead ; dissolve, and beat up with 12 lbs. flour, and 2 gallons sulphate of lead bot- toms ; boil all together. The sulphate of lead here is the by-product in making red mordant No. 8, and is drained to a thick paste. No. 72. Orange. — Make a standard liquor by dissolving 24 lbs. W’hite acetate of lead in 6 gallons water, and stirring 12 lbs. litharge in it till perfectly white, then let settle, and use the clear. For the orange color take two gallons of this standard liquor, instead of the gallons of water in the above yellow color. I — •/ V CALICO PKINTD^G. 267 Follow the same routine iih dipping, &c., as for blue and white. After wincing in sul- phuric acid sours, wash well, a nd wince 10 minutes in bichromate of potash solution, \ oz. per gallon at 100° F. Wash Well, and wince in dilute muriatic acid at -^° T. containing 1 oz. oxalic acid per gallon, till the yellow is quite bright. The small quantity of chromic acid set free oxidizes and des troys the indigo that may be attached to the yellow color. After this souring, wash and dr!y. If orange was printed instea\d of yellow, treat as for yellow ; and after the murio-oxalic sour, wash, and raise orange in', the following ; — 10 lbs. bichromate of potash, 300 gallons water, and sufficient slaked Fine to make slightly milky; heat to 180° F., and wince the pieces in till the orange is futh and bright ; then take out, and wash well, and dry. Other varieties of blue d yeing are : — c. Two blues. / D. Two blues and whiite. E. Two blues, white', and yellow or orange. F. Dark blue and ^^reen. G. Two blues and yellow. For c and e a/ pale shade of blue is first given the cloth. The light blue vat is thus composed : — / (No. 3.) Li^ht Blue Vat. — 1,000 gallons water, 40 lbs. indigo, 70 lbs. copperas, 80 lbs. lime. For Dip light blue by three immersions, drawing well between ; unhook, wince in water, ■'chen in sulphuric sours at 2° T. ; wash, squeeze, and dry ; then print on a reserve paste, an.d proceed as for dark blue and white ; when finished, the pale blue having been protected by the reserve, has remained unaltered, all the rest being dark blue. For' F. Instead of reserve paste, print on yellow No. 71, and dip dark blue, sour and raise the yellow with bichromate of potash, omit the souring after chroming, and wash and dry. The yellow falling on the pale blue, makes a green. I'or D. On white cloth print a nobject in muriate of manganese, thickened with dark British gum, raise this as described under the head Broyizes, dry and block in a reserve paste No. 65, then lime and dip in the dark blue vat, letting stay in half an hour, remove, oxidize in the air, wash and sour with dilute muriatic acid, to which some muriate of tin li quor has been added, wash and dry ; where the peroxide of manganese has been is now o' ark blue, the ground pale blue with white object. • For E. Print as d, with yellow or orange in addition, and after the sulphuric sours, raise ysllow or orange as before. ‘1 Dip light blue, print reserve paste and yellow, dip dark blue, wince, sour in sulphuric sdurs at 6° T., wince in water, chrome at 140° F. 10 minutes at 2 oz. bichromate per gallon, wince, wash, and sour in the following : — 7 lbs. oxalic acid, 3 lbs. strong sulphuric acid ; dilute with water to standard 8° T. ; wince till the yellow is bright, then wash and dry. A style formerly very much in vogue, but now scarcely ever used, is the neutral or Laz- ulite style. It consists in combining mordants with reserves, and dipping blue ; the colors throw off the blue, and are subsequently dyed with madder. Neutrals are of two sorts : 1. Where reds and chocolate, or black, with resist white are printed, and dipped light blue, the resist white being only required to resist the blue. 2. Where the white is required to cut through the block, reds or chocolate in addition to the blue. The following are examples of lazulite colors for the first variety ; No. 73. Black., {Machine.) — 4 quarts logwood liquor at 12° T., 1 quart gall liquor at 9° T., 1 quart red liquor at 20° T., 1 quart iron liquor at 24° T., 1 quart acetic acid, thicken with 3 lbs. flour, and 8 oz. starch ; when boiled, add 1 pint Gallipoli oil, and 1 pint tur- pentine. No. 74. Chocolate, {Machine.) — 5 quarts red liquor at 12° T., 1 quart iron liquor at 24° T., li lbs. sulphate of copper, 24 oz. measure of nitrate of copper at 100° T., thicken with 2| lbs. flour, and \ lb. dark British gum. No. 75. Chocolate, {Block.) — 5 quarts red liquor 12° T., 1 quart iron liquor 24° T., 2| lbs. sulphate of copper, 36 oz. measure nitrate of copper at 100° T., 9 lbs. pipe-clay beat up well, and add 3 quarts of gum Senegal solution at 5 lbs. per gallon. No. 76. Dark Resist Red, {Block.) — 2 quarts red liquor 22° T., 6f oz. white acetate of lead, 4^ oz. sulphate of copper, dissolve, and beat up in it 6| lbs. pipe-clay. Thicken sepa- rately 2 quarts red liquor at 12° T., with 12 oz. flour, and add, when boiling hot, 8 oz. of soft soap melted ; mix well, add the pipe-clay mixture to this, and then 2 quarts red liquor at 2° T., thickened by dissolving gum Senegal in it. Stir the whole well together. No. 77. Dark resist Red, {Machine.) — 20 quarts nitrate of zinc at 36 B., 10 quarts water colored with a little peachwood, 12^ lbs. alum, 10 lbs. acetate of lead ; dissolve all together with heat, stir till cool, thicken all together with 8 lbs. flour, and 1-^ lbs. dark British gum. No. 78. Any shade of pale red is made for block by substituting the red liquor in color No. 76 by the mordant No. 8 reduced with water, according to the shade wanted. 268 CALICO PKINTING. No. YO. Any shade of pale red for machine is made by rc/ducing the quantities of alum and acetate of lead in color No, 77. The white reserve for this variety of neutrals is either of i he mild pastes. No. 80. Resist Brown. — 2 gallons water, 24 lbs. catechu|| 6 lbs. sal ammoniac, 1 gallon acetic acid ; boil 15 minutes, and add gallons gum solutio’ n, 6 quarts nitrate of copper at 100° T. / Process. — The colors after printing are aged 3 days, th*en dipped light blue in the fol- lowing blue vat. r (No. 4.) Neutral vat. — 1,000 gallons water, 120 lbs. ind^ti^o, 135 lbs. copperas, 150 lbs. lime ; rake up for two days, and let settle. A frame with rollers top and bottom is lowered into t,his, and the pieces are run through ; after leaving the vat, they are made to travel over rolRtrs in the air for a sufficient distance to turn them blue ; then into a pit of water, from that irPto a beck with cow dung and water, at 160° F., where they run 15 minutes, then washed anc dyed madder or garan- cin, &c. &c. In the second variety of neutrals, the white is required to resist bot.ii mordants and blue, and is made thus : — No. 81. Neutral White for Blocks. — 7 quarts lime juice at 30° T., 1 quipt water, 4-|- lbs. sulphate of copper, 24 lbs. pipe-clay, 3^ quarts lime juice at 30° T., previously thickened with gum Senegal. No. 82. Neutral White for Machine. — 1 gallon lime juice at 42° T., 2 lbs. sulphate of copper, 32 oz. measure nitrate of copper at 100° T., thickened with lbs. starch. The black is the ordinary madder or garancin black. Nos. 4 and 5 process. i The neutral white is first printed either by block or machine ; if the latter, it cannot be in a pattern which should register accurately with the subsequent colors, as it must be dried perfectly before the other colors are printed, to avoid obtaining irregular shapes ; the above reserve colors are then printed over the neutral white. Mild paste Nos. 71, 72 may also be printed along wjth the other colors, to reserve a white under the blue only. The subsequent process is the same as for the first variety. ! After dyeing madder and garancin, and clearing with soap, &c., steam or spirit cololrs are generally blocked in. Parts of the yellow being made to fall over the blue form green. Sixth Style : China Blues. ^ China blues., so called from the shade of blue resembling that on porcelain. In this style indigo is printed on, and made to penetrate and fix in the cloth by the subsequent process. The color is made thus : — No. 83. Standard China Blue. — In an indigo mill are put 45 lbs. indigo, 9 gallons iron liquor at 24° T., and 18 lbs. copperas, the whole ground till quite fine ; then add 7^ gallons gum Senegal solution at 6 lbs. per gallon ; grind an hour longer, take out and wash the mill with 6 quarts hot water, and add to the above. No. 84. China blue gum. — Gum Senegal solution at 3 lbs. per gallon, containing 4 oz. copperas per gallon. Colors are made by reducing the standard blue with the gum, according to the pattern and strength required. For instance, for two blues of medium shades : — No. 85. Strong Blue. — 1 volume standard, 2 volumes gum. No. 86. Pale Blue. — 1 volume standard, 10 volumes gum. After printing, age one night, and raise as follows : — Two vats similar to indigo vats are set. No. 1. 1,000 gallons water, 500 lbs. slaked and dry lime, — No. 2. Solution of cop- peras at 5° T. In each vat is lowered a frame, which is provided with rollers at top ajid bottom, and in addition has a pair of bushes at each side of the frame, just above the surface of the liquor, in which are put beams, on which the pieces are wound alternately ; the bear- ings of the beams being just above the surface of the liquor, allows the roll of pieces to be always half in and half out of the liquor. The course of proceeding is this : — A beam con- taining two or three pieces stitched end to end is placed on a small frame at one side of vat No. 1, and by means of a cord previously threaded through the rollers in the vat, the pieces are slowly wound through the vat and on to a beam placed in the bearings at the opposite side of the vat, by means of a winch handle fitted on this beam ; when the pieces have thus passed through vat No. 1, which is kept in a milky state all the time, the beam is lifted out and transferred to one of the pair of bearings in vat No. 2 ; the pieces are wound through this vat in the same manner ; after this vat, they are removed to No. 1 vat, and worked through ; this alternate liming and copperasing is continued till the pieces have been 4 times through each vat ; then detach and wince in water ; then put into sulphuric sours at 10° T., immersing completely in the liquor till the whites appear quite clear ; then wash well, soap in a beck at 1 20° F. a quarter of an hour with a ^ lb. soap per piece ; wash again and sour in sulphuric sours at 1° T. at 110° F, ; wash well and dry. The various phenomena which occur in the dipping of China blues are not difficult of ■ . ^ CALICO PRINTING. 269 explanation with the lights of ^modern chemistry. We have, on the one hand, indigo and sulphate of iron alternately app 4ied to the cloth ; by dipping it into the lime, the blue is de- oxidized, because a film of the Tsulphate of iron is decomposed, and protoxide of iron comes forth to seize the oxygen of th p indigo, to make it yellow-green, and soluble at the same time in lime water. Then, it pc inetrates into the heart of the fibres, and, on exposure to air, absorbs oxygen, so as to becon^^e insoluble, and fixed within their pores. On dipping the calico into tlie second vat of sulibhate of iron, a layer of oxide is formed upon its whole sur- face, which oxide exercises an r.ction only upon those parts that are covered with indigo, and deoxidizes a portion of it ; Ihus rendering a second dose soluble by the intervention of the second dip in the lime bath/. Hence we see that while these alternate transitions go on, the same series of deoxidizerofent,^ solution, and re-oxidizement recurs ; causing a progres- sively increasing fixation of /'indigo wdthin the fibres of the cotton. Other indigo styles are/ dipped greens, blue with white discharge. Dipped Greens. — Thj^re are 4 vats similar to indigo vats in a row, set with : — First: (No. 5.) Lv^ht blue Vats for Greens. — 1,000 gallons water, 25 lbs. indigo, 45 lbs. copperas, 65 lbs.,- lime, dry slaked, lY lbs. caustic soda, 24" T. ; raked up 2 days, and settled clear. , Second : (No, '6.) Yellow Vat for Greens. — 1,000 gallons water, 250 lbs. brown acetate of lead, 130 lh< dry slaked lime ; rake up till dissolved, and let settle clear. Third : (N o. Y.) Filled with water only. Fourth^..: (No. 8.) Set with bichromate of potash at 4° T. Each bf these vats is mounted with a frame with rollers top and bottom ; the pieces to be dipped are stretched end to end, and a length of cord being threaded through all the vats andi fastened to a drawing roller at the end of the fourth, the pieces are drawn slowly thoroujgh between the first and second ; the cloth is made to travel several yards, so as to insure, oxidation of the indigo before going into the lead vat ; after leaving the fourth, they are detached, winced, and washed well. For dipped greens, either white cloth is printed in patterns, as spots, &c., with mild paste. Nos. 69, YO ; or a pattern previously printed in madder colors and dyed, &c. is covered up' with mild paste by block ; the cloth being now dipped green, the pattern or spots are re- served or untouched by the green : a very good effect is produced by dipping the Burgundy af d acid No. 4, green, when the Burgundy part comes out a beautiful chocolate, and the w'Aite part green. Acid Discharge on Blue. — A blue and white style, but which permits the most delicate pattern to be printed, which is not the case with the ordinary blue and white style. The cloth is first dipped a medium shade of blue, washed and dried, then padded in bichromate of 'potash at 6° T., and carefully dried in the shade, without artificial heat, and printed in the following color : — No. 8Y. White Discharge for Blues. — 1 gallon water, thicken with 2 lbs. flour, and 2 lbs. dark British gum ; when partly cooled, add 2 lbs. oxalic acid, and when quite cold, Y| oz. measure sulphuric acid. A few seconds after the color is printed on the padded cloth the blue is discharged, and a dirty white left in the printed parts ; after printing, the pieces are dried, so as to leave them slightly damp, and immediately winced in chalk and w'ater, then winced in sulphuric sours at 2° T., winced and well washed ; the printed pattern is now a pure white, and if care has been taken not to dry the bichromate too hard, and not expose it to sunlight, the blue is bright and good. This ingenious process was the invention of Mr. John Mercer. At the moment the block applies the preceding discharge to the bichromate dye, there is a sudden decoloration, and a production of a peculiar odor. The pieces padded with the bichromate must be dried at a moderate temperature, and in the shade. Whenever watery solutions of chromate of potash and tartaric acid are mixed, an effervescence takes place, during which the mixture possesses the power of destroying vegetable colors. This property lasts no longer than the effervescence. Seventh Style : Discharge on Turkey Red Ground. No. 88. White Discharge., {Machine.) — 8 lbs. light British gum, 1 gallon tartaric acid liquor 62° T., 1 gallon acetic acid 6° T. No. 89. White Discharge., {Block.) — The above color a little thinner. No. 90. Black for Turkey Red. — Y gallons logwood liquor at 8° T., 1 gallon pyroligne- ous acid, 10 lbs. starch ; boil and add 2 lbs. 10 oz. copperas ; boil again and cool, then add pints pernitrate of iron at 80° T., and 1 gallon of blue paste. No, 91. Blue Paste. — {a) 6 lbs. copperas, 2 quarts water; dissolve. (6) 4 lbs. prussiate of potash, 1 gallon of water ; dissolve. Mix a and h together, and add 1 quart standard red liquor No. 8, 1 quart nitric acid 60° T. No. 92. Yellow Discharge., {Block.) — 1 gallon lime juice at 50° T., 4 lbs. tartaric acid, 4 lbs. nitrate of lead ; dissolve, thicken with 6 lbs. pipe-clay, and 3 lbs. gum Senegal. No. 93. Yellow Discharge., {Machine.) — Thicken the above with 1-^ lbs. starch, instead of the pipe-clay and gum. -i- 270 CALICO PRINTING. ^ No. 94. Yellow Discharge^ {Machine.') — 1 gallon lime jiMce at 40° T., 4|- lbs. tartaric acid, 5 lbs. white acetate of lead, 1 J lbs. starch ; boil and cvpol, then add 1 lb. 14 oz. nitric acid, at 60°. i No. 95. Blue Discharge., {Machine.) — (a) 1 lb. Prussiam blue, 1 lb. oxalic acid, 1 quart » hot water ; grind well together, and leave to react on eao?h other 24 hours ; then (b) 3 quarts of water, 1^ lbs. starch ; boil, and add 2 lbs. tartaric 'acid, and mix a and b together. No. 96. Green Discharge., {Machine.) — 1^ gallons No. S*5 blue, 1 gallon No. 94 yellow. Process : — Print in any of the above colors, and as soon as dry from the machine, put thi’ough the decoloring vat. ^ (No. 9.) Decoloring Vat. — 1,000 gallons water, 1,000 k^s. chloride of lime ; rake well up, till quite smooth and free from lumps, then immerse^ a fn'jime with rollers top and bot- tom, as in dipping greens, &c. ; keep the vat stirred up so as to ,be milky, and run the pieces through at the rate of 1 piece of 28 yards in 3 minutes ; on leauving the squeezing rollers, conduct into water and rince, then wince 10 minutes in bichromate of potash at 4° T. ; wash and wince in very dilute muriatic acid ; wash well and dry. In this style, such is the permanence of the Turkey red dye, that it*’ is not much altered by passing through chloride of lime, whilst in the parts printed in the discharge colors, an instantaneous disengagement of chlorine takes place, which decolorizes tihe dyed ground, and where a mineral color or mordant formed part of the discharge, it is lefi\ in place of the red dye. This style was invented in 1811 by M. D. Koechlin, and patented iu England by Mr. James Thompson, of Primrose, who printed immense quantities of it. The Bandanna printing, being a business of itself, is more fitly described in another place. (See Bandanna.) Eighth Style : Steam Colors. The printing of steam colors may be considered as a mode of dyeing at one operation, for in most cases one or more mordants are mixed with dye-wood decoctions, and printed on the cloth, the subsequent steaming causing the mordant to combine with the coloring matter, and both with the cloth. Steam colors, in some cases, are made so as to produce a fair color when printed on ordinary white calico ; but much superior colors are produced by mordanting the cloth first, so as to fix peroxide of tin in the fibre ; and as this is the almost universal rule, it is this sort of steam printing alone that will be described. Woollen fabrics, indeed, require a good preparation by tin, &c., before lively and substantial coloirs can be fixed on them by steam. The following is the mode of preparing calicoes for steam colors : — , Pad the pieces stitched together, in a padding machine with wooden bowls, through a solution of stannate of soda at 10° T. twice over, letting them lie wet an hour between ; immediately after padding the second time, run through a cistern with rollers, containing dilute sulphuric acid at 1^° to 3° T., thence into a pit of water, wince well, and run through a washing machine. It has been observed by Mr. James Chadwick, that if the cloth, with oxide of tin newly precipitated on it, is subjected to any severe washing, it loses a consider- able quantity of oxide, so that no moro washing must be given at this stage than will remove the free sulphuric acid. It appears that the cloth, once dried with the oxide in it, does not part with the oxide again by severe washing. After washing, the pieces are unstitched, and put in the hydro-extractor, then dried gently over the steam cylinders, and are then ready for printing. The following list of steam colors comprises the usual variety of shades printed on calico : — No. 97. Steam Black., {Machine.) — 1 gallon logwood liquor at 12° T., 1 quart gall liquor at 9° T., 1 quart mordant, 2 lbs. flour, 6 oz. starch ; boil 10 minutes, and add ^ pint nitrate of iron. Steam Black Mordant. — 1 quart acetic acid, 1-^ quarts acetate of copper at 3° T., 1| quarts iron liquor at 24° T., 1 quart red liquor at 20° T. No. 98. Chocolate., {Machine.) — 3 gallons logwood liquor at 12° T., 2 gallons Sapan liquor at 12° T., 1 gallon nitrate of alumina, ^ gallon bark liquor at 12° T., 4 gallons water, 17 lbs. starch ; boil, and add 8 oz. chlorate of potash, 2|- lbs. red prussiate. No. 99. Dark Blue., {Machine.) — 7 gallons water, 14 lbs. starch, 2f lbs. sal ammoniac ; boil, and add whilst hot 12 lbs. yellow prussiate of potash in powder, 6 lbs. red prussiate of potash, 6 lbs. tartaric acid, and when nearly cold, 1 lb. sulphuric acid, (specific gravity 1-85,) 1 lb. oxalic acid dissolved in 2 quarts hot water, and 6 gallons prussiate of tin pulp. No. 100. Dark Blue. — 8 quarts water, 4 lbs. yellow prussiate of potash, 3 lbs. pale British gum ; boil, and add 1 lb. bisulphate of potash, 2 lbs. muriate of ammonia, 8 oz. alum, 4 oz. oxalic acid, 4 oz. sulphuric acid at 170° T., 4 quarts tin pulp No. 103. No. 101. Cinnamon. — 1 quart cochineal liquor at 8° T., 1 quart logwood liquor at 8° T., 1 quart berry liquor at 10° T., 6 oz. alum, 4 oz. cream of tartar, 8 oz. starch ; boil, and whilst warm add 3 oz. muriate-of-tin crystals. No. 102, Orange. — 12 lbs. annatto, 1 gallon caustic soda at 70° T., 6 gallons water ; CALICO PRINTING. 271 boil 20 minutes, strain, and adc^ 3 quarts red mordant No. 146, 6 lbs. alum ; heat till clear, and add 4 gallons thick gum-sujbstitute water. No. 108. Tin Pulp. — To pi'rotochloride of tin solution add as much yellow prussiate of potash in solution as will precip itate all the tin as ferroprussiate ; this is washed by decan- tation, and filtered to a stiff past e. No. 104. Light Blue for 3Uachine. — 1 gallon dark blue No. 99, 3 gallons 4*lb. gum- substitute water. t No. 105. Green., {Machine.)-^1 gallons Persian-berry liquor at 12° T., 15 lbs. yellow prussiate of potash, 8 lbs. alum,/ 28 lbs. gum-substitute; boil, and add 2 lbs. muriate-of-tin crystals, 2 lbs. oxalic acid. ? No. 106. Pink., {Machine.^- — 4 gallons cochineal liquor at 6° T., 2 lbs. alum, 2 lbs. bitar- trate of potash, 8 oz. oxalicfacid, 4 gallons thick gum-Senegal water. No. 107. Purple, {Maflhine.) — 2 gallons logwood liquor at 12° T., 12 oz. alum, 8 oz. red prussiate of potash, 4/oz. oxalic acid, 8 gallons gum-substitute water. If for block, add 12 gallons gum water hnstead of 8 gallons. No. 108. Dark Bjed, {Machine.) — 8 quarts Sapan liquor at 12° T., 2 quarts bark liquor at 8° T., 2 quarts nitrate of alumina No. 109, 6^ lbs. starch, 1 lb. gum-substitute, 4 quarts water, 4 oz. chloraite of potash, 12 oz. alum. No. 109. Nxtrate of Alumina. — 8 gallons boiling water, 24 lbs. nitrate-of-lead crystals, 24 lbs. alum, 5 lbs. carbonate-of-soda crystals ; let settle, and use the clear. No. IIOj. Blue Standard. — 1 gallon water, 12 oz. alum, 4^ oz. oxalic acid. If lbs. yellow prussiate of potash, 1 gallon gum-substitute water. No. 111. Lavender Liquor — 2 gallons red liquor at 18° T., 6 lbs. ground logwood ; let steep fo 48 hours, then strain off the liquor. No. '112. Lavender. — 4 gallons lavender liquor No. Ill, 4 gallons blue standard No. 110, from 24 to 48 gallons gum water, according to shade wanted. No. 113. Drab. — 4 gallons lavender liquor, 4 gallons blue standard, 1 gallon bark liquor at 8'° T., from 40 to 70 gallons gum water, according to shade wanted. No. 114. Stone. — 4 gallons lavender liquor No. Ill, 6 gallons blue standard No. 110, 1 gailon bark liquor at 12° T., reduced same as drab. No. 115. Sage Green for Blotch Grounds. — 2 gallons yellow No. 48, 2 gallons blue standard No. 110, from 28 to 56 gallons gum water, according to shade wanted. ‘ No. 116. Yellow. — 4 gallons berry liquor at 12° T., 1^ lb. alum. No. 117. Brown Standard. — 14 quarts bark liquor at 12° T., 3^ quarts Sapan liquor at 12° T., P} quarts logwood liquor at 12° T., 12 quarts 8-lb gum-substitute water, 3f lbs. alum, 2 oz. chlorate of potash, 5 oz. red prussiate. All shades of light browns are made from this by reducing with gum-substitute water, according to shade wanted. No. 118. Yellow. — 4 gallons bark at 8° T., 2 quarts red liquor at 18” T., 2 quarts ni- trate of alumina No. 109, 12 oz. tin crystals, 5 lbs. starch. No. 119. Green for Block. — 28 lbs. yellow prussiate of potash, 6 gallons hot water; in a separate vessel, 10 gallons 6-lb. gum-Senegal water, 2 gallons water, 1 gallon muriate of tin at 120° T. ; mix the prussiate solution with the tin and gum by pouring one into the other, and violently agitating; when quite fine and free from flocculent matter, add 12 gal- lons berry liquor at 10° T., then add 12 lbs. and 2} lbs. oxalic acid, dissolved in 5 gallons water, then 3 quarts acetic acid, and 2^ gills extract of indigo. No. 120. Brown. — 6 quarts berry liquor at 20° T., 6 quarts Brazil wood liquor at 8° T., 3 lbs. alum, 3 quarts lavender liquor, 6 quarts 6-lb. gum-Senegal water, 24 oz. nitrate of copper at 100° T. After printing, the pieces are hung for some hours to equalize their temperature, and are then steamed. There are two methods of steaming now commonly employed : — the column and the chest. The column is a hollow cylinder of copper, from 3 to 5 inches in diameter, and about 44 inches long, perforated over its whole surface with holes of about Vie of an inch, placed about f of an inch asunder. A circular plate, about 9 inches diameter, is soldered to the lower end of the column, destined to prevent the coil of cloth from sliding down off the cylinder. The lower end of the column terminates in a pipe, mounted with a stopcock for regulating the admission of steam from the main steam boiler of the factory. In some cases, the pipe fixed to the lower surface of the disk is made tapering, and fits into a coni- cal socket, in a strong iron or copper box, fixed to a solid pedestal ; the steam pipe enters into one side of that box, and is provided, of course, with a stopcock. The condensed water of the column falls down into that chest, and may be let off by a descending tube and a stopcock. In other forms of the column, the conical junction pipe is at its top, and fits there into an inverted socket connected with a steam chest, while the bottom has a very small tubular outlet, so that the steam may be exposed to a certain pressure in the column when it is encased with cloth. The pieces are lapped round this column, but not in immediate contact with it ; for the copper cylinder is first enveloped in a few coils of blanket stuff, then with several coils of ( — — 1 ^ — — - 1 - 1 272 CALICO PRINTING. white calico, next with the several pieces of the printed gooils, stitched endwise, and lastly, with an outward mantle of white calico. In the course of tho.^ lapping and unlapping of such a length of webs, the cylinder is laid in a horizontal frame, in which it is made to revolve. In the act of steaming, however, it is fixed upright, by one iOf the methods above described. The steaming lasts for 20 or 30 minutes, according to the mature of the dyes ; those which contain much solution of tin admit of less steaming. Whomever the steam is shut off, the goods must be immediately uncoiled, to prevent the chargee of any aqueous condensation. The unrolled pieces are free from damp, and require only to be exposed for a few minutes in the air to appear perfectly dry. Were water condensed during the process, it would be apt to make the colors run. i The other method of steaming, and the one now most geiuprally employed, is that of the chest. This is a rectangular iron chamber, with penthouse tb'p ; its dimensions are about 12 feet in length by 6 feet in width, by 9 feet in height at the h.vghest part. It is provided with closely-folding doors at one end, with a cross bar, which can^ be fastened with wedges or screws. There is a perforated false bottom, at the same level a s the room in which the steam chest stands ; underneath the false bottom is a perforated pip'T, running round three sides of the chest ; this pipe admits the steam, which is further diffuse*.’ by the holes in the false bottom. On the false bottom is laid a pair of rails parallel with the^^sides of the chest; these rails are continued outside the chest into the room, the parts next ti'iy chest for about 3 feet being hinged so as to be moved on one side when the doors are openea ;or shut. Upon the rails moves a rectangular frame of wood, which just fits inside the chest, aird stands as high as the commencement of the slope of the roof. This frame, when drawn out into the room, is filled with pieces in the following manner : — They are first wound on an open reel, one by one, the selvages of each fold being kept as parallel as possible. The piecci is then slid off the end of the reel, pulled flat, and a needle and thread passed through all the sel- vages of one side, and loops made, through which are passed wooden rods, which rest on tlie sides of the carriage. The pieces being thus suspended with selvages downwards, the carriage, being filled with the rods,, is run into the chest, the doors firmly shut, and steam turned on, the steam escaping by a safety valve. They hang thus for 46 minutes, are taken out, unfolded, and loosely folded for washing off. They are next stitched end to end, and passed through a cistern with water, from that into a cistern containing a very weak solu- tion of bichromate potash ; they are then put into a washing machine, hydro-extracted, starched, and dried. The colors that are fixed by steaming, may, with one or two exceptions, be described as colored lakes temporarily held in solution by acids, and during the steaming, the cloth grad- ually withdraws these lakes from solution, the acid being either dissipated or so modified as to be incapable of holding the lakes dissolved. The state of the steam is an important matter. It is not the heat alone that produces the effect ; for it may easily be demonstrated that heating cloth, when printed and dried., has no effect whatever. The steam, to be effective, must be as saturated with moisture as possible, and for this reason the steaming apparatus should never be near the boiler : it is no disadvantage for the steam to travel a considerable distance before being applied. In some print work^s the steam is made to pass through water in a vessel placed below the steam chest, so that it arrives in the chest per- fectly saturated with water. At the same time, the steam must not be of so low tension as to cause a deposit of moisture on the pieces, which would be very injurious, by causing the colors to run or mix. Steam blue depends for its fixation on the decomposition of ferrocy- anic acid by the high temperature and presence of vapor water into white insoluble ferrocy- anide of iron and potassium, which, by acquiring oxygen from the air or during the wash- ing-off, becomes Prussian blue. The shade of it is much modified by the oxide of tin in the cloth, and the prussiate of tin that forms part of the color. It appears that tin substitutes iron, forming a compound ferrocyanide of tin and iron, or a ferro-stanno-cyanide of iron, which is of a deep violet-blue color. Greens are mixtures of yellow lakes with the Prussian blue, formed by decomposition. In both these colors there is a large quantity of hydrocy- anic acid disengaged during the steaming ; steam being decomposed, its hydrogen going to form hydrocyanic acid. Mousseline de laines are treated somewhat in the same manner, the preparation of the cloth being different, and the colors are made in such a manner as to fix equally on both the wool and the cotton of the fabric. The steaming and washing-ofif is nearly the same as for calicoes. The following is the method in detail : — The cloth is first well bleached (See Bleaching) and sulphured. This operation is usu- ally performed by hanging the goods in a stone or brick chamber. Trays of sulphur being lighted, the door is closed tight, and the pieces stay in the sulphurous gas for several hours, and are then removed and washed. An improvement on this method was patented by John Thom, and is here shown : — Thorn's Sulphuring Apparatus. — Fig. 138. a is the roof, made of sheet lead, 4 lbs. to the foot. B is a lead pipe, of one inch diameter, taking off the excess of sulphurous acid to the flue, c and c are rolls of pieces, going in on one side and coming off at the other, n F%^. 139 shows the chamber ; it is six feet in length by four feet in breadth, and about five feet high. There are two windows, which are placed opposite each other, p is a cast- iron tray for burning the sulphur. It is placed on a flag, inclining towards the chamber at about one inch to a foot. It is furnished with a slide, on which to put the sulphur to be pushed in, and to admit what air may be wanted. The space for air may be from half an inch to an inch wide. It costs £18 to £20. Preparation . — Pad the pieces, previously well bleached, (see Bleaching,) in a wooden padding machine through stannate of soda at 10° twice over, then pass through a cistern with rollers, containing dilute sulphuric acid at 3° T., wash gently, and partially dry, then pad through sulphomuriate of tin at 4° T. twice. No. 121. Sulphomuriate of Tin , — 3 quarts muriate of tin at 120° T., 1 quart sulphuric acid at 170° T., mixed together gradually, and 4 quarts muriatic acid added ; reduce to 4° T. Run from this without washing into a large cistern with rollers, containing dilute chloride of lime at ^° T., then wash, put in the hydro-extractor, and dry. When wanted for print- VoL. III.— 18 274 CALICO FEINTING. ing, pad through gum-Senegal water at 8 oz. to the gallon, ji^and dry. After printing, they are hung the same as calicoes to equalize the temperature, fLen hung in the steam chest in the same manner as calicoes, and steamed 45 minutes. A/fter steaming, they are unrolled and loosely folded for washing-off, which is done by wincpng over a reel in a pit of water gently for ^ of an hour, then transferred to a washing n^iachine or large automatic wince reel, and washed till no more colored liquor comes away, 'then hydro-extracted, and dried over the steam cylinders. After drying, it is found advan^tageous to hang the pieces in a cool room, with covered shutter sides, for a day or two, so that they may imbibe a little moisture, and the colors appear richer. The wool in mousiseline de laines is apt to be par- tially decomposed during steaming, and sulphuretted hydrog'en liberated, which decomposes the metallic salts, such as nitrate of copper, used in some colors, and produces a very disa- greeable effect, termed silvering. To avoid this, it is now cuS’tomary to wind on the reel for steaming, at the same time as the printed piece, a gray or uivbleached piece, which has been padded in a weak solution of acetate of lead, and dried. jPy this means the printed piece is steamed in contact with the prepared piece, and any sulp^huretted hydrogen that may be disengaged is immediately absorbed by the acetate of lead. '' The following are the colors used in mousseline de laine printing : — No. 122. Dark Red. — 4 gallons cochineal liquor at 10° T., 7 lbs. starsch ; boil, and when cooled to 180° F., add IJ lbs. oxalic acid, and when this is dissolved, IJ libs, muriate-of-tin crystals. No. 123. Chocolate. — 6 gallons Sapan liquor at 12° T., 2 gallons logwood liquor at 12° T., 1 gallon bark liquor at 12° T., 16 lbs. starch; boil, and add 6f lbs. alum, 12 ok. chlorate of potash, 4|- lbs. red prussiate of potash. No. 124. Yellow. — 4 gallons berry liquor at 10° T., 5| lbs. starch, 1 lb. pale British gum ; boil, and add If lbs. muriate-of-tin crystals. No. 125. Dark or Royal Blue. — 6 gallons water, 6^ lbs. starch, 2^ lbs. sal ammoniac; boil well, and add 6 gallons tin pulp No. 103; mix well into the paste, and add 16 lbs. pounded yellow prussiate of potash, 8 lbs. red prussiate, 24 lbs. tartaric acid, and l|^i lbs. oxalic acid previously dissolved in 4 pints hot winter. \ No. 126. Pale Blues are made from the dark blue No. 125, by reducing with gum-sqb- stitute water, say 1 of dark blue and 7 of gum water for pale blue, for two blues, and 1 ,bf dark blue and 14 of gum water for blotch or ground blue. 1 No. 127. Green. — 4 gallons berry or bark liquor at 12° T., 3 lbs. alum, 6 lbs. starclh ; boil, and add 6 lbs. powdered yellow prussiate of potash, 1 lb. muriate of tin crystals, 1 lb. oxalic acid, and 2f pints extract of indigo. No. 128. Pale Green. — 3 quarts berry liquor at 6° T., If lbs. yellow prussiate of potash, 9|- oz. alum, f pint acetic acid, 16 quarts 4-lb. gum-Senegal w^ater, 8 oz. weight muriate of tin liquor at 12° T., f pint extract of indigo. No. 129. Dark Brown. — 2^ quarts Sapan liquor at 8° T., 1 pint logwood liquor at 12° T., 5 quarts bark liquor at 10° T., 12 oz. alum, 1 oz. chlorate of potash, 6 lbs. gum-substi- tute ; boil, and add 4 oz. red prussiate of potash, 2 oz. oxalic acid. No 130. Pale Browns are made from the dark brown No. 129, by reducing with gum water, say 1 to 3 or 1 to 5. No. 131. Pale Red. — 1 lb. fine ground cochineal, 1 lb. liquor ammonia, specific gravity 0-88 ; put ill a jar with tight-fitting cover, which may be luted down ; keep in a warm place for 48 hours, then mix with 2 gallons boiling w'ater, and simmer in a mug down to 1 gallon, then strain off, wash the cochineal with a little water, and strain again ; to the liquor made up to 1 gallon add 4 oz. alum, 4 oz. muriate of tin crystals, 4 oz. oxalic acid, and 1 gallon 6-lb. gum-Senegal water. No. 132. Scarlet. — 2 gallons cochineal liquor, at 12° T., 4 lbs. starch ; boil, and add 4 oz. oxalic acid, 4 oz. binoxalate of potash, 8 oz. pink salts, (double permuriate of tin and ammonia,) and 8 oz. muriate-of-tin crystals. No. 133. Scarlet. — 3 gallons standard No. 136, 1 quart berry liquor at 10° T., 4f lbs. starch ; boil, and add 8 oz. binoxalate of potash, 8 oz. oxalic acid, 1^ lbs. pink salts, ^ pint oxymuriate of tin at 120° T. No. 134. Standard. — 2 lbs. fine ground cochineal, 6 quarts water, 1 quart red liquor at 20° T., 4 oz. nitric acid, 2 oz. oxalic acid ; boil 20 minutes, and strain off. No. 135. Medium Blue. — 6 gallons standard blue No. 136, 1-^ quarts oxymuriate of tin at 120° T., added gradually, and beaten fine, then 2f quarts extract of indigo. No 136. Standard Blue. — 10 lbs. yellow prussiate of potash, 3 lbs. alum, 2 lbs. oxalic acid, 4 gallons water, 4 gallons 6-lb. gum water. No. 137. Medium Green. — 8 quarts berry liquor at 8° T., 3 lbs. yellow prussiate of pot- ash, 1-1^ lbs. alum, 7 quarts 6-lb. gum water, 1 quart water, 1 quart acetic acid, 14 oz. weight muriate-of-tin liquor, 1 pint extract of indigo. No. 138. Lilac. — 8 quarts lavender liquor No. Ill, 6 oz. oxalic acid, 2 oz. measure ex- tract of indigo. No. 139. Lavender Liquor. — 2 gallons red liquor, 10 lbs. ground logwood; steep 12 hours, and strain off. i CALICO FEINTING. 275 No. 140. Dove. — 6 quarts J)lue for doves No. 141, 4 quarts lavender liquor No. Ill, 8 quarts 6-lb. gum-Senegal water*. No. 141. Blue for Doves. — 15 quarts water, 2 lbs. yellow prussiate of potash, 2 lbs. alum, 6 quarts 6-lb. gum water, 1 pin^ extract of indigo. No. 142. Orange. — 3 galloips berry liquor at 10° T., 9 lbs. gum-Senegal, 3 pints red mordant No. 146, 12 oz. muriat,e-of-tin crystals; boil 16 minutes. No. 143. Drab Standard. — 6 quarts purple liquor No. 144, 1 quart bark liquor at 10° T., ^ pint red liquor at 20° T., pint extract of indigo. Drabs are made from this b> reducing with gum water about 1 to 3. No. 144. Purple Liquor . — i gallon lavender liquor No. Ill, 3 oz. oxalic acid. No. 145. Silver-drab Stavodard. — 3 quarts gall liquor at 12° T., 2 quarts standard blue No. 136, 1 quart lavender Ihquor No. 111. Colors reduced with gum water from this, 1 to 2 or 3. No. 146. Red Mordg.nt. — 1 gallon water, 6 lbs. alum, 3 lbs. white acetate of lead ; stir till dissolved, let settle, and use the clear. No. 147. Buff SUandard. — 1 quart cochineal liquor at 8° T., 3^ quarts berry liquor at 10° T., 1 quart red ^mordant No. 146, 20 oz. oxalic acid. Colors reduced from this with gum water. No. 148. OVive. — 1 quart lavender liquor No. Ill, 2 quarts berry liquor at 10° T., 2 quarts 8-lb. gum-Senegal water. In moiL-sseline-de-laine printing success depends more on the bleaching and preparing qf ■'he n|f)th than in any other style. To Mr. John Mercer is due the mei'it of having effected ' xn in/ -mvement in the preparation of woollen fabrics, the importance of which can hardly be o't^^ rated. Before his discovery of the power of prepared wool to absorb chlorine, mousseline de laines could only be effectively printed by block, which allows a large body •of color to be laid on, and the fibre supersaturated with it. Machine colors were meagre and 'dull. But mousseline de laines prepared with tin, and then subjected to the action of chlorine gas, (as in the process given above, where the acid salt of tin remaining in the cloth, disengages chlorine from the chloride of lime,) have their power of absorbing and retaining color considerably enhanced. The exact part the chlorine plays is not well known, probably a compound similar to the chloro-protein of Mulder is formed. The effect produced is not one, as might be supposed, of oxidation ; but apparently a merely heightened power of the wool to assimilate coloring matter. Wool subjected to chlorine without tin is much im- proved in its capacity for color, but nothing like the same when prepared with tin also. The whiole of the chlorine may be removed from the cloth by passing through an alkali, which renders it necessary to give the stannate-of-soda padding previously to the chlorinating. It may fairly be assumed that the development of mousseline-de-laine printing by cylinder to the present perfection is due in a great measure to this chlorinating process. It ought also to be stated that, with rare liberality, Mr. Mercer gave the discovery to the trade, reserving for himself no right whatever. Ninth Style : Spirit Colors. Topical colors of great brilliancy, but possessed of very little solidity, are made some- what like steam colors, but with much larger proportions of “ spirits,” by which term is meant the metallic salts and acids, which, combining with the dyestuff decoctions, give the peculiar tone and vivacity to these colors. These colors, from the large admixture of these salts, are necessarily very acid, and cannot be steamed without the destruction of the cloth. They are merely gently dried after printing, and hung in the ageing room for several hours, then rinsed in water, washed, and dried. The following are examples of spirit colors : — No. 149. Black. — 1 gallon logwood liquor at 8° T., 1 gallon water, 10 oz. copperas, 3 lbs. starch ; boil, and add ^ pint pernitrate of iron at 80° T. No. 150. Fink. — 1 gallon Sapan liquor at 8° T., 1 gallon water, 2 lbs. common salt, 1-^ lbs. starch; boil, cool, and add 1 pint oxymuriate of tin at 120° T., 3 oz. measure nitrate of copper at 80° T. No. 151. Blue. — 1 gallon water, 1 lb. yellow prussiate of potash, 6 oz. alum, 1^ lbs. starch ; boil, and add f pint nitrate of iron at 80° T., 1|- gills oxymuriate of tin at 120° T. No. 152. Brown. — 1 gallon berry liquor at 8° T., 2 lbs. light British gum ; boil, and add 1 lb. muriate-of-tin crystals, 2 quarts spirit pink No. 150, 2 quarts spirit purple No. 153. No. 153. Purple. — 1 gallon logwood liquor at 8° T., 1 gallon water, 10 oz. copperas, 2 lbs. starch ; boil, and add 1 pint protomuriate of iron at 80° T., 1 pint oxymuriate of tin at 120° T. No. 154. Orange. — 1^ gallons berry liquor at 8° T., 12 lbs. light British gum; boil, and add 6 lbs. muriate-of-tin crystals, 4 gallons spirit pink No. 160. No. 155. Chocolate. — 2|- gallons spirit pink No. 150, 1 gallon spirit blue No. 151. No. 156. Red. — 3 gallons Sapan liquor at 4° T., 1 lb. sal ammoniac, 1 lb. verdigris, 4^ lbs. starch ; boil, cool, and add 6 lbs. pink salts, 1 lb. oxalic acid. ♦ 276 CALICO FEINTING. No. 157. Yellow. — 1 gallon berry liquor at 10° T., ^ lb. salum, 1 lb. starch; boil, and add 1 pint muriate-of-tin liquor at 120° T. ^ ^ No. 158. Green. — 1 gallon spirit blue No. 151, 1 gallon f5pirit yellow No. 157. No. 159. Spirit Pink for Blocking bladder Work. — 4^i gallons Brazil wood liquor at 10° T., 9 lbs. pink salts, 3 lbs. sal ammoniac, 2 lbs. sulpha'ise of copper, 5:^ oz. oxalic acid, dissolved in 1 pint water, 4|- gallons of 6-lb. gum-Senegal waiter, 1^ quarts oxymuriate of tin at 120° T. 1 Tenth Style : Bronzes, f The cloth is padded in solution of sulphate of manganes^e, the strength of which deter- mines the shade of brown produced ; for a medium shade brown, suitable for discharge colors, the liquor may be 80° T. ' After padding and drying, pad the pieces through caustiiT soda at 24° T., and again through caustic soda at 12° T., wince well in water, and then in solution of chloride of lime at 2° T. till perfectly brown ; wash well in water, and dry. The colors for printing on this dyed ground are so made as to discharge the brown and substitute their own color in place of it. No. 160. Blue Discharge. — (a) 6 gallons water, 3f lbs. yellow pruS'siate of potash, 10 lbs. starch, 6 lbs. light British gum ; boil, and add 12 lbs. tartaric acid, V6 lbs. oxalic acid, 1 J quarts pernitrate of iron ; then take {h) 5 quarts of this standard, 3 quarts muriate of tin at 120° T. No. 161. Discharge Yellow for Chroming. — (a) 1 gallon water, 5 lbs. nitrate'/)f lead, 4 lbs. light British gum ; boil, and add 4 lbs. tartaric acid ; then take (6) 3 quarts th 's stand- ard, 1 quart muriate of tin at 120° T. No. 162. Discharge Green. — 2 quarts yellow standard No. 161 (a), 1 quart blue -Stand- ard No. 160 (a), 1 quart muriate of tin at 120°. No. 163. Discharge Pink. — (a) 2 gallons Brazil-wood liquor at 12° T., 4 oz. sulphate of copper, 4 oz. sal ammoniac, 4 lbs. starch ; boil, and add 8 oz. measure oxymuriate of tin at 120° T. ; then take (6) 2 quarts of this standard, 1 quart muriate of tin at 120°. No. 164. White Discharge. — 2 gallons water, 8 lbs. light British gum ; boil, and add 8 lbs. tartaric acid, and 1 gallon muriate of tin at 120° T. Black. — Spirit black No. 149. After printing, hang for a few hours, and wince in a pit with water freely flowing inl^o it ; then wince in chalky water, again in water, then wince in bichromate of potash at 4° T., to raise the green and yellow ; wash and dry. The discharging agent in these colors is the protomuriate of tin, which, by its superior attraction for oxygen, robs the peroxide of manganese of a portion. The protoxide of man- ganese formed by this change being then soluble in the acid, and subsequently washed away, the pigment Prussian blue and chromate of lead, also the Brazil lake, being left fixed in the discharged place. Eleventh Style : Pigment Printing. In this style, the ordinary pigments, such as used in oil-painting, are mechanically at- tached to the cloth by a species of cementing. The first fixing vehicle used was a solution of caoutchouc in naphtha, which was mixed with the pigment so as to make colors of suffi- cient viscosity to print. The naphtha was then driven off by steaming, and the pigment was then cemented to the cloth by a film of caoutchouc. This method makes very fast colors, not affected by soaping and moderate friction ; but, unfortunately, the naphtha volatilizing during the printing process, rendered the use of it too dangerous, and after it was found that explosions of the naphtha vapor frequently took place, calico printers turned their at- tention to some other fixing vehicle. Animal substances, of which the white of eggs is the type, and which, soluble in water, are coagulated by heat, are now usually employed. Of these three may be particularized : — albumen of eggs, lactarine, gluten. The first is made by simply drying gently the white of eggs, and powdering. The second is made by separating the solid part of buttermilk, purifying it from butter and free acid, and drying it. The third is the residue of starch making from wheat flour by the simple washing pro- cess, the gluten being gently dried. The two latter thickeners require a small quantity of alkali to bring them in solution ; they then resemble albumen in their power of coagulating by heat. There are few colors of this style printed, chiefly ultramarine blue and carbon drab. No. 165. Ultramarine Blue with Lactarine. — 1-^ lbs. lactarine, 3^ pints water; mix well, and add 2^ oz. measui’e liquid ammonia, specific gravity '880, 5 oz. measui’e caustic soda at 32° T. ; then having beaten up 3 lbs. ultramarine with pints water, mix with the lactarine solution. No. 166. Ultramarine Blue with Alh^imen. — 4 lbs. ultramarine, 3-J quarts water; mix well and add slowly 3 lbs. albumen in powder ; let it stand a few hours, stirring occasionally ; when dissolved, add 1 pint gum-tragacanth water at 12 oz. per gallon. CALICO PRINTING. 277 No. 167. Ultramarine Blut". with Gluten. — 6 lbs. ultramarine, 5 quarts water; mix, and add gradually lbs. ground gluten ; let it stand a few minutes, then add 1 quart caustic soda at 16° T. ; mix well, and let it stand a few hours before using. Other shades of blue are maide by altering the quantity of ultramarine. No. 168. Drab. — 3 lbs. lampblack, 3 pints acetic acid at 8° T. ; mix well together, and add a solution of 3 lbs. albumeu in 3 pints water ; then add 3 pints 12-oz. gum-tragacanth water. I After printing these colors, steam half an hour, wince in water, and dry. Colors fixed in this manner are not intended 'to resist severe treatment. No. 169. Pencil Blue. — 10 gallons of pulp of indigo, containing 40 lbs. indigo, 40 lbs. yellow orpiment, 11| gallons bf caustic soda at 70° T., 18|^ gallons of water, 4 lbs. lime; boil till quite yellow, when spread on glass ; let settle, and thicken the clear with 120 lbs. gum-Senegal. Pieces printed in pencil blue are washed in water immediately after drying and some- times soaped a little. Mr. Bennet Woodcroft, struck with the waste of indigo attending the printing of either China blue or pencil blue, some few years ago invented and patented a method of printing pencil blue by the cylinder machine. His plan was to attach to an or- dinary single-color machine an Indian-rubber apparatus, which enveloped the color-box and piece after printing ; this apparatus was filled with coal gas : a glass plate formed part of the long bag through which the piece travelled after printing, so as to enable the printer to see the progress of his work. By this means the deoxidized indigo was fairly applied to the cloth, and oxidation only ensued when the piece left the apparatus. The saving of in- digo wrb said to be considerable, but the plan was not generally adopted. Si^6/LOWER Dyeing. — The beautiful but fugitive coloring matter of safflower is applied in the printing for dyeing a self color, generally after the goods have been printed in black and red mordant, or black alone, and dyed madder or garancin. It is commonly used for cotton velvets, the color given to velvet appearing very brilliant, from the nature of the cloth. The process is as follows : — Safflower contains two distinct coloring matters : one yellow, being soluble in water, and the other pink, insoluble in water, the latter only being valuable. The yellow matter is therefore carefully washed away. To effect this, the safflower is put into canvas bags, 4 lbs. in a bag, and these bags put into running water and occasionally trodden upon till the water runs off perfectly colorless from them. 1 2 of these bags are then emptied into a cask with 90 gallons of water and 10 quarts of pearlash liquor at 24° T., stirred up for two hours : after standing all night, drain off the liquor, add 90 gallons more water and 3 pints of pearlash liquor ; stir up well, and after standing for three hours, drain off again ; this weak liquor is saved for putting on fresh safflower ; about 30 gallons of the safflower solution is put in a tub mounted with a wince over it, and a mixture of vinegar and lime juice is added to it till it is feebly acid to test paper. The carthamic acid, a red coloring matter of safflower, is thus precipitated, and remains as an exceedingly fine powder in suspension in the liquid ; 2 pieces of 30 yards of velvet are put in and winced backwards and forwards 5 times, then wound upon the reel, and allowed to stay there half an hour, then wince 5 times more, wind up again, and let stay half an hour ; wince again 5 times, and wind up again ; run off the liquor and put in 30 gallons of fresh liquor and acid as before ; repeat the process, wincing 3 times of 5 ends each, and letting lie wound on the reel half an hour each time ; then take out and wince in very dilute acetic acid, hydro-exr tract, and dry. The pieces, when wound on the reel, should be opened out flat, or they might be uneven. Carthamic acid, being of a resinous nature, has the property of attaching itself to cloth, and dyeing in a beautiful pink like the petals of a rose ; this dye is very fugi- tive, strong sunlight even being injurious to it. There has been no way yet discovered of making it permanent. Muuexide. — The purpurate of ammonia, or murexide, was discovered by Liebig and Wohler in 1838, and in its pure state is one of the most beautiful products of chemistry. It is a crystalline substance of a beautiful metallic green, like the wings of the can than des fly, and is produced when uric acid is dissolved in dilute nitric acid, the solution evaporated somewhat, and ammonia added ; from the beautiful crimson liquid, murexide crystallizes. This substance had, until a short time ago, no practical application. M. Albert Schlum- berger discovered that metallic insoluble salts, possessing all the brilliancy of the original substance, could be made ; and this fact was soon applied to a practical use by the French chemists, who succeeded in fixing a beautiful murexide crimson upon cotton cloth. The process was patented in this country for French interests in February, 1857, and is now in extensive use. The process is as follows : — Print in the color. No. 170. 1 gallon water, 4 lbs. nitrate of lead, 1 lb. murexide, 1^ lbs. starch ; boil. After printing, hang a few hours, then run through a cistern with rollers above and below, and provided with a cover, through apertures in which the pieces enter and leave. This cistern is kept supplied with ammoniacal gas ; on leaving this cistern, they pass into water, and from that into a cistern charged with 2 lbs. bichloride of mercury, 4 lbs. acetate of- 278 CALICO PEINTING. ■ soda, ^ lb. acetic acid, 80 gallons water ; run very slowly throwgli this, wash and dry. In the first operation purpurate of lead is formed on the cloth, aind in the second, or changing bath, the lead is wholly or partly removed, and oxide of n^jercury left in its place ; the re- sulting lake is a color of great brilliancy and purity, so m’ ich so that few of the ordinary colors will bear to be looked at along with it. Though peri'fectly fast as to soap, it appears that strong sunlight is rather injurious to its permanency. A few outline illustrations of the various madder styles will render them more dear. 1 a. Black, 2 reds, purple and brown on white ground. Print by machine in colors 4, 5, 6, 9, 27, (No. 12 shade,) and 18 ; age 3 nights, fly-dungf at 160° F., second dung at 150° F., wash and dye with French or Turkey madder, bringing'^to boil in If hours, and boiling f hour; wash and soap twice at 180° F., wash; chloride of jJjme bath, (see No. 1 plate pur- ples,) wash and dry. 1 6. Black, red, white, and brown figures, covered in purple.'v Print in colors 4, 11, 34, and 18; when dry, cover with a fine pattern in 27, (12 shade;) d^ge 3 nights; fly-dung at 170° F., second dung at 160° F., wash, dye, and clean as 1 a. 1 c. Print in colors 6, 7, (No. 3 shade,) 34 ; dry and cover in 7, (6 shade,) and blotch } (or pad with a roller engraved with a pin, which has the effect of givixrg a uniform shade) in 7, (10 shade;) age three nights, and treat as described under the hea«d Pinks. 1 d. Some printers prefer to mordant for Swiss pinks with alkaline mordants, consider- ing the composition of the colors to be a guarantee against their containing .Von ; in such case, they print in colors 31, 32, and 35, covering in paler shades of 32 after dyeing; fly- ! dung with 3 cwts. cow-dung, 12 lbs. sal-ammoniac, 1,000 gallons water at 110° F. ; second ; dung with | cwt. cow-dung at 110° 16 minutes; wash and dye as for 1 c. In thisi method of mordanting, the aluminate of soda that has escaped decomposition by the carbd) >ic acid ! of the air, is decomposed by the muriate of ammonia, and alumina precipitated on the cloth. ' 2 a. Black, chocolate, red, and brown on white ground. Print in colors, 5, 13, (6 | shade,) 14, and 22; age 3 or 4 nights; fly-dung at 160° F., second dung at 160° F., and dye with chocolate garancin or garanceux, (see p. 263.) 2 h. Black, chocolate, red, and purple. Print as 2 6, but dye with purple garancin, (See : p. 263.) 1 3 a. For chintz work treat as 1 «, then in the parts of the pattern meant for ground- ing-in, block the colors 118 yellow, 119 green, and 129. If the pattern is such as to admit ' of it, all these colors may be printed at once from one block, using the tobying sieve, p. 226 : | the colors, however, for this method must be thickened with gum ; steam, &c., as descril>ed for steam colors. , i 3 6. Black, 2 reds, blue, green, and yellow covered in drab, or other shades. Print in | 4, 6, and 7 ; dye, &c., as 1 a; block-in color 38 with a block which covers all the pattern, and also those portions which are intended for the steam colors : when this paste is dry, cover by machine in any of colors 40 to 47, age 2 or three nights ; fly-dung at 160° F., second dung at 160° F., and dye with bark, or bark and logwood or cover in color 48, and ' dye madder and bark as No. 6 (p. 251) for chocolate ; or cover in color 49 or 51, and after drying and ageing, wincing in chalky water ; or in any of colors 55, 56, or 57, rinsing in carbonate of soda liquor at 5° T. when dry. After obtaining the ground shade by any of these processes and drying, ground-in by block colors 118, 119, and 135, steam, wash, and dry. 3 c. For furniture hangings, which are generally printed in large groups of flowers, a very pretty pea-green ground is often blocked-in as groundwork, which is made and fixed as follows : — 171. Pea Green. — (a) Standard : 6 lbs. sulphate of copper, 1 gallon water, 4 lbs. brown acetate of lead; dissolve, let settle, and use the clear. — (6) Color: 2 measures of standard, 1 measure of 7 lb. gum-Senegal solution. After printing, age 2 nights, and pass through a cistern with rollers, set with caustic potash liquor at 15° T., which has 8 oz. per gallon of arsenious acid dissolved in it. The liquor should be heated to 110° F. ; out of this wash and dry. Instead of blocking-in steam blue and green, fast blue and green are introduced where the colors are required to be particularly permanent ; colors 62 or 63 or both are blocked-in and raised as follows: — 5 stone cisterns, each mounted with a hand reel, and containing about 200 gallons each, are set with carbouate-of-soda liquor. No. 1 at 7° T., No. 2 at 6° T., No. 3 at 5° T., No. 4 at 4° T., and No. 5 at 3° T. ; wince 10 times backwards and forwards in each pit, beginning with No. 1, and ending with No. 5 ; wince in water and wash. The change that takes place here is similar to that in raising China blues. The indigo is main- tained in a deoxidized state by the protoxide of tin formed, until it has fixed itself in the cloth by reoxidation in the air. Wjiere fast green has been printed, the pieces are winced in bichromate-of-potash liquor at 4° T. for 10 minutes, then washed and dried. 3 e. Black and purple and white with buff* ground. Print in 4 and 27, (12 shade,) age, dung, and dye, &c., as directed for plate purples, (p. 252 ;) block over the pattern and por- .tions of the unprinted part the paste No. 39; block with pad roller in No. 53, (6 shade,) dry ii CALICO PRINTmC. 279 and raise as follows! : — Wince 14 minutes in caustic soda at 2° T. at 110° F,, then wince in water till quite buff, then wince in 400 gallons water with 1 quart chloride of lime at 12° T. 10 minutes ; wash and dry. Silk Printing. Silk, in its capacity for receiving colors, holds a medium place between cotton and wool. From its being an animal substance, it is difficult to obtain white grounds or objects after dyeing mordanted silk, the silk itself attracting coloring matter somewhat as a mordant. Previously to printing silk, it is well scoured by boiling for 2 hours with ^ lb. of soap to every pound of silk, then, well washed and dried. For handkerchiefs, black, chocolate, and red mordants are printed, aged, and dunged off same as for cottons, and dyed with madder or garancin, soaped, washed, and dried. Purples cannot be obtained on silk by mordanting and dyeing madder, the color produced being a mixture of red and purple. All sorts of colors can be prod.uced on silk by steam, the whites remaining brilliant. For steam colors, silk is mordanted with tin, by steeping 4 hours in a solution of sulphomuriate of tin at 2° T., made by dissolving 1 lb. of muriate-of-tin crystals in water, and adding 1 lb. of sulphuric acid at 1V0° T., and reducing to 2° T. After steeping, the silk is washed with water, and dried. The following are specimens of steam colors for silk : — Black . — 2 gallons logwood liquor at 8° T., 1 quart iron liquor at 10° T., 1 lb. flour, 1 lb. light British gum ; boil, and add 6 oz. yellow prussiate of potash ; cool, and add 2 oz. sul- phate of copper, 1 pint muriate of iron at 80° T., ^ pint pernitrate of iron at 80° T. Chocolate . — 2 gallons of sapan liquor at 12° T., 5 quarts logwood liquor at 12° T., 1 quart b?u’k liquor at 16° T., 2 lbs. alum, 1^ lbs. sal ammoniac, 14 lbs. gum-Senegal. Red . — 3 gallons of cochineal liquor at 4° T., 1^ pints bark liquor at 12° T., 3 lbs. starch; boil, then cool, and add 1 lb. oxalic acid, 1 lb. muriate-of-tin crystals. Yellow . — 3 gallons of bark liquor at 16° T., 8 oz. alum, 3 oz. muriate-of-tin crystals, 3 oz. oxalic acid, 9 lbs. gum-Senegal. Green . — 1 gallon yellow, ^ pint extract of indigo, 2^ oz. measure of muriate of tin at 120° T. Blue . — 1 gallon water, 1 lb. yellow prussiate of potash, ^ lb. oxalic acid, ^ lb. tartaric acid, 2 oz. sulphuric acid at 170° T., 1 gallon 6 lbs. gura-Senegal water. Calico, &c., printing has, since the repeal of the duty, risen steadily in importance, tilt it is now one of the most influential manufactures of Great Britain. From a table compiled by the late Mr. Binyon, and communicated by Mr. John Graham, there were in 1840, the following number of machines, &c., in use : — List of Machines^ Tables.^ In value, I should be disposed to estimate our export* of printed goods at £5,775,000., “ In reference to the entire export of manufactured cotton g'Oods, (exclusive of yarns,) it may be assumed that out of £23,447,103, given as the ex/port of 1851, about one- fourth may be placed to the account of the print trade. I haive endeavored to estimate, from the Table of Exports for 1851, the probable quantity of \low-priced prints we export, and should be disposed to class them as follows: — ' Coast of Africa and the Cape - New Zealand and South Sea Islands China, Manilla, and Singapore British W est Indies, Foreign West Indies St. Thomas - . - India . . - - Mauritius and Batavia Chili and Peru - - - Brazil and East Coast of South America Egypt Turkey, Ionian Isles, Greece, and Malta Pieces. 300.000 36.000 \ 650,000 .300,000 30\0,000 200.000 1,570,000 325.000 800.000 1,000,000 84.000 1,000,000 Total r 6,466,000 “ I find those countries which take our lowest description of goods, and whi^re the duties are chiefly very light — our colonies, India, and China, receive from us about 6| millions of pieces, or about 40 per cent, of our exports in printed goods. A great pro- portion of the finer part of our exports, perhaps three-fourths, are very seriously taxed, either for protection, as in the United States, the Zollverein, and Belgium, or for revenue, as in Brazil and the other South American markets. A part, however, of these better goods find their way into consumption in Canada, Turkey, the Ionian Isles, Egypt, &c., subject to very moderate duties.” {Potter.) Exports of Calicoes printed and dyed in 1857. Russia Yards. 1,513,080 Declared real value. £ 42,913 Sweden, 624,418 11,836 Norway - - - 787,269 16,235 Hanover - 1,954,664 49,814 Hanse Towns 25,208,601 616,004 Holland 12,899,706 254,199 Belgium • 903,764 22,600 France 5,130,577 93,366 Portugal, Azores, and Madeira 18,966,056 297,178 Spain and Canaries 3,767,747 93,084 167,807 Sardinia 11,003,456 Tuscany 6,602,902 106,110 Papal States 4,814,905 67,227 Two Sicilies 7,438,118 123,625 Austrian Territories 7,191,273 101,663 Greece 3,379,548 50,694 Turkey 70,909,268 1,145,361 Wallachia and Moldavia 1,180,001 19,779 Syria and Palestine 16,061,817 208,140 Egypt 11,543,986 173,122 West Coast of Africa (Foreign) 18,817,282 318,982 286,274 Java - - - 16,911,802 Philippine Isles - 9,548,904 213,757 China 12,030,344 203,443 South Sea Islands 1,552,337 29,995 249,760 Cuba 14,144,771 Porto Rico 3,109,890 43,518 Cura^oa - 783,478 13,356 St. Thomas 20,529,211 290,956 Haiti 6,191,059 96,936 United States 106,328,353 1,972,049 Mexico 10,203,738 195,946 CALICO PRINTING. ♦ 281 Exports of Calicoes printed and dyed in 1857. (Continued.) Yards. Declared real value. £ Central America - 5,721,458 86,607 New Granada - - 14,618,606 229,316 Venezuela - - - - 6,564,167 107,417 Brazil - 84,304,766 8,749,894 1,543,479 Uruguay 149,294 Buenos Ayres - - 17,870,263 319,670 Chili ..... - 21,536,565 365,982 Peru - 23,426,258 396,362 Gibraltar - 7,860,972 125,567 Malta 3,203,445 3,790,985 46,912 Ionian Islands - 55,868 West Coast of Africa (British) - 7,286,177 9,875,247 7,556,658 137,879 South Africa (British) 196,859 Mauritius 111,725 British East Indies ... - 89,717,006 1,515,807 Hong Kong .... 2,621,464 - 15,769,817 41,201 Australia - - - - - 310,660 British North America - 19,479,981 331,106 British West Indies and B. Guiana - 21,277,609 293,710 Honduras 4,090,657 45,375 Other Countries ... 1,964,383 36,007 808,308,602 £13,921,428 “ The home-consumption,” says Mr. Potter, “ I estimate at 4,500,000 ; the excise returns for 1830, gave it as 2,281,512 pieces. The repeal of the duty, and the decrease in the cost of production, giving the consumer goods in much better taste and value at one- half the price, have greatly tended to this increase.” “ The immense increase of produc- tion in lower goods has not decreased the taste in the higher in this country, though it may have caused it to make less apparent progress than when the larger part of the supply was of fine goods. We find specimens of good taste on the lowest material, printed at the lowest possible price for export, showing a taste superior to that in use for our best work twenty years ago, employing greater talent in design, greater skill in engraving, — the cost of production cheap, because repaid by the quantity produced. This diffusion of art and of a better taste cannot be otherwise than beneficial, even to the higher class of productions, as preparing a taste and demand for them in countries where high price would never have given prints any admission. The improvement of the lower cannot militate against that of the higher, either in the moral, intellectual, or artistic world. The productions of the highest class of French goods of to-day, whether furniture or dresses, are superior in taste and execution to those of any former period. The productions of the first-class printers of Great Britain maintain an equal advance, and are superior in taste and execution, in every respect, to those of former years. Great competition and rapidity of production are not immediately beneficial to high finish and execution in art ; but this tendency to quickness of production, rather than perfection, rectifies itself ; and machinery, which perhaps at first does not give the polish that excessive labor formerly supplied, ultimately exceeds it by its cheaper and more regular application. It is remarkable how taste or novelty in that class of demand, which would strike the casual observer as the one fitted for its greatest develop- ment, is limited in quantity. The limit or commencing point in which taste or novelty enters freely into the composition of a print, is for the supply of the working and middle classes of society. They require it quiet, modest, and useful ; and any deviation, for the sake of novelty, which calls in the aid of the brighter and less permanent color, quickly checks itself. The sober careful classes of society cling to an inoffensive taste, which will not look obsolete and extravagant after the lapse of such a time as would render a garment compara- tively tasteless and unfashionable in a higher class. This trade is, to the printer, most ex- tensive and valuable, and has its necessary and practical bearing on his taste ; and hence it is in this branch of the business the English printer is most decidedly superior to his French competitors.” It would appear that occasionally attempts were made, during the early days of printing, to produce work possessing a high degree of artistic excellence ; and as the specimens that have been preserved to our time are very rare, it is fair to conclude that these experiments were not successful in a pecuniary point of view. In the museum of the Peel Park, at Sal- ford, there is a curious and interesting piece of printed linen, bearing the date 1761, (at this period cloth of all cotton was prohibited,) and which must have been printed from copper plates of very unusual size. Apparently, the pattern has been produced by two plates, each about 4 feet 6 inches by 3 feet. The design is printed in madder red, and is thus described CALOMEL. 282 by Mr. Plant, the curator of the museum : “ The printed piece of linen measures, in the full length of the design, 6 feet 10 inches, by 3 feet 2 inches in breadth. The composition in the design is very bold and free — in my opinion indicating very strongly the feelings of an artist who had been educated in the Flemish school. The grouping of the trees, figures, cattle, and fowls is probably a direct copy from an engraving or sketch by Berghem, whose paintings and engravings of such subjects are well known for their truth to nature. His works bear date 1638 to 1680. Perhaps, to fill up the design, and form a picturesque com- position, the artist has borrowed from the French painters the classic ruins which form the sides of the design ; it has had the effect of producing an anachronism. The upper group represents a peasant seated upon the wall of a well, blowing a flute ; near him, stands a woman with a distaff ; a group of sheep, cow, and a dog, in the foreground. The back- ground shows a landscape, and on each side this group are ruins, columns, and trees, re- flected in the stream below. On a broken bank, midway between the two groups, are two dogs chasing a stag. The lower group, although there is no defined line of separation between the groups, represents a peacock, fowls, and chickens, upon a bank and ruins ; landscape and river scenery beyond. Over, a hawk carrying a chicken, the sides occupied with a ruined portico, tomb, and pedestal and vase, trees, and broken ground ; and below are ducks swimming, and water-plants on the bank. At the bottom of the piece are those parts of the pattern which would print or fit on the top part of the design. On the stone- work of the well, in the upper group, is printed, ‘ R. JONES, 1761 ; ’ on the broken stone- work, in the centre of the lower group, is printed, ‘ R. I. and Co., OLD FORD, 1761.’ ” Old Ford is situated at Bow, where the East London Water Works now are, and where there was a print work at the time specified. This design was no doubt printed for furniture hangings or tapestry, for which it is exceedingly well adapted, the work being altogether a remarkable production for the period. CALOMEL. Professor Wohler proposes to prepare calomel in the humid way by de- composing a solution of corrosive sublimate by sulphuric acid. The commercial salt is dissolved in water at 122° to saturation. Sulphurous acid gas, evolved by heating coarse charcoal powder with concentrated sulphuric acid, is passed into the hot solution : the separation of the calomel commences immediately. When the solution is saturated with the gas, it is digested for some time, then left to get cold, and filtered from the calomel, which is afterwards washed. The filtrate usually contains some unchangeable corrosive sublimate, which may be converted into calomel, either by heating to boiling, or by a fresh introduc- tion of sulphurous acid and heating. Calomel obtained in this manner is a crystalline pow- der of dazzling whiteness, glittering in the sunlight. The presence of corrosive sublimate in calomel is easily detected by digesting alcohol upon it, and testing the decanted alcohol with a drop of caustic potash, when the character- istic brick-colored precipitate will fall, if any of that salt be present. To detect subnitrate of mercury in calomel, digest dilute nitric acid on it, and test the acid with potash, when a precipitate will fall in case of that contamination. As it is a medicine so extensively administered to children at a very tender age, its purity ought to be scrupulously watched. 117‘75 parts of calomel contain 100 of quicksilver. H. M. N. CAMBOGIA. See Gamboge. CAMEO. {Camee^ Fr. ; Cammeo^ It.) Correctly a precious stone engraved in relief, as opposed to an intaglio, which is cut into the stone. The earliest cameos appear to have been cut upon the onyx, and, subsequently, on the agate. The true cameo is formed upon a stone having two or more layers, differing in color ; and the art of the cameo engraver consists in so cutting as to appropriate those differently colored layers to distinct parts or elevations of the work. Many of the varieties of calcedony present in section transparent and opaque layers ; and beautiful works have been cut upon such specimens of this material. The calcedony and agate are, however, not unfrequently colored artificially. The layers vary very much in their structure, some being absorbent and others not so. Such stones are taken, and if it is desired to have black and white layers, they are boiled in a solution of sugar or honey, and then in sulphuric acid. The sugar or honey is, in the first place, absorbed by the more porous layers, and then decomposed by the acid. Red or brownish-red layers are produced, by occasioning the stone to absorb a solution of sulphate of iron, and then, by exposure to heat, effecting the oxidation of the metal. This being done, layers very strongly contrasted in color are the result, and very fine cameos have been cut upon stones so prepared. In Italy and in France, the art of producing the cameo dur has been, to some extent, revived; but the immense labor which such hard materials require, renders them so expensive, that these cameos have not come into general use. Porcelain and glass have been employed as substitutes for the natural stones, but the results were so inferior, that these materials have of late been entirely neglected for this purpose. The shells of several molluscous animals are now commonly used. Many of these shells afford the necessary variety of color, are soft enough to be worked with facility, yet bard enough to wear for a considerable time without injury. CAMPHENE. 283 The natural history of the mollusca producing the shells, and the best account of the manufacture of cameos, was given by J. E. Gray, of the British Museum, in a paper read before the Society of Arts in 1847, to which, and to his paper in the Philosophical Transac- tions, we are indebted for much of the information contained in this article. It was the custom in Holland to use the pearly nautilus as a cameo shell, and several kinds of turbines or wreath shells, which have an opaque white external coat over an inter- nal pearly one. These are now rarely employed. The shells now used are those of the flesh-eating univalve, {Gasteropoda ptenohranchiata zoophaga,) which are peculiar for being all formed of three layers of calcareous matter, each layer being composed of three perpen- dicular laminae placed side by side ; the laminae comprising the central layer, being placed at right angles with one of the inner and outer ones ; the inner and outer being placed longitudinally with regard to the axis of the line of the shells, while the inner laminae are placed across the axis, and concentrically with the edge of the mouth of the cone of the shell. {Gray, Phil. Trans.) This structure furnishes the cameo cutter with the means of giving a particular surface to his work, a good workman always putting bis work on the shell in such a manner, that the direction of the laminae of the central coat is longitudinal to the axis of his figure. The central layer forms the body of the bas-relief, the inner lamina being the ground, and the outer one, the third or superficial color, which is sometimes used to give a varied ap- pearance to the surface of the figure. The cameo cutter, therefore, selects for his purpose those shells which have thi*ee layers of different colors, as these afford him the means of relieving his work ; and secondly, those which have the three layers strongly adherent to- gether, for, if they separated, his labor would be lost. The following are the kinds of shells now employed: 1. The bull’s mouth, {Cassis rufum,) which has a red inner coat, or what is called a sardonyx ground. 2. The black helmet, {Cassis Madagascar iensis,) which has a blackish inner coat, or what is called an onyx ground. 3. The horned helmet, {Cassis cornutum,) with a yellow ground. 4. The queen’s conch, {Strornbus gigas,) with a pink ground. The bull’s mouth and the black helmet are the best shells. The horned helmet is apt to separate from the ground, or double, and the last, the queen’s conch, has but seldom the two colors marked with sufficient distinctness, and the finish of the ground color flies on exposure to light. The red color of the bull’s mouth extends only a slight distance into the mouth of the shell, becoming paler as it proceeds backwards. The dark color extends further in the black and yellow varieties. Hence, the bull’s mouth only affords a single cameo large enough to make brooches of, and several small pieces for shirt-studs. The black hel- met yields on an average about five brooches, and several pieces for studs, while the queen’s conch affords only one good piece. Forty years since, very few cameos were made from any shells but the black helmet, and the number of sliells then used amounted to about 300 annually, nearly all of which were sent from England, being all that were then imported. The black helmet is imported into England from Jamaica, Nassau, and New Providence. They are not found in Mada- gascar, though naturalists have for a long period called them Madagascar helmets. {Gray.) Of the bull’s mouth, half are received direct from the Island of Bourbon, to which place they are brought from Madagascar, and the other half are obtained from the Island of Ceylon, being received by the way of Calcutta ; hence they are often called “ Calcutta shells.” So rapidly has the trade in those shells increased, that Mr. Gray informs us, that in Paris 100,500 shells are used for cameos annually. These are divided as follows: Bull’s mouth - - 80,000 Price. Is. 8d. - - Value. £6,400 Black helmet - 8,000 - - 5 0 - - 1,920 Horned helmet 500 - _ 2 6 - - 60 Queen’s conch - 12,000 - - 1 - - 725 Sterling £9,105 The manufacture of shell cameos was for some time confined to Italy ; about twenty years since, an Italian commenced making them in Paris, and now the trade is confined principally to the French capital, where not less than 300 persons are engaged in the manu- facture. Nearly all the cameos made in France are sent to England. In Birmingham, many of them are mounted as brooches, and exported to America and the British colonies. In 1856 we imported, of shell cameos not set, to the value of £6,683. CAMPHENE. Rectified oil of turpentine is sold in the shops under this name for burning in lamps. Crude oil of turpentine is redistilled with potash, and then with water, and lastly, to secure its perfect purity, with chloride of calcium. The oil thus prepared CAMPHOLE. 284 forms a limpid, colorless liquid; its specific gravity is about 0'870, but it is subject to some slight variations ; appears fairly to represent this and several other similar oils. It is very inflammable, burning with a bright white flame, and without a proper supply of air it evolves much dense smoke, hence peculiar lamps {Camphene lamps) are required. Where it has, from exposure to air, absorbed oxygen, and become vesinified^ it is unfit for pur- poses of illumination. Such camphene very rapidly clogs the wick with a dense carbon, and is liable to the thick black smoke, which is so objectionable in the camphene lamps if they are not properly attended to. To purify old camphene^ it must be redistilled from carbonate of potash, or some simi- larly active substance to deprive it of its resin. See Lamps. CAMPHOLE. One of the oils obtained from coal tar. Mansfield gives this name to the oils cumole and cymole^ which boil at 284° and 338° Fahrenheit, when collected to- gether. The specific gravity of crude camphole ranges frqm "88 to '98, and the less vola- tile portions frequently contain naphthaline, which raises their specific gravity. T his sub- stance, either alone or mixed with pyroxylic spirit, is applicable for burning in lamps or for dissolving resins, as a substitute for oil of turpentine. CAMPHOR. There are two kinds of camphor imported : — Japan Camphor, called Dutch Camphor, because it is always brought by the Dutch to England. It comes by the way of Batavia, and is imported in tubs (hence it is called tub camphor) covered with matting, and each surrounded by a second tub, secured on the out- side by hoops of twisted cane. China Camphor, or Formosa Camphor, is imported from Singapore and Bombay in chests lined with lead-foil containing about cwts. It has been suggested to introduce the camphor trees into other countries. South Georgia and Florida are named as suitable localities. The Laura camphoravs commonly found in all the nurseries around Paris, and sold at 5 francs for a plant 30 inches high. At full growth the tree attains an altitude of from 40 to 50 feet. The wood of the camphor tree is in favor for carpenter’s work ; it is light, easily worked, durable, and not liable to be attacked by insects. It is said that in Sumatra numbers of trees are cut down before one is found to repay. Not a tenth part of the trees attacked yield either camphor or camphor oil. The camphor is distinguished by the names of head, belly, and foot, when in bulk. The head camphor is in large white flakes ; the belly camphor, small brown flakes, transparent, like resin coarsely powdered ; the foot, like dark-colored resin. A native “ catty ” may be divided into : — 1. Capello, or large head =2*2 2. Capello cachell, or small head - - - - =3*5 3. Baddan, or belly = 4'2 4. Cakee, or foot =6*1 = 1 Catty 16 The inquiries of Royle and Roxburgh agree with the records of Sir G. Staunton, Dr. Abel, and Mr. C. Grove, of the estimation placed upon the camphor of Borneo by the Chi- nese, who actually give a greater price for the coarser article than they afterwards sell it for, when in a purified state for commerce. Hence it is inferred that the Borneo camphor, being so strong, communicates its odor and virtues to other matters, and thus an adulter- ated drug is sold by the Chinese ; or it may be mixed with the camphor obtained by cutting and macerating the wood of the Laura camphora^ that grows in China. Sir G. Staunton, however, declares the Chinese sell the camphor at a lower price than they give for it at Borneo. Our importations in 1856 were: — Camphor, unrefined 4,505 cwts. “ refined 626 “ CAMPHOR, ARTIFICIAL. When hydrochloric acid (muriatic) is passed into oil of turpentine, surrounded by ice, two compounds are obtained, one solid, and the other fluid. The first, solid artificial camphor, C^°ID®HC1, is white, transparent, lighter than water, and has a camphoraceous taste. The fluid is termed liquid artificial camphor, or terebine. CAMPHOR, OIL OF LAUREL. When the bi-anches of Camphora officinarum are distilled with water, a mixture of camphor and a liquid essential oil is obtained. This is the oil of camphor; it has a density of 0-910, and its composition is C“H“0. By ex- posure to oxygen gas, or to the aetion of nitric acid, it absorbs oxygen, and becomes solid camphor, C%^«0^ This is an esteemed article in the eastern market ; it undergoes no preparation, and though named oil, it is rather a liquid and volatile resin. The natives of Sumatra make CANDLES. 285 a transverse incision in the tree to the depth of some inches, the cut sloping downwards, so as to form a cavity of the capacity of a quart ; a lighted reed is placed in it for about 10 minutes, and in the space of a night the cavity is filled with this fluid. The natives consider this oil of great use as a domestic remedy for strains, swellings, and inflamma- tions. Dr. Royle states the trees are of large dimensions, from to V feet in diameter. The same tree that produces the oil, would have produced the camphor if unmolested, the oil being supposed to be the first stage of the camphor’s forming, and is consequently found in younger trees. CAMPHOR STORM GLASSES. Glasses called usually storm glasses, and sold as indi- cators of atmospheric changes. “ Storm glasses” are made by dissolving : — Camphor 2^ drachms Nitre 38 grains Sal ammoniac ..-----38 grains Water 9 fluid drachms Rectified spirit of wine 11 fluid drachms. Plumose crystals form in the glass, and are said to condense and collect at the bottom of the bottle on the approach of a storm, and to rise up and diffuse themselves through the liquid on the approach of fine weather ; but Dr. Parrion thinks that their weather-predict- ing qualities are false, and that light is the agent which, together with temperature, influ- ences the condition. CAM-WOOD. An African dye-wood, shipped principally from Sierra Leone in short logs. Mr. G. Loddiges, in his botanical cabinet, figures the plant, producing it under the name of Baphia nitida ; it is a leguminous plant, aitd has been introduced into, and has flowered in, this country. CANADIAN BALSAM. A product of the Abies halsamea^ or balm of Gilead fir. The finer varieties of this balsam are used for mounting objects for the microscope. See Balsams. CANARY WOOD. A wood is imported into this country under the name of Madeira mahogany, which appears to be this canary wood. It is the produce of the Royal Bay, Laurus indica, a native of the Canary Islands. It is rather a light wood, and of a yellow color. CANDLES. In a lecture delivered at the Society of Arts by Mr. Wilson, and published in their journal, he described the progress of the more recent improvements. In this he says : “ Candles, beautiful in appearance, were made by distilling the cocoa-nut acids ; but, on putting them out, they gave off a choking vapor, which produced violent coughing.” This prevented those candles from being brought into the market. “ By distilling cocoa- nut lime soap, we made beautiful candles, resembling those made from paraffine, burning perfectly ; but the loss of material in the process was so great, that the subsequent improve- ments superseded its use. Under one part of this patent, the distillation was carried on sometimes with the air partially excluded from the apparatus, by means of the vapor of water, sometimes without, the low evaporating point of the cocoa-nut acids rendering the exclusion of air a matter of much less importance than when distilling other fat acids.” At this time, in conjunction with Mr. Jones, Mr. Wilson appears to have first tried using the vapor of water to exclude the air from the apparatus during distillation. This led, in 1842, E. Price and Co. to patent, in the names of Wilson and Jones, which involved the treat- ment of fats, previously to distillation, with sulphuric acid, or nitrous gases. M. Fremy, in his valuable paper in the “ Annales de Chimie,” describes treating oils with half their weight of concentrated sulphuric acid, by which their melting point was greatly raised. He gave, however, particular directions that the matter under process should be kept cool. Instead of doing this, Mr. Wilson found it advantageous to expose the mixture of fat acid and fat to a high temperature, and this is still done at Price’s works. “ Our process of sulphuric acid saponification was as follows : — Six tons of the material employed — usually palm oil, though occasionally we work cheap animal fat, vegetable oils, and butter, and Japan wax — were exposed to the combined action of 6| cwts. of concen- trated sulphuric acid, at a temperature of 350° F. In this process the glycerine is decom- posed, large volumes of sulphurous acid are given off, and the fat is changed into a mixture of fat acids, with a very high melting point. This is washed, to free it from charred matter and adhering sulphuric acid, and is then transferred into a still, from which the air is ex- cluded by means of steam. The steam used by us is heated in a series of pipes similar to those used in the hot-blast apparatus in the manufacture of iron, the object of heating the steam being only to save the still, and reduce to a small extent gaseous loss in distillation.” “ We still,” says the patentee, “ employ this process, and in some cases reduce the quantity of acid employed to 4 lbs. and even 3 lbs. to a cwt. of the fat.” In 1854, Mr. Tighlman obtained a patent for the exposure of fats and oils to the action CANDLES. 286 of water at a high temperature, and under great pressure, in order to cause the combination of the water with the elements of the neutral fats ; so as to produce at the same time free fat acid and solution of glycerine. See Glycerine. He proposed to effect this by pumping a mixture of fat and water, by means of a force- pump, through a coil of pipe heated to about 612° F., kept under a pressure of about 2,000 lbs. to the square inch ; and he states that the vessel must be closed, so that the requisite amount of pressure may be applied to prevent the conversion of water into steam. Mr. Wilson improved upon this process, by passing steam into fat at a high temperature; and by this process hundreds of tons of palm oil are now treated. The glycerine and fat distil over together, but no longer combined ; and the former, being separated, is subjected to a redistillation, by which it is purified. This distillation is effected by transmitting through the fat contained in an iron still, steam at about 600° or 700° F., heated bypassing through iron pipes laid in a fire. The steam is transmitted till the oily matter is heated to about 350° ; the vapors produced being carried into a high shaft by a pipe from the cover of the iron vessel. The hot oily matter is then run into another vessel made of brick lined with lead, and sunk in the ground, for the purpose of supporting the brick work under or against the internal pressure of the fluid. It has a wooden cover lined with lead, directly beneath which, and extending across the vessel, is a leaden pipe, 1 inch in diameter, having a small hole in each side, at every 6 inches of its length ; and through this pipe is introduced a mixture of 1,000 lbs. of sulphuric acid, sp. gr. 1-8, and the same weight of water. The in- troduction of the mixture, which falls in divided jets into the heated fat, produces violent ebullition ; and by this means the acid and fat are perfectly incorporated before the action of the acid becomes apparent by any considerable discoloration of the fat. As the ebullition ceases, the fat gradually blackens ; and the matter is allowed to remain for 6 hours after the violent ebullition has ceased. The offensive fumes produced are carried off by a large pipe, which rises from the top of the vessel, then descends, and afterwards rises again into a high chimney. At the downward part of this pipe a small jet of water is kept playing, to con- dense such parts of the vapors as are condensable. At the end of the 6 hours above men- tioned, the operation is complete, and the product is then pumped into another close vessel and washed, by being boiled up (by means of free steam) with half its bulk of water. The water is drained off, and the washing repeated, except that in the second washing the water is acidulated with 100 lbs. of sulphuric acid. The ultimate product is allowed to settle for 24 hours ; after which it is distilled in an atmosphere of steam — once, or oftener, — until well purified, and the product of distillation is again washed, and after being pressed in the solid state, is applied to the manufacture of candles. The following definitions of terms applied to candles are by Mr. Wilson : — Belmont Sperm. — Made of hot pressed, distilled palm acid. Belmont Wax. — The same material tinged with gamboge. Be^t Composite Candles. — Made of a mixture of the hard palm acid, and stearine of cocoa-nut oil. Composites, Nos. 1, 2, and 3, are made of palm acids, and palm acids and cocoa-nut stearine, the relative proportions varying according to the relative market prices of palm oil and cocoa-nut oil at the particular time when the candles are manufactured. Composite, No. 4. A description of candle introduced at a price a very little above the price of tallow dip candles. They are somewhat dark in color, but give a good light. The highest-priced candles are usually made in the ordinary mould ; but at Price and Co.’s manufactory they have a machine for moulding the ordinary stearine candles, and others of a similar nature. When one set of candles is discharged from the moulds, the moulds are re-wicked for the next process of filling. These moulds are arranged, side by side, eighteen in number, on a frame ; and for each mould there is a reel capable of holding sixty yards of wick, enclosed in a box. The moulded candle, being still attached to the cotton wick, when it is forced out of the mould, brings the fresh wick into it. The moulded candles are, by a very ingenious contrivance, held firm in a horizontal position while a knife passes across and severs the wick. The wicks for the new set of candles are secured, by forceps, firmly to the conical caps of the moulds ; these are carried into a vertical position, and slid upon a railway to a hot closet, where they become sufficiently warm to receive the fat, which, kept at the melting point by steam pipes, is held in a cistern above the rails ; from this cistern the moulds are filled by as many cocks, which are turned by one impulse. If we imagine an extensive series of these sets of moulds travelling from the machine over a railway, in regular order, and that, when the fat has become solid, these return, the can- dles are discharged, and the process is renewed, — the machine will be tolerably well under- stood. Each machine holds about 200 frames of moulds, and each contains 18 bobbins, starting each with 60 yards of cotton wick. Night-Lights. — These are short thick cylinders of fat, with a very thin wick, so propor- tioned one to the other, that they burn any required number of hours. The moulds in which these are made are metal frames, perforated with a number of cylindrical holes, and having a movable bottom, with a thin wire projecting from it into every mould. These are CAOUTCHOUC. 287 filled with melted fat, and, when cold, the bottoms are forced up, and all the cylinders of fat ejected, each having a small hole through which the wick, a cotton previously impregnated with wax, is inserted. This being done, the night-light, being pressed on a warm porcelain slab, is melted sufficiently to cement the wick. These night-lights are burned in glass cylinders, into which they fit. Child's Night-Lights are melted fat poured into card-board boxes, which have a hole in the bottom, through which the wick and its metallic support are placed. CANES. Canes of various kinds are employed in manufactures, as the Sugar cane. Bamboo canes, and Rattan canes, &c. The bamboo is a plant of the reed kind, growing in the East Indies, and other warm climates, and sometimes attaining the height of 60 feet. Old stalks grow to five or six inches diameter, and are so hard and durable as to be used for building, and for all sorts of furniture, for water-pipes, and for poles to support palanquins. The smaller kinds are used for walking-sticks, flutes, &c. In 1856, we imported 309,000 Bamboo canes into England. Rattan canes are often confounded with the Bamboo. They are, however, the produce of various species of the genus Calamus. They are cylindrical, jointed, very tough and strong, from the size of a goosequill to that of the human wrist, and from fifty to a hmidred feet in length. They are used for wicker-work, seats of chairs, walking-sticks, &c. In 1856, we imported of Rattan canes, 7,840,'702, the computed value of which was £15,681. CANGICA WOOD, called also in England Augiga. It is of a rose-wood color, is im- ported from the Brazils in trimmed logs from eight to ten inches diameter. As a variety in cabinet work, small quantities of this wood are employed. CANNABIC COMPOSITION. This material, for architectural decoration, is described by Mr. B. Albano to have a basis of hemp, amalgamated with resinous substances, carefully prepared and worked into sheets of large dimensions. Ornaments in high relief, and with great sharpness of detail, are obtained by pressure of metal disks, and they are of less than half the weight of papier mache ornaments, suffi- ciently thin and elastic to be adapted to wall surfaces, bearing blows of the hammer, and resisting all ordinary actions of heat and cold without change of form. Its weather qualities had been severely tried on the continent, as for coverings of roofs, &c., remaining exposed without injury. This composition is of Italian origin, and in Italy it has been employed for panels, frames, and centres. It is well fitted to receive bronze, paint, or varnish, the material is so hard as to allow gold to be burnished, after gilding the ornaments made of it. CANNED COAL. Cannel coal is obtained in Lancashire, in Derbyshire, in Warwick- shire, and in Scotland, in considerable quantities ; there are some other localities in which it is procured, but not so extensively. Its use as a fuel and for gas making will be found in the articles devoted respectively to these subjects. This coal has a dark grayish black color, the lustre is glistening and resinous, it takes a good polish, and is hence made into a variety of ornaments. It is not equal to jet, (see Jet,) being more brittle, heavier, and harder; but cheap ornaments made of cannel coal are not unfrequently sold for jet : cannel coal is made up of horizontal layers, and has a grain something resembling wood. The coal, when worked for ornaments, is cut with a saw, and the pieces are rough- shaped with a chopper. For making a snuff-box, whether plain, screv/^ed, or eccentric turned, the plank loag^ or the surface parallel with the seam, is most suitable ; it is also proper for vases, the caps and bases of columns, &c. Cylindrical pieces, as for the shafts of columns, should be cut from either edge of .the slab, as the laminm then run lengthways, and the objects are much stronger : cylindrical pieces thus prepared, say 3 inches long and f of an inch diameter, are so strong, they cannot be broken between the fingers. Similar pieces have been long since used for the construction of flutes, and in the British Museum, may be seen a snuff-box of cannel coal, said to have been turned in the reign of Charles I., and also two busts of Henry VIII. and his daughter Lady Mary, carved in the same mate- , rial. The plankway surfaces turn the most freely, and with shavings much like those of wood ; the edges yield small chips, and at last a fine dust, but which does not stick to the hands in the manner of common coal. Flat objects, such as inkstands, are worked with the joiner’s ordinary tools and planes. The edges of cannel coal are harder and polish better than flat surfaces. — Holtzapffel. See Coal and Boghead Coal. Sgg j^rtillkry CAOUTCHOUC, GUM-ELASTIC, or INDIAN-RUBBER {Caoutchouc, Fr., Kautschuk Federharz, Germ.) occurs as a milky juice in several plants, such as the siphonia, cahuca, called also hevea guianensis, cautschuc, jatropha elastica, castilleja elastica, cecropia pel- , leta, ficus religiosa and undica, nrceolaria elastica, &c. The juice itself has been of late years imported. It is of a pale yellow color, and has the consistence of cream. It becomes covered in the bottles containing it with a pellicle of concrete caoutchouc. Its specific gravity is 1*012. When it is dried it loses 56 per cent. CAOUTCHOUC. 288 of its weight ; the residuary 45 is elastic gum. When the juice is heated it immediately coagulates, in virtue of its albumen, and the elastic gum rises to the surface. It mixes with water in any proportion ; and, when thus diluted, it coagulates with heat and alcohol as before. I. Caoutchouc Manufactures. But before entering upon their special divisions we may advert to some of the steps that have created this new employment for capital, commerce, and skill, especially as Mr. Han- cock conceives it but just to the memory of the late Mr. Macintosh, to record the circum- stances which led to his invention of the “ Waterproof double textures,” that have been so long celebrated through the world by the name of “ Macintoshes.” It will be recollected that, on the introduction of coal gas, the difficulties were very great to purify it from matters that gave a most disagreeable odor to the gas and gas apparatus ; the nuisance of these products led to many inconveniences. Mr. Macintosh, then employed in the manufacture of cudbear, in 1819 entered into arrangements with the Glasgow Gas Works to receive the tar and ammoniacal products. After the separation of water, ammo- nia, and pitch, the essential oil termed naphtha was produced, and it occurred to him that it might be made of use as a solvent for Indian-rubber, and by the quality and quantities of the volatile naphtha, he could soften and dissolve the Indian-rubber ; after repeated ex- periments to obtain the mixtures of due consistency, Mr. Macintosh, in 1823, obtained a patent for water-proof processes, and established a manufactory of articles at Glasgow, and eventually, with partners, entered upon the extended scale of business at Manchester, now so well known as the firm of Charles Macintosh and Co. The action of many solvents of Indian-rubber is first to soften and then to form a sort of gelatinous compound with Indian-rubber, requiring mechanical action to break the bulk so as to get complete solution, when the original bulk is increased twenty or thirty times to form a mass : it may be imagined that in the early trials much time was occupied, and manual labor, to break up the soft coherent mass, &c., while hand-labor, sieves, the painter’s slab and muller, and other simple means were resorted to. Macintosh, Hancock, and Goodyear alike record the simple manipulations they first em- ployed, and the impression produced at the last, when they compare their personal efforts with the gigantic machinery to effect the same results. Mr. T. Hancock’s first patent was in April, 1820 : “ For an improvement in the applica- tion of a certain material to various articles of dress and other articles, that the same may be rendered elastic.” Thus, to wrists of gloves, to pockets, to prevent their being picked, to waistcoats, riding belts, boots and shoes without tying and lacing, the public had their attention directed. To get the proper turpentine to facilitate solution, and remedy defects of these small articles, and to meet the difficulties of practice and failures, Mr. Hancock gave constant zeal, and pursued the subject until, united with the firm of C. Macintosh and Co., he has been constantly before the world, and produced one of the most important manufac- tures known. To get two clean pieces to unite together at their recently cut surfaces, to obtain facile adhesion by the use of hot water, to cut the Indian-rubber by the use of a wet blade, to col- lect the refuse pieces, to make them up into blocks, and then cut the blocks into slices, were stages of the trade which required patience, years of time, and machinery to effect with satisfaction to the manufacturer. To operate upon the impure rubber was a matter of absolute necessity for economic reasons : the bottles made by the natives were the purest form, but larger quantities of rub- ber could be cheaply obtained, full of dirt, stones, wood, leaves, and earth. To facilitate the labor of cutting or dividing, Mr. Hancock resorted to a tearing action, and constructed a simple machine for the purpose. (See^^. 140.) a shows the entrance for pieces of rub- ber ; B, interior of fixed cylinder, with teeth ; c, cylinder to revolve, with teeth or knives ; D, the resulting ball of rubber. This machine had the effect of tearing the Indian-rubber into shreds and small fragments by the revolution of a toothed roller ; the caoutchouc yielded, became hot, and ultimately a pasty mass or ball resulted ; when cooled and cut it appeared homogeneous. Waste cut- tings put, in the first instance, on the roller, were dragged in, and there was evidence of ac- tion of some kind taking place ; the machine was stopped, the pieces were found cohering together into a mass, this being cut showed a mottled grain, but being replaced and sub- jected to the revolving teeth of the rollers, it became very hot ; and was found to be uni- formly smooth in texture when cooled and cut open. The first charge was about 2 ounces of rubber, and required about the power of a man to work it. The next machine soon formed a soft solid, with speed and power, from all kinds of scraps of Indian-rubber, cuttings of bottles, lumps, shoes, &c. ; a charge of one pound gave a smooth uniform cylindrical lump of about 7 inches in length and 1 inch in diameter. This process, including the use of heated iron rollers, was long kept secret ; it is known as the masticating process now, and the machines are called “ Masticators.” In CAOUTCHOUC. 289 140 the works at Manchester the charges now are 180 lbs. to 200 lbs. of Indian-rubber each, and they produce single blocks 6 feet long, 12 or 13 inches wide, and 7 inches thick, by steam- power. The Mammoth machine of Mr. Chauffee, in the United States, weighs about 30 tons, and appears to have been invented about 1837, and is a valuable machine, differing in con- struction from Hancock’s masticators, but answers well in many respects ; it may be con- sidered as the foundation of the American trade. In 1820 the blocks were cut into forms of square pieces, sold by the stationers to rub out pencil marks, and then thin sheets for a variety of purposes. A cubical block cut by a keen sharp blade constantly wet, gave a sheet of Indian-rubber, the block raised by screws and the knife guided, enabled sheets of any thickness to be cut, sometimes so even and thin, as to be semi-transparent ; when warm, the sheets could be joined edge to edge, and thus large sheets be produced : from these blocks, rollers of solid rubber could be made, cylinders were covered for machinery, billiard tables had evenly cut pieces adjusted, tubes and vessels for chemical use were employed, and constantly increasing trials were made of the masticated rubber. These remarks upon the early and successful manufacturers will better enable the outline of improvements to be followed : it can readily be imagined that when capital and interest combine with the changing requirements of the public, that it would de- mand more space than a volume would afford to give the insights into trade applications, still guarded with secret means to produce success. But the foregoing remarks may lead to the appreciation of many of the following arrangements: I. Of the Water-proof double Fabrics. In 1837, Mr. Hancock obtained a patent to produce cloth water-proof with greatly re- duced quantities of dissolved caoutchouc, and in some cases without any solvent at all. The masticated rubber, rolled into sheets, was moistened on both sides with solvent and rolled up. The following day these were submitted to rollers of different speeds, and the whole became a plastic mass. Instead of a wooden plank as the bed of the machine, a revolving iron cylinder was used, kept hot by steam or water, and the coated cloth passed over flat iron chambers, heated the same way, to evaporate the small quantity of solvent. Masticated rubber has been spread without any solvent by these machines; but the spreading is best effected by the rubber being in some degree softened by the ad- dition of small quantities of the solvent. Sheets of rubber have been prepared by saturating the cloth with gum, starch, glue, &c., then rubber dough was placed on this smoothed surface; sufficient coatings of the rubber were spread to make up the desired thickness, the cloth was immersed in warm water to dissolve the gum, when the sheet of rubber came off with ease, and the plastic, or dough state, was th^e precursor of vulcanization experiments and success. The clamminess of caoutchouc is removed by Mr. Hancock in the following manner: 10 pounds of it are rolled out into a thin sheet between iron cylinders, and at the same time 20 pounds of French-chalk (silicate of magnesia) are sifted on and incorporated with it, by means of the usual kneading apparatus. When very thin films are required, (like sheets of paper,) -the caoutchouc, made plastic with a little naphtha, is spread upon cloth previously saturated with size, and when dry is stripped off. Mixtures of caout- chouc so softened may be made with asphalt, with pigments of various kinds, plumbago, sulphur, &c. Yol. III. — 19 290 CAOUTCHOUC. The first form of bags or pillows, or ordinary air-cushions, is well-known, and manu- factured by C. Macintosh and Co. as early as 1825 and 1826 ; when pressure is applied they yield for the instant to the compressing body, and then become rigid, and the whole strain is borne by the inelastic material of the bag, which then resistingly bears the strain. Mr. T. Hancock once tried an ordinary pillow between boards in a hydraulic press, and records that it bore a pressure of V tons before it burst. To remedy the evils of this forni an ingenious arrangement was made of inserting slips of Indian-rubber into the fabric, so that it expanded in every direction. This yielding of the case, and divisions into strengthened partitions, enabled seats, beds, and other applications to be made. Par- ticular details will be found in Hancock’s patent for 1835. The gas bags so commonly used appear, by Mr. Hancock’s statement, to be made for experimental purposes in the year 1826 ; and in May, 1826, at the suggestion and for the use of Lieut. Drummond, they were employed in the Trigonometrical Survey, with the oxy-hydrogen jets of gas on balls of lime. They were made strong and of rough materials — fustian made air-proof with thin sheet rubber. Mr. Hancock, to try whether the rubber was absolutely impervious to water, had a bag made and weighed it during 30 years; the decrease of weight is shown: — lb. oz. drcb. Oct. 21st 1826 weight - - - - -114 Oct. 25th 1827 “ 112 Oct. 2d 1835 “ 10 0 Nov. 1844 “ 0 14 12 Oct. 1849 “ 0 13 4 Feb. 1851 “ 0 7 8 May 1854 “ 0 3 14 In 1856 it was cut open and weighed - - 0 3 12 It was quite dry. Thus 12 oz. of water had evaporated or escaped in a quarter of a cen- tury, and 13 oz. 8 dr. in 30 years of observation. He remarks that bags of such cloth made with a thin coating of rubber, soon evap- orated sufficient water to cause mildew, when laid upon each other ; but this slow evap- oration does not interfere with their ordinary applications. The porosity of caoutchouc explains the readiness with which it is permeated by dif- ferent liquids which have no chemical action upon it. Thin sections of dry caoutchouc of the best kinds absorb from 18 to 26 per cent, of water in the course of a month, and become white from having been brown. To enumerate the applications of these double fabrics for cushions, life-preservers, beds and boats, would be out of place here, however important and ingenious the plans. Thus, instead of one bag, several tubes or compartments gave the required form, and this again may be divided into cells, very small, and kept apart by wool or hair : of the advantage of this plan to divide the air spaces there can be no doubt. For single texture fabrics, or cloth with one side only prepared, the process is the same as that described for double fabrics, only that one side is proofed, or covered with Indian-rubber solution or paste; and this kind of water-proof has an advantage over the old, that the surface worn outside, being non-absorbent, imbibes no moisture and requires no drying after rain or wear. The objection to single texture fabrics, of being liable to ' decomposition by the heat of the sun and from close? packing, has been obviated by a discovery adopted by Messrs. Warne and Co., termed by them the Sincalor process, {sine calore, without heat;) by which the properties of the rubber are so changed that heat, grease, naphtha, and perspiration, which decomposes the ordinary Indian-rubber water- proof, in no way affects the water-proof goods of the “ Sincalor ” process. The singular changes effected by this process are especially shown by the application of a hot iron to the surface, which destroys without the usual decompositions; the substance is burnt but is not rendered sticky. The process is stated to be secret. II. Vulcanization. Of all the changes effected by chance, observation, or chemical experiments of late years, few cases have been so important as the change in Indian-rubber by the process called Vulcanization. The union of sulphur with caoutchouc to give new properties so valuable, that it may be said the former well-known quality of elasticity is now rendered so variable that almost every range, from the most delicate tenuity to the hardness of metals, has been obtained at will by the manufacturer. These changes in the caoutchouc are produced with a degree of permanence to defy air, water, saline and acid solutions; the material is incapable of being corroded, and more permanent under hafsh usage than any other set of bodies in the world. Such are the results of the processes that induce a “change” in caoutchouc when sulphur and heat are employed; where metals and miner- CAOUTCHOUC. 291 als are employed, “metallized” and “mineralized,” “ thionized,” and a number of other terms have been Used. When caoutchouc is mixed with sulphur from 2 to 10 per cent, and then heated to 270° and 300°, it undergoes a change, it acquires new characters, its elasticity is greatly increased, and is more equable ; it is not affected, nor is the substance altered by cold, no climate effects a change, heat scarcely affects it, and when it does it does not become sticky and a viscid mass; if it yields to a high temperature it is to become harder, and will ultimately yield only at the advanced temperature to char and to decompose. All the ordinary solvents are ineffectual. The oils, grease, ether, turpentine, naphtha, and other solvents scarcely alter it, and the quantity of sulphur that will effect the change is known not to exceed 1 or 2 per cent. Further, if peculiar solvents, such as alkalies, remove all apparent sulphur from it, still the change remains ; indeed, the analogy of steel to iron by the changes of condition effected by some small quantities of other bodies seems to be an analogous condition. Whatever the theory, which is exceedingly obscure, still the practice, by whatever name, is to obtain this changed state and exalted elastic prop- erties. “ Vulcanization” had its discovery in America. Mr. Goodyear relates that, having made a contract for Indian-rubber mail bags, they softened and decomposed in service, and while he thought a permanent article had been made, the coloring materials and the heat united to soften and to destroy the bags ; hence, by this failure, distress of all kinds arose, and the trade was at an end. During one of the calls at the place of aban- doned manufacture, Mr. Goodyear tried a few simple experiments to ascertain the effect of heat upon the composition that had destroyed the mail bags, and carelessly bringing a piece in contact with a hot stove, it charred like leather. He called the attention of his brother, as well as other individuals who were present, and who were acquainted with the manufacture of gum elastic to the fact, as it was remarkable, and unlike any before known, since gum elastic always melted when exposed to a high degree of heat. The occurrence did not at the time appear to them to be worthy of much notice. He soon made other trials, the gum always charring and hardening. As ordinary Indian-rubber is always tending to adhere, many plans have been tried to prevent this. Chalk, magnesia, and sulphur had been patented in England and Amer- ica, but no one seems to have supposed any other change would be produced by heat. Mr. Goodyear proceeded to try experiments, and produced remarkable results ; samples of goods were shown about and sent to Europe. The late Mr. Brockedon, so well known for his talents and love of scientific investiga- tions, had long pursued means to obtain a substitute for corks, and, after much ingenuity, had devised Indian-rubber stoppers. As soon as all mechanical difficulties were over, objections were taken to the color of the substance. Some samples of a changed rubber came into his possession, of which it was declared they would keep flexible in the cold, and were found not to have an adhesive surface. These caused numerous experiments, as it was recognized that a change had been effected, and although Mr. Brockedon failed, yet Mr. Hancock kept on working, combining sulphur, with every effect but that of vul- canization, as he was ignorant of the power of heat to effect this change. He used melt- ed sulphur, and produced proof of absorption, for the pieces of caoutchouc were made yel- low throughout ; by elevating the temperature he found they became changed, and then the lower end of slips. “ nearest the fire turning black, and becoming hard and horny,” (the sulphur was melted in an iron pot.) By these simple observations, as they now seem, Mr. Goodyear in America and Mr. Hancock in England, were induced to take out patents, and commence that series of manufacturing applications to which there seems no limit. The first English patent was by Mr. Hancock. The general method is to in- corporate sulphur with caoutchouc, and submit it to heat ; if any particular form is re- quired, the mixture is placed in moulds, and takes off any delicate design that may be upon the iron or metal mould, and if these are submitted to higher degrees of heat, the substance and evolved gases expand, and thus a very hard, horny, or light but very strong substance is produced, called hard Indian-rubber, or “vulcanite.” Mouldings, gun-stocks, combs, cabinet work, and hundreds of forms may be obtained by these curious means. The terra vulcanization was given by Mr. Brockedon to this process, which seems by the employment of heat and sulphur to partake of the attributes of the Vulcan of mythology. For the “change” or “vulcanizing” to get a yielding but per- manently elastic substance, steam heat is usually employed in England, but in America, ovens, with various plans for producing dry heat, are generally employed. The articles thus made being more elastic, unaffected by heat, cold, or solvents, at- tracted much attention, and Mr. Parkes was engaged to find out a method of producing the same effects now secured by patent: all ordinary means were used and given up, but he finally succeeded. The process of cold sulphuring of Mr. Parkes consists in plunging the sheets or tubes of caoutchouc in a mixture of 100 parts of sulphuret of carbon, and 2^ parts of protochloride of sulphur, for a minute or two, and then immersing them in OAOUTOHOUO. 292 cold water. Thus supersulphuration is prevented in consequence of decomposing the chloride of sulphur on the surface by this immersion, while the rest of the sulphur passes into the interior by absorption. Mr. Parkes prescribes another, and perhaps a prefer- able process, which consists in immersing the caoutchouc in a closed vessel for 3 hours, containing a solution of polysulphuret of potassium indicating a density of 25° Beaume at the temperature of 248° Fahr., then washing in an alkaline solution, and lastly in pure water. A uniform impregnation is thus obtained. In the first instance sulphur, caoutchouc, and heat were alone employed. The tempera- ture and the time to which the mixtures are subjected to heat afford conditions to be best understood by the practical man. V ulcanized rubber now is not only the changed sub- stance as produced by sulphur, but it contains metallic oxides, &c. Metallic and mineral substances, and these compounds, are perhaps much better fitted for their respective uses than the pure sulphur and Indian-rubber. \Vbite lead, sulphuret of antimony, black lead, and other substances enter into these combinations. After the early experiments with vul- canized rubber, there seemed reason to believe that changes slowly took place. The rubber was found to become brittle, and bands stretched out broke immediately. To a great ex- tent this has been remedied by the use of lead, which seems to combine with the sulphur, for changes are believed by practical men to take place with pure elastic vulcanized caout- chouc, which do not occur when metallic matters are duly mixed. This is a trade statement, which may be true for some special uses. The brittleness may perhaps more fairly be ad- mitted to be due to inexperience, and the difficulties to meet the demands of the public for a new article ; but to those whom it may most concern, we have raised this question so far as to obtain the conscientious opinion of Mr. Thomas Hancock, (now retired from business,) who considers that by the peculiar plan of vulcanizing by a bath of sulphur, and employing high-pressure steam, (described in Patent of 1843,) he obtains what he calls pure vulcaniz- ing, that is, the use of sulphur, rubber, and heat. He states “ That by this mode, the greatest amount of extensile elasticity is obtained, and that this quality is diminished in proportion as other matters are present in the compound.” It may, however, be useful to record some of the results of early trials made by competent authorities, with the view of testing its ultimate employments. Mr. Brockedon stated at the Institution of Civil Engi- neers, that he had kept vulcanized Indian-rubber in tranquil water for 14 years without vis- ible change, and he summed up the then knowledge of trade production, that there was per- haps no manufacturing process of which the rationale was so little understood as that of vulcanizing caoutchouc ; all was conducted on the observation of facts, a given quantity of sulphur to a certain thickness of rubber, at a certain temperature ; and certain results were reckoned upon with confidence, but more from practice than theory. Mr. Brockedon had placed vulcanized rubber for 10 years in damp earth, and it exhibited no change. When articles were moulded, the metal of the mould w'as not a matter of indifference ; if of tin, the article was usually delivered perfectly clean, but if of brass or copper, then the material adhered to it, probably from the greater affinity of the sulphur for the metal than for the caoutchouc : these surface effects may well be borne in mind, for it appears not to be an easy matter to vulcanize large masses of caoutchouc, while sheets and thin films are readily changed. The soft masses of materials are placed in moulds, strongly secured, if a high temperature is to be used, and the mass comes out with the form thus given to it, and more or less elastic ; hence the surface of a mass is always likely to be advanced in the vulcanizing changes. At present, a very large proportion of the articles made have the forms given to them in the plastic state, and then subjected to heat ; the change is effected, and they retain their form, although rendered permanently elastic. Mr. Brockedon and Mr. Brunei tried this substance on the Great Western Railway in place of felt, to be used between the under sides of bearing rails and sleepers of railways. It appeared, by constant trials of nearly a year, to be quite indestructible to any action to which it had been exposed ; the slips were indented by the edge of the rail, but not per- manently so, and the surface was glazed, as if by friction ; the slips were 6 inches wdde, and weighed 8 oz. to the yard in length ; the transit of the carriages was easier over that part of the line. To test the power of endurance to heavy blows, Mr. Brockedon subjected a piece of vulcanized Indian-rubber, 14 inches thick and 2 inches area, to one of Nasmyth’s steam hammers of 5 tons ; this first rested on the rubber without effect, then was lifted 2 feet and dropped upon it without injury, then lifted 4 feet, the vulcanized cake was torn, but its elasticity was not destroyed. Still more severe trials were made ; a block of vulcanized caoutchouc was placed as between cannon balls, with the whole power of the heaviest steam hammers employed, but the iron spheres split the block, and the elasticity of the vulcanized caoutchouc was not destroyed. The natural and the vulcanized rubber have both been proposed as absolutely resisting the power of shot and rifle balls. Instructive cases are known of projectors offering to be clothed in their own cuirasses, and meet the charge of a fired rifle ; when a deal board or leg CAOUTCHOUC. 293 of mutton has been substituted in the interior, they have been found perforated by the rifle ball, while back and front the cuirass showed no change, the truth being that the bullet cut its way through, and the edges of the aperture closed and joined, so that, no hole being visible, led to the conclusion that the ball had declined to penetrate the rubber. Among the applications may be named the construction of boats and pontoons. On the first trial in the Arctic regions, they were adopted to give possible conveyance when other boats could not be carried ; the Indian-rubber boat soon won its character ; it took the icy channels, and bore the brunt of all collisions, and without damage met rock, and ice, and storm, where it was believed no other boat could live. Since then, they have been employed on the rivers of Africa by missionaries and travellers, and on lakes in England. Sheets of enormous size, — ship-sheets, — have been made 60 yards long, and 66 inches wide, others, 10 feet square ; these are proposed to pass over a steam-vessel’s side, to adapt a valve, fix a pipe, or repair, from the interior, the vessel itself without going into dock. These stout sheets, f inch thick, are let down by ropes over a ship’s side, and brought over the hole or place for repair by the pressure of the water on the elastic sheet, the leak may be stopped and the ship pumped dry, pipes renewed, shot-holes and leaks stopped. In- deed, an early application of compounds of native rubbers and other materials was applied directly as sheathing for ships with success ; but litigation among the parties caused the business to cease. Since the various plans for getting a flexible material have been success- ful, there seems no doubt but many unexpected applications will be made. Messrs. Macintosh had coated some logs of wood with vulcanized Indian-rubber, and caused them to be towed in the wake of a vessel all the way to Demerara and back, and it was found that the coated logs were quite intact, while the uncoated timber was riddled by , ' _ marine insects. The same fi^rm stated : “ That the only effect they could trace upon long immersed vulcanized caoutchouc, was a slight change of color, perhaps a hydrate produced by superficial absorption, but this change of color disappeared on being dried. If they were called upon to select a situation for the substance to retain its properties for the longest pe- riod, they would select immersion in water. After years of experience in the use of hose- pipes, pipe-joints, valves for pumps and steam-engines, they had never known an injury from the contact of any kind of water.” Mr. Goodyear sums up the advantages of vulcanized rubber under the following heads, as being either properties new, or superior to those possessed by the natural caoutchouc : — 1. Elasticity. 2. Pliability. 8. Durability. 4. Insolubility. 6. Unalterability by climate, or artificial heat, or cold. 6. Inadhesiveness. 7. Impermeability to air, gases, and liquids. 8. Plasticity. 9. Facility of receiving every style of printing. 10. Facility of being ornamented by painting, bronzing, gilding, japan- ning, and mixing with colors. 11. Non-electric quality. 12. Odor. We are indebted for the following facts and remarks to Messrs. Silver and Co., of Lon- don and Woolwich : The chief improvements operated in caoutchouc by the process of vulcanization, are the properties of resisting and remaining unaffected by very high degrees of heat and cold, and increased compressibility and elasticity. In its natural state, Indian-rubber becomes rigid by exposure to cold, and soft and plastic by heat, under the action of boiling water. Arti- cles manufactured of this substance suffer and lose the qualities which constitute their value in cold and in hot countries. A piece of Indian-rubber cloth, for instance, taken to Moscow in December or January, would assume all the qualities of a piece of thin sheet iron, or thick pasteboard ; the same cloth would in India or Syria become uncomfortably pliable, and present a moist and greasy appearance ; and, indeed, after being folded up some time, it will be found to be glued together. Nothing but vulcanization insures the equable condi- tion of the articles in the most intense cold, and, in heat up to and above 300°, makes In- dian-rubber fit for practical purposes. These advantages have conduced to its being very extensively used in connection with machinery of every description ; and as steam power is still further employed, and as the numerous other advantages possessed by vulcanized Indian-rubber become known, (for it is only of late that any idea of their extent has been realized,) its application will be extended and proportionally its consumption increased. The compressibility and the return to its former dimensions, when the pressure has ceased, in one word, the elasticity of the Indian-rubber, is increased to such a degree by vulcanization, that comparing the improved with the original article, it may be said that the native Indian-rubber is almost devoid of elasticity. The high degree of elasticity which it obtains by vulcanization is shown by the results of the following experiments, in which a block of the vulcanized Indian-rubber, of the kind used for the manufacture of railway car- 294 CAOUTCHOUC. riage springs, measuring 6 inches outside disk, 1 inch inside disk, and 6 inches deep, was taken and exposed to pressure : — pressure of i ton . reduced it to - - - - 57,6 deep. ditto 1 ditto 5Vi6 do. ditto H ditto - • - 47.6 do. ditto 2 ditto " • * 47 1 6 do. ditto H ditto • - - 37,6 do. ditto 3 ditto - - - 3%. do. ditto H ditto - - - 3i do. ditto 4 ditto 3 do. The block was left under pressure for 48 hours, and in each case returned to its original dimensions after a short period when the pressure was removed. Indian-rubber and canvas hose are now generally used where leathern pipes were used in former times, viz. where a flexible tube is required, in fact, where it is not possible to use a metal pipe. The advantages which the Indian-rubber and canvas hose has over the leathern pipe, are, that it does not require draining and greasing after being used, that it can be left in the water without rotting, and that it does not harden or lose its flexibility. Leathern pipes, on the contrary, require the most careful treatment, and even with the greatest care they are liable to frequent leaking. Indian-rubber and canvas hose are made to resist atmospheric and hydraulic pressure, say up to 1,000 lbs. pressure on the square inch. Of this Indian-rubber and canvas hose, the descriptions mostly in use are the fol- lowing : — 1 Ply which will stand a pressure of about 2 Ply for conducting water “ 2 Ply stout “ 8 Ply for brewers, &c. “ 4 Ply for steam and fire-engines “ 20 lbs. to square inch. 30 to 40 “ 15 “ 15 “ - 115 Among the most recent uses of Indian-rubber and canvas, are those of its manufacture into gas and ballast bags ; the former are used for the transport of gas, and applied to the various emergencies of gas engineering. Indian-rubber gas tubing is now in general use, the great advantage over metal tubes being the ease with which gas can be conveyed to whatever part of the building it may be required ; this, where any alterations are being effected, is a great desideratum. Ballast bags, large stout bags of Indian-rubber and can- vas, capable of holding from 1 to 5 or 10 tons of w'ater, are coming into use as the most convenient form of ballast, thus saving valuable space, which is made available for cargo. These bags may be emptied at any time, and when flattened down and rolled up, they can be stowed away. Indian-rubber bags for inflation have also in a few cases been made use of for buoying up vessels, but hitherto the practice has been experimental only, and such floating machines are not as yet generally in use. The vulcanizing Indian-rubber on silk or woollen was for a long time considered im- practicable, because the process of vulcanization destroyed the fibre and texture of the two substances ; and it is stated that now this process is effected in a manner which deprives neither silk nor wool of their natural qualities and strength. By this improvement,. com- bined with Silver’s patent process of annihilating the unpleasant smell which all Indian- rubber goods used to acquire in the process of manufacture, the advantages of that sub- stance for clothing purposes are extended to the lightest and the warmest of our textures. Silk and Indian-rubber garments are made without any deterioration of the strength and durability of the stuff, while they are perfectly free from odor of any kind. (See page 302.) III. Mechanical Applications of Caoutchouc. Numerous important applications of caoutchouc have been made in the mechanical arts, among which we may mention springs for railway and common road carriages, military carriages, lifting springs for mining ropes and chains, towing ropes and cables, rigging of ships, recoil of guns on ships, the tires and naves of railway and other wheels, to axles and axle bearings, to windows of railway carriages, railway switches, bed of steam-hammer, couplings for locomotives and tenders, packing for steam and water joints, shields for axle boxes, sockets for water pipes, bands for driving machinery, valves for pumps, tubes for conveying acids, beer, water, and other fluids, packing for pistons. Many of these improvements have been the subject of patents, a list of the principal of which is given, stating the name of patentee, date, and object of so much of patent as re- lates to the use of caoutchouc. CAOUTCHOUC. 295 List of Patents. No. Name. Date. Object of Patents. 1 Lacey - 29th Mar., 1825 Indian-rubber springs for carriages en- closed in cases with dividing plates. 2 Melville - 13th April, 1844 Springs for buffers and bearing, sphere, of Indian-rubber and air, with divid- ing plates, and enclosed in iron cases. 3 Walker and Mills - 3d July, 1845 Buffers, Indian-rubber bags, enclosing air, in iron cases. 4 W. C. Fuller - 23d Oct., 1845 Buffer and bearing springs of Indian- rubber, cylindrical rings with divid- ing plates of iron. 5 Adams and Richardson 24th May, 1847 Elastic packing for axles. 6 C, De Bergue - • 26th July, 1847 Indian-rubber buffer, bearing and draw springs. n Wrighton . 22d Dec., 1847 Indian-rubber shield for axle box. 8 C. De Bergue - - 5th Jan., 1848 Anti-recoil buffers of Indian-rubber, and improvements in dividing plates. 9 Normanvllle . 2d May, 1848 Indian-rubber shield for axle box. 10 C. De Bergue - * 15th April, 1850 Station buffers of Indian-rubber, and carriage buffers. 11 P. R. Hodge - - 8th Mar., 1852 Packing for steam joints. 12 G. Spencer * 2d Feb., 1852 Indian-rubber cones as buffer, bearing, and draw springs. 13 P. R. Hodge 8th Mar., 1852 Indian-rubber compound springs, In- dian-rubber to wheel naves, and to axle box shields. 14 W. Scott - 8th Mar., 1852 Indian-rubber as check springs, wheel nave, suspensor springs. 15 J. E. Coleman - 2d June, 1852 Indian-rubber applied to buffer, bear- ing, and draw springs, rails, chairs and sleepers, wheel tires, windows, axle bearings, plummer blocks, con- necting rods, steam hammer beds. 16 Fuller and Knivett 6th Oct., 1852 Common road springs of Indian-rub- ber. n C. De Bergue - 26th Mar., 1853 Indian-rubber bearing springs. (Pat- ent refused.) 18 G. Spencer 2d July, 1853 Improved cones for buffer, bearing and draw springs. 19 R. E. Hodges - 2d Nov., 1854 Improvements in fastening Indian-rub- ber springs. 20 G. De Bergue - 4fh Mar., 1854 Buffers for railways. 21 W. C. Fuller - 10th May, 1854 Indian-rubber springs applied to an- chors, cables, towing ropes, deck ropes. 22 E. Lund - 18th Aug., 1854 Indian rubber to feed-pipe, coupling and water joints. 23 W. C. Fuller - 10th Jan., 1855 Indian-rubber springs to common roads. 24 E. Miles - 12th Jan., 1855 Indian-rubber to water-pipe couplings. Indian-rubber buffers with Spencer’s cones. 25 G. Richardson - 28th Nov., 1855 26 W. Scott - 14th May, 1856 Indian-rubber to axles and tires of wheels. 27 G. Spencer • 25th July, 1856 Indian-rubber to feed-pipe, couplings for locomotives and tenders. 28 R. Eaton - 20th Nov., 1856 Indian-rubber springs for railways. 29 R. Eaton - 8th Dec., 1856 Indian-rubber springs in thin laminae for buffer, bearing, and draw springs, and lifting-purposes. 30 H. Bridges 14th Mar., 1857 Spencer’s cones applied to wood blocks in buffers, bearing springs, &c. 31 J. Williams nth Nov., 1867 Indian-rubber springs applied to the side or safety chains of trucks, &c. 32 W. E. Nethersole Do. do. do. 296 CAOUTCHOUC. We have been at some pains to ascertain the progress that has been made in the prac- tical application of these inventions, and notice them below, under the several heads mentioned above. Springs. — The first proposal to use caoutchouc for springs that we are aware of, oc- curs in Lacey's patent, (see list,) in 1825, when blocks of caoutchouc were proposed to be used, having dividing plates of iron between each series ; but little seems to have been done towards any practical application at that time : later in 1844, (see list,) Melville pro- posed to use spheres of caoutchouc, enclosing air, and separated by disks of wood or metal, the whole being enclosed in iron cases, and used for buffers and bearing springs for railway carriages. In 1845, (see list,) Walker and Mills proposed to use bags of caoutchouc enclosing air, and contained in cases of iron, for use as buffer springs. The next improvement is contained in Fuller's patent of 1845, which consists in the use of cylindrical rings of vulcanized Indian-rubber, in thicknesses varying from | to 3 inches, and with diameter of ring suitable to the power of spring required ; between each of these cylindrical rings he places a thin iron plate, through a hole in the centre of which passes a guide rod. Fig. 141 shows Fuller’s spring in section and plan. These 141 springs have been extensively used as buffer, bearing, and draw springs for railway uses alone and in combination with Be Bergue's improvements : some defects have been found in practice in this form, to obviate which, the ingenuity of later inventors has been ex- ercised ; the defects alluded to are, the tendency to swell out at the central unsupported part of the ring, thus from the undue tension rendering it liable to break under sudden concussion, and occasioning complete disintegration of the material where not breaking. To obviate these defects, George Spencer list. Nos. 12, 18) proposed to mould the caoutchouc at once in the form it assumes under pressure, and then to place a confining ring of iron on the larger diameter. (See Jig. 142.) By this ingenious plan, the caout- 142 chouc loses its power of stretching laterally, being held by the ring 6, secured in a groove moulded in the cone to receive it ; when the pressure is applied to the ends, the rubber is squeezed into the cup-like spaces c, and thus the action of the spring is limited. By this plan, rubber of a cheaper and denser kind can be used than on the old cylindrical plan, and the patentee states that many thousands of carriages and trucks are fitted with these springs which give entire satisfaction; among which, are those on the Brighton, South-Western, North London, South Wales, Yale of Neath, Bristol and Exeter, Taff Yale, Lancashire and Yorkshire, St. Helen’s, Bombay and Baroda, Theiss Railways, and many others. These cones are used as buffer, bearing, and draw springs for railway car- riages, and are made in several sizes to suit various uses. To show the power that such CAOUTCHOUC. 297 springs are equal to, we append the result of an experiment on a No. 1 cone, (for inside buffers,) 3 inches in length, 3| inches diameter at ring, 6 inches diameter of ring. Experiment, without the confining ring, weight of cone lbs. Without any pressure the cone measured - With pressure — 280 lbs. “ “ _448 lbs. “ “ —672 lbs. “ Inches. 3 2 n Giving a stroke of inch. 1 “ H “ 2cZ Experiment. With the confining ring 6, on the same double cone ; the following were the results:— Without any pressure the cone measured - - - 3 inches, as before. With— 448 lbs. “ “ - - - 2i “ With— 1,680 lbs. “ “ . . . 2 “ With— 2,912 lbs. “ “ ... If “ With— 15,680 lbs. “ “ » - - H “ The advantages are stated to be, less first cost than steel ; less weight, 6 cwt. being saved in each carriage by their use ; and great durability. Coleman^ improvement (see list, No. 16) consists in the use of iron rings to confine the lateral swelling of Indian-rubber cylinders. (See/^^. 143.) They are used as bearing springs for engines and tenders on the North-Western railway, by J. E. M’Connell, Esq., who prefers them to steel, as being easy in action, durable, safe, and easy of repair ; they are used also as buffers and draw-springs, but not to the extent of Fuller’s and Spencer’s form. To give an idea of the power of such a spring, we append the result of an experi- ment of one that we witnessed at Messrs. Spencer and Co.’s. Experiments Avith one of Coleman’s cylinders with and without the rings. Cylinder 6 inches long, 6 inches diameter, 1 inch hole, weight 9 lbs. Tons pressure. "Without the confining rings. Inches Length. With the 2 confining Inches Length. 0 6 6 i - - - - 5Vi6 - - - - 5^7i6 1 5 - - 5| H • . . . 4^ - - ‘ - H 2 - . - 4i - - - - H 2i - - - 3f - - - - The next form of these springs is R. Eaton's, (see 144 ; and list. Nos. 28, 29.) This 144 CAOUTCHOUC. 298 spring seems to be peculiarly adapted to use where a powerful spring, acting through a small space, and taking little room, is required, as for use in mining ropes and chains, (see Safety Cage ;) iron ropes, for ship-rigging, for engine-springs, station buffers, and pow- erful draw-springs. Eaton’s main idea is the use of laminae of Indian-rubber, of a maxi- mum thickness of ^ an inch, with dividing plates, as in Lacey’s and Fuller’s, which avoids the objections stated above, by supporting the Indian-rubber at smaller intervals ; for springs, where great power is wanted in little compass, and to act through short dis- tances, — as in engine bearing-springs, lifting springs, and some kinds of draw-springs, — this form proves to be well suited. We give below the result of one such spring of the following dimensions : the spring was built up of 24 laminse, ^ of an inch thick, 4^ inches square, with a thin iron plate between each, and a hole of one inch diameter for the guide rod through all; this, and several of the other experiments were made in a press of great delicacy and power, constructed for Messrs. Geo. Spencer and Co., for the purpose of testing such springs, at their oflSce, in Cannon Street West, London, (see Proving Machines.) Tons. 0 1-0 2-0 3 - 0 4 - 0 5 - 0 6- 0 'T-O 8-0 9-0 10*0 Experiment. Length including plates. Area of spring, 19 square inches, 87i6 n r/ie ^ Vl6 6| 6f 6f H 6 | Hodge's compound spring (No. 13) is designed to obviate the frequent breakage of the steel springs on locomotive engines. Fig. 145 shows one of these springs ; a block of 145 Indian-rubber is placed on each end of the steel spring, or is suspended under the engine frame ; they are in use on several of the English railways, and are said to answer the purpose intended well. Scott’s patent (see/^r. 146 ; and list. No, 14) consists in the use of blocks of Indian- rubber, or cones, placed over the centre of spring ; they are to obviate the danger of overloading carriages and trucks, a frequent source of danger to the springs, and are made to take the whole load in case of a spring breaking: they are in use on the Brighton and Crystal Palace Railway, Eastern Counties, Bombay and Baroda, and others. The same patentee has several ingenious applications of Indian-rubber to carriages to wheel tires, to the bosses of wheels, to shackle pins, and to the axle. Bridges' Patent . — (See list, No. ?>0,fig. 147.) This inventor proposes to use Spencer’s cones in blocks of wood, instead of iron confining rings. A series of them are enclosed in a case formed in the side timbers of the underframe of the railway truck or carriage; the cup space is formed in the block of wood, as our figure shows, and no guide rods are CAOUTCHOUC. 299 146 required : the same principle is applied to draw and bearing springs. The advantages proposed by this arrangement are, the dispensing with guide rods and the taking the ulti- mate blow on blocks of wood, which deadens its effect ; they are 'said to answer very well, and are used almost exclusively on the South Western and Bristol and Exeter Rail- ways. 147 In 1847, Mr. De Bergue patented some improvements in the application of Fuller’s spring to buffer, bearing, and draw springs for railway uses. Mr. Fuller's -The applications for common road carriages, patented by Mr. Fuller of Bucklersbury in 1852 and 1855, have been extensively us^d, both in the form of cylindrical rings acting by compression and also of suspension springs for lighter kinds of vehicles. Respecting these springs, 148, 149, we have been furnished by the patentee with the following particulars : — The form generally used for heavy purposes, such as drays, vans, wagons, &c., con- sists of a series of rings of cylindrical or circular form, working on a perpendicular rod or spindle, on each side the axle, with the usual separating plates or washers ; the depth and diameter of the rings being regulated by the weight to be sustained and the speed required. During the late war, these springs were introduced by Mr. Fuller to the notice of the Government authorities at the Royal Arsenal, Woolwich, and were in consequence ex- tensively adopted for all kinds of military carriages, store wagons, ammunition wagons, &c. They are also applied in the suspensory form for the medical cars and ambulance wagons for the wounded, for which purposes the use of Indian-rubber on the principle of extension is found to produce the easiest and most satisfactory spring hitherto dis- covered. When the material is used as a suspension spring, the most advantageous form for the purpose is found to be round cord of the best and purest quality, prepared by solvents, aud about i or f inch diameter. A continuous length of such cord is wound at a considerable tension over the ends of two metal sockets or rollers, in shape something resembling a cotton reel, and whilst in a 800 CAOUTCHOUC. state of tension, bound at each end with strong tape or other suitable binding ; the num- ber of cords composing the spring, varying from 10 to 20, 30, or 40, according to the strength required. 148 149 Another important adaptation of Indian-rubber by Mr. Fuller, is that of anchor springs, towing ropes, and springs for the recoil of guns and mortars. During the Russian war, about 120 mortar boats were constructed of light draught, each carrying a 13-inch mortar on a revolving pivot and platform in the centre of deck. It was considered desirable, if possible, to diminish the shock produced by the tremen- dous recoil of such heavy artillery on the deck of small vessels, and after a series of trials at Shoeburyness, which proved perfectly satisfactory, the plan was adopted of mount- ing each platform upon twenty powerful rings of Indian-rubber, the united force of which, at 1-inch deflexion, would resist about 400 tons. The performance of these mortar ves- sels at Sweaborg, the Black Sea, and also subsequently in China, has been highly satisfac- tory ; the intervention of this elastic material being found effectually to preserve the timbers of the vessel. The application to towing ropes and anchor cables, has not yet been tried to an ex- tent sufficient to test its merits ; but it is universally admitted by engineers and practical men, that a powerful spring adapted to the chain cables of vessels w'hen riding at anchor (acting on the principle of the buffer and draw-springs) would often prove of invaluable service in preventing the parting of the cable and its disastrous results. ' In the list of patents, we have indicated the nature of several other improvements, which, being merely variations of the more important ones, we do not dwell on here. Support for railway chairs. — Several proposals have been devised to this end, and a number of plans are given in ColemarHs patent, 1852. He places the Indian-rubber under the chair, between the chair and rail, between the rail and sleeper. The plan has been only partially tried, but the proposer is very sanguine that the plan will prove useful. Wheel tires. — Fig. 150 shows an important application to the tires of wheels for railway purposes. A thin band of Indian-rubber is inserted between the tire and spoke ring, by first covering it with a thin plate of iron, to protect the Indian-rubber while the hot tire is put on, when the wheel is instantly thrown into water and cooled. This has been severely tested for some time, and found to answer very well; the advantage gained, is the saving in the breaking and \fear of the tires. For windows. — Small ropes of Indian-rubber are inserted in grooves at each side of the window, and so stop out draught and prevent noise. For steam-hammer beds. — A plate of Indian-rubber f thick, is placed under the bed of the hammer; the effect is greatly to diminish the transmission of shocks to the building, and to cheapen the foundation : as an instance of useful appli- cation, we may state, that at Messrs. Ransome and May’s works, at Ipswich, the working of the steam-hammer shook the building and windows to an alarming extent; but the insertion of blocks of vulcanized rubber under the anvil, almost entirely obviated these effects. Joints between engines and tenders. — Messrs. Lundy Spencer^ and Fenton have also 151 150 CAOUTCHOUC. 301 introduced the use of rings of this material to form a joint between the locomotive and tender, {jig. 151.) They are extensively used, and entirely prevent the leakage common to the old ball and socket joints, and are much cheaper in first cost. Rings of Indian- rubber were proposed by Mr. Wickstead, for closing the socket joint of water pipes, and they are used in a variety of forms for that purpose. Messrs. W. B. Adams^ Normanville^ Wrighton, and Hodge have also introduced the use of shields and rings of Indian-rubber for keeping the backs of axle boxes tight, so as to prevent the escape of the grease or oil, or the entry of dust and dirt. A large trade has been established in the supply of bands of Indian-rubber for driving machinery ; for many purposes they answer better than leather, water having no effect on them and there being little or no slip and fewer joints, they are made in all widths, and belts costing £150 each have been used in some cases. They are made with two or more layers of thread cloth between, and outside of which the rubber is placed. As valves for steam and water pumps, Indian-rubber prepared to suit the use is also much used by all our large engine-makers. As tubes for conveying beer, water, and acid, Indian-rubber is also found to answer well, and is used largely. The tubes are made in all sizes and strengths, and the best are made by alternate layers of cloth and Indian-rubber. Very good tubes are also imported from America. Another useful application of this material, is for the joints of steam and hot-water pipes ; for this and similar purposes, a peculiar compound, known as Hodge’s compound, is used, (patent No. 11.) This consists in the mixture of cotton fibre with the rubber used for springs, known as the triple compound. The success of these applications depends, of course, entirely on the composition being suitable to the various purposes to which they are applied ; some being made to resist the effect of heat, others of acids, grease, and oils, the study of which has become an important element in the commercial adaptations of the various inventions enumerated. IV. SoLARIZATION OF CaOUTCHOUC. Singular as caoutchouc is in its properties and in its application, it is probable that, besides the mechanical and electrical qualities and general resistance to chemical action, it may yet be found to have other modifications peculiar and valuable. The practical men most conversant with this substance, and deeply involved with patents and successful manufac- tures, record their conviction of the influence of solar light, and the marked distinctions supposed to exist between the influence of solar and terrestrial heat upon this substance. Mr. Hancock says, “ In my early progress, I found that some of the rubber I employed was very quickly decomposed when exposed to the sun : as the heat was never more than 90°, and rubber exposed to a much higher temperature was not injured by it, I suspected that light had some effect in producing this mischief. To ascertain this, I cut two square pieces from a piece of white rubber ; one of these I colored black, and exposed it to the sun’s rays ; in a short time, the piece which had been left white wasted away, and the sharp angles disappeared ; it seemed like the shape of a thin piece of soap after use ; the blackened piece was not at all altered or affected. The lesson taught me by this experiment was of great value ever after.” Speaking of the annoyances and failures in the early Macintosh goods by heat, grease, &c., Mr. Hancock says, “ The injurious effect of the suit's rays upon thin films of rubber we discovered and provided against before much damage accrued.’” Mr. Goodyear says, “ In anticipation of the future, as relates to a mode of treatment in manufacture, which, though lightly esteemed and little thought of now, I believe will be extensively practised hereafter, I feel bound to make a strong though qualified claim to the process of solarization. This process consists in exposing caoutchouc, when combined with sulphur, to the sun’s rays.” Again, “ When exposed to the sun’s rays for several hours, a change is produced, which may be called natural vulcanization, in all thin fabrics or thin sheets of caoutchouc.” “ Solarization is an effectual and cheap process of curing Indian- rubber.” He further says, “ It is well established that Indian-rubber melted at about 200°, and in the sun’s rays at 100° or less. Another effect yet more remarkable in the treatment of gum elastic, is that of the sun’s rays upon it : when combined with sulphur and exposed to the sun, either in hot weather or cold, it becomes solarized, or divested of its adhesive qual- ity ; whereas, no other kind of light or heat has any similar effect, until the high degree of heat is applied to it, about 270°, which is used in vulcanizing.” — Goodyear^ p. 114, vol. I. New Haven, U. S. V. Trade Applications of Vulcanized Indian-Rubber. Macintosh and Hancock give the following descriptions of their trade quality, to guide practical men ; other manufacturers may also have similar scales of rubber. A quality is the most elastic, it weighs about 60 lbs. per cubic foot, or V29 of a lb. per 302 CAPILLAIKE. cubic inch, (this is understood to mean pure sulphur and caoutchouc, all other qualities are mixtures.) D quality weighs 82 lbs. per cubic foot, or V 21 of a lb. to 1 cubic inch. E quality, more elastic than d, weighs about 92 lbs. to the cubic foot, or Yis of a lb. to 1 cubic inch. F. c. Fibrous compound, used for flange washers, valves, and pump-buckets, weight V 25 of a lb. per cubic inch. Many applications of caoutchouc can only be named. Surgical apparatus, and remedial adaptations for hospital purposes, would alone occupy great space ; to call attention to the various ingenious contrivances, other information and specialities may be referred to the heads of Indian-rubber and vulcanite, or hard rubber, vulcanization, hose-pipes, pontoons, life-preserving apparatus, shoes, water-proof fabrics, washers for joints, valves for engines and pumps, elastic, endless, and driving bands. For hot and cold water valves this sub- stance has been one of the most valuable applications to ocean steamers for many years. The old mode of thread-making is now entirely obsolete, having given way to a new one rendered necessary by the introduction of vulcanized Indian-rubber, which now, for the purpose of thread-cutting, is always produced in the sheet by the spreading process before described, and of a thickness exactly agreeing with the widths of the thread to be cut ; that is, if No. 28 be required, which means, if 28 of the threads were spread side by side they would measure one inch; then the sheet is spread Vas of an inch in thickness, and conse- quently when 28 are cut out of the inch, square threads, i. e. threads with a rectangular section, are produced. The sheets are wound upon rollers, which are then fixed on centres in the lathe, and by means of a slide rest and a suitable knife, slices of the sheet are cut oflf, varying in thickness from */i6 of an inch to Veo of an inch ; and one of the greatest advan- tages of the vulcanized thread is the great length that can be cut ; from, a sheet of rubber wound upon a roller, hundreds of feet or yards may be cut at once into one continuous thread, whereas from the bottles the lengths were short, had to be joined, and differed in quality from each other. Vulcanized thread is covered with silk and cotton ; both are wound round it ; the vul- canized thread is considerably more elastic than the native thread cut from bottles or sheets. Belts and bandages made from the vulcanized thread are very superior to the old sort, now completely obsolete. The vulcanized rubber thread has lately been introduced into the Jacquard loom, by Messrs. Bonnet and Co., Manchester ; the thread used is, by its elastic force, to supersede the use of the weights commonly employed, the number of which sometimes amounts to from two to three thousand in one loom. In preceding editions, the names of Hancock and Goodyear were scarcely mentioned, yet for thirty-six years Mr. Hancock has labored to make a manufacture. For many years Messrs. Hancock and Macintosh were alone in the trade, indeed until Macintosh’s patent ceased, when the trade widened. His first patent was dated 1820, and the masticating machine was the foundation of the manufacture. Mr. Goodyear had his attention drawn to the subject by the manufacture of gum elastic in the United States, about 1831-2. Both have contributed to the literature of the art, (mingled with personal narratives, and trade affairs,) and it is presumed that, had the late Dr. Ure had their practical works before him, eulogistic mention would have been offered for past neglect.* Both gentlemen’s patents are being worked by other men, and of the value of their processes, and the trade, some idea may be entertained when “ The Scientific American ” recently, while opposing the re- newal of the terms for certain patents about to expire, gives the estimate of worth at 2,000,000 dollars for Chauffee’s patents, and Goodyear’s several patents are set at 20,000,- 000 dollars. It is probable that the trade was not a really profitable one in America until about 1850. Of the value of the works in England and France of caoutchouc applications no adequate data appear. Of the facts involved in some of these patents, we may quote Mr. Hancock’s words, p. 106 : “I think I might venture to state, not boastfully, but as a matter of fact, that there is not to this day, 1856, any document extant, (including those referred to in it,) which contains so much information upon the manufacture and vulcaniza- tion of rubber, as is contained in this specification. If any of my readers,” he goes on to say, “ can point out such a document, I shall feel obliged if they will inform me of it.” This is the patent of 1843. C API LL AIRE. Originally a kind of syrup, extracted from maiden-hair. The term is now applied to a finely clarified simple syrup, which is made chiefly with orange-flower water. CAPNOMORE. (C‘“’H*^0^[?].) One of the substances discovered by Reichenbach in * Personal Narrative of the Orifrin and Progress of Caoutchouc or Indian-Eubber manufactured in England, by Thomas Hancock. London, 1857: Longman and Co., 8vo. pp. 283, (plates.) Gum Elastic and its Varieties, with a detailed Account of its Applications and Uses, and of the Dis- covery of Vulcanization ; by Charles Goodyear. New Haven, U. S. Published for the Author, 1853, 2 vols. 8vo. pp. 246, 379, (plates.) CAKBOLIO ACID. 303 wood-tar. It appears to be a product of the metamorphosis of creosote under the influence of heat, or of the alkalies or alkaline earths. It has not been sufficiently examined to allow of its formula being considered as established. The above formula is founded on the anal- ysis of M. Voelckel. When those oils from wood-tar which are heavier than water are treated with a strong potash lye, creosote and capnomore dissolve. Pure capnomore is not soluble in potash, but it appears to dissolve owing to the presence of creosote. When the alkaline solution is distilled, the capnomore comes over. (Voelckel.) It is more probable that the capnomore, instead of dissolving under the influence of the creosote, and subse- quently distilling over with the water, is, in fact, produced by a decomposition of the creo- sote, for I have found that if the latter be long boiled with potash lye, it gradually diminishes in quantity, and finally almost disappears. The density of capnomore is 0’995. It boils between 350” and 400°. This variation of the boiling point is indicative of a mixture. — C. G. W. CAPRYL AMINE. (C^^H^^’N.) A volatile base obtained by Squire, and also by Cahours, by acting on ammonia with iodide of capryle. It is homologous with methylamine, &c. — C. G. W. CAPUT MORTUUM, literally, dead matter ; a term employed by the alchemists to ex- press the residuum of distillation or sublimation, the volatile portions having been driven off. CARAMEL. Burnt or dried sugar, used for coloring spirits and gravies. It is a black, porous, shining substance, soluble in water, to which it imparts a fine dark-brown color. The French are in the habit of dissolving the sugar, after it has been exposed for some time to a temperature sufficiently high to produce the proper color, in lime-water ; this is sold under the name of “ coloring.” CARAT. The term carat is said to be derived from the name of a bean, the produce of a species of erythina^ a native of the district of Shangallas in Africa, a famous gold dust mart. The tree is called kuara^ a word signifying sun in the language of the country, be- cause it bears flowers and fruits of a flame color. As the dry seeds of this pod are always of nearly uniform weight, the savages have used them from time immemorial to weigh gold. The beans were transported into India at an ancient period, and have been long employed there for weighing diamonds. The carat of the civilized world is, however, an imaginary weight, consisting of four nominal grains, a little lighter than four grains troy, (poids de marc.) It requires Y4 carat grains and Vie to equipoise 72 of the other. It is stated that the karat., a weight used in Mecca, was borrowed from the Greeks, and was equal to the 24th of a denarius or denier. The Encyclopedists thus explain the. carat : — “ The weight that expresses the fineness of gold. The whole mass of gold is divided into 24 parts, and as many 24th parts as it con- tains of pure gold it is called gold of so many carats. Thus, gold of twenty-two parts of pure metal is gold of twenty-two carats. The carat of Great Britain is divided into four grains ; among the Germans into 12 parts ; and among the French into 32.” Among as- sayers, even in this country, the German division of the carat is becoming common. CARBOLIC ACID. Syn. Phenic Acid, Phenole, Phenylic Alcohol, Hy- drate of Phenyle.) The less volatile portion of the fluids produced by distillation of coal tar contain considerable quantities of this substance. It may be extracted by agitation of the coal oils (boiling between 300° and 400°) with an alkaline solution. The latter, separated from the undissolved portion, contains the carbolic acid in the state of carbolate of the al- kali. On addition of a mineral acid, the phenole is liberated, and rises to the surface in the form of an oil. To obtain it dry, recourse must be had to digestion with chloride of cal- cium, followed by a new rectification. If required pure, only that portion must be received which boils at 370°. If, instead of extracting the carbolic acid from coal products boiling between 300° and 400°, a portion be selected distilling between 400° and 428°, and the same treatment as before be adopted, the acid which passes over between 347° and 349° will consist, not of carbolic acid, but of its homologue, cresylic acid, Commercial carbolic acid is generally very impure. Some specimens do not contain more than 50 per cent, of acids soluble in strong solution of potash. The insoluble portion contains naph- thaline, fluid hydrocarbons, and small portions of chinoline and lepidine. Carbolic acid, when very pure and dry, is quite solid and colorless. The crystals often remain solid up to 95°, but a trace of water renders them fluid. Its specific gravity is 1'065. Carbolic acid, when mixed with lime and exposed to the air, yields rosolic acid. The lime acquires a rich red color, during the formation of the acid. No means of dyeing reds permanently with this substance have yet been made known. Unfortunately, the red tint appears to require an excess of base to enable it to exist, consequently the carbolic acid of the air destroys the color. {Dr. Angus Smith.) I find that homologues of carbolic acid exist, which boil at a temperature beyond the range of the mercurial thermometer, and that all the acids above carbolic acid afford rosolic acid, or homologues of it, when treated with lime. Creosote of commerce appears to consist of a mixture of carbolic and cresylic acids. If only that por- tion be received which distils at the temperature given by Reichenbach as the boiling point 1 CAEBON". 304 of creosote, it will, if prepared from coal oil, consist almost entirely of cresylic acid. ( Wil- liamson and Fairlie.) A splinter of deal wood, if dipped first in carbolic acid, and then in moderately strong nitric acid, acquires a blue tint. For a comparison of the properties of Creosote and Carbolic Acid, see Creosote. — C. G. \V. CARBON. {Equivalent 6 ; hypothetical density of vapor, 0-8290 ; combining measure one volume.) Carbon exists in a considerable variety of forms, most of which are so unlike each other, that it is not surprising the older chemists should have believed them to be compounds. The purest variety of carbon is the diamond. The latter crystallizes in octo- hedrons and derived forms. The diamond does not owe its hardness and brilliancy solely to its purity, for many specimens of graphite consist of carbon as free from admixture as the best diamonds. The density of graphite and diamond, however, is very different ; for while the former seldom exceeds 2-45, and is often much lower, the diamond is very constant, generally ranging between 3-50 and 3-55. Diamonds, if perfectly transparent, leave scarcely any residue when burnt in oxygen gas. If not clear, they yield from 0-05 to 0-20 of ash, consisting chiefly of peroxide of iron, but also containing traces of silica. The refractive power of diamonds is as high as 2-439. Sir Isaac Newton, observing that oily or inflam- mable bodies generally possessed the greatest refractive powers, inferred from the high in- dex of refraction of the diamond, that it was “ an unctuous body congealed.” This idea will appear the more happy, when it is considered that the ashes of the diamond exhibit a structure resembling that of vegetable parenchyma. In freedom from ashes, certain graph- ites nearly approach the diamond, some natural varieties not yielding more than 0.33 per cent. Graphite . — This kind of carbon is found in many parts of the world, and in different degrees of purity ; it is also formed artificially. Some native varieties are exceedingly soft, of a black or grayish tint, metallic lustre, and, in consequence of making a streak on paper, of various degrees of blackness, according to the mode of preparation and other circumstances, are invaluable for the manufacture of artists’ pencils. See Plumbago. A very hard graphite is found lining the retorts in which coal gas is made : it is, when cut into plates or rods, used in galvanic arrangements, either for the poles or the inactive elements of batteries. Coke . — This variety of carbon is produced by the distillation of pit-coal. The largest quantities are produced in the manufacture of coal gas. It of course varies greatly in qual- ity with the coal from which it is procured. The density of coke varies not only with the quality of the coal, but also with the greater or less rapidity of the firing, and the duration of the operation. From 1-2 to 1-4 is a not uncommon range of density in gas-cokes toler- ably free from ash. I find that a coke of the density 1-223 will have its specific gravity raised to 1-540, if the air in the interstices be removed by placing it in water, under the re- ceiver of the air-pump. Some varieties of coke, such as those produced in the manufacture of gas from bitu- minous shales and cannel coals, leave an aluminous residue almost equal in bulk to the coke itself. Anthracite is a very dense natural variety of carbon, its specific gravity varying from 1-390 to 1-Y. It differs considerably in quality, some kinds being almost as free from ex- traneous matters as graphite, while others approach nearer to the nature of coals. Thus, the hydrogen in anthracite oscillates between 1-0 and 4-0. Some varieties of coal have only 4-5 to 5-0 per cent, of hydrogen, thus approximating to those anthracites which have high hydrogens. Charcoal . — There are several varieties of charcoal : among them may be mentioned those from wood, bones, and the peculiar substance found between the layers of certain pit coals, and known as mineral charcoal. Ordinary charcoal from wood contains many sub- stances besides carbon, among which may be mentioned oxygen, hydrogen, traces of nitro- gen, and ashes. Bone charcoal contains a large quantity of earthy phosphates and carbonates, besides other matters. The mineral charcoal is merely a scientific curiosity. Charcoal is remark- able for its power of absorbing and oxidizing animal and vegetable coloring matters, also for the property it possesses of absorbing gases. The bleaching and disinfecting powers of charcoal appear to depend chiefly on some peculiarity in its structure, enabling it to con- dense oxygen in a manner somewhat resembling platinum black. Animal charcoal is used as a bleaching agent in the form of coarse grains : when once used, it may be partially restored to activity by re-burning ; but, eventually, it becomes worthless for that purpose, and is then only fit for conversion into superphosphate of lime for manure, by the agency of sulphuric acid. Where acid solutions are to be decolorized by animal charcoal, it is necessary before use to remove the earthy phosphates, &c., by digestion with hydrochloric acid. It is essential that the purified charcoal should be washed with a great quantity of water, in order to remove the acid and the salts formed by its action. Advantage has been taken, by Dr. Stenhouse, of the absorbent power of char- coal, in order to prevent danger arising from putrid or offensive vapors. For this purpose OARBON'ATES. 305 he has contrived a charcoal respirator, which fulfils its intended office with remarkable suc- cess. See Charcoal. For a description of the jnethod of preparing the variety of carbon known as Lamp- Black, see Lamp-Black. The description of the charcoal best adapted for pyrotechnic purposes will be found un- der the head Gunpowder. Carbon combines with several elements, forming in general well marked and highly im- portant substances. Several of these compounds will be found under the head of Carbonic Acid. The quantities of charcoal yielded by various kinds of wood have been given by more than one experimenter ; but the results are so widely different that no great value can be attached to them. It is evident that the most extreme care would be required in selecting the various woods and preparing them for anaylsis, if results were desired capable of being employed as standards for reference. Charcoal is extremely indestructible under ordinary circumstances ; it is, therefore, usual to char stakes or piles of wood which are to be em- ployed for supporting buildings, or other erections, in damp situations. It will be seen, from what has already been said, that absolutely pure carbon is scarcely to be met with, even in the diamond. In determining the atomic weight of carbon by com- bustion of the diamond in oxygen, according to the method employed by MM. Dumas and Stas, it was always necessary to determine and allow for the ashes remaining after the com- bustion. The purest charcoal that can be obtained by the calcination of sugar for several hours at the highest temperature of a powerful blast furnace, contains oxygen and hydro- gen, the former to the extent of about per cent., and the latter 0‘2. Carbon, on uniting with sulphur, forms the curious foetid volatile fluid known as bisul- phide or sulphuret of carbon. In constitution it resembles carbonic acid, and it may, in fact, be considered as that gas in which the oxygen is replaced by sulphur. A new gas has been recently described by M. Baudrimont, bearing the same relation to carbonic oxide that bisulphide of carbon does to carbonic acid : its formula, therefore, is C S. When certain hydrocarbons are treated alternately with chlorine and alkalies, substitu- tion compounds are formed, in which the hydrogen in the original substance is replaced by chlorine ; thus olefiant gas (C^H'‘), by this mode of operating, yields C^CF. It is true that this formula might be written, for simplicity’s sake, CCl, but such an expression would be incorrect ; because, in the first place, it would not indicate its relation to the parent sub- stance, and in the next, it would not correspond to tha, at present, almost universally re- ceived axiom, that an equivalent of an organic body is that quantity which is represented by four volumes of vapor. A bromine of carbon exists ; its mode of formation appears to be of a somewhat similar character to the chlorine, for it is sometimes found in commercial bromine, which has been prepared with the agency of ether. See Bromine. It is doubtless formed by the gradual replacement, by bromine, of the hydrogen in the ethyle. — C. G. W. CARBON”, BISULPHIDE OF, (formerly Carburet of Sulphur or Sulphuret of Carbon^ also called by the elder chemists the Alcohol of Sulphur ; a limpid volatile liquid possessing a penetrating foetid smell and an acrid burning taste. Bisulphide of carbon is prepared by distilling, in a porcelain retort, from pyrites, the bi- sulphide (bisulphuret) of iron, with a fourth of its weight of well-dried charcoal, both in a state of fine powder, and intimately mixed. The vapor from the retort is conducted to the bottom of a bottle filled with cold water to condense it. The equivalent of the bisulphide of carbon is 38 ; its formula CS*. The bisulphide of carbon is insoluble in water, but it is soluble in alcohol. It dissolves sulphur, phosphorus, and iodine. The solution of phosphorus in this liquid has been em- ployed for electrotyping very delicate objects, such as grasses, flowers, feathers, &c. Any of these are dipped into the solution : by a short exposure in the air, the bisulphide of car- bon evaporates, and leaves a film of phosphorus on the surfaces ; they are then dipped into nitrate of silver, by which silver is precipitated in an exceedingly minute film, upon which, by the electrotype process, any thickness of silver, gold, or copper can be deposited. If a few drops of the bisulphide of carbon are put into a solution of the cyanide of silver, from which the metal is being deposited by the electrotyping process, it covers the article quite brightly, whereas, without the bisulphide, the precipitated metal would be dull. See Elec- tro-Metallurgy. CARBONATES. By this term is understood the salts formed by the union of carbonic acid with bases. The carbonates are among the most valuable of the salts, whether we regard their physi- cal, geological, chemical, or technical interest. Were limestone and marble the only car- bonates familiarly known, they would be sufficient to stamp this class of salts as among the most important. The carbonates of lime, potash, soda, ammonia, and lead are articles of immense importance to the technologist, and are prepared on a vast scale for various pur- poses in the arts. The carbonates of iron and copper are the most valued ones of those metals. Numerous processes of separation in analysis are founded on the various degrees VoL. III.— 20 306 CARBUNCLE. of solubility in water and certain reagents of the different carbonates. By taking advantage of this fact, baryta, strontia, and lime may be separated from magnesia and the alkalies. There are few analytical problems which have attracted more attention than the accurate determination of the carbonic acid in the carbonates. This has partly arisen from the fre- quency with which the potashes, soda ashes, limestone, and other carbonates of commerce, are sent to chemists for analysis. The number of instruments contrived for the purpose is something extraordinary, especially when the simplicity and ease of the operation are con- sidered. Among them all, there is none more convenient or easy to use than that of Par- nell. “It consists of a glass flask {Jig. 152) of about two ounces’ capacity, fitted with a sound cork, through which two tubes pass, one serving to connect a chloride-of-calcium tube a, while the other, 6, will be described presently. A small test-tube, c, is so placed in the flask, and is of such a size, that it cannot fall down, but its con- tents may be made to flow out by inclining the apparatus to one side. To perform the experi- ment, a weighed quantity of the carbonate is placed in the flask, and water added up to the level seen in the figure ; the test-tube is then filled nearly to the top with concentrated sulphuric acid, and is carefully lowered into the flask ; the cork with the tubes attached is then affixed, the aperture h being closed with a small cork. The whole apparatus is now carefully weighed ; the flask is then to be in- clined so as to allow some of the acid to flow out, and, when the effervescence has subsided, a little more, and so on, until no more carbonic acid is evolved. The flask is now to be so inclined as to cause the whole of the acid to mingle with the aqueous fluid, and thus cause a considerable rise of temperature ; this expels the carbonic acid from the liquid ; but as an atmosphere of the latter gas fills the flask, it must be removed and replaced by air, as the difference in density of the two is very considerable. For this pur- pose, the cork b is removed and air is sucked out of d, until it no longer tastes of carbonic acid ; the flask is then allowed to become perfectly cold, and, the little cork being replaced, it is then re-weighed ; the difference in the two weighings is the amount of carbonic acid in the specimen. On drawing air for some time through the apparatus, it begins slowly to ac- quire weight, arising from the moisture in the atmosphere being absorbed by the chloride of calcium, and although the error introduced by this means is too minute to affect ordinary experiment, it must not be neglected where, from the quantity of material in the flask being limited, or other causes, a small difference has an important bearing on the result. In this latter case another chloride-of-calcium tube is to be attached to the aperture 6, and the air must be drawn through by means of a suction-tube applied at c?.” — C. G. W.’s Chemical Manipidation. The commercial value of the carbonates of potash and soda may equally well be deter- mined by ascertaining the quantity of dilute sulphuric acid required to neutralize them. — C. G. W. CARBUNCLE. A gem much prized by the ancients, and in high repute during the middle ages, from its supposed mysterious power of emitting light in the dark. Benvenuto Cellini affirms, in his treatise on jewellery, that he had seen the carbuncle glowing like a coal with its own light. “ The garnet was, in part, the carbunculus of the ancients, a term probably also applied to the spinel and oriental ruby. The Alabandic carbuncles of Pliny were so called because cut and polished at Alabanda. Hence the name Almandine now in use. Pliny describes vessels of the capacity of a pint formed from carbuncles, ‘ non claros ac plerumque sordidos ac semper fulgoris horridi,’ devoid of lustre and beauty of color, — which probably were large common garnets.” — Dana. CARBURETTED HYDROGEN, or HYDROCARBON. A term used to denote those bodies which consist of carbon and hydrogen only. The number of hydrocarbons now known is very great, and the list is increasing every day. They were very little understood until lately, but so much has now been done that the anomalies and difficulties attending their history are rapidly disappearing. Although the number of individual bodies is, as has been said, very considerable, they are derived from a few great families. The principal are the following : — Homologues of Olefiant gas. “ Methyle. “ Marsh gas. “ Benzole. “ Naphthaline. Isomers of Turpentine. 152 OARBURETTED HYDROGEiq-. 307 The other families which yield hydrocarbon derivatives are less important than the above, and will not be noticed here. It is curious that the destructive distillation of organic matters is, of all operations, the most fruitful source of these bodies. Coal yields a great number, the nature varying with the temperature. When ordinary coals are distilled at very high temperatures, as in the production of gas, hydrocarbons belonging to the first four families are produced, and also a considerable quantity of naphthaline ; but when, on the other hand, they are distilled at as low a heat as is compatible with their thorough decomposition, they yield fluid hydrocarbons, principally belonging to the first two classes, accompanied, however, by a considerable quantity of paraffine. The homologues of olefiant gas have acquired extreme interest, owing to the brilliant results obtained by MM. Berthelot, and De Luca, by Cahours, and Hofmann in the study of their derivatives. The homologues of methyle have attracted considerable attention, in consequence of the successful isolation, by MM. Frankland and Kolbe, of the singular group of hydrocarbons known as the organic radi- cals, and which, until then, were regarded as hypothetical bodies, existing only in combi- nation. The hydrocarbon homologues with benzole not only exist in considerable quantity in ordinary coal naphtha, but are produced in a great variety of interesting reactions. Those at present known are contained in the following Table : — Table of the Physical Properties of the Benzole Series. Name. Formula. Boiling Point. Specific Gravity. Specific Gravity of Vapor, Benzole - - - 176” 0-850 Experiment. 2-77 Theory. 2-699 Toluole - C>^H« 230 0-870 3-26 3-183 Xylole - - - C16H10 259 - - 3-668 Cumole ... 298 - 3-96 4-150 Cymole - C20^JM 347 0-861 4-65 4-636 Benzole has already been sufficiently described, and will not, therefore, be further alluded to. All these hydrocarbons yield a great number of derivatives, when treated with various reagents. By first treating them with strong nitric acid, so as to obtain nitro-compounds, that is to say, the original substance in which an equivalent of hydro- gen is replaced by hyponitric acid (NO^), strongly odorous oils are produced. When treated with sulphide of ammonium or protacetate of iron, these oils become reduced, and yield a very interesting series of volatile organic bases or alkaloids ; these are aniline, toluidine, xylidine, cumidine, and cymidine. Mr. Barlow has shown that special precau- tions are necessary in converting cymole into nitrocymole, preparatory to the formation of the alkaloid cymidine. Cymole is acted on too violently by nitric acid to allow of the nitro-compound, being formed, unless the precaution is taken of cooling the acid and hy- drocarbon, by means of a freezing mixture, before allowing them to react on each other. The nitro-compound when well formed, may be reduced in the ordinary manner. These alkalies have lately acquired special importance in consequence of the valuable dyes that Mr, Perkins has succeeded in producing from them. Paraffine is a solid hydrocarbon of great interest; it is found both in wood and coal tar. When coal is distilled for the purpose of producing gas, the temperature is so high as to be unfavorable for its production, and consequently mere traces only are found in ordinary coal tar. But if any kind of coal be distilled at the lowest possible tempera- ture, not only is the resulting naphtha of much lower density than that produced in the ordinary manner, but considerable quantities of paraffine are found in the distillate. The last-mentioned substance is every day becoming more important, in consequence of the valuable illuminating properties that have been found to belong to it. Colorless, inodor- ous, hard at all moderate temperatures, it forms the most elegant material for candles yet discovered. See Paraffine. Modern researches have shown that the hydrocarbons generally are formed on one type, viz,, hydrogen. Assuming hydrogen in the free state to be a double molecule, HH, the hydrocarbons are formed by the substitution of one or two equivalents of a positive or negative radical for one or two of the equivalents of hydrogen ; thus methyle, the formula of which (for four volumes) is or C^H”, is hydrogen in which both equiva- lents are reflected by methyle. Olefiant gas is hydrogen in which one equivalent is re- placed by the negative radical acetyle, or vinyle, and so on. There is one large class of hydrocarbons the rational formulas for which are not known, and which will probably remain in this condition for some time. We allude to the numerous essential oils isomeric with oil of turpentine. Many of these have almost CARMINE. 308 the same boiling point and precisely the same vapor density as their type ; but in odor, fluidity, density in the liquid state, and various other minor points, are essentially difier- ent. The following Table exhibits some of their physical properties : — Table of the Physical Properties of some Isoiners of Oil of Turpentine. Name. Formula. Boiling Point. Specific Gravity. Specific Gravity of Vapor. Oil of turpentine - 02OJJ16 322 0*864 Experiment. 4*764 Theory. 4*706 “ athanmnta - 325 *4 0*843 . do. “ bergamot C20£16 361*4 0*869 - do. “ birch tar C20H16? 313*0 0*847 5*28 do. Caoutchine • - - C20H1G? 338*0 0*842 4*46 do. Oil of carui, or caruene - C20H16 343*4 - . do. “ lemon - - - C20H10 343*4 0*8514 4*87 do. “ copaiva 473*0 0*878 . do. “ cubebs C-'H'® 490.0 0*929 - do. “ elemi - 345*2 0*849 - do. “ juniper C20_^l^ 320*0 - - do. Terebric oil accompanying oil of gaultheria (^20H16 320*0 . 4*92 do. Terebric oil in clove oil - C20H16 483*8 0*9016 . do. “ “ pepper C20JJ1G 332*0 0*864 4*73 do. “ “ balsam of tolu C20H16 320*0 0*837 . do. “ “ oil of valerian 320*0 - 4*60 do. An inspection of the above Table will show that while, beyond doubt, a great number of essential oils are truly isomeric with turpentine, there are some the constitution of which is by no means well established. The oil of birch tar (used for preparing Russia leather) and caoutchine are by no means sufficiently investigated. The latter is being studied afresh by the author of this article. The above account of some of the more prominent hydrocarbons is necessarily brief and imperfect; partly because the limits of this work preclude the possibility of entering minutely into the details of their history, and partly because many of them are described at greater length in other articles, especially under Naphtha. — C. G. W. CARMINE. {Carrnin., Fr. ; Karminstoff^ Germ.) The coloring matter of the cochi- neal insect. See Cochineal. There are several methods of preparing carmine, the following being the most ap- proved : — Dr. Pereira speaks highly of this process. A decoction of the black cochineal is made in water ; the residue, called carmine grounds., is used by paper-stainers. To the decoction is added a precipitant, usually bichloride of tin. The decoction to which the bichloride of tin has been added is put into a shallow vessel and allowed to rest. Slowly a deposit takes place, which adheres to the sides of the vessel, and the liquid being poured off, it is dried : this precipitate is carmine. The liquid, when concentrated, is called liquid rouge. Carmine is, according to Pelletier and Caventou, a triple compound of the coloring substance and an animal matter contained in cochineal, combined with an acid added to effect the precipitation. The most successful investigator into the coloring matter of the cochineal has been Mr. Warren de la Rue. This chemist had the opportunity of submit- ting the living insect to microscopical examination. He found it to be covered with a white dust, which was likewise observed on the adjacent parts of the cactus leaves on which the animal feeds. This dust, which he considered to be the excrement of the ani- mal, has, under the microscope, the appearance of white curved cylinders of a very uni- form diameter. On removing the powder with ether, and piercing the side of the insect, a purplish-red fluid exudes, which contains red coloring matter, in minute granules assem- bled round a colorless nucleus. These groups seem to float in a colorless fluid, which appears to prove, that whatever may be the function of the coloring matter, it has a dis- tinct and marked form, and does not pervade, as a mere tint, the fluid portion of the insect. To this coloring matter, Mr. De la Rue has given the name of Carminic Acid, which see. There are some remarkable peculiarities about the production of carmine : the shade and character of the color are altered by slight, very slight, differences of the tempera- ture at which it is prepared ; and with every variation in the circumstances of illumina- tion, a change is discovered in the color. Sir H. Davy relates the following anecdote in illustration of this CARNELIAN. 309 “A manufacturer of carmine, who was aware of the superiority of the French color, went to Lyons for the purpose of improving his process, and bargained with a celebrated manufacturer in that city for the acquisition of his secret, for which he was to pay £1,000. He saw all the process, and a beautiful color was produced, but he found not the least difference in the French method and that which had been adopted by himself. He ap- pealed to his instructor, and insisted that he must have kept something concealed. The man assured him that he had not, and invited him to inspect the process a second time. He very minutely examined the water and the materials, which were in every respect similar to his own, and then, very much surprised, he said : — ‘ I have lost both my money and my labor ; for the air of England does not admit of our making good carmine.’ — ‘Stay,’ said the Frenchman, ‘ don’t deceive yourself; what kind of weather is it now ?’ — ‘ A bright sunny day,’ replied the Englishman. ‘ And such are the days,’ replied the Frenchman, ‘ upon which I make my colors ; were I to attempt to manufacture it on a dark and cloudy day, my results would be the same as yours. Let me advise you to make your carmine on sunny days.’” Experiments on this subject have proved that colored precipitates which are brilliant and beautiful when they are precipitated in bright sunshine, are dull, and suffer in their general character, if precipitated in an obscure apartment, or in the dark. CARMINIC ACID. The following is the best method of obtaining, in a state of purity, the coloring principle of cochineal, or carminic acid: The ground cochineal is boiled for about twenty minutes with fifty times its weight of water ; the strained decoc- tion, after being allowed to subside for a quarter of an hour, is decanted off and precipi- tated with a solution of the acetate of protoxide of lead, acidulated with acetic acid, (1 acid to 6 of the salt.) The washed precipitate is decomposed by hydrosulphuric acid, {sulphuretted hydrogen,) the coloring matter precipitated a second time with acidulated acetate of protoxide of lead, and decomposed as before. The solution of carminic acid thus obtained is evaporated to dryness, dissolved in boiling absolute alcohol, dissolved with a portion of carminate of protoxide of lead, which has been reserved, (for the separ- ation of the phosphoric acid,) and then mixed with ether, to precipitate a small portion of nitrogenous matter. This filtrate yields, upon evaporation in vacuo, pure carminic acid. When thus prepared, it is a purple-brown friable mass, transparent when viewed by the microscope, and pulverizable to a fine red powder, soluble in water and in alcohol in all proportions, and very slightly soluble in ether, which does not however precipitate it from its alcoholic solution. It decomposes at temperatures above 136°. The aqueous solution has a feebly acid reaction, and does not absorb oxygen from the air ; alkalies change its color to purple ; in the alcoholic tincture, they produce purple precipitates ; the alkaline earths also produce purple precipitates. Alum gives with the acid a beautiful crimson lake, but only upon the addition of a little ammonia. The acetates of the pro- toxides of lead, copper, zinc, and silver give purple precipitates ; the latter is immediately decomposed and silver deposited. Protochloride and bichloride of tin give no precipi- tates, but change the color to a deep crimson. The analyses of carminic acid led to the formula C^®H^‘‘0’®. The compound of pro- toxide of copper appeared to be the only salt that could be employed with any certainty for the determination of the atomic weight, as the other salts furnished no satisfactory results. The salt of copper was prepared by adding cautiously to an aqueous solution of carminic acid, acidulated with acetic acid, acetate of protoxide of copper, so as to leave an excess of carminic acid in the liquid. When dried it is a brown-colored hard mass. — Liebig and Kopp's Report. CARNELI AN, or CORNELIAN. {Cornaline,'Fr.\ /lomco/. Germ. ; Cm'nalina, ItaX.) A reddish variety of chalcedony, generally of a clear bright tint; it is sometimes of a yellow or brown color, and it passes into common chalcedony through grayish red. Herntz, by his analyses, shows that the color is due to oxide of iron. He found Per Cent. Peroxide of iron 0*050 Alumina 0*081 Magnesia 0*028 Potash 0*0043 Soda 0*075 the remainder being Silica. — Dana. Carnelians are the stones usually employed when engraved for seals. The French give to those carnelians which have the utmost transparency and purity, the name of Cornaline d'ancienne roche. See Agate. The late James Forbes, Esq., long a resident in India, and with ample means of refer- ence to the province of Guzerat, thus describes the locality of the carnelian mines : — “ Carnelians, agates, and the beautifully variegated stones improperly called Mocha Stones, form a valuable part of the trade at Cambay. The best agates and carnelians are found in peculiar strata, thirty feet under the surface of the earth, in a small tract CARRAGEEN. 310 among the Rajepiplee hills on the banks of the Nerbudda; they are not to be met with in any other part of Guzerat, and are generally cut and polished in Cambay. On being taken from their native bed, they are exposed to the heat of the sun for two years : the longer they remain in that situation, the brighter and deeper will be the color of the stone. Fire is sometimes substituted for the solar ray, but with less effect, as the stones frequently crack, and seldom acquire a brilliant lustre. After having undergone this pro- cess, they are boiled for two days, and sent to the manufacturers at Cambay. The agates are of different hues ; those generally called carnelians are dark, white, and red, in shades from the palest yellow to the deepest scarlet. “The variegated stones with landscapes, trees, and water beautifully delineated, are found at Copper-wange, or, more properly, Cubbeer-punge, ‘ The Five Tombs,’ a place sixty miles distant.” — Oriental Memoirs^ vol. i. p. 323, 2d ed. At Neemoudra, a village of the Rajepiplee district, and three miles east, are some celebrated carnelian mines. The country in the immediate vicinity of the mines is but little cultivated ; and on account of the jungles, and their inhabitants the tigers, no human inhabitants are found nearer than Rattumpoor, which is seven miles off. The miners have huts at this place when stones are burned. The carnelian mines are situated in the wildest parts of the jungle, and consist of numerous shafts worked down perpendicularly about 4 feet wide, the deepest about 50 feet. Some extend at the bottom in a horizontal direction, but usually not far, the nature of these pits being such as to prevent their being worked a second year, on account of the heavy rains causing the sides to fall in ; so that new ones must be opened at the con- clusion of every rainy season. The soil is gravelly, and consists chiefly of quartz sand, reddened with iron and a little clay. The nodules weigh from a few ounces to even two or three pounds, and lie close to each other, but for the most part distinct, not being in strata, but scattered through the masses in great abundance. On the spot, the carnelians are mostly of a blackish-olive color, like common dark flints, others somewhat lighter, others still lighter with a milky tinge ; but it is quite un- certain what appearance they will assume after tlmy have undergone the process of burn- ing. From Neemoudra they are carried by the merchants to Cambay, where they are cut, polished, and formed into beautiful ornaments, for which that city is so justly celebrated. — Copeland^ Bombay Researches; Hamilton's Description of Hindostan, 4to. 1820. The stones from Cambay, are offered in commerce, cut and uncut, as roundish pebbles from 1 to 3 inches in diameter. The color of red carnelian of Cambay varies from the palest flesh-color to the deepest blood-red ; the latter being most in demand for seals and trinkets. The white are scarce, but when large and uniform they are valuable ; the yellow and variegated are of little estimation in the Bombay market. The following is a statement of the Carnelians exported by sea from the port of Bom- bay to foreign and Indian stations not subject to the Presidency of Bombay, from 1st May, 1856, to 30th April, 185Y African Coast 20,583 Arabian Gulf 26,157 Ceylon 2,192 China, Hong Kong 946 “ Penang, Singapore, and Straits of Malacca - 3,635 Persian Gulf 7,777 Suez - - - 4,755 East Indian ports of Malabar 400 Total value in rupees, 69,046 ; the rupee being' valued at two shillings. CARRAGEEN. {Chondrus crispus.) Irish Moss. See Alg^. CARRAGEENIN. The mucilaginous constituent of carrageen moss. It is called by some writers vegetable jelly or vegetable mucilage^ by others pectin. “ It appears to me {Pereira) to be a particular modification of mucilage, and I shall therefore call it carra- geenin. It is soluble in boiling water, and its solution forms a precipitate with diacetate of lead, and silicate of potash, and, if sufficiently concentrated, gelatinizes, on cooling. Car- rageenin is distinguished from ordinary gum by its aqueous solution not producing a pre- cipitate on the addition of alcohol, from starch by its not assuming a blue color with tinc- ture of iodine ; from animal jelly, by tincture of nutgalls causing no precipitate ; from pectin, by acetate of lead not throwing down any thing, as well as by no mucic acid being formed by the action of nitric acid.” The composition of carrageenin dried at 212° F., according to Schmidt, is represented by the formula so that it appears to be iden- tical with starch and sugar. Mulder, however, represents it by the formula CARTHAMUS, or SAFFLOWER. The coloring matter of safflower has been exam- ined by Salvetat, who has found much difference in cartharaus of reputed good quality ; a few of his results will suffice : — CARVING BY MACHINERY. 311 1. 2. 3. 4. Water 6-0 11-5 4-5 4-8 Albumen 3-8 4-0 8-0 V7 Yellow coloring matter a - 2'7*0 30*0 30-0 26-1 “ « 6 . . . . 3-0 4-0 6-0 2-1 Extractive matter - - - - - 5-0 4-0 6*0 4-1 Waxy matter 1-0 0-8 1'2 1*5 Carthamine ------ 0*5 0-4 0-4 0-6 Woody fibre 50*4 41*7'7 38-4 66-0 Silica 2-0 1-5 3-5 1-0 Sesquioxide of Iron and Alumina 0-6 0-1 1-6 0-5 “ “ Manganese - 0-1 0-1 0*3 Salvetat has found it advantageous to mix the red of safflower with the pigments used in porcelain painting for purple, carmine, and violet, colors which, in consequence of the difference of their shade before and after firing, are very liable to mislead. To avoid this, he imparts to the pigment, (consisting of flux, gold, purple, and chloride of silver,) by means of the red of carthamus suspended in water, the same shade which he desires to obtain after firing. CARVING BY MACHINERY is an art of comparatively modern date, nearly, if not the whole of the originators and improvers of it, being men of the present day. It is true that the Medallion Lathe and many other appliances for ornamental turning and drilling can claim a much earlier origin, but these can scarcely be called carving machines, and are alto- gether incapable of aiding the economy of producing architectural decorations of any kind. We are not aware of any practical scheme for accomplishing this object prior to the patent of Mr. Joseph Gibbs, in 1829, which we believe was used by Mr. Nash in ornamenting some of the floors of Buckingham Palace, and on many other works of inlaying and tracery. The cutting of ornamental forms in low relief seems to have been the principal object of the inventor ; and this he accomplished satisfactorily by a series of ingenious mechanical arrangements, which greatly reduced the cost, while securing unusual accuracy in this kind of work. Some modifications of machinery for copying busts, bosses, and other works in bold relief are also described in Mr. Gibbs’s patents, but these were never carried into suc- cessful practice. The tracery and inlaying machine is illustrated by Jig. 153, which is a plan of the machine, a is a shaft capable of vertical motion in its bearings, which are in the fixed framing of the machine ; b, c, and d, e, are swing frames jointed together by a 312 CARVING BY MACHINERY. short vertical shaft a, and securely keyed to the shaft a. The point h is the axis of a revolving tool, which is driven by the belts c, c?, e, and the compound pulleys/, A, which increase the speed at each step ; f, g, h, is the table on which the work is fixed ; i, k, the work ; and Z, a templet of brass pierced with the horizontal form of the pattern to be produced in the wood ; this templet is securely fixed on the top of the work, or over it, and the machine is adjusted for action. There is a treadle, not shown in the figure, which enables the workman to lift or de- press the shaft a, and the swing frames and tool attached to it ; he can thus command the vertical position of the tool with his foot, and its horizontal position with his hand by the handles ?«, n, which turn freely on a collar of the swing frame surrounding the mandril or tool-holder. The tool, having been brought over one of the apertures of the templet when in rapid action, is allowed to sink to a proper depth in the wood underneath, and the smooth part of its shaft is then kept in contact with the guiding edges of the templet and passed round and over the entire surface of the figure, until a recess of the exact size and form of that opening in the templet is produced ; this process is repeated for every other open- ing, and thus a series of recesses are formed in the oak flooring planks which correspond* with the design of the templets used. To complete the work, it is requisite to cut out of some darker or differently colored material a number of thin pieces which will fit these recesses, and these are produced in the same way from templets which will fit the various apertures of that first used ; these pieces are next glued into the recesses, and the surface when planed and polished exhibits the pattern in the various colors used. For inlaying it is important that the cutting edge of the tool should travel in the same radius as the cylin- drical shaft, which is kept against the edge of the templet ; but if the tool is a moulded one, a counterpart of its mouldings will be produced in the work, while the pattern, in planes parallel to that of the panel, will have the form of the apertures in the templet used. In this way, by great care in the preparation of the templets and the tools, much of the gothic tracery used in church architecture may be produced, but the process is more appli- cable to Bath stone than to wood when moulded tools are requisite. Mr. Irving’s patents for cutting ornamental forms in wood and stone are identical in principles of action and in all important points of construction with the arrangements pre- viously described. In that of 1843 he particularly claims all combinations for accomplish- ing the purpose, “ provided the swing frame which carries the cutter, and also the table on which the article to be wrought is placed, have both the means of circular motion.” The pierced templet is the guiding power, and the work and templet are fixed on a circular iron table, which is at liberty to revolve on its axis. The swing frame which carries the cutter is single, as in Mr. Gibbs’s curved moulding machine, and its radius so adjusted, that an arc drawn by the tool would pass over the centre of the circular table. The mode of operating with this machine was to keep the shaft of the tool against the guiding edge of the templet, by the joint movements of the table on its centre, and of the swing frame about its shaft ; and it will be obvious that by this means any point of the table could be reached by the tool, and therefore any pattern of moulded work within its range produeed, in the way already described in speaking of Mr. Gibbs’s machinery. But as these modifications of the original idea are not, strictly speaking, carving machines, seeing that they only produced curved mouldings, we need not further describe them. Perhaps the most perfect carving machine which has been made for strictly artistic works is that used by Mr. Cheverton for obtaining his admirable miniature reductions of life-sized statuary; but we can only judge of the perfection of this machine by its work, seeing that the inventor has more faith in secrecy than patents^ and has not made it public. The carving machinery which is best known, and has been most extensively used, is that invented by Mr. Jordan and patented in 1845, since which date it has been in constant operation in producing the carved decorations of the interior of the Houses of Parliament. Its principle of action and its construction is widely different from that above described, and it is capable of copying any carved design which can be produced, so far as that is pos- sible by revolving tools ; the smoothness of surface and sharpness of finish are neither pos- sible nor desirable, because a keen edge guided by a practised hand will not only produce a better finish, but it will accomplish this part of the work at less cost ; the only object of using machinery is to lessen the cost of production, or to save time ; and in appp)roaching towards the finish of a piece of carving, there is a time when further progress of the work on the machine would be more expensive than to finish it by hand. This arises from the necessity of using smaller tools towards the finish of the work to penetrate into its sharp recesses, and the necessarily slow rate at which these cut away the material ; it is conse- quently a matter of commercial calculation, how far it is desirable to finish on the machine, and when to deliver it into the hands of the artist, so as to secure the greatest economy. This depends in a great measure on the hardness of the material ; rosewood, ebony, box, ivory, and statuary marble should be wrought very nearly to a finish ; but lime, deal, and other soft woods should only be roughly pointed. Fig. 154 is a plan of the machine. Jig. 165 a front elevation, and Jig. 156 a side eleva- CARVING BY MACHINERY. 313 tion. The same letters indicate the same part in all the figures. The carving machine con- sists of two distinct parts, each having its own peculiar motions quite independent of the other, but each capable of acting simultaneously and in unison with the other. The first, or horizontal part, is the bed plate “ floating-table,” &c., on which the pattern and work are fixed ; all the motions of this part are horizontal. The second, or vertical part, is that which carries the cutters and tracer, the only motion of which, except the revolution of the tools, is vertical. 154 The horizontal part consists of three castings : The bed plate a, b, c, d, which is a rail- way supported on piers from the floor and fixed strictly level. The carrying frame i, J, k, L, mounted on wheels and travelling on the bed plate, (the long sides of this frame are planed into (v) rails,) and the “ floating-table ” m, n, o, p, which is also mounted on wheels to travel on the rails of the carrying frame. It is called the “floating-table,” because it can be moved in any horizontal direction with almost as much facility as if it were a floating body. Primarily this table has two straight-lined motions at right angles to each other, but by combination of these it may move over any figure in an horizontal plane ; and because this is accomplished without angular motiotl about a centre, every point in the surface of the table moves through the same figure at the same time ; hence the power of producing many copies of a pattern simultaneously. The second, or vertical part of the machine, is a cast-iron bridge supported on columns across the centre of the bed plate ; on the centre of this bridge piece is a wide vertical slide, 5, 6, with a (t) slotted bar on its lower edge ; to this bar the mandril heads or tool- holders, 9, 10, 11, are bolted, at such distances apart as suits the width of the work in hand, and in sueh numbers as it is convenient to work at one time. If the framing of the ma- chine is massive and well fixed, six or eight narrow pieces may be carved at once ; but if the width of the work is equal to half that of the table, only one can be done, as in that case half the table is required for the pattern. The motion of the vertical slide is governed by the workman’s foot on the treadle r, q, s ; at s balance weights are placed, so as to CASE-HARDENINa. 815 adjust the force with which the tools will descend on the work ; any pressure on the foot- board R lifts the slide, and with it the tools and tracing point. Returning to the horizontal part of the machine, o?, e, /, is the pattern or original carving which is to be copied, and A, A:, two copies in progress. The movements of the floating-table are managed by the workman with the hand-wheels u, v ; the left hand, on u, directs the lateral motion on the frame, and the right, on v, directs the longitudinal motion on the bed plate ; the left-hand movement is communicated by the cord x, x, which is fixed to brackets w, w, underneath the table, and makes one turn round a small pulley on the axis of the wheel u. The right-hand movement is communicated by the cord z, which is fastened to each end of the bed plate, and makes one or two turns round the pulley k. When at work the man stands inside the frame of the bed plate, with his right foot on the board r and his hands on the steering wheels ; on releasing the pressure of the foot, the vertical slide descends by its unbalanced weight until the tracer h comes in contact with the pattern ; the cutters m, are made to revolve by steam power at the rate of seven thou- sand times per minute, and are so shaped as to cut like a revolving gouge, so that they instantly cut away all the superfluous material they come in contact with ; and, by the time the tracer has been brought over every part of the pattern, the pieces A, a, k will have become exact copies of it. So far as panel carving is concerned, the whole machine has been described ; but it is requisite to elaborate its construction a little more for the purpose of carving on the round, and copying subjects which require the blocks to be cut into in all possible directions. Various modifications have been used, but we shall only explain that which we think best adapted to ornamental carving. It is not requisite that we should go into the various applications of this machine, to the manufacture of printing blocks, ship’s blocks, gunstocks, letter cutting, tool handling, cabinet shaping, &c., &c., all of which have been shown from time to time to be within its power ; nor is it requisite to describe more recent inventions founded on it, as they will more properly come under other heads. When the machine is intended to copy any form which can be carved by hand, the floating-table is differently constructed, but all other parts remain as before. In the float- ing-table used for this purpose, there is an opening in the centre of the table, and a turning plate, which is mounted a few inches above the level of the table, to turn in bearings in standards. Underneath the turning plate, and forming a part of it, there is an arc of rather more than half a circle, having its centre in the axis on which the plate turns, and this arc is cogged on its edge to fit the threads of the tangent screw on the axis of the wheel, so that by turning this wheel, and dropping its detent into any cog, the workman can fix the plate at any angle with the horizon. There are three chucks fitted into sockets of the turn plate, and these are similarly divided on their edges by holes or cogs, into which detents fall, so as to secure them steadily in any required position. When in use one chuck carries the pattern, and two other chucks the work. The pro- cess of carving is precisely the same as before ; but in consequence of the work and pat- tern being so mounted that it can be turned into every possible position with respect to the cutters, any amount of undercutting which is possible in hand carving is also possible in machine carving. In going through the process the workman will, of course, attack the work when it is placed in a favorable position for the tools to reach a large portion of its surface ; and hav- ing completed as much as possible on that face, he will turn all the chucks through the same number of divisions ; the pattern and work will still have the same relative position to each other as before, but an entirely new face of both will be presented to the tools ; this will be carved in like manner, and then another similar change made, and so on until all has been completed which can be reached without changing the angular position of the turning plate. This can be done by the wheel, and when a sufficient number of these changes have been gone through, the work will be complete on every face, although the block may have re- quired to be pierced through in fifty different directions. — T. B. J. CASE-HARDENING. When case-hardening is required to terminate at any particular part, as a shoulder, the object is left with a band or projection ; the work is allowed to cool without being immersed in water ; the band is turned off, and the work, when hardened in the open fire, is only effected as far as the original cemented surface remains. This inge- nious method was introduced by Mr. Roberts, of Manchester, who considers the success of the case-hardening process to depend on the gentle application of the heat ; and that, by proper management not to overheat the work, it may be made to penetrate three-eighths of an inch in four or five hours. — Holtzapffel. The recent application of prussiate (fcrrocyanate) of potash to this purpose is a very interesting chemical problem. The piece of iron, after being polished, is to be made brightly red-hot, and then rubbed or sprinkled over with the above salt in fine powder, upon the part intended to be hardened. The prussiate being decomposed, and apparently dissi- pated, the iron is to be quenched in cold water. If the process has been well managed, the surface of the metal will have become so hard as to resist the file. Others propose to smear 816 CASK. over the surface of the iron with loam made into a thin paste with a strong solution of the prussiate, to dry it slowly, then expose the whole to a nearly white heat, and finally plunge the iron into cold water, when the heat has fallen to dull redness. See Steel. CASK. {Tonneau, Fr. ; Fass, Germ.) Much ingenuity has been displayed in cutting the curvilinear and bevelled edges of the staves of casks by circular saws. Sir John Robinson proposed many years back that the stave should be bent to its true curve against a curved bed, and that while thus restrained its edges should be cut by two saws s s, placed in radii to the circle, the true direction of the joint as shown by the dotted circle Jig. 15Y, representing the head of the cask. Mr. Smart cuts the edges of thin staves for small casks on the ordinary saw-bench, by fixing the thin wood by two staples or hooks to a curved block, the lower face of which is bevelled to give the proper chamfer to the edges. Jig. 158. One edge having been cut, the stave is released, changed end for end, and refixed against two pins which determine the position for cutting the second edge, and make the staves of one common width. The curved and bevelled block is guided by two pins pp, which enter a straight groove in the bench parallel with the saws. This mode of bending is from various reasons found inappli- cable to large staves, and these are cut, as shown in three views, Jig. 159, whilst attached 158 159 157 to a straight bed, the bottom of which is also bevelled to tilt the stave for chamfering the edge. To give the curve suitable to the edge, the two pins on the under side of the &ock run in two curved grooves g g in the saw-bench, which cause the staves to sweep past the saw in the arc of a very large circle, instead of in a right line, so that the ends are cut narrower than the middle. Mr. Smart observes {Trans. Soc. of Arts, vol. xlvii.) that in staves cut whilst straight, the edges become chamfered at the same angle throughout, which although theoretically wrong is sufficiently near for practice ; the error is avoided when the staves are cut whilst bent to their true curvature. The necessary flexibility which is required for bending the staves of casks is obtained by steaming them in suitable vessels in contact with rigid moulds. By Taylor’s patent ma- chinery for making casks, the blocks intended for the staves are cut, out of white Canada oak, to the size of thirty inches by five, and smaller. They are well steamed, and then sliced into pieces one-half or five-eighths of an inch thick, at the rate of 200 a minute, by a process far more rapid and economical than sawing, the instrument being a revolving iron plate, of 12 or 14 feet diameter, with two radical knives arranged somewhat like the irons of an ordinary plane or spokeshave. CASSAREEP or CASSIREEPE. The concentrated juice of the roots of the bitter , cassava flavored by aromatics. It is used to flavor soups, and other dishes, and is the basis of the West Indian dish pepper-pot. In French Guiana, the term cahion is applied to a similar condiment. — Pereira. CASSITERITE. Oxide of Tin ; Stream Tin. Stream Tin is the alluvial debris of tin veins. (See Tin Ore.) This is one of the very objectionable names, of which a very great number have, of late years, been introduced into the science of Mineralogy. CASSIUS, purple powder of. Professor Graham, in his “ Elements of Chemistry,” gives that following account of the purple of cassius, and of its preparation : “ When protochloride of tin is added to a dilute solution of gold, a purple powder falls. It is obtained of a finer tint when protochloride of tin is added to a solution of the sesquichlo- ride of iron till the color of the liquid takes a shade of green, and the liquid in that state added, drop by drop, to a solution of sesquichloride of gold free from nitric acid, and very dilute. After 24 hours a brown powder is deposited, which is slightly transparent, and purple-red, by transmitted light : when dried and rubtied to powder, it is of a dull blue color. Heated to redness it loses a little water but no oxygen, and retains its former appearance. If washed with ammonia, on the filter, while still moist, it dissolves, and a purple liquid passes, which rivals the hypermanganate of potash in beauty It may also be formed by fusing together 2 parts of gold, 3^ parts of tin, and, 16 parts of silver, under borax, to prevent the oxidation of the tin, and treating the alloy with nitric acid, to dissolve out the silver ; a purple residue is left, containing the tin and gold that were employed.” • CEDAE. 317 “ Berzelius proposed the theory that the powder of Cassius may contain the true prot- oxide of gold combined with sesquioxide of tin, AuOSn'^O^, a kind of combination contain- ing an association of three atoms of metal, which is exemplified in black oxide of iron, spinele, Franklinite, and other minerals A glance at its formula shows how readily the powder of Cassius, as thus represented, may pass into gold and binoxide of tin, Au0Sn'^0^=Au-[-2Sn02.” — Graham and Watts. CASTORINE, A substance existing in castoreum. Its chemical formula is not known, and its entire history requires to be freshly investigated. It is obtained by treating the secretion of the castors with hot alcohol, and filtering through a Platamour’s ebullition funnel. On cooling, the alcohol deposits crystals of a fatty substance. The castorine is retained in the mother liquor, and is procured by evaporation on the water-bath to a small bulk, and then setting aside to allow crystals to form. Castorine crystallizes in needles possessing a slight odor of castoreum. — C. G. W. CASTOR OIL. The expressed oil of the seeds of the Palma Chrisii or Ricinus com- munis^ a native tree of the West Indies and South America ; but which has been cultivated in France, Italy, and Spain. In England the castor oil is expressed from the seeds by means of powerful hydraulic presses fixed in rooms artificially heated. It is purified by repose, decantation, and filtra- tion, being bleached in pale-colored Winchester quart bottles which are exposed to light on the tops of houses. Unbleached castor oil is certainly more acrid and possesses more pur- gative properties than such as has been long exposed to the light ; we may therefore infer that the acrid resin of the oil has undergone some chemical change. In America the oil is expressed from the seeds by pressure between heated plates. In the East Indies, women shell the fruit ; the seeds are placed between rollers and crushed ; they are then put into hemp cloths, and pressed in the hydraulic press. The oil thus procured is afterwards heated with water in a tin boiler, until the water boils, by which the mucilage or albumen is sepa- rated as a scum. The East Indian castor oil is sold in England as cold drawn. The follow- ing is the composition of castor oil : — ' Ure. Saussure. Carbon 74-00 74*178 Hydrogen 10*29 10*034 Oxygen 15*71 14*718 100*000 100*000 CATALYSIS. A term introduced to denote the very peculiar phenomenon of one body establishing, by its mere presence, a like condition in another body to that which exists in itself. Thus a piece of meat undergoing the putrefactive fermentation, almost immediately sets up a similar action in fresh meat, or produces in a saccharine fluid that motion which is known as vinous fermentation. The action of the yeast plant, — a living organization, — establishes an action throughout a large quantity of an infusion of fermentation^ or that disturbance which leads to the conversion of sugar into alcohol. This catalytic power is ill understood, and we are content to hide the imperfection of our knowledge under a sounding name. CATECHINE. Catechuic Arid. When Gamhir catechu is treated with water, an insoluble residue is left, which has been termed by Nees resinous tannin. Its composition is C‘^H®0®. CAT’S EYE. A translucent quartz, presenting peculiar internal reflections. This effect is said to be owing to filaments of asbestos. When cut en cahochon.^ it is esteemed as an ornamental stone. CEDAR. {Cedre., Fr. ; Ceder., Germ.) The cedar of Lebanon, or great cedar, {Pinus cedrns,) is a cone-bearing tree. This tree has been famous since the days of Solomon, who used it in the construction of the temple. The wood has been obtained from Crete and Africa. Specimens have also been procured from Morocco, showing the probability that the range of the tree not only extends over the whole group of mountains which is situate between Damascus and Tripoli in Syria, and which includes the Libanus and Mounts Ama- nus and Taurus of antiquity, and various others, — but that its distribution on the moun- tainous regions of North Africa is extensive. Indeed, if we are to suppose that the cedar and the cedar wood mentioned by many of the ancient writers referred exclusively to the Lebanon species, we must believe that its distribution at one period extended over countries where no trace of its having existed now remains. Egypt, Crete and Cyprus are mentioned by Pliny and Theophrastus as native habitats of the cedrus ; we may thus fairly infer that the cedrus of the ancients as fre- quently had reference to the other coniferae as to the Lebanon species. The pencil cedar is the Juniperus Virginiana. It is imported from America in pieces from 6 to 10 inches square. The grain of the wood is remarkably regular and soft, on which account principally it is used for the manufacture of pencils, and from its agreeable scent for the inside of small cabinets ; it is also made into matches for the drawing room. 318 CEDEIRET. The general use of the cedar wood dates from the highest antiquity. Pliny makes men- tion of cedar wood and the uses to which it was applied, and cites, as examples of its dura- bility and imperishable nature, the timber of a temple of Apollo at Utica, in Africa, which, when nearly 2,000 years old, was found to be perfectly sound, — and the famous statue of Diana in the temple of Saguntum in Spain. Cedria, an oil or resin extracted from a cedar, was also, according to Vitruvius, used to smear over the leaves of the papyrus to prevent the attacks of worms ; and Pliny states that the Egyptians applied it with other drugs in the preparation of their mummies ; but whether this extract was obtained from the Leba- non cedar or from trees belonging to the genus Ctipresms or Juniperus^ which also afford odoriferous resins, it is now impossible to ascei’tain. In regard to the cedar and cedar wood mentioned in profane history, it is difficult, from what we have already stated, to determine what has reference to the true cedar, and what belongs to other coniferous species; all that we can know for certainty is that a wood called cedar, distinguished for its incorruptible nature, was frequently used for purposes most important in the eyes of the pagan, viz., in the building and decoration of their temples, and for the statues or images of their heroes and gods. The peculiar balsamic odor of cedar has long been held as a means to preserve articles from the attacks of insects ; chips and shavings of the wood have been in this way kept in collections of linen, papers, and objects of preservation. Cabinets have been recommended, or at least the drawers and fittings, to be made of cedar. That the popular character may receive its due limitation, it may be useful to call attention to some facts when cedar is em- ployed as a means of preservation. That the odoriferous substance when diffused may affect some forms of organic life, is not disputed, but it is as probable some of the effect may be due to covering the insect with a coating of varnish, alike irritating and interfering with the texture of the surfaces of the body ; but the rule cannot be general ; if the creatures have a sufficient hardihood they may, and indeed do, attack the wood itself. The following cases will show that the substances emanating from cedar may produce unexpected interference. Mr. Yulliamy states that George III. had a cabinet in the obser- vatory at Kew with drawers of cedar wood in them ; watches were placed with the inten- tion of keeping them going. In a short time they all came to rest ; the experiment, how- ever, repeated, had the same result ; on examination, the oil used in different parts of the watches was found to be completely changed into a substance like gum. Mr. Farey’s obser- vations, also communicated to the Institution of Civil Engineers, still more show the extraordinary atmosphere produced in close cabinets of cedar wood, and of the effects upon delicate objects. The late Mr. Smith, of Derby, having shown him a small collection of minerals which had been locked up in closely fitted drawers of cedar wood ; on opening the drawers for the first time after some months, the minerals were found to be covered with a gummy matter having the sti’ong odor of cedar, and troublesome to remove ; the bright surface of the crystals appeared as if varnished in an unskilful manner. The ced^r had given off a vapor that had condensed on all the minerals, and the same effect might be expected to be produced upon watches, metals, and other substances. Indeed, cases are known where the action of cedar has produced unpleasant effects, and not without exciting the idea of remote danger. A bundle or package of black lead pen- cils, the wood as usual of cedar, had been kept in stock upon a shelf, wrapped in paper : by the heat of the gas, &c., the cedar vapor had attacked the paper and its materials ; the paper seemed thick and stiffened as with varnish, forming one mass with the pencils, and damaging other paper and articles of stock near, while the paper was rendered highly inflammable, burning with a great flame. This case was laid before the officers of the So- ciety of Arts, who are desirous of extending the proper uses of cedar wood, and of avoid- ing the evils arising from unsuspected chemical action. — T. J. P. CEDRIRET. A singular compound of unknown composition existing in wood-tar. When crude creosote is dissolved in potash and acetic acid is added, creosote separates. If the creosote be decanted and the solution of acetate of potash be distilled, a fluid is obtained at a certain epoch of the distillation, which, when dropped into persulphate of iron, forms a network of crystals. This is cedriret. It has not yet been observed in coal naphtha. CELESTINE. {Strontiane sulfatee^ Fr. ; Colesfris, Germ.) Celestine is usually asso- ciated with secondary or Silurian limestone or sandstone, also with trap-rocks ; and it is found in the red marl formations associated with gypsum. In Sicily it is commonly asso- ciated with sulphur. The celestine of Girgenti was found by Stromeyer to be composed as follows : — Sulphuric acid 43 '08 Strontian 56’35 Red oxide of iron - 0*03 Carbonate of lime 0*09 Water 0*18 CHARCOAL. 319 This mineral is found in Sicily, at Bey in Switzerland and Corril in Spain. It exists at Aust Ferry near Bristol, in trap-rocks near Tantellan in the East Lothians, and at Calton Hill, Edinburgh. Dana gives several localities for celestine in America. It is decomposed by ignition with charcoal into sulphide of strontia, which is converted into the nitrate by the action of nitric acid. CEMENTS. (^Giment/t, Fr. ; Cdmente, Kitte, Germ.) Substances which are capable of assuming the liquid form and of being applied between the surfaces of bodies so as to unite them firmly when solidifying. They are of very varied character. Gum, glue, and paste are cements, the uses of which are well known. Sir John Robinson’s cement he thus describes : — “ If it be wished to dissolve good isinglass in spirits of wine, it should first be allowed to soak for some time in cold water, when swelled it is to be ^ put into the spirit, and the bottle containing it being set in a pan of cold water may be brought to the boiling point, when the isinglass will melt into a uniform jelly, without lumps or strings, which it is apt to have if not swelled in cold water previously to being put into spirits. A small addition of any essential oil diminishes its tendency to become mouldy. “ If gelatine, which has been swelled in cold water, be immersed in linseed oil and heated, it dissolves, and forms a glue of remarkable tenacity, which, when once dry, per- fectly resists damp, and two pieces of wood joined by it will separate anywhere else rather than at the joint. Ordinary glue may be thus dissolved, and sometimes a small quantity of red lead in powder is added.” Lapidaries’ cement is made of resin, tempered with beeswax and a little tallow, and hardened with red ochre or Spanish brown and whiting. Opticians’ cement, for fixing glasses for grinding, is made by sifted wood ashes with melted pitch, the essential oil of which is absorbed by the wood ashes, and the adhesiveness of the pitch is therefore reduced. The proportions are somewhat dependent on the tem- perature of the weather and the qualities of the pitch ; but generally about 4 lbs. of wood asl>es to 14 lbs. of pitch are employed, and the cement, if too hard and brittle, is softened with hog’s lard and tallow. Japanese cement is said to be prepared by mixing rice flour intimately with cold water, and then boiling the mixture : it is white, and dries nearly transparent. See Mortar. CEYLON MOSS. {Plocaria Candida.) See Alg^. CHALLIS. About the year 1832 this article was introduced, certainly the neatest, best, and most elegant silk and worsted article ever manufactured. It was made on a simi- lar principle to the Norwich crape, only thinner and softer, composed of much finer mate- rials ; and instead of a glossy surface, as in Norwich crapes, the object was to produce it without gloss, and very pliable and clothy. The best quality of challis, when finished with designs and figures, (either produced in the loom or printed,) was truly a splendid fabric, which commanded the attention of the higher circles, and became a favorite article of apparel at their fashionable resorts and parties. The worsted yarn for the weft of this article was spun at Bradford, from numbers 52’s to 64’s. The making of the challis fabric soon afterwards commenced in the north. — James's History of Woollen Manufacture. CHALCEDONY. A hard mineral of the quartz family, often cut into seals. Under it may be grouped common chalcedony, heliotrope, chrysoprase, plasma, agate, belonging to the rhombohedral system, onyx, cat’s eye, sardonyx, carnelian, and sard. CHAMOMILE FLOWERS. The Anthemis nohilis of Linnaeus. The chamomile grows very abundantly in Cornwall, and some other parts of England. It is cultivated at Mitcham and in Derbyshire, for the London market. The chamomile is used medicinally, and is em- ployed by some brewers to substitute hops in bitter beer. It would be well if no more objectionable bitter were employed. In 1856 we imported 72,751 lbs. CHARCOAL. The fixed residuum of vegetables when they are exposed to ignition out of contact of air. For the purpose of showing, within a limited space, the products of dry distillation OF WOOD, the following list has been compiled for this work by the kindness of a friend engaged in those manufactures. For more specific information, see Destructive Dis- tillation, and the articles enumerated under their special heads. The only products of the dry distillation of wood at present of any commercial im- portance, are charcoal, acetic acid, naphtha, and, in a minor degree, tar and creosote. The products of wood are, however, very numerous, and, when examined chemically, found to be very complex in character and constitution, many of them being very little understood. They are gaseous, liquid, and solid. The gaseous products are those not condensible by ordinary means, viz. : — Carbonic oxide. Carbonic acid. Light carburetted hydrogen, or marsh gas. Olefiant gas. -f- 820 CHEESE. These are usually employed (such as are combustible) for heating purposes in the manufactories where found. The liquid products are water, containing from 6% to 10% of dry acetic acid, am- monia, and, associated with them under the ordinary names of tar and naphtha, numerous oily, ethereal, and resinous bodies. The following list will comprehend the greater number of these bodies : — Water. Acetic acid in its crude state, called pyroligneous acid. Ammonia. Ordinary naphtha, or pyroligneous spirit. Hydrate of methyle^ syn. with spirit of wood and Acetate of methyle^ or methyle acetic aether. Acetone^ syn. with pyroacetic spirit. methylic alcohol. ) Benzole, Toluole, Xylole, Cumole, Cymole. f According to the researches of Cahours these are all hydro- I carbons, and separated by him from crude spirit of wood. From the distillation of tar are obtained, besides many of the foregoing, which would come under the name of “ light oilsf from their low specific gravity : Oils heavier than water., besides residuary resin or pitch — Xylite. Picamar. Paraffine. Mesite. Cedrirete. Resin or pitch. Capnomore. Pittacal. Solid Products : Pyroxanthine, Charcoal. — C. H. B. H. CHEESE {composition of ) : — Water. Ash of the substance. Nitrogen. Fat. Normal. Dry. Normal. Dry. Free from ash. Normal. Dry. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Cheese from Chester 30-39 4-78 G-88 5-56 8-00 8-59 25-48 36-61 Parmesan 30-31 7-09 10-18 5-48 7-87 8-76 21-68 31-12 (C Neufchatel Gl-87 4-25 11-17 2-28 6-99 6-07 18-74 49-15 (( Brie 53-99 5-63 12-08 2-39 5-14 6-85 24-83 53-29 ii u Holland 41-41 6-21 10-61 4-10 7-01 7-84 25-06 42-78 u Gruyere 32-05 4-79 7-05 5-40 7-96 8-56 28-40 41-81 Payen Journal Pharma. CHEMICAL FORMULH5. The term formula, in ordinary chemical language, is always understood to mean the collection of symbols indicating a compound substance. Thus, if we allude to the letter or letters indicating an element, we say its symbol ; but if we are speaking of a compound, we say its formula. The symbols of all the elements will be found under the head of “Elements,” vol. i. In constructing formulae there are several rules to be observed, the neglect of which will lead to misapprehension of the meaning in- tended to be conveyed. Substances in the most intimate union are expressed by placing the symbols in juxta-position. Thus, oxide of lead is represented by PbO, dry sulphuric acid by SO^, acetic acid by C^H^O^ But where a compound is to be expressed which is itself formed by the union of two compounds of the class first mentioned, such as an acid and a base, a comma is placed between them thus ; Sulphate of lead is PbO,SO®, nitrate of copper CuO,NO^. The number of atoms, when more than one enters into a compound, is expressed by writing the number on the upper part of the right hand of the element. But if only one atom is to be expressed, the mere symbol is written. Thus, oxide of copper is CuO, but the sub-oxide is Cu'^O. If it be intended to multiply a formula not containing a comma or other sign, such as SO^, C^H^O'*, &c., the number is to be written on the left hand of the formula, and is to be made larger than would be the case if it merely multiplied the atoms of an element. Thus, two atoms of oxide of lead are written 2PbO, three atoms of acetic acid, 3C^H'^0^ But it is to be remembered that a number placed on the left hand of a symbol or formula only multiplies as far as the first comma or sign, so that, if we wish to multiply a formula containing a comma or other sign, the formula must be placed between parentheses. Thus, two atoms of sulphate of lead are written 2(PbO,SO®). If it be intended to express the fact that one substance is to be added to another, with a view to the production of a given compound or reaction, the substances to be added together are connected by a plus sign. For example, suppose it be necessary to express the fact that one equivalent of oxide of lead added to one equivalent of sulphuric acid produces sulphate CHEMICAL FORMULAE. 821 of lead, we write, PbO -j- SO® forms sulphate of lead. But it is more usual and brief to put down the terms connected by the plus sign, followed by the sign of equality, and then the formula of the resulting compound, thus : — PbO -j- SO® = PbO,SO®. A collection of symbols expressing the nature of a reaction or decomposition, the two terms being united by the symbol of equality, is called an equation. Equations are of the highest value to the chemist, as enabling him to express in the simplest possible manner the most complicated reactions. Moreover, these equations enable us to see at a glance the true nature of a de- composition. To take a simple case, namely, that of the decomposition of terchloride of antimony by carbonate of ammonia, we have SbCl® -f 3 (NH^O,CO®) = SbO® -f SNH^Cl + SCO®. Or, in words, terchloride of antimony plus three equivalents of carbonate of ammonia, yields one equivalent of teroxide of antimony, three equivalents of chloride of ammonium, and three equivalents of carbonic acid. The above illustrations will suffice to show the principles upon which formulae and equations expressive of chemical decompositions are constructed. In writing equations showing the metamorphoses of substances with which it may be supposed the reader of them may not be very fully acquainted, it is proper to place beneath them the names of the substances in full ; thus, in writing the change supposed to be experienced by amygdaline under the influence of a ferment which does not itself contribute any substance to the reac- tion, we might say : — -f 4HO = -f- C®NH -f- 2C'®H'®0'® Amygdaline. Bitter al- Prussic Grape sugar. mond oil. acid. In writing the formulae of substitution compounds, it is convenient to place the replaced and replacing substances in a vertical line, so as at a glance to indicate the substitution which has taken place. As an illustration, we shall place side by side the chemical type ammonia and some bodies derived from it by substitution. ( H ( C®H® ( C®H® n4h N-^ h N-^C®H® (H ( H ( H (C®H® N \ C®H® ( C®H® N^ H (pt 3 (C®H® P \ C®H® ( C®H® Ammonia. Methylamine. Bimethy- lamine. Trimethy- lainine. Aniline. Platina- mine. Triphosphme- thylamine. In the first of the above formulae we have the type or starting point, ammonia itself. In the next we find one atom of hydrogen (two volumes) replaced by one atom (two volumes) of the radical methyle. In the third we find two atoms of hydrogen replaced ; and in the fourth illustration all three have been replaced by methyle. The fifth formula is that of ammonia, in which one equivalent of hydrogen is replaced by phenyle, forming phenyla- mine, or, as it is more usually termed, aniline. The sixth illustrates a very peculiar substitu- tion. In it we find two atoms of hydrogen replaced by the platinicum of the late illustrious chemist, M. Gerhardt, who regards platinum as entering into substitutions with two atomic weights, as if it were two metals. The one being the platinum of chemists generally, its atomic weight being 99, (and its symbol Pt ;) this he calls platinosum. The other being platinicum, (pt,) with an atomic weight half that of platinosum, namely, 49'5. The last formula is that of the singular base, triphosphmethylamine. In it we see the nitrogen of the original type replaced by phosphorus, and each equivalent of hydrogen by methyle. It is a fruitful source of annoyance to students and others to find, on looking through chemical works, the same substance represented by different authors with totally different formulae. We shall endeavor to give a few instances and such explanations as will assist in enabling the student to overcome the difficulty. It is often the case that the differences in the formulae arise from the works consulted having been written at different dates ; the older one is then, in most cases, to be rejected, because it is probable that the formulae in it have been corrected by subsequent and more accurate researches. It not unfrequently happens that an author writes nitrous acid NO*, and the true nitrous acid (NO®) is called hyponitrous acid. It may serve to assist the student in correcting any errors on this point, to consult a list of the oxides of nitrogen according to the nomenclature at present em- ployed ; for which, see some standard work on chemistry. A still more common cause of difficulty is owing to the different theoretical views of chemists regarding the constitution of chemical substances. The papers of MM. Laurent and Gerhardt, and the more advanced of their followers, are at times almost unintelligible to the beginner, owing to their adoption of different atomic weights to those employed in this country. Whatever opinion may be held by individuals respecting the necessity for the changes adopted by them, it must be re- membered that the arguments in favor of their doctrines are in general of the most weighty kind ; and, moreover, that chemical reactions can often be explained and generalized when VoL. III.— 21 622 CHEMICAL FOKMUL^. seen through the medium of their theoretical views, which present exceedingly embarrassing points if viewed under the old system. It will serve, to a great extent, to remove the diffi- culties alluded to, if it be remembered that, in order to pass from the ordinary atomic weights used in this work to those employed by M. Gerhardt, it is merely necessary to double the atomic weights of carbon, oxygen, sulphur, and selenium, while the hydrogen, nitrogen, phosphorous metals, chlorine, bromine, iodine, and fluorine remain unaltered. Some of the more advanced chemists of the present day write carbonic acid instead of CO^. This is in consequence of their regarding it as a bibasic instead of a monobasic acid. The same thing applies to sulphuric acid. It is also to be remembered that most modern chemists assume organic bodies to undergo a condensation to four volumes ; conse- quently, ether becomes instead of C‘‘H®0. The same remark applies to many other substances. Bodies that cannot have their vapor relations properly studied, in conse- quence of their not being volatile without decomposition, are often written in two or three different ways by various authors. It is probable that these anomalies will, for a time, in- crease rather than diminish, because recent discoveries are constantly showing the inade- quacy of the older views of the chemical constitution of bodies to explain the reactions that occur. It will greatly assist the student in his endeavors to recollect chemical formulae, if he commits to memory the principal types and the substances which are regarded as formed on their model. The following are those which are best established : — Type, two atoms of water . — This type is written in such a manner that the replacement of the hydrogen can be distinctly seen. By its side are placed a few of the substances formed on the same model. Two atoms of water. Acetic acid. Alcohol. Ether.* Hydrate of potash. Anhydrous potash. 0,|cW 5 ^ In the above simple illustrations of the type water we have, in the case of acetic acid, one atom of hydrogen replaced by the oxidized radical acetyle and the other by one atom of basic hydrogen. By basic hydrogen is meant, that it acts the part of, and can be re- placed by, a metal. The opinions of chemists with regard to the nature of the radical exist- ing in acetic acid are divided. Some consider the acid as the hydrated teroxide of the non- oxidized radical acetyle, and therefore write its formula -{- HO. But as the chloride of the oxidized radical can be isolated, we cannot doubt its existence. Moreover, there is no doubt of the existence of the other radical, C‘'H®, because we find it replacing hydrogen in the base acetylamine. But the conclusion must be drawn from these facts that there are two radicals, one existing in acetic acid, which Williamson calls othyle ; and another, sometimes called vinyle, C^H®, which exists in aldehyde, in olefiant gas, and several other bodies. The radical in acetic acid is, consequently^ not C^H®, but The next illustration is that of alcohol, which consists of two atoms of water, in which one atom of hydrogen is replaced by ethyle, and the other by hydrogen. Ether, on the other hand, is derived from the same type, both atoms of basic hydrogen being replaced by ethyle. Hydrate of potash and anhydrous potash will, after what has been said, explain themselves. It will be seen that in all these illustrations, the same vapor volume is pre- served, and by this means the exceeding anomaly of ether and alcohol being of different vapor volumes is removed. While the type two atoms of water (=4 volumes) has an ac- tual existence, it remains for chemists to discover whether we are justified in receiving as types bodies which have no real existence, such as three atoms of water. Type, two atoms of hydrogen . — The type ammonia has already been sufficiently illus- trated ; it remains, then, only to show what substances are to be regarded as formed on the type hydrogen. M. Gerhardt, in addition to these, adopts hydrochloric acid as a type ; but when we consider that that acid is itself formed on the hydrogen model, it appears unneces- sary to raise it to the dignity of a separate type. Two atoms of Olefiant Marsh Hydrochloric Prussic Chloride hydrogen. gas. gas. acid. Benzole. acid. of ethyle. H C'H^ C"H® Cl C'“H* C’N H H H H H H Cl The above will be sufficiently plain after what has been said, it being remembered that C'^H^ is methyle, C^H® ethyle, C^^H® phenyle, and C^N cyanogen. It is sometimes a source of perplexity to the beginner to find that the formulae of salts are written by different authors in a somewhat different manner. Thus, sulphate of potash * For the typical representation of the mixed and composed ethers, see the article Ether. CHEMICAL FOKMUL^. 823 will, by one, be written SO^,KO, and by another SO^K. The reason of this will become plain from the following considerations : — All salts are derived from acids by the substitu- tion of metals for hydrogen. Thus, if instead of writing sulphuric acid SO^,HO we write SO^H, we shall at once see that sulphate of potash, SO^K, is sulphuric acid in which one equivalent of hydrogen is replaced by potassium. It is true that the relation between acids and salts may be more completely seen by using a different class of formulae, founded on the theory of types ; but, nevertheless, the above illustrations will serve to explain why one person will write acetate of potash ^ ^ ’ another ^ ^ ^ ^ third C‘H®0^,K0, and perhaps a fourth C^H®0^,K0^ On the modes of determining the empirical and rational formulae of substances from the results of their analysis. — It now remains to show how the formulae of bodies are deter- mined. There are two kinds of formulae — the empirical and rational. An empirical for- mula merely indicates the simplest ratio existing between the elements present ; a rational formula shows the absolute constitution of an atom or equivalent of any substance. Some- times the expression rational formula is used in a more extended sense, and then signifies the actual manner in which the elements are arranged in a compound molecule, but this happens so seldom, that we shall in this work understand the term in the sense first given. An empirical formula can always be deduced from the mere result of an accurate analy- sis. A rational formula, on the other hand, demands a knowledge of the atomic weight of the substance. The latter datum can be best determined — 1st, by the analysis of a com- pound with a substance the atomic weight of which is well established ; 2d, by determining the density of its vapor. Empirical formulae. — The percentage composition of a compound having been accu- rately found, the empirical formula may be deduced from the following rule : — Divide the percentage of each constituent by its atomic weight, and reduce the number so obtained to its lowest terms. Suppose, for example, the empirical formula of nitric acid to be required, the composition being : — Nitrogen - - 25 ‘9 Oxygen - - '74*1 100-00 These numbers, divided by their respective atomic weights, give : — 25-9 8 “ To reduce these numbers to their lowest terms, it is merely necessary to divide 9*26 by 1-85. The simplest terms being : — Nitrogen, 1*00: Oxygen, 5-00. Nitric acid consequently consists of one equivalent of nitrogen and five of oxygen. Rational formulae. — In the above illustration we found the simplest ratio existing be- tween the elements of nitric acid. But it will be seen that, for aught that appears there, it may consist of n times NO®. It becomes necessary, therefore, to find the atomic weight of the acid, and then to find the number of atoms of the elements, (combined in the above ratio,) which will make that atomic weight. In order to do this, it will be proper to deter- mine the atomic weight of the acid from the data procured by the first method, given above. In order to accomplish this, a salt was analyzed for the percentages of soda and nitric acid. with the annexed result : — Soda . 36-47 Nitric acid - 63-53 100-00 The required datum, namely, the atomic weight of the acid, can easily be obtained by saying, — As the percentage of base is to the percentage of acid., so is the atomic weight of the base to the atomic weight of the acid. In the instance given we have, therefore 36-47 : 63-53 31 : 53-999 Percentage of Percentage of Atomic weight of Atomic weight of base. acid. base. acid. It is evident that 53-999 may be written 54-0 without any inaccuracy. If, therefore, we add together the equivalents of nitrogen and oxygen in the ratio found in the empirical formula, we shall have : — 324 CHICORY. 1 equivalent of nitrogen = 14 5 equivalents of oxygen = 40 64 = the atomic weight of the acid. We will now consider the mode of determining the rational formula of a substance from the results of the analysis and the density of the vapor. Suppose a hydrocarbon to have yielded on analysis : — Carbon - - - SS'YU Hydrogen - - 14-286 100-000 85-714 14-286 And— — ~ = 14-286 = 14-286 The quotient being the same, the empirical formula becomes C"H“. It remains, there- fore, to determine the value of n. The density of the vapor was found to be 2-9064. Now, the hydrocarbons always possess a condensation to four volumes. For four volume formulae the rule is : — Divide the density of the gas by half the den- sity of hydrogen. Applying this rule, we have : — 2-9064 •0846 = It is, therefore, necessary to find what multiple of the atomic weight of CH will make 84*00. Now C-j-H = 6-|-l = 7, and 7x12 = 84. Consequently the formula is 12(CH,) or, as it is always written, The above rules will suffice to enable any person to determine the empirical and rational formulae of substances from the results of analysis. — C. G. W. CHICORY. The root of the Gichorium intyhus. Wild Succory or Chicory. This plant is cultivated in various parts of England, growing well in a gravelly or chalky soil ; also in Belgium, Holland, Germany, and France. The roots of the wild succory were formerly used medicinally ; it possesses properties in many respects resembling those of the dandelion, but it is rarely employed for curative purposes in the present day. Chicory root roasted has been employed as a substitute for coffee for more than eighty years. (Constantini Nachricht von d. Cichoriamvurzel^ 1771.) It is now employed ex- tensively as a mixture with coffee, which, although allowed, cannot be regarded other than an adulteration. Chicory root is heated in iron cylinders, which are kept revolving as in the roasting of coffee. In this country about two pounds of lard are added to every cwt. of chicory during the roasting process ; in France butter is used ; by this a lustre and color resembling that of coffee are imparted to it. When roasted, the chicory is ground to powder and mixed with the coffee. Chicory has been supposed by some persons to be wholesome and nutritive, while others contend that it is neither one nor the other ; however, no obvious ill effects have been observed to arise from its employment, if we except the occasional tendency to excite diarrhoea, when it has been used to excess. The analysis of chicory root by John gave 25 parts watery hitter extractive^ 3 parts resin^ besides sugar, sal ammoniac, and woody fibre. Waltl procured imdin from it, but the quantity varies greatly in different roots. The following remarks on the adulteration of chicory are by Dr. Pereira. “Roasted chicory is extensively adulterated. To color it, Venetian red and, perhaps, reddle are used. The former is sometimes mixed with the lard before this is introduced into the roasting machine ; at other times it is added to the chicory during the process of grinding. Roasted pulse, (peas, beans, and lupines,) corn, (rye and damaged wheat,) roots, (parsnips, carrots, and mangold wurzel,) bark, (oak-bark tan,) wood dust, (logwood and mahogany dust,) seeds, (acorns and horse chestnuts,) the marc of coffee, coffee husks, (called coffee-flights,) burnt sugar, baked bread, dog biscuits, and baked livers of horses and bullocks, (!) are substances which are said to have been used for adulterating chicory. A mixture of roasted pulse (peas usually) and Venetian red has been used, under the name of Hambro* powder, for the same purpose. “ The following are the chief modes of examining chicory with the view to the detection of these adulterations : — “1st. Careful examination of the odor, flavor, and appearance to the naked eye of the suspected powder. In this way foreign substances may sometimes be detected. “ 2d. A portion of the dried powder is to be thrown on water ; the chicory rapidly imbibes the water and falls to the bottom, whereas some intermixed powders (as the marc of coffee) float. “ 3d. The suspected powder is to be submitted to careful microscopical examination. Pulse and corn may be detected by the size, shape, and structure of the starch grains. The CHLORIDE. 325 tissues of bark, woods, and other roots may also be frequently distinguished from those of chicory. “4 th. A decoction of the suspected chicory is then to be prepared, and, when cold, to be tested with solution of iodine and persulphate of iron. “ Iodine colors a decoction of pure chicory brownish ; whereas it produces a purplish, bluish, or blackish color with decoctions of roasted pulse, roasted corn, baked bread, roasted acorns, and other substances containing starch. Persulphate or perchloride of iron does not produce much effect on a decoction of pure chicory, but it communicates a bluish or blackish tint to a decoction of oak-bark, of roasted acorns, and other substances containing tannic or gallic acids. “ 5 th. By incineration, pure dried chicory yields from 4 to 5 per cent, of a gray or fawn-colored ash. If Venetian red, or any other earthy or mineral substances, be present, a larger amount of ash is obtained. Moreover, when Venetian red has been employed, the color of the ash is more or less red.” CHINA CLAY. Kaolin, or Porcelain Clay, v)hich see. A fine white clay produced by the decomposition of the felspar of the granite rocks. It is found and prepared in this country in Cornwall and Devonshire. CHINA STONE. A semi-decomposed granite, {Pcturdze^ which has nearly the same composition as the China clay, (see Porcelain Clay.) “ Indeed, the China clay can be considered as little more than this granite in a more advanced state of decomposition.” — De la Beche. The China stone is a kind of granite, the felspar of which has undergone a partial decomposition. It is carefully selected so as to be entirely free from schorl, and requires no other preparation for the market than to be broken into a size convenient for carriage. This granite is of a peculiar nature ; it does not contain any mica, but numerous glossy scales of greenish-yellow talc. It has been stated by some authors that “this rock, {Pegma- tite or Graphic granite.) after exposure to the decomposing action of the weather, is the chief source ” of the China stone and clay. This represents but very imperfectly — indeed, incorrectly — the conditions. The decomposition of the granite is not brought about by the action of the weather, but by some peculiar decomposition proceeding to a considerable depth through the whole mass. In many places, from the very surface to the depth of more than 100 feet, this decomposition is equally apparent ; and possibly it extends to much greater depths in some places. The same stone exposed to the air does not, in any ordinary time, exhibit any signs of disintegration. No satisfactory explanation has yet been offered of the conditions under which granite is decomposed to produce the Kaolin and the China stone. There was an agreement existing amongst the producers of China stone to send off annually only 12,000 tons; but when the demand is brisk, this has been extended to 18,000 tons, and sometimes even more. The value of the China stone at the works in Cornwall is annually about £1,800. The whole that is raised is sent to the Staffordshire potteries. CHLORIC ACID. This acid, which is only known in combination with one equivalent of water, is exceedingly unstable, being instantly decomposed by contact with organic mat- ter ; undergoing gradual spontaneous decomposition in diffused daylight, and being instantly decomposed, at a temperature of a little above 100° F., into chlorine, oxygen, and perchlo- ric acid, the two former escaping as gases. It is prepared by decomposing chlorate of pot- ash by the addition of hydrofluosilicic acid, which forms with potash an insoluble com- pound. CHLORINE, one of the most energetic of the undecomposed substances, exists, under ordinary circumstances, as a greenish-yellow gas ; but, when exposed to a pressure of 4 atmos- pheres, it becomes a transparent liquid, which remains unfrozen even at the cold of — 220° F. In the first state, its density, compared to air, (reckoned 1*000,) is 2*47; in the second, its density, compared to water, (1*000,) is 1*33. It is obtained either by the action of sulphuric acid on a mixture of common salt and binoxide of manganese, or by the action of moderately strong hydrochloric acid on binoxide of manganese alone. In the first case, the proportions are 1 parts by wfight of oil of vitriol, previously diluted with 7 parts of water and 4 parts of common salt, intimately mixed with 3 parts of binoxide of manganese ; in the latter, which is the most convenient method, hydrochloric acid, specific gravity 1*15 is gently heated with the finely powdered binoxide, in the proportions of about 3 oz. of oxide to half a pint of acid. The hydrochloric acid should not be more diluted than above indicated, otherwise an explosion may occur, probably in consequence of the formation of one of the explosive oxides of chlorine. The gas must be collected either over brine or over warm water. In fumigating the Millbank Penitentiary, Mr. Faraday found that a mixture of one part of common salt and 1 part of binoxide of manganese, when acted upon by two parts of oil of vitriol previously mixed with one part of water, (all by weight,) and left till cold, produced the best results. Such a mixture at 60°, in shallow pans of red earthenware, liberated its 326 CHLORIDE OF LIME. chlorine gradually, but perfectly, in four days. The salt and manganese were well mixed, and used in charges of 3^ pounds of the mixture. The acid and water were mixed in a wooden tub, the water being put in first, and then about half the acid ; after cooling, the other half was added. The proportions of water and acid were 9 measures of the former to 10 of the latter. In the year 1846, Mr. Pattinson patented an improved mode of manufacturing chlorine. In this process he made use of a stone vessel or generator, enclosed in a double iron vessel. The hydrochloric acid, specific gravity 1-16, is poured into the generator, and on a grating or false bottom is placed the binoxide of manganese in lumps. The temperature of the con- tents of the generating vessel is then raised to 180° F., by means of steam, made to circu- late between the stone vessel and the iron casing. This heat is continued for about 18 hours, and then, by means of a suitable pipe passing to the bottom of the generator, steam, under a pressure of 10 lbs. to the inch, is injected into the vessel for about two minutes, and this is repeated every half hour for about six hours. In this process no mechanical agi- tation is required, as the steam enters with sufficient force, under the pressure above men- tioned, to effect the requisite agitation of the contents, and, by clearing the lumps of manganese from all adhering matters, expose a fresh surface continually to the action of the acid. In carrying this process into practical operation, Mr. Pattinson found that the apparatus is liable to be completely deranged, and the iron vessel destroyed by the action of the hydrochloric acid, if the stone generating vessel should happen to get broken ; to obviate which inconvenience, and to enable the generator to be used though in a broken condition, the inner iron vessel is perforated ; and the spaces between the two iron vessels’ and between the inner iron vessel and the stone generator, are filled with coal tar, or pitch, thickened by boiling to sucli a consistence as to be tough, but not brittle, when cold. Steam, circulating through a coil of pipe passing between the iron vessels, serves to maintain the tar at the requisite degree of heat ; and in the event of the breakage of the stone gener- ator, the liquified tar flows into the fissure, and prevents the escape of the hydrochloric acid into the steam vessel. A method of treating the residuum obtained in the manufacture of chorine was patented in 1855 by Mr. C. Tennant Dunlop. It consists in transforming the chloride of manganese, first into carbonate and then into oxide, by the action of heat. Whatever impurity the chloride of manganese may contain — as chloride of iron, for instance — is first separated, either by calcination or by the agency of a suitable precipitant. Practical working has shown that the carbonate of manganese thus treated yields an oxide of a richness equivalent to that of 80 per cent, pure peroxide. The carbonate of manganese may be obtained by precipitation from the chloride by carbonate of ammonia. The chloride of ammonium re- sulting from this treatment may either be employed as such, or it may be re-transformed in the usual way into carbonate for the precipitation of fresh chloride of manganese. Hydrate of lime is also used as a precipitant, the resulting hydrated oxide of manganese being sub- sequently converted into carbonate by the transmission through it of a stream of carbonic acid. By another process, carbonate of manganese is obtained by passing carbonic acid through the solution of’ chloride of manganese which has been previously mixed with a quantity of carbonate of soda. The carbonate of soda, under the influence of carbonic acid, decomposes the chloride of manganese into carbonate, from which the oxide can be obtained. The essential feature of this invention is the production of artificial oxide of manganese, by first converting the chloride into carbonate, and afterwards this latter into oxide, by the joint agencies of heat and atmospheric air. CHLORIDE OF LIME. Mr. Graham found that hydrate of lime, dried at 212°, absorbed afterwards little or no chlorine ; but that, when dried over sulphuric acid, it was in the most favorable condition for becoming chloride of lime. .A dry, white, pulverulent com- pound is obtained by exposing the last hydrate to chlorine, which contains 41 -2 to 41*4 chlorine in 100 parts, of which 39 parts are available for bleaching, the remainder going to form chlorine of calcium and chlorate of lime. This appears to be the maximum absorption of chlorine by dry hydrate of lime ; but the bleaching powder of commerce rarely, even when fresh prepared, contains more than 30 per cent, of chlorine, and after being kept for several months, the proportion often falls as low as 20 per cent. A compound containing one equivalent of chlorine and one equivalent of hydrate of lime, should contain 48 ’57 chlorine and 51*43 hydrate of lime ; a compound of one equivalent of chlorine and two of hydrate of lime, should contain 32*42 chlorine and 67’58 hydrate of lime; and these are about the proportions in good commercial specimens. It would not be advisable to attempt to manufacture a more highly chlorinated product, as the stability of the compound is in- creased by an excess of lime. Where a stream of chlorine is transmitted through water holding hydrate of lime in suspension, the lime is entirely dissolved, and the full equivalent of chlorine is absorbed. Water poured upon bleaching powder dissolves out the bleaching combination, leaving a large residue of lime. Ten parts of water are required for one part CHLOROMETKY. 327 of dry chlorine. The solution emits the peculiar odor of hypochlorous acid ; and if we re- gard bleaching powder as hypochlorite of lime, the reaction which occurs in its formation will be thus represented : — 2Ca0-f2Cl=CaCl+Ca0,C10. But good bleaching powder is not deliquescent, neither does alcohol dissolve anything from it, both which should occur if the compound contained free chloride of calcium. It is possible, however, that the two salts may exist in bleaching powder in the form of a double salt, or that the chlorine is in direct combination with the oxide. If the compound be sup- posed to be pure chloride of lime, the reaction is simply an absorption of chlorine ; and the same should be the case With the other bleaching compounds — chloride of soda, for instance. But when carbonate of soda, saturated with chlorine (Labarraque’s Liquor) is evaporated, no chlorine is evolved, and the residue still possesses bleaching properties. The true nature of bleaching powder is* open, therefore, to speculation. The bleaching action of solution of chloride of lime is very slow unless an acid be added to it. When dilute sulphuric acid in insufficient quantity is employed, no chlorine is evolved but hypochlorous acid, which may be distilled off and condensed in a suitable re- ceiver ; but with excess of acid, chlorine only is liberated. When calicoes and other woven goods are to be bleached, they are first thoroughly cleansed by boiling successively with lime-water and a weak solution of caustic soda ; they are then digested in a solution of bleaching powder, specific gravity 1’02, containing about 2^ per cent, of chloride of lime; after which they are immersed in very dilute sulphuric acid, which, by liberating the chlo- rine within the fibres of the cloth, rapidly removes the color. The goods are then washed, a second time steeped in alkali, and again passed through a weaker solution of chloride, and then through dilute acid ; after which they are thoroughly washed in water. The quantity of liquor necessary for VOO lbs. of cloth is 971 gallons, containing 3884- lbs. of chloride. W'hen white figures are required on a colored ground, the pattern is printed on the cloth with tartaric acid, thickened with gum. The color is discharged in those places where the acid was present, but elsewhere untouched. When chloride of lime is heated, it evolves oxygen gas, and sometimes chlorine, and it becomes converted into a mixture of chlorate of lime and chloride of calcium, which has no bleaching properties. Half an ounce of chloride of lime boiled in two ounces of water yields, according to Keller, 165 cubic inches of oxygen contaminated with chlorine. The property of chlorine to destroy offensive odors and to prevent putrefaction, gives to the chlorides of lime and soda a high value. On this important subject Pereira has the following remarks (Mat. Med. vol. I.) with reference to medical police. “ If air be blown through putrid blood, and then through a solution of chloride of lime, carbonate of lime is precipitated, and the air is disinfected ; but if the air be first passed through putrid blood, then through caustic potash, or milk of lime, to abstract the carbonic acid, and afterwards through the solution of chloride of lime, it retains its stinking quality. Chloride of lime may be employed to prevent the putrefaction of corpses previous to interment ; — to destroy the odor of exhumed bodies during medico-legal investigations ; — to destroy bad smells and prevent putrefaction in dissecting-rooms and workshops in which animal substances are em- ployed (as catgut manufactories ;) — to destroy unpleasant odors from privies, sewers, drains; wells, docks, &c. ; to disinfect ships, hospitals, prisons, stables, &c. The various modes of applying it will readily suggest themselves. For disinfecting corpses, a sheet should be soaked in a pailful of water containing a pound of chloride, and then wrapped round the body. For destroying the smell of dissecting-rooms, &c., a solution of the chloride may be applied by means of a gardening pot.” Of equal importance is this substance to the medical practitioner. “We apply them,” observes Pereira, “to gangrenous parts, to ulcers of all kinds attended with fbul secretions ; to compound fractures accompanied with offensive discharges ; in a word, we apply them in all cases accompanied with offensive and fetid odors. Their efficacy is not confin^ to an action on dead parts, or on the discharges from wounds and ulcers ; they are of the greatest benefit to living parts, in which they in- duce more healthy action, and the consequent secretion of less offensive matters. Further- more, in the sick chamber, many other occasions present themselves on which the power of the hypochlorites to destroy offensive odors will be found of the highest value : as to coun- teract the unpleasant smell of dressings, or bandages, &c., &c. In typhus fever a handker- chief, or a piece of calico, dipped in a weak solution of an alkaline hypochlorite, and sus- pended in the sick chamber, will be often of considerable service both to the patient and to the attendants.” The poisonous exhalations from foul sewers may be counteracted by a slight inhalation of chlorine gas, as obtained from a little chloride of lime placed in the folds of a towel wetted with acetic acid. — H. M. N. CHLOROMETKY. The processes or series of processes by which the strength or com- mercial value of substances containing chlorine, or from which chlorine may be rendered available, is ascertained, is called Chlorometry. Chloride (hypochlorite) of lime, of potash, or of soda, and the ores of manganese, are the most important of these substances. Chloride of lime is a mixture of hypochlorite of lime, chloride of calcium, and hydrate CHLOEOMETKY. 828 of lime (Ca0,C10-f-CaCl+Ca0,H0,) and is decomposed by the weakest acids — even by cj^r- bonic acid ; and therefore, by exposure to the air, it gradually loses its chlorine, and being converted into carbonate of lime, it may become perfectly valueless. This decomposition by all acids is common to all decolorizing chlorides (hypochlorites,) and may be explained, either by admitting that the decomposing acid (say, for example, the carbonic acid of the air) simply eliminates the hypochlorous acid, the oxygen of which oxidizes in a direct manner the calcium of the chloride of calcium mixed with the hypochlorite of lime, thus : — Ca0,C10-f-CaCl-f-2C02 = 2Ca0,C0^-f 2C1 ; or by considering the decolorizing chloride (chloride of lime, for example) not as a hypo- chlorite, but as a compound resulting from the direct combination of chlorine with CaO(CaO,Cl ;) in which view of the case the decomposition is explained as follows : — CaO,Cl-fCO'“=:CaO,CO"-fCl. The value of the decolorizing chlorides in general, and of chloride of lime in particular, de- pends upon the quantity of chlorine which may be liberated from it under the influence of an acid. For technical purposes this estimation is exceedingly important, and should never be neglected by the bleacher. Chlorine, whether in the free state, or combined with weak alkalies, or caustic lime, having the property of destroying coloring matter of an organic nature, this reaction was from the first resorted to as a means of determining the commercial value of these chlo- rides ; namely, by ascertaining the quantity of a solution of indigo of known strength which could be decolorized by them ; for this purpose a test liquor is prepared by dissolving a given quantity of sulphate of indigo in water, and pouring therein, drop by drop, a certain quantity of the sample of chloride of lime previously dissolved in a measured quantity of water. The solution of chloride of lime must be added, drop by drop, to the sulphate of indigo test liquor until the latter turns from blue to yellow, the operator taking care to stir the mixture without intermission. This method of chlorometry, however, is objectionable, and is, in fact, the worst of all, on account of the difficulty of ascertaining when the reaction is complete ; for the yellow color, resulting from the decomposition of the indigo, (chlorisatine,) mixing with the original blue color of the solution, produces a green color, which interferes with the correctness of the observation. On the other hand, the test liquor of sulphate of indigo always undergoes spontaneous and gradual decolorization by standing, not only when exposed to diffused light, but even though it be kept in well stoppered bottles, and in the dark. The process generally adopted now is one which gives exceedingly accurate results ; it was contrived by Gay-Lussac, and it is based on the property which arsenious acid (AsO®) in solution in chlorhydric acid possesses of becoming peroxidized, that is to say, converted into arsenic acid (AsO=), in the presence of chlorine and water. This reaction may be represented by the following equation : — AsO® 4- 2C1 -f 2HO = AsO" -f 2HC1. That is to say, one equivalent of arsenious acid (AsO®) in presence of two equivalents of chlorine (2C1) and of two equivalents of water (2HO), produces one equivalent of arsenic acid (AsO®) and two equivalents of chlorhydric acid (2HC1.) This reaction is so rapid, that, if organic substances capable of being decolorized by the action of chlorine are present while it is taking place, the color is not destroyed so long as any portion of arsenious acid remains unconverted into arsenic acid ; but as soon as the last portion of the arsenious acid has been peroxidized, the liquid is instantly decolorized, which reaction at once indicates that the experiment is at an end. Taking the equivalent of arsenious acid = 99, and that of chlorine = 35*5, it is evident that 99 grains of arsenious acid will correspond to 71*0 of chlorine (85*5 x 2 = 71* ;) or, which is the same thing, 139*436 grains of arsenious acid will correspond very nearly to 100 of chlorine. Take, therefore, a certain quantity of the arsenious acid of commerce, reduce it to pow- der, and dissolve it in hot diluted chlorhydric acid ; allow it to recrystallize therefrom, wash the crystalline powder with cold water, dry it well, reduce it into fine powder, and of this dry and pure arsenious acid take now 139*44 grains, prepared as above said, put them into a flask, and add thereto about 3 ounces of pure chlorhydric acid,/ree from sulphurous and nitric acid, and diluted with three or four times its bulk of water ; keep the whole at a boiling heat until all the arsenious acid has totally dissolved. Pour now the solution into a glass cylinder graduated into 10,000 grains-measures, rinse the flask with water, and pour the rinsings into the graduated glass cylinder until, in fact, it is filled up to the scratch marked 10,000. This done, it is clear that each 1,000 grains-measure of that liquor will contain 13*944 grains weight of arsenious acid, corresponding to 10 grains weight of chlo- rine. This should be labelled “ arsenious acid test liquor.” If it be desired to prepare a CHLOROMETRY. 329 larger quantity of test liquor, instead of 139’44, the operator may take, for example, ten times that quantity of arsenious acid, namely, 1394*44 grains, (or, more correctly, 1394*36,) and dissolve them in as much liquid as will form 100,000 grains-measures ; but he will have to take care to keep it in one or more well stoppered jars, in order that the strength of the solution may not be altered by evaporation. Having thus prepared a quantity of arsenious acid test liquor, weigh off 100 grains from a fair average sample of the chloride of lime to be examined, and after triturating them first in the dry state, and then with a little water in a glass mortar, and then adding more water, pour the whole into a flask or glass vessel capable of holding 2,000 grains-measure, and marked with a scratch at that point. The mortar in which the chloride of lime has been triturated must be rinsed with more water, and the rinsings poured into the 2,000 grains- measure glass vessel first mentioned, until the whole of the 2,000 grains-measures are filled up to the scratch. The whole must now be well shaken, in order to obtain a uniformly turbid solution, and half of it (namely, 1,000 grains-measure) is transferred to an alka- limeter, which therefore will thus be filled up to 0°, and will contain fifty grains of the chlo- ride of lime under examination ; and as the 1,000 grains-measure of the alkalimeter are divided into 100 degrees, each degree or division will therefore contain 0*6, or half a grain of chloride of lime. On the other hand, pour also 1,000 grains-measure of the arsenious acid test liquor into a somewhat large beaker, and add thereto a few drops of a solution of sulphate of indigo, in order to impart a distinct blue color to it ; shake the glass, so as to give a circular motion to the liquid, and while it is whirling round, pour gradually into it the chloride of lime liquor from the alkalimeter, watching attentively the moment when the blue tinge of the arsenious acid test liquor is destroyed. Care must be taken to stir the liquor well during the process, and to stop as soon as the decolorizing is effected, which indicates that the whole of the arsenious acid is converted into arsenic acid, and that the process is finished. The quantity of chlorine contained in the sample is then determined in the following manner : — We have seen that the 1,000 grains-measure of the arsenious acid test liquor, into which the chloride of lime liquor was poured from the alkalimeter, contained 13*944 grains weight of arsenious acid, corresponding to 10 grains weight of chlorine. And the 1,000 grains- measure of chloride of lime liquor poured from the alkalimeter contained 50 grains weight of chloride of lime, each degree of the alkalimeter containing, therefore, half a grain of chloride of lime. Let us suppose that, in order to destroy the blue color of the 1,000 grains-measure of the arsenious acid test liquor, 80 divisions (800 grains-measure) of the chloride of lime liquor in the alkalimeter have been employed. It is evident that these 80 divisions contained the 10 grains weight of chlorine necessary to destroy the color of the arsenious acid test solution, or rather to peroxidize all the arsenious acid (13*944) contained in that solution tinged blue with indigo. And since each division represents half a grain of chloride of lime, 40 grains weight of chloride of lime, containing 10 grains weight of chlorine, must have been present in the 80 divisions employed. If, now, 40 grains of the chloride of lime under examination contained 10 grains of chlorine, what is the percentage of chlorine in that same chloride ? The answer is 25. 40 : 10 :: 100 : 25. The chloride of lime submitted to the experiment contained, therefore, 25 per cent, of chlorine. In the method just described it will be observed that, instead of pouring the arsenious acid test liquor into the solution of the sample, as in alkalimetry, it is, on the contrary, the solution of the sample which is poured into that of the test liquor. It is necessary to ope- rate in this manner, because otherwise, the chlorhydric acid of the arsenious acid test liquor would disengage at once more chlorine than the arsenious acid could absorb, and thus ren- der the result quite incorrect. On the contrary, by pouring the chloride of lime into the solution of arsenious acid, the chlorine being disengaged in small portions at a time, always meets with an abundance of arsenious acid to react upon. It is better, also, to employ the turbid mixture of chloride of lime, than to allow it to settle and to perform the experiment on the decanted portion. Instead of arsenious acid, protosulphate of iron may very conveniently be employed ; and this method, first proposed, I believe, by Ruiige, yields also exceedingly accurate re- sults. This method is based upon the rapid peroxidization which protosulphate of iron under- goes when in contact with chlorine in the presence of water and of free suphuric acid, two equivalents of the protosulphate being thereby converted into one equivalent of persul- phate, on account of one equivalent of chlorine liberating one equivalent of oxygen from the water, which equivalent of oxygen adds itself to the protoxide of iron which thus be- comes converted into peroxide, and consequently into persulphate of iron, while the equiva- 330 CHLOROMETRY. lent of hydrogen, liberated at the same time, forms with the chlorine one equivalent of chlorhydric acid ; thus : — 2FeO,SO=’ + 2SO^ + HO + Cl = Fe"=0^3S0® -j- HCl ; by which it is seen that two equivalents of protosulphate of iron correspond to one equiva- lent of chlorine. Protosulphate of iron may be obtained in a state of great purity as a by-product of the action of sulphuric acid upon protosulphuret of iron in the preparation of sulphuretted hy- drogen, the evolution and reducing action of the latter gas preventing the formation of any peroxide. All the operator has to do is to redissolve in water, with addition of a little sul- phuric acid, the crystals which have formed in the sulphuretted hydrogen apparatus, to fil- ter the whole liquor and to recrystallize it ; or else to pour the hot and very concentrated solution into strong alcohol : by the latter process, instead of obtaining the protosulphate in crystals, it is in the shape of a fine clear blue precipitate. Or else, as much piano-forte wire may be dissolved in moderately diluted sulphuric acid as will nearly neutralize it ; the liquor is then filtered and left to crystallize, taking care, however, to leave a few fragments of the wire suspended in it, that no peroxidization may take place ; or else the iron solution may be concentrated by heat, and while hot pour into strong alcohol, by which a clear blue crystalline precipitate of pure protosulphate of iron will be obtained. In either case the protosulphate of iron so produced contains V equivalents of water, of crystallization (Fe0,S0^7H0.) Take, accordingly, 2 equivalents, or 278 grains, of the crystallized protosulphate of iron, before alluded to, and previously dried between folds of blotting-paper, or moistened with alcohol, and left to dry in the air until all odor of alcohol has vanished, and dissolve these 278 grains of protosulphate of iron in water strongly acidified with either sulphuric or chlor- hydric acid, so that the liquor may occupy the bulk or volume of 3,650 grains of water. 1,000 grains of such a solution will therefore contain 78-31 grains of crystallized protosul- phate of iron, and will accordingly b,e peroxidized by, or will correspond to, 10 grains of chlorine. When only one experiment is contemplated, 78-31 of crystallized protosulphate of iron may be at once dissolved in 1,000 grains (1 alkalimeter full) of water acidified with sulphuric acid ; and this is the protosulphate of iron test liquor. Weigh now 100 grains of the chloride of lime under examination, and dissolve them, as before mentioned, in a glass mortar, with a sufficient quantity of water, so that it may oc- cupy the bulk of 2,000 grains-m ensures of water ; pour half of this, namely, 1,000 grains- measure, into an alkalimeter, divided, as usual, into 100 divisions or degrees, each degree of which will therefore contain half a grain of chloride of lime. Pour gradually the chlo- ride of lime from the alkalimeter into a glass beaker containing 1,000 grains-measure of the test solution of protosulphate of iron, above alluded to, stirring all the while, until it is completely converted into persulphate of iron, which may be ascertained by means of strips of paper, previously dipped into a solution of red prussiate of potash, and dried, more chlo- ride of lime being poured from the alkalimeter as long as a blue stain is produced by touch- ing the red prussiate of potash test paper with a drop of the solution of protosulphate of iron operated upon. The quantity of chlorine contained in the chloride of lime under examination, is estimated as follows: — Since 1,000 grains-measure of the protosulphate of iron test liquor, into which the solution of chloride of lime is poured, contains, as we said, 78-31 grains of protosulphate of iron, corresponding to 10 grains of chlorine ; and since, on the other hand, 1,000 grains-measure of the solution of chloride of lime in the alkalimeter contains 50 grains of chloride of lime, that is to say, ^ grain of that substance in each divi- sion of the alkalimeter : Let us suppose, for example, that the quantity of chloride of lime required to peroxidize the iron of the 1,000 grains-measure of protosulphate amounts to 90 divisions, it is evident that the solution contained 45 grains of chloride of lime, and if these 45 grains of chloride of lime contained the 10 grains of chlorine necessary to peroxidize the iron of the protosul- phate in the glass beaker, the 100 grains of the same chloride under examination evidently contain 22-22. This calculation is readily effected by dividing 1,000 by half the number of the divisions poured from the alkalimeter. The half of 90 (number of divisions employed) being 45, dividing 1,000 by 45 is 22-22. Or, instead of 100 grains, the operator may take only 50 grains of the chloride of lime to be examined, and this will prove a more convenient quantity, in that case, the dividing 1,000 by the number of divisions employed, will at once give the percentage. Let us sup- pose, for example, that 45 divisions only of the 50 grains of chloride of lime solution, taken as sample, to have been employed ; then, since these 45 divisions contained the 10 grains of chlorine necessary to peroxidize the iron contained in the 1,000 grains-measure of the protosulphate, it is evident that 100 grains will contain 22-22 of chlorine, thus : — Divisions. Grains of Chlorine. Divisions. Grains of Chlorine. 46 : 10 : : 100 : x = 22-22 OHLOROMETRY. 331 There are other accurate methods of determining the amount of chlorine in chloride of lime, provided a proper care be bestowed on the operation ; but the processes by arsenious acid and by proto-sulphate of iron are by far the less liable to error from the circumstance, among other reasons, that their solutions are less liable to become altered. The other methods also require a longer time, and we shall only mention the rationale of their mode of action. Thus the process by chloride of manganese consists in decomposing a test solution of it by the chloride of lime, to be examined as long as a brown precipitate is produced. The reaction is as follows : — MnCl -I- CaO,Cl -f HO= MnO" -f- CaCl + HCl. The process with yellow prussiate of potash depends upon the following reaction : — 2(FeCy -f 2KCy) -f Cl = (3KCy -h Fe"Cy") -f KCl. That is to say, 2 equivalents of yellow prussiate (ferrocyanide of potassium) produce 1 + equivalent of red prussiate, (ferricyanide of potassium,) 1 equivalent of chloride of potas- sium ; and, therefore, 2 equivalents = 422 grains of the yellow prussiate will correspond to 1 equivalent = 35-5 of chlorine. The chloride of lime is, as usual, poured into the solu- tion of the chloride of manganese, and the operation is completed when a brown color begins to appear. The process by subchloride of mercury^ (Hg^Cl,) which is insoluble in water, is based upon its conversion by chlorine into chloride of mercury, (HgCl,) which is soluble in water, thus : — Hg"Cl + Cl= 2HgCl. The modus operandi is briefly as follows : — As subnitrate of mercury is difficult to obtain in a perfectly neutral state, and free from basic, or from pernitrate, take a known volume of pernitrate of mercury, precipitate it by an addition of chlorhydric acid, collect the precipitate formed, wash it, dry it at 212° F., and weigh it. Having thus ascertained the quantity of subchloride of mercury contained in the known bulk of pernitrate, 1,000 grains- measure of it are measured off, and precipitated by an excess of chlorhydric acid, and the whole is then well shaken, so as to agglomerate it ; a given weight of chloride of lime, say 60 grains, are dissolved, as usual, in water, so as to obtain one alkalimeter full, which is then gradually poured into the liquor containing the precipitated subchloride of mercury, until it completely disappears, and the liquor becomes as clear as water, which indicates that the operation is at an end. The number of divisions of the chloride of lime liquor used are then read off, and the quantity of chlorine present in the chloride of lime is easily calculated from the quantity of subchloride of mercury which was known to have existed in the known bulk of pernitrate employed, and which has been converted into perchloride of mercury by the chlorinated liquor poured into it. Testing of Black Oxide of Manganese for its available Oxygen. Manganese is found, in combination with more or less oxygen, in a number of minerals, but the principal ores of that substance are the pyrolusite, (binoxide of manganese,) MnO^, braunite, (sesquioxide of manganese,) Mn^O^, manganite, (hydrated sesquioxide of man- ganese,) Mn^O^ + HO, hausmannite, (red oxide of manganese,) Mn^O^ &c., &c. The first, namely the pyrolusite, is by far the most important of these ores, which are chiefly employed for the preparations of chlorine, and their commercial value depends upon the quantity of this gas which a given weight of them can evolve, which quantity is propor- tionate to that of the oxygen contained in the ore beyond that which constitutes the protoxide of that metal, as will be shown presently. The manufacturer who uses these ores, ought also to take into consideration the amount of impurities which may be present in them, such as earthy carbonates, peroxide of iron, alumina, silica, sulphate of barytes, since these impurities diminish, pro tanto^ the value of the ore. The estimation of the commer- cial value of a manganese ore may be accomplished in various ways. One of these methods consists in first reducing into fine powder a sample of the ore, and treating it by moderately diluted nitric acid. If this produces an effervescence, it is owing to the presence of carbonates, and an excess of nitric acid should then be used, so as to dis- solve them entirely. When all effervescence has ceased, even after a fresh addition of acid, the whole should be thrown on a filter and the residue within the filter should be washed and dried. For technical purposes, the weight of these carbonates may be thus easily effected, namely, by weighing a certain quantity of the sample, (for example 100 grains,) digesting it for a few hours in dilute nitric acid, collecting on a filter, washing, and drying until it no longer diminishes in weight. The loss indicates, of course, the quantity per cent, of the carbonates which it contained. This being done, take a weighed quantity CHLOROMETRY. 332 of the sample, dry it well, as just said, introduce it into a small counterpoised retort, at the extremity of which a tube containing fragments of fused chloride of calcium, also weighed, should be adjusted. Apply then to the retort the strongest heat that can be produced by an argand spirit lamp, or by my gas furnace-lamp, and, after some time, disconnect the chlo- ride of calcium tube and weigh it. The increase of weight indicates the quantity of water which has volatilized, and which was yielded principally by the hydrate of sesquioxide, (manganite, Mn'O^-fHO,) some portion of which is always found mixed with the peroxide ; every grain of water thus evaporated corresponds to 9*7'7 of manganite. The contents of the small retort should now be emptied into a counterpoised platinum capsule or crucible, and ignited therein, until, after repeated weighings, the weight is ob- served to remain uniform ; this converts the mass completely into manganoso-manganic oxide (Mn®0^). The crucible is then weighed, and the loss indicates the quantities of oxy- gen evolved, from which that of the peroxide is calculated. Each grain of oxygen corre- sponds to 2’71 of pure peroxide. This experiment should evidently be carried on with great care, since a small quantity of oxygen represents a large quantity of peroxide. In order to effect the complete conversion of the peroxide in the sample into red oxide of manganese, as above mentioned, the ignition should be continued for a long time, and the quantity operated upon should be small ; if a larger quantity be treated, a common fire should be used instead of an argand lamp. The value of manganese may also be very accurately estimated by measuring the quan- tity of chlorine which a given weight of the ore produces, when treated by chlorhydric acid. In order to understand the rationale of this method, the reader must bear in mind that all the oxides of manganese, when heated in contact with chlorhydric acid, evolve a quantity of chlorine exactly proportionate to that of the oxygen above that which it contained in the protoxide. For example, protoxide of manganese being treated by chlorhydric acid, pro- duces only protochloride of manganese, but yields no free chlorine, as shown by the follow- ing equation ; MnO + HCl=MnCl-j- HO. Not so, however, the red oxide of manganese, or manganoso-manganic oxide (Mn®0^), which, when treated by chlorhydric acid, forms proto- chloride of manganese, but disengages one third of an equivalent of chlorine, as shown by the following equation : Red oxide of manganese, or manganoso-manganic oxide, may be represented by the formula MnO-f-Mn^O^, or by Mn^O"*, or by 3Mn01^ ; therefore : l^MnO + liHCl= li'HO MnCl -i- iCI. Sesquioxide of manganese, when treated by chlorhydric acid, yields half an equivalent of free chlorine for each equivalent of protochloride of manganese formed ; as shown by the following equation : Sesquioxide of manganese, Mn“0®, is the same as 2Mn01^ ; therefore HMnO -t- UHCl = HHO -F MnCl + iCl. Lastly, peroxide of manganese, when treated by chlorhydric acid, yields one entire equivalent of chlorine for each equivalent of protochloride formed, as shown by the follow- ing equation : Peroxide of manganese is MnO^ ; therefore MnO’^-i-2HCl=2HO-f MnCl-f-Cl. And as the commercial value of the ores of manganese depends, as already said, upon the amount of chlorine which they can evolve when treated by chlorhydric acid, the object in view will evidently be attained by determining that quantity. Runge’s method, which we detailed at the beginning of this article in the testing of chloride of lime, may also be applied for the testing of the ores of manganese. That method, it will be recollected, is based upon the rapid peroxidization which sulphate of protoxide of iron undergoes when in contact with chlorine, water being present, which reac- tion is represented as follows: 2FeO,SO^-f HO-f- Cl=Fe’0®,S0*-|- HCl. Showing that two equivalents of protosulphate of iron represent one equivalent of chlorine, since one equiva- lent of chlorine is required to convert two equivalents of protosulphate of iron into one of the persulphate of that base. The experiment is performed as follows : Pulverize 278 grains (2 equivalents) of crystallized protosulphate of iron, (2FeO,SO®,7HO,) and mix them in a small flask with 43 ’6 grains of the manganese under examination, and previously re- duced into very fine powder. These 43 '6 grains represent one equivalent of pure binoxide of manganese, (MnO^,) and would, therefore, if pure, peroxidize exactly the two equivalents, or 278 of protosulphate of iron. About three fluid ounces of strong chlorhydric acid should now be poured upon the mixture in the flask, which flask must be immediately closed with a perforated cork, provided with a tube-funnel drawn to a point, in order that the vapor may escape, and the whole is then rapidly boiled. The chlorine disengaged by the man- ganese is immediately absorbed by the protosulphate of iron. We just said that 43'6 grains of peroxide of manganese would, if pure, exactly peroxidize the 278 grains of protosulphate of iron, but as the peroxide of manganese of commerce is never pure, it is evident that the 43-6 grains of the sample employed will prove insufficient to peroxidize the iron, and hence, the necessity of ascertaining the amount of protosulphate which could not be peroxidized, and which remains in the acid solution. This may be done by means of a chlorate of potash test-liquor, as follows : Since 1 equivalent (=rl22‘6 grains) of chlorate of potash (=K0,C10®) produce, under the influence of boiling chlorhydric acid, 6 equivalents of chlorine, as OHLOROMETRY. 333 shown by the equation : K0,C10“ + 6HC1=KC1 + 6HO + 6C1, it follows that 20-41 of chlorate of potash would be sufficient to peroxidize 278 grains (2 equivalents) of protosulphate of iron, and would therefore represent 35'5 (1 equivalent) of chlorine, or 43-6 of peroxide of manganese. The chlorate of potash test liquor, therefore, is prepared by dissolving 20-41 of chlorate of potash in 1,000 water-grains’ measure of water. The solution is then poured carefully, drop by drop, from a glass alkalimeter through the tube funnel into the boiling hot solution containing the salt of iron. The whole of the chlorine which is disengaged is immediately absorbed by the protosulphate of iron, but as soon as the latter is completely peroxidized, the free chlorine which is evolved immediately reacts upon the coloring matter of a slip of paper, stained blue by sulphate of indigo, or litmus, previously placed by the operator be- tween the cork and the neck of the flask, which piece of paper becoming bleached indicates that the operation is terminated. The operator then reads off the number of measures of the chlorate of potash test liquor which have been employed to complete the peroxidization of the protosulphate of iron. Let us suppose that 50 divisions of the alkalimeter (500 water-grains’ measures) have been employed ; it is clear that half the quantity only of the protosulphate of iron employed has been converted into persulphate, and that consequently the quantity of the sample of manganese contained half its weight of valueless material ; or, in other words, each measure of the test solution of chlorate of potash employed to complete the peroxidization of the protosulphate represents 1 per cent, or 21-8 grains of useless matter contained in the 43‘6 grains of the ore of manganese operated upon. The air should be excluded from the flask during the peroxidization of the protosulphate of iron, else the oxygen of the air acting upon the salt of iron, would peroxidize a portion of it and vitiate the result. Instead of protosul- phate, protochloride of iron may be used, for which purpose 56 grains (2 equivalents) of piano-forte wire should be put into a matras or flask as above mentioned, and about four fluid ounces of pure concentrated chlorhydric acid poured upon them. The flask being closed, as directed in the preceding process, with a cork provided with a funnel tube drawn to a point at the lower end, a gentle heat is then applied to promote the solution of the iron. When all the metal has dissolved, the operator introduces 43-6 grains of the peroxide of manganese under examination, previously reduced into fine powder and kept in readiness, weighed and folded up in a piece of paper ; the flask is immediately closed with its cork, the liquor is slightly agitated and then brought to the boiling point. The chlorine disen- gaged by the manganese is completely absorbed by the protochloride of iron, the excess of which is determined by the chlorate of potash test liquor precisely as explained just above. By the methods which we have described the proportion of chlorine which a sample of manganese can evolve may be ascertained, but this alone is far from constituting the com- mercial value of the article as a source of chlorine, and it is not less important to determine the proportions of the other substances, such as peroxide of iron, earthy carbonates, &c., which are contained in the sample, and which unprofitably consume a certain quantity of hydrochloric acid without evolving chlorine, and merely producing chlorides of iron, of cal- cium, of barium, &c. Hence the necessity of estimating not only the quantity of chlorine which a given weight of peroxide of manganese can yield, but likewise the proportion of hy- drochloric acid which is uselessly saturated by the foreign substances contained in the ore. For this purpose the following method, which was first recommended by Gay-Lussac, may be resorted to : — One equivalent, or 43-6 grains, of the peroxide of manganese under examination are treated by an excess of hydrochloric acid ; for example, by 500 water-grain measures of chlorhydric acid of specific gravity 1-093, which quantity contains, according to Dr. Ure, 100 grains of real acid. The amount of chlorine corresponding to that of the pure manganese in the sample is then determined as mentioned before by means of protosulphate or protochloride of iron. Since 43-6 grains (one equivalent) of pure peroxide of manganese require 74 grains (two equivalents) of pure chlorhydric acid to evolve 35-5 of chlorine, if we saturate the excess of chlorhydric acid employed by means of a solution of carbonate of soda, as in acidimetry, and thus determine the quantity of free acid, the difference will at once show what quantity of acid has been consumed both by the peroxide of manganese and by the foreign sub- stances conjointly ; but if we now subtract from that number the quantity consumed by the manganese, which will have been ascertained in the first part of the experiment, the re- mainder will, of course, represent the proportion which has been uselessly consumed by the impurities. Taking a test solution of carbonate of soda of such a strength that 100 alkaliraetrical divisions contain exactly 53 grains (one equivalent) of it, and are consequently capable of saturating exactly 36-5 grains (one equivalent) of pure chlorhydric acid, let us suppose that in order to saturate the excess of free acid left after the determination of the chlorine evolved by the manganese, it is found that 140 alkalimetrical divisions of the test solution of carbonate of soda just alluded to have been required. Since 100 alkalimetrical divisions CHLOPvOPHANE. 334: or measures of carbonate of soda can saturate 36‘5 grains of pure chlorhydric acid, the 140 divisions or measures employed represent, therefore, 61 *1 grains of acid left in excess and in a free state, which being deducted from the 100 grains (contained in the 600 grain measures of acid of specific gravity 1-093 employed) leave 48-9 grains as the proportion of real acid consumed by the manganese and impurities of the sample. Let us suppose, now, that the 43 -6 grains of manganese operated upon have been found in the first part of the experiment to contain only 21-8 grains, or 60 per cent, of peroxide of manganese as before mentioned ; these will, therefore, have consumed 36-6 grains of chlorhydric acid, which being deducted from the 48 -9 grains, (the joint quantity of acid consumed by the acid and impurities,) leave 12 -4 as the proportion of pure chlorhydric acid wasted or uselessly taken up by the impurities alone, and therefore the 43*6 grains of peroxide of manganese operated upon consisted oL Pure peroxide of manganese 21*8 = 60*00 Impurities unprofitably consuming chlorhydric acid - 12-4 = 28*44 Other impurities 9*4 = 21*66 43*6 = 100*00 The amount of water contained in the sample may be separately estimated by exposing a given weight of it (100 grains, for example,) in a capsule, at a temperature of about 216° Fahr. until they no longer lose weight. The loss, of course, indicates the percentage of water. The economy of any sample of manganese in reference to its consumption of acid, in generating a given quantity of chlorine, may be ascertained by the oxalic acid test : — 44 grains of the pure peroxide, with 93 grains of neutral oxalate of potash, and 98 of oil of vitriol disengage 44 grains of carbonic acid, and afford a complete neutral solution ; be- cause the one half of the sulphuric acid, =49 grains, goes to form an atom of sulphate of manganese, and the other half to form an atom of sulphate of potash. The deficiency in the weight of carbonic acid thrown off will show the deficiency of peroxide of manganese ; the quantity of free sulphuric acid may be measured by a test solution of bicarbonate of potash, and the quantity neutralized, compared to the carbonic gas produced, will show by the ratio of 98 to 44, the amount of acid unprofitably consumed. — A. N. CHLOROPHANE. A name given to some of the varieties of fluor spar. See Fluor Spar. CHROMATES OF POTASH. (For the preparation of these salts, refer to Chrome Iron.) Bichromate of potash^ by slow cooling, may be obtained in the form of square ta- bles, 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. The composition of bichromate of potash is Potash 31*6 Chromic acid 68*4 100*0 That of the neutral Chromate of Potash is Potash 48-0 Chromic acid 62*0 100-0 These salts are much employed in Calico Printing and in Dyeing, which see. The value of a solution of chromate of potash, if it be tolerably pure, may be ferred from its specific gravity by the following table : — At specific gravity 1*28 it contains about 60 per cent of the salt *4 44 1-21 U “ 33 ti (( 44 44 1*18 “ 25 (( (( 4 4 44 1*15 U “ 20 a (( 44 44 1*12 a “ 16 i( (( 44 <4 1-11 u “ 14 C( a 44 44 1*10 “ 12 u a in- In making the red bichromate of potash from these solutions of the yellow salt, nitric acid was at first chiefly used ; but in consequence of its relatively high price, sulphuric, muriatic, or acetic acid has been frequently substituted upon the large scale. CHROMATE OF LEAD, the chrome yellow of the painter, is a rich pigment of various shades, from deep orange to the palest canary yellow. It is made by adding a limpid solu- tion of the neutral chromate of potash, to a solution, equally limpid, of acetate or nitrate of lead. A precipitate falls which must be well washed and carefully dried out of the reach of CHROME IRON. 335 any sulphuretted vapors. A lighter shade of yellow is obtained by mixing some solution of alum or sulphuric acid with the chromate before pouring it into the solution of lead ; and an orange tint is to be procured by the addition of subacetate of lead in any desired proportions. It was ascertained by MM. Riot and Delisse, that the proportion of chromic acid in chromate of lead may be much diminished without any injury to the color, and that the same color is produced with 25 parts of neutral chromate for 100 of chrome yellow, as when 54 parts are used. They give the following formula for the preparation of this pigment. Acetate of lead is dissolved in water, and sulphuric acid in quantity necessary to convert the oxide of lead into sulphate is added. The clear liquid contains acetic acid, and may be drawn off and preserved for the preparation of fresh acetate of lead. The sulphate of lead is washed and treated with a hot solution of neutral chromate of potash, 25 parts being used for every 75 parts of sulphate of lead. The liquid then contains sulphate of potash which may be made available, and the precipitate consists of chromate of sulphate of lead. To prepare chrome red, Runge directs an intimate mixture to be made of 448 lbs. of litharge, 60 lbs. of common salt, and 500 lbs. of water. As soon as the mass becomes white and swells up considerably, more water is added to prevent it from becoming too hard. After four or five days, the mass becomes a compound of chloride and hydrated oxide of lead. Without separating the mother liquor, which contains undecomposed chloride of sodium and soda, 150 lbs. of powdered bichromate of potash are to be added, and the whole well stirred together, and finally washed. Liebig and Wohler have lately contrived a process for producing a subchromate of lead of a beautiful vermilion hue. Into saltpetre, brought to fusion in a crucible at a gentle heat, pure chrome yellow is to be thrown by small portions at a time. A strong ebullition takes place at each addition, and the mass becomes black, and continues so while it is hot. The chrome yellow is to be added till little of the saltpetre remains undecomposed, care being taken not to overheat the crucible, lest the color of the mixture should become brown. Having allowed it to settle for a few minutes, during which the dense basic salt falls to the bottom, the fluid part, consisting of chromate of potash and saltpetre, is to be poured off, and it can be employed again in preparing chrome yellow. The mass remaining in the crucible is to be washed with water, and the chrome red being separated from the other matters, it is to be dried after proper edulcoration. It is essential for the beauty of the color, that the saline solution should not stand long over the red powder, because the color is thus apt to become of a dull orange hue. The fine crystalline powder subsides so quickly to the bottom after every ablution, that the above precaution may be easily observed. CHROME IRON”. The only ore of chromium which occurs in sufficient abundance for the purposes of art, is the octohedral chrome ore, commonly called chromate of iron, though it is rather a compound of the oxides of chromium and iron. The fracture of this mineral is imperfect conchoidal, or uneven. Hardness=5’5 ; specific gravity 4*4 to 4-6; but the usual chrome ore found in the market varies from 3 to 4. Its lustre is semi-metallic or resinous ; color, iron, or brownish black ; streak, yellowish to reddish brown. It is some- times magnetic. Before the blowpipe it is infusible alone, but in borax it is slowly soluble, forming a beautiful emerald green bead ; fused with nitre it forms a yellow solution in water. Chrome ore was first discovered in the Yar department in France ; it is also found in Saxony, Silesia, Bohemia, and Styria ; in Norway at Roraas ; in the Ural near Katherinen- berg ; in the United States at the Barehills near Baltimore, Chester in Massachusetts, and Hoboken in JS’ew Jersey. In Scotland it is found in the parishes of Kildrum and Towie in Aberdeenshire ; in the limestone near Portsoy in Banffshire ; near Ben Lawes in Perthshire, and at Buchanan in Stirlingshire. It occurs massive and in considerable quantity at Swi- naness, and Haroldswick in Unst, one of the Shetlands ; also in Fetlar and in other of the smaller Shetland Islands. Composition of Chrome Iron Ores. 1. 2. 3. 4. 6 . Sesquoxide of Chromium 36-0 54-08 39-51 60-04 43-00 » Protoxide of Iron ... 87-0 25-66 36-00 20-13 34-70 Alumina 21-5 9-02 13-00 11-85 20-30 Magnesia - - 6-36 - 7-45 - Silica 6 0 4-83 10-60 - 2-00 99-5 98-95 99-11 99-47 100-00 (1) From St. Domingo, analyzed by Berthier; (2) from Roraas, in Norway, analyzed by Von Kobell; (3) from Baltimore, analyzed by Seybert; (4) crystallized, from Baltimore, analyzed by Abich; (5) ana- lyzed by Klaproth. 336 CHEOME IRON. The chief application of this ore is to the production of Chromate of Potash, from which salt the various other preparations of this metal used in the arts are obtained. Treatment of the Ore . — According to the old method, it 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 several hours, on a reverberatory hearth, where it is stirred about occasionally. In the large manufactories of this country, the ignition of the above mixture in pots is laid aside as too operose and expensive. The calcined matter is raked out and lixiviated with water. The bright yellow solution is then evaporated briskly, 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. The 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 concentrated solution with nitric, muriatic, sul- phuric, or acetic acid, or indeed any acid exercising a stronger affinity for the second atom of the potash, than the chromic acid does. The first great improvement in this manufacture was the dispensing with nitpe, and oxidizing entirely by means of air admitted into the reverberatory furnace, in which the ore mixed with carbonate of potash is calcined. Stromeyer afterwards suggested the addition of lime, by which the oxidation was much quickened, and Mr. Charles Watt substituted the sulphates of potash and soda for the nitrates of those alkalies. The sulphate was first inti- mately mixed with the ground ore, and then the lime well incorporated with the mixture, which was heated to bright redness for four hours, with frequent stirring. In 184'7 Mr. Tighman obtained a patent for the use of felspar in the manufacture of cer- tain alkaline salts, and amongst them of chromate of potash : he directs 4 parts by weight of felspar, 4 parts of lime, or an equivalent quantity of carbonate of lime, and one part of chromic ore, all in fine powder, to be intimately mixed together, and kept at a bright red heat for from 18 to 20 hours in a reverberatory furnace, the mixture being turned over frequently, so that all parts may be exposed equally to heat and air ; thg temperature is not to rise high enough to cause even incipient fusion, and the charge should be kept in a porous state ; when, on being examined, the charge is found to contain the proper quantity of alkaline chromate, it is withdrawn from the furnace, and lixiviated with water. Mr. Swindell mixes the powdered ore with an equal weight of common salt, muriate of potash, or hydrate of lime, and exposes the mixture to a full red heat, passing over it while in fusion highly heated steam, and stirring it every 10 or 16 minutes ; the hydrochloric acid and iron escape in the form of sesquichloride of iron. In treating chromium, (chromate of iron,) the ore is pulverized and mixed with common salt, muriate of potash, or hydrate of lime, and exposed in a reverberatory furnace to a red or even a white heat, the mixture being stirred every ten or fifteen minutes, and steam at a very elevated temperature introduced during the operation, until the desired effect is ob- tained, which may be ascertained by withdrawing a portion from the furnace and testing it, as customary. The products of this operation ai-e finally treated in the manner usual for the chromic and bichromic salts. The mixture of chromium and common salt produces chromate of soda, the greater por- tion, or perhaps all of the iron contained in the chromium being absorbed by the hydro- chloric acid evolved from the salt, and carried off in the form of sesquichloride of iron. From the first mixture is manufactured pure bichromate of soda, which, by the addition of hydrochloric acid, may be converted to chlorochromate ; and from the last, or lime mix- ture, is produced a chromate of that earth, from which, by the addition of soda or potash, there may be obtained a compound salt, which, with those previously mentioned, may be advantageously employed. M. Jacquelin first prepares chromate of lim.e by calcining at a bright red heat in a rever- beratory furnace, for 9 or 10 hours, an intimate mixture of chalk and chrome ore. The friable and porous mass is then crushed, suspended in water, and sulphuric acid added until the liquid slightly reddens blue litmus paper ; the chromate of lime is hereby converted into bichromate ; chalk is now added, until the whole of the sesquioxide of iron is precipi- tated, and the clear liquid, which now contains only bichromate of lime and a little sulphate, may be used for the preparation of the insoluble chromates of lead, zinc, baryta, &c., by mixing it with the acetates or chlorides of these metals. To prepare bichromate of potash, the bichromate of lime is mixed with solution of carbonate of potash, which gives rise to insoluble carbonate of lime, which is easily washed, and a solution of bichromate of potash which is concentrated and set aside to crystallize. Mr. Booth (patent sealed Nov. 9th, 1852) mixes powdered chrome ore with one-fifth of its weight of powdered charcoal, and heats it on the hearth of a reverberatory furnace, protecting it carefully from the air. The ore is by this means decomposed, and the iron reduced to the metallic state, and is dissolved out by dilute sulphuric acid ; the residue is washed and dried, and afterwards mixed with carbonate of potash and saltpetre, and heated CHROMIUM, OXIDE OF. 837 in the same manner that the chrome ore itself is heated in the process usually employed. The solution of sulphate of iron is evaporated to crystallization so as to produce copperas in a state adapted for commerce. Analysis of Chrome Iron Ore. — Various methods have been proposed. The following, suggested by Mr. T. S. Hunt, gives accurate results : — The ore, finely levigated in an agate mortar, is mixed with 10 or 12 times its weight of fused bisulphate of potash, and preserved at a gentle heat for about half an hour. The fused mass is extracted with hot water, and boiled for a few minutes with excess of carbonate of soda ; the precipitate is dried and fused with five times its weight of a mixture of equal parts of nitre and carbonate of soda, in a platinum or silver crucible. The mixture is kept in fusion for 10 or 15 minutes, and when cold, is extracted with water. The alkaline chromate thus obtained may be precipi- tated by a salt of lead, or it may be supersaturated by hydrochloric acid, and boiled with alcohol, by which it is converted into chloride of chromium, from which the oxide is to be precipitated by adding ammonia in excess and boiling for a few minutes. Chrome iron ore is so difficult of decomposition, that the method of fusing it at once with nitre and an alkaline carbonate frequently fails in oxidizing the whole of the chromium into chromic acid. Mr. Calvert mixes the well-pulverized ore with three or four times its weight of a mix- ture made by slaking quicklime with caustic soda, and then dries and calcines the mass. He then adds one-fourth part of nitrate of soda, and calcines for two hours more, by which time he finds the whole of the chromium is converted into chromic acid. Another process, which Mr. Calvert finds to produce good results, consists in calcining the pulverized chrome ore with nitrate of baryta, adding a little caustic potash from time to time towards the end of the process. — H. M. N. CHROMIC ACID. There are several methods of preparing this acid ; the simplest con- sists in decomposing bichromate of potash by oil of vitriol : — 1. An excess of oil of vitriol is mixed with a warm solution of bichromate of potash, the liquid is poured off from the chromic acid, which separates in small red crystals ; the crystals are drained in a funnel having its stem partly filled with coarsely pounded glass, and are afterwards dried on a porous tile under a bell-glass. 2. Mr. Warrington mixes 10 measures of a cold saturated solution of bichromate of potash with from 12 to 15 measures of oil of vitriol free from lead, and presses the red acicular crystals, wliich separate as the liquid cools, between porous stones. If it be desired to remove the last traces of sulphuric acid, the crystals should be redissolved in water, and a solution of bichromate of baryta should be added in quantity just sufficient to throw down the whole of the sulphuric acid as sulphate of baryta ; the solution may be recrystallized by evaporation in vacuo. 3. Meissner prepares the acid direct from chromate of baryta by digesting that salt with a quantity of dilute sulphuric acid, not sufficient for complete saturation ; the solution which contains chromic acid and acid chro- mate of baryta is precipitated by the exact amount of sulphuric acid required, so that the solution is neither affected by sulphuric acid, nor by a salt of baryta ; it is then evaporated to dryness. ' CHROMIUM. The metallic base of the oxide of chromium. It may be obtained by exposing to a very high temperature, in a crucible lined with charcoal, an intimate mixture of sesquioxide of chromium and charcoal. The spongy mass obtained is powdered in an iron mortar and mixed with a little more sesquioxide of chromium, (to oxidize as much as possible of the carbon ;) it is then again exposed in a porcelain crucible to a very high tem- perature, when a coherent metal is obtained. This metal is grayish in color, hard, and brittle, and is magnetic at low temperatures. It has received no practical applications. CHROMIUM, OXIDE OF. The green oxide of chromium has come so extensively into use as an enamel color for porcelain, that a fuller account of the best modes of manufactur- ing it must prove acceptable to many of our readers. That oxide, in combination with water, called the hydrate, may be economically prepared by boiling chromate of potash, dissolved in water, with half its weight of flowers of sulphur, till the resulting green precipitate ceases to increase, which may be easily ascertained by filtering a little of the mixture. The addition of some potash accelerates the operation. This consists in combining the sulphur with the oxygen of the chromic acid, so as to form sulphuric acid, which unites with the potash of the chromate into sulphate of potash, while the chrome oxide becomes a hydrate. An extra quantity of potash facilitates the deoxi- dizement of the chromic acid by the formation of hyposulphite and sulphuret of potash, both of which have a strong attraction for oxygen. For this purpose the clear lixivium of the chromate of potash is sufficiently pure, though it should hold some alumina and silica in solution, as it generally does. The hydrate may be freed from particles of sulphur by heating dilute sulphuric acid upon it, which dissolves it ; after which it may be precipitated, in the state of a carbonate, by carbonate of potash, not added in excess. By calcining a mixture of bichromate of potash and sulphur in a crucible, chromic acid is also decomposed, and a hydrated oxide may also be obtained ; the sulphur being partly converted into sulphuret of potassium, and partly into sulphuric acid, (at the expense of the VoL. III.— 22 838 CHROMIUM, BLUE OXIDE OF. chromic acid,) which combines with the rest of the potash into a sulphate. By careful lixi- viation, these two new compounds may be washed away, and the chrome green may be freed from the remaining sulphur by a slight heat. Preparation of Green Oxide of Chromuim for Calico-printing. — The following direc- tions are given by De Kerrur : At the commencement of the process the green hydrate of the oxide of chromium is first prepared by dissolving 4 kilogrammes of bichromate of pot- ash in 22 litres (39 pints) of boiling water. Then into a boiler or vessel containing 108 litres (24 gallons) of boiling water, 4 or 5 kilogrammes (8 or 10 lbs.) of pulverized white arsenic are thrown, and boiled for 10 minutes ; a precipitate will be formed, and must be allowed to settle : the clear liquor is then run off, and immediately mixed with the solution of bichromate of potash, stirring all the time : in a short time the mixture acquires a green tint, and the hydrated oxide of chromium will be formed and precipitated. After being several times well stirred, and allowed to cool, the whole is thrown upon a filter of white wool, and the hydrate of chromium remaining on the filter is carefully washed with boiling water. It is then dried, and ready to be employed for the preparation of the chloride. In order to obtain that salt, hydrochloric acid of 22° Beaume is diluted with water, until the acid no longer gives off vapor. It is then heated, and, whilst hot, as much of the hydrated oxide of chromium, prepared as above, is added as will saturate the acid and leave a slight excess of the oxide undissolved. The whole is then left to settle, and the clear liquor is decanted from the dissolved matter. In this state the solution of chloride of chromium still presents some traces of free acid, which would act injuriously upon the fibres of the cotton. To remove this, and to obtain the product in a neutral state, potash lye (marking 36° Beaume) is poured in very gradually, until the oxide of chromium begins to be precipitated. The solution of chloride of chromium thus prepared, and which is of a dark green color, is evaporated until it marks 46° Beaume ; after cooling, oxide of chromium of the finest green color is obtained. This preparation is sold under the name of Sea-green. This oxide may also be prepared by decomposing, with heat, the chromate of mercury, a salt made by adding to nitrate of protoxide of mercury, chromate of potash, in equivalent proportions. This chromate has a fine cinnabar red, when pure ; and, at a dull red heat, parts wuth a portion of its oxygen and its mercurial oxide. From M. Dulong’s experiments it would appear that the purest chromate of mercury is not the best adapted for preparing the oxide of chrome to be used in porcelain painting. He thinks it ought to contain a little oxide of manganese and chromate of potash to afford a green color of a fine tint, especially for pieces that are to receive a powerful heat. Pure oxide of chrome preserves its color well enough in a muffle furnace ; but, under a stronger fire, it takes a dead-leaf color. — H. M. N. CHROMIUM, BLUE OXIDE OF. The following directions have been given for the preparation of a blue oxide of chromium : The concentrated alkaline solution of chromate of potash is to be saturated with weak sulphuric acid, and then to every 8 lbs. is to be added 1 lb. of common salt, and half a pound of concenti’ated sulphuric acid ; the liquid will now acquire a green color. To be certain that the yellow color is totally destroyed, a small quantity of the liquor is to have potash added to it, and filtered ; if the fluid is still yellow, a fresh portion of salt and of sulphuric acid is to be added : the fluid is then to be evaporated to dryness, redissolved, and filtered ; the oxide of chrome is finally to be precip- itated by caustic potash. It will be of a greenish-blue color, and, being washed, must be collected upon a filter. — H. M. N. CHRYSOBERYL, or GOLDEN" BERYL, is composed of alumina 80-2 and glucina 19'8 = 100. It is of various shades of yellowish and light green, sometimes with a bluish opa- lescence internally. It has a vitreous lustre, and varies from translucent to transparent. Fracture, conchoidal or uneven. Specific gravity = 3 ’5 to 3 ‘8. It belongs to the trime- tric system. This stone, when transparent, furnishes a beautiful gem of a yellowish-green color, which is cut with facets, unless it be opalescent, in which case it is cut en cahochon. It occurs in the Brazils and Ceylon, in rolled pebbles in the alluvial deposits of rivers ; in the Ural, in mica-slate ; and at Haddam, Connecticut, U. S., in granite, traversing gneiss. — H. W. B. CHRYSOLITE, or PERIDOT. The name given to the paler and more transparent crystals of olivine, the latter name being restricted to imbedded masses or grains of inferior color and clearness. It is usually found in angular or rolled pieces, rarely crystallized. The crystals (generally 8, 10, or 12-sided prisms) are variously terminated, and often so com- pressed as to become almost tabular. They are generally very fragile, and therefore unfit for ornamental purposes. Oriental chrysolite is composed of silica 39*73, magnesia 50*13, protoxide of iron 9*19, alumina 0*22, protoxide of manganese 0*09, oxide of nickel 0*32 =: 99*68. — Stromeyer. As a gem, chrysolite is deficient in hardness and play of color ; but when the stones are large and of good color, and well cut and polished, it is made into necklaces, &c., with good effect. From its softness, which is little less than that of glass, it requires to be worn with care, or it will lose its polish. The best mode of displaying the colors to the greatest ad- CLOVE OIL. 339 vantage is to cut it in small steps. To give it the highest polish, a copper wheel is used, on which a little sulphuric acid is dropped. During the process, a highly suffocating smell is given out, produced, probably, by the oxidation of the copper and the decomposition of the acid. Chrysolite is supposed to have been the topaz of the ancients. It is found near Constantinople ; at Vesuvius ; and the Isle of Bourbon, at Real del Monte ; in Mexico ; in Egypt ; and at Expailly, in Auvergne. — H. W. B. CHRYSOPRASE. An apple-green or leek-green variety of chalcedony, the color of which is caused by the presence of nickel. It occurs at Kosemeitz, in Silesia, and Belmont’s lead mine, St. Lawrence County, New York. This stone was probably the chrysoberyl of the ancients. — H. W. B. CINCHONICINE. An alkaloid isomeric with cinchonine and cinchoni- dine. It is produced by the action of heat on any of the saline combinations of cinchonine. {Pasteur.) To obtain cinchonicine, it is only necessary to add a small quantity of water and sulphuric acid to sulphate of cinchonine, and, after driving off all the water at a low temperature, to keep the salt for a few hours at a temperature between 250° and 270°. The product is pure sulphate of cinchonicine. By a similar reaction quinine becomes converted into quinicine ; quinidine also is susceptible of a similar metamorphosis. — C. G. W. CINCHONIDINE. C'^H^'N^O^ This alkaloid, the quinidine of Leers, is one of the isomers of cinchonine. There is much confusion to be found in works on the cinchona al- kaloids, partly arising from the troublesome system of giving them names greatly resembling each other, and partly from mixtures having been analyzed under the impression of their being pure bases. For some remarks on this subject, see Quinidine. Cinchonidine was first noticed by Winckler ; it is found accompanied by a little quinine in the Cinchona Bo- gota, also in that of Macaraibo. For the reactions of cinchonidine, and its associated bases with chlorine water and ammonia, see Quinine. — C. G. W. CINCHONINE. C^°H^^N^O^. An alkaloid or organic base accompanying quinine. In consequence of its being considered less febrifuge than quinine, it is always carefully re- moved from the latter. Some of the differences of properties on which processes for their separation may be founded are the following ; Cinchonine crystallizes more readily than quinine from an alcoholic solution, in consequence of its being less soluble in that fluid. Sulphate of quinine, on the other hand, is less soluble than sulphate of cinchonine. Cin- chonine is insoluble, while quinine is freely soluble in ether. Cinchonine forms a great number of salts, which for the most part are well defined, and crystallize readily. It is not so bitter as quinine. In cold water it is quite insoluble, and even when boiling, 2,500 parts are required to dissolve one of cinchonine. Laurent has studied the action of the halogens on it at considerable length, but there are several points connected with this portion of their history which requires re-investigation. Treated with potash at a high temperature, a basic fluid is obtained, formerly considered to be pure chinoline, but which has been shown by the author of this article to contain pyrrol, all *the pyridine series, chinoline, and a new base, lepidine. — C. G. W. CINNABAR, is the principal and only valuable ore of the mercury of commerce, which is prepared from it by sublimation. It is a sulphide {sulphuret) of mercury, composed, when pure, of quicksilver 86’2, sul- phur, 13 ’8, in which case it is a natural vermilion, and identical with the vermilion of commerce ; but it is sometimes rendered impure by an admixture of clay, bitumen, oxide of iron, &c. Cinnabar is of a cochineal red color, often inclining to brownish-red, and lead- gray, with an adamantine lustre, approaching to metallic in dark varieties, and to dull in friable ones. It varies from sub-transparent to opaque, has a scarlet streak, and breaks with a sub-conchoidal uneven fracture. H — 2 to 2-5, specific gravity = 8*99. In a matrass it entirely sublimes, and with soda yields mercury with the evolution of sulphurous fumes. When crystallized, it belongs to the rhombohedral system. Cinnabar occurs in beds in slate-rocks. The chief European beds are at Almaden near Cordova, in Spain, and at Idria in Upper Carinthia, where it usually occurs in a massive form, and is worked on a thick vein belonging to the Alpine carboniferous strata. It also occurs abundantly in China, Japan, Fluanca Vilica in South Peru, and at New Almaden in California, in a mountain east of San Jose, between the Bay of Francisco and Mon- terey where it is very abundant, and easy of access. The chief source of the mercury used in England is Spain, whence 10 cwt. of cinnabar and 14,544 lbs. were imported in 1857. Cinnabar in the arts is used as a pigment, in the state of a fine powder, which is known by the name of vermilion. See Vermilion. — H. W. B. CLOVE OIL. (C^“H*^0‘‘. Syn. Eugenic acid., Carophyllic acid.) When cloves are distilled with water, a large quantity of oil passes over. It has been examined by Dumas, Ettling, Bdckmann, Stenhouse, Calvi, and, more reeently, by Greville Williams. Treated with solution of potash, the greater portion dissolves, leaving a small quantity of a hydro- carbon isomeric with oil of turpentine. See Carburetted Hydrogen. The potash solu- COAL. 340 tion, on being supersaturated with a mineral acid, allows the eugenic acid to rise to the sur- face in the form of an oil. When freshly distilled it is colorless, and boils at 483° S. Its density at 67° *2 F. is 1-0684. On analysis it gave : — Greville Williams. Calculation. Carbon - - - 73*1 73-1 - . - 120 73-17 Hydrogen - - 7-7 7-6 - - - H'2 12 7-32 Oxygen - - - 19-2 19-3 - - - 0^ 32 19-51 100-0 100-0 100-00 The density of its vapor was found to be 5 *86. Theory requires 6-67. The above results were confirmed bv a determination of the percentage of baryta in the eugenate. — C. G. W. ' COAL. The coal-fields of the United Kingdom are the most important of any worked in the world. Their production has been variously estimated as being between thirty-one and fifty-four millions of tons annually. It has now been determined by inquiries carefully made by the Keeper of Mining Records that these amounts were far exceeded, as is shown by the following returns : — Tons. Tons. Tons. Tons. Northumberland and Durham Cumberland .... Yorkshire ----- Derbyshire - - - - - Nottinghamshire - - - - Warwickshire - Leicestershire - - - . Staffordshire and Worcestershire - Lancashire - Cheshire Shropshire - Gloucester, Somersett and Devon Wales Scotland - - - - Ireland - - - - 1854. 15,420,615 887.000 7.260.500 2,406,696 813,474 255.000 439.000 7.500.000 9.080.500 786,500 1.080.000 1,492,366 9.643.000 7.448.000 148,750 1855. 15,431,400 809,649 7,747,470 2.256.000 809,400 262,000 425,000 7.323.000 8.950.000 755,600 1,105,250 1,430,620 9,677,270 7.325.000 144,620 1856. 16,492,969 913,891 9,083,625 [3,293,325 335,000 632,478 7,305,500 8.950.000 754,327 752,100 1.630.000 9,965,600 7.500.000 136,635 185T. 15,826,625 942,018 8,875,440 3,687,442 398.000 698,750 7,164,625 8,565,500 750,500 750.000 1,225,000 8,178,804 8,211,473 120,630 64,661,401 64,453,070 66,645,450 65,394,707 The total number of collieries in the United Kingdom being — England 1,943 Wales 235 Scotland 405 Ireland 71 2,654 The distribution of coal in the United Kingdom is one of vast importance to the coun- try. It is spread over large areas, commencing with Devonshire in the south, and extend- ing to the northern divisions of the great Scotch coal-fields. A careful examination of all these deposits cannot but prove useful. Devonshire. Lignite of Bovey-Heathjield. — Lysons (^Magna Britannia) informs us that this so-called Bovey coal was worked for use early in the last century ; and Dr. Maton described those beds in 1797 as being from 4 to 16 feet in thickness, alternating with clay, and he stated that the pits were about 80 feet deep, and worked for the supply of a neigh- boring pottery. A pottery was established at Ideo in 1772, and one at Bovey Tracey in 1812, both of which were supplied with fuel from those lignite beds. Those beds are sup- posed to have been formed towards the latter part of the supercretaceous periods. The wood of which they are formed has been sometimes supposed to be analogous to the oak and other existing trees. The offensive smell emitted by this lignite when burnt has always prevented its use for domestic purposes, except among the poorer cottages of the neighbor- hood. The supply from those beds of “ Bovey coal ” is now falling off, the adjoining pot- tery being compelled to use some coal as fuel. — Be la Beche. Bideford Anthracite. — The beds of Anthracite stretch across the country from Barn- staple Bay, by Bideford and Averdiscot, towards Chittlehampton, a distance of about COAL. 341 twelve miles and a half. The anthracite is mixed with the black shales of the carbonaceous deposits. “ The anthracite is mixed with those shales in the manner represented beneath,/^. 160 ; a, sandstones ; b, shales ; c, culm 160 or anthracite; so that the culm itself seems the result of irregular accumulations of vegetable mat- ter intermingled with mud and sand. As so frequently happens with carbonaceous deposits of this kind, nodules of argillaceous iron- stone are often found in the same localities with the shales and an- thracite, reminding us of the intermixture of iron ores and vegetables matters in the bogs and morasses of the present day .” — De la Beche. Somersetshire and Gloucestershire. — The Dean Forest coal-field, and the coal meas- ures, extending further south forming the Bristol coal-field, are included in this division. The workable seams of coal in the forest are the following : — Dog Delf Smith Coal Little Delf Park End High Delf Stakey Delf Little Coal Rocky Delf Upper Churchway Delf Lower Churchway Delf Braizley Delf Nag’s Head, or Weaver’s Whittington Delf Coleford High Delf Tipper Trenchard Lower Trenchard (having a thickness of) There is a small coal-field north of the Forest of Dean, which is a long narrow strip, containing two and a half square miles, or 1,600 acres. — Maclauchlan, Geological Transac- tions ^vo\. V. About nine miles and a half to the south of Dean Forest a considerable mass of coal measures has been preserved from destruction, by the denuding causes which have carried off the connecting portion between it and Dean Forest, leaving at least two outlying patches on the north of Chepstow. The Bristol coal-field occupies about fifty square miles, or 32,000 acres. The seams of coal are very thin in comparison with those which ai-e worked in other districts. Buckland and Coneybeare (Geological Transactions, vol. i.) have well described this coal- field. The total thickness of the whole series of strata in this Bristol coal-field has been shown by De la Beche to be as follows : — Upper shales and limestones 1,800 feet, with 10 beds of coal. Middle sandstone 1,725 feet, with 6 beds of coal. Lower shales 1,565 feet, with 36 beds of coal. Farewell Rock 1,200 feet. 6,290 South Wales Coal-field. — The total thickness of the coal strata in this important district is very great. Logan and De la Beche have accumulated evidence which appears to justify the admission of 11,000, or even 12,000 feet thickness from the carboniferous limestone to the highest part of the coal series about Llanelly ; in other parts of the field the series is found to be on proportions only less gigantic. The most general view which can be afforded seems thus, giving the true coal measure about 8,000 feet : — feet. Llanelly series, with several beds of coal 1,000 Penllergare series of shales, sandstones, and beds of coal, 110 beds ; 26 beds of coal 3,000 J 342 . COAL. Central series, (Townhill sandstones of Swansea, Pennant grit of the Bristol field ;) 62 beds, and 16 beds of coal 3,246 Lower shales, coals, and iron-stones, (Merthyr ;) 266 beds, 34 beds of coal 812 Abundance of iron-stone beds and unionidce occur. Farewell-Rock and Gower shales above ; the carboniferous limestone below. The coal on the north-eastern side of the basin is of a coking quality, excellent for the iron manufacture ; on the north-western it contains little or no bitumen, being what is called stone-coal or anthracite ; on the south side, from Pontypool to Caermarthen Bay, it is of a bituminous or binding quality. — Phillips. Shropshire. — This district includes the small coal-field of Coalbrook Dale, and that of the plain of Shrewsbury. The Coalbrook Dale field, according to Mr. Prestwick, has some remarkable features. {Geological Transactions.) Perhaps there is no coal track known,, which in so small a compass, about twelve miles long, and, at most, three and a half miles wide, exhibits so many curvatures in the outcrops, crossed by so many continuous faults, some varying north by east, others east-north-east ; these crossed by many of shorter length, and directed west-north-west, and in several other lines. The total thickness is supposed to be 1,000 or 1,100 feet, divided into 80 distinct strata. The coal varies in total thickness from 16 feet to 55, and in the number of its beds from 7 to 22, the increase being to the north. The “ cleat ” or systems of joints run from west-north-west to east-south- east. The coal is, for the most part, of the variety called slate coal in Scotland, and hard coal in Derbyshire. Cannel coal is rare — sulphureous coal (pyritous) very common. Pe- troleum abounds in the central and upper part of the field. The beds are mostly thin ; the ten uppermost are too sulphureous for other uses than lime-burning, and are called stinkers ; twelve beds of good coal, in all 25 feet thick, the thickest being five feet, succeed, and the lowest bed of the whole formation, eight inches thick, is sulphureous. — Phillips^ Prestwick. Staffordshire. — The coal-field of South Staffordshire^ which has been described by Mr. J. Beete Jukes, who states its boundary would be roughly described as the space in- cluded within a boundary line drawn from Rugeley through Wolverhampton to Stourbridge ; hence to the southern end of the Bromsgrove Lickey, and returning through Harborne (near Birmingham) and Great Barr back to Rugeley. This geologist classes these coal strata in three divisions, by the well-traced band of thick coal. The total thickness of coal near Dudley being about 57 feet, and between Bilston and Wolverhampton upwards of 70 feet. The thick coal is formed of eight, ten, or thirteen distinguishable parts, the whole seam varying in thickness from three feet to thirty-nine feet five inches; it is very irregular in parts, divided by sandstone, splitting with wide-shaped offshoots, and cut into “ swiles ” or “ horse backs,” which rise up from the floor. Below the thick coal are numerous beds of sandstone-shales, coal, and iron-stone, having on the average a thickness of 320 feet ; and above the thick coal the thickness is 280 feet on the average. — Records of the School of Mines. North Staffordshire Coal-field. — This field is comprised in the space between Congleton, Newcastle-under-Lyne, and Lane End. About 32 beds of coal have been determined, rising eastward between Burslem in the centre of the field and its eastern limit near Norton church. Derbyshire and Nottinghamshire. — The Derbyshire and Nottinghamshire coals are classed as to structure in two varieties, as “ hard'''' coal, in which the divisional structures are chiefly derived from the planes of stratification, crossed by one set of “ cleat ” or natural joints, (called “ slines,” “ backs,” &c. ) so that large prismatic masses result ; “so// ” coal, where the cleat fissures are numerous, and broken by cross cleat. In respect of the quality., some of the coal is of a “ crozling ” or coking nature, easily fusible, and changing its figure by “ coking ; ” the rest, (and this is specially the case with the “ hard ” variety,) makes both good furnace coal and excellent coke, which, however, is hardly melted at all, and the masses are not changed in figure by the process. — Phillips's Manual of Geology. The names by which the more important beds of coal worked within this district are known, are as follows : Tupton coal, hard coal, soft coal, black shale or clod coal, low hard coal and low soft, windmill coal, Dansil coal, Ganister coal, Parkgate coal, Aston coal, Kil- burn coal, furnace coal. Hazel coal. Eureka coal, main and deep coal. Leicestershire and Warwickshire. — The Leicester coal-field is best developed about Ashby de la Zouch, (see Mammatt on “ the coal-field of Ashby de la Zouch,”) where the coal is much like the hard coal of Derbyshire. Amongst the seams of coal is one variety called cannel ; and another, formed by the concurrence of more than one band, from seven- teen to twenty-one feet in thickness. The beds near Ashby de la Zouch are as follows : — In the Moira district — COAL. Eureka coal Stocking coal Woodfield coal - Slate coal Nether main coal Fourfoot coal The Earl coal 343 Thickness of beds. 4 to 6 feet. 6 to 7 “ 5 “ to 4 “ 14 to 15“ 4 to 5 “ 4 ft. 6 in. In the Coleorton district — Heath End coal 9 feet. Lount coal (3 beds.) Main coal - - - - - - - - 10 to 12 feet. The Warwickshire Coal-field is from a point east of Tamworth to a point east of Coven- try, about twenty miles from N. W. to S. E. parallel to the Ashby coal tracts. The strata are most productive of coal near the southern extremity, where by the coming together of two seams, — worked separately at Griff, — the five-yard seam is worked. The beds are known as the seven-feet coal and rider, slate coal, two yards, lower seam, cannel, and Ell coal. Yorkshire. — Professor John Phillips gives the following mode of classification as the most natural and convenient for the Yorkshire coal. Magnesian limestone unconformably covers the coal seams. { Shales and Badsworth coal. Ackworth rock. Wragby and Sharlston coals. Red rock of Woolley Hooton-Roberts, &c. Middle coals - 'Furnace coals Intermediate coals Iron-stone coals - - Barnsley thick coal. ( Rock of Horbury. ’ \ Middle coals. i Silkstone and Flockton beds. ' ( Low Moor coals. Flagstone rock of Woodhouse, Bradford, Elland, Peniston, &c. r Shales and ganister stone. Coals. Lower coals - -{ Shales and ganister stone. I Coals. [^Shales, &c. Millstone grit lies below the “ coal series.” The important middle coal series are again divided by Professor Phillips as follows Red rock of Woolley Edge. F urnace coals of Barnsley, &c. including the eight or ten feet seam. Rock of Horbury and Wentworth House. i Swift burning coals of Middleton, Dewsbury, &c., with bands of “ mussels.” Bituminous coals of Silkstone and Low Moor. Flagstone rocks beneath. The small coal-field of Ingleton and Black Burton in Lonsdale is thrown down on the south side of the great Craven fault. Lancashire. — The coal-field of Lancashire occupies an area extending from Maccles- field to Colne, 46 miles, and from Torboch, near Liverpool, to Todmorden, about 40 miles. Excluding the millstone grit, its area is about 250 square miles. — Heywood. In a line through Worsley, Bury, and Burnley to the limestone shales of Pendle Hill, we have 36 seams of coal, 10 of them not exceeding 1 foot in thickness, making in all 93 feet of coal. The series is divisible into three parts above the millstone grit : Upper part^ containing a bed of limestone at Ardwich near Manchester. Middle part^ containing the greater part of the thick and valuable seams, especially the cannel coal of Wigan. Lower part^ corresponding to the ganister series of Yorkshire. Cheshire. — The coal-field of Cheshire is not of great importance. North Wales. — Flintshire and Denbighshire . — The Flintshire coal basin extends from north to south, somewhat more than 30 miles from Llanassa to near Oswestry in Shropshire. The coal strata dip generally eastward and form in the northern part a trough beneath the estuary of the Dee. This coal basin in Flintshire commences with beds of shale and sand- stone. The coal is of various thickness, from f to 5 yards, and consists of the common, cannel, and peacock varieties . — Phillips and Conybeare. 844 COAL. Cumberland. — This coal-field extends as a narrow crescent from Whitehaven to near Hesket Newmarket : — around Whitehaven and at Workington the coal is worked extensively. At the latter place, a few years since, a very valuable colliery was destroyed by the bursting in of the sea. There are three workable seams in the Cumberland coal-field in the neighborhood of the three undermentioned towns, and these are known in each place by the names given : — ■Whitehaven. Workington. Maryport. Bannock band. Main band. Six-quarter coal or Low- bottom seam. Moorbanks. Main seam. Hamilton seam. Ten quarters. Cannel and metal seams, (divided with shale from 2 feet to 5 fathoms thick.) Northumberland and Durham. — The total thickness of the coal measures of this dis- trict is about 1,600 feet. The number of distinct layers or beds, as usually noted by the miners, about 600. The total thickness of the beds of coal rarely exceeds — does not, on the average, equal — 60 feet. No bed of coal is of greater thickness, even for a short dis- tance, than 6 or 7 feet ; several are so thin as to be of no value at present. The total thickness of “ workable coal,” supposing all the beds to be found in a given tract, is not to be estimated at above 20 or 30 feet. The most part of the coal in this great district is of the coking quality, but, in this respect, there is much variation. The best coke for locomo- tive engines is now made from the lower coals in the Auckland district of Durham, and the Shotley Bridge district of Northumberland. The best “ steam coal ” is obtained from the north side of the Tyne and the Blyth district. The best “ house coal ” still comes from the remains of the “ High chain ” on the Tyne, and from the “ Hutton seam ” on the Wear ; but the collieries north of the Tees have acquired a high reputation. As a general view of the groups of strata the following summaries may suffice . — {Foster and Buddie.) Upper groups of coal measures, including chiefly thin seams of small value (8 or more) in a vast mass of sandstone and shales, with some iron-stone. At the base is a mussel band ; we estimate this at 900 feet. On the Tyne : — Ft. In. Ft. In. Ft. In. 'High main coal - - 6 0 Unknown Strata and thin coals - 60 0 Five-quarter coal - 3 9 to 6 9 Metal coal - - 1 6 Strata and thin coals - 30 0 Stone coal - - 3 0 o Strata - 83 0 Yard coal - - 3 0 Main coal ... 6 6 to 6 0 1 Strata - 90 0 Bensham seam - 3 0 Mandlin seam 4 6 to 6 0 Strata with several variable beds and some layers of mussels - . 150 0 Low main or Hutton ^ Low main coal - 6 0 seam . . - 4 6 to 6 6 Strata - 200 0 Hervey* s seam - 3 0 Beaumont seam - 3 0 to 6 0 Strata - 300 0 Brochwell seam - 3 0 Brockwell seam - 3 0 to 6 0 Strata above millstone grit - 200 0 — Phillips. On the Wear and Tyne: — The seams which are principally worked in this district are the high main, five-quarter main, Bensham seam, Hutton seam, Beaumont seam, low five-quarter, three-quarter seam, Brockwell and stone coals. These seams are known by other names, each district usually adopting its own peculiar term to designate the workable seams. Thus the Bensham seam of the Tyne is known as the Mandlin seam of the Wear. The Beaumont or Hervey seam is the Townley seam of the Townley colliery and the main eoal of Wylam colliery. At Het- ton the high main seam of the Cramlington district separates into two, and is called the three-quarter seam at Pontoss ; where it unites again it is known as the Shieldrow seam. The Cramlington gray seam is the metal-eoat seam and stone coal seam of Sherriff Hill, where it is divided ; while it unites at Hetton and forms the five-quarter seam of that and the Auckland district. The Cramlington yard seam becomes the main coal seam at Hetton, Haswell, and some other localities, the Brass Thill at Pontoss, and the main coal in Auck- land. Again the Cramlington five-quarter seam divides and forms the six-quarter, and the five-quarter at Sherriff Hill the Brass Thill seam at Pittington ; they again unite and form COAL. 345 the Hutton seam at Pontoss colliery, and so with regard to a few others. — Mineral Sta- tistics. Scotland. — “ A memoir on the Mid-Lothian and East Lothian coal-fields,” by David Milne, gives the most exact account of the carboniferous system of Scotland. There are three principal coal basins in Scotland : 1. that of Ayrshire ; 2. that of Clydesdale ; and 3. tW of the valley of the Forth, which runs into the second in the line of the Union canal. If two lines be drawn, one from Saint Andrews on the north-east coast, to Kilpatrick on the Clyde, and another from Aberlady, in Haddingtonshire, to a point a few miles south of Kirkoswald in Ayrshire, they will include between them the whole space where pitcoal has been discovered and worked in Scotland. According to Mr. Farey, there are 337 principal alterations of strata between the surface in the town of Fisherrow, on the banks of the Frith of Forth, (where the highest of these strata occur,) and the commencement of the basaltic rocks, forming the general floor and border of this important coal-field. These strata lie internally in the form of a lengthened basin or trough, and consist of sandstone, shale, coal, limestone, ironstone, &c. Sixty-two seams of coal, counting the double seams as one ; 7 limestone ; 72 assemblages of stone and other strata ; in all 5,000 feet in thickness. '• Professor Phillips remarks of this district, “ On the whole, allowing for waste, unattain- able portions, and other circumstances, this one district may be admitted as likely to yield to the miner for actual use 2,250 millions of tons of coal.” The coal is partly “ splint,” partly “ rough ” or “ cherry,” partly of the “ cannel ” or “ parrot ” variety ; the first con- taining most oxygen, the last, most hydrogen and nitrogen, and the least carbon. See Boghead Coal. Ireland. — The coal-fields of Ireland, if we include in this term the millstone grit, occu- py large tracts of land in that country, and are upon the whole analogous, in general mineral character and organic contents, to those of England. The same absence of limestone, the same kind of succession of sandstones and shales is remarked in them. Anthracite or stone-coal like that of South Wales abounds in the Leinster and Munster districts ; bitumi- nous coal occurs in Connaught and Ulster. In Ulster the principal collieries are at Coal Island and Dungannon. The Munster coal district is stated by Mr. Griffith to be of greater extent than any English coal-field, but it is much less productive. At Ballycastle the coal is found in connection with basalt. — Phillips. Such is a general and rapid sketch of the distribution of fossil fuel over the Islands of the United Kingdom. The importance of a correct knowledge of the distribution of coal in other parts of the world, especially to a commercial people whose steamers now trav- erse every sea, has led to the compilation, from the most reliable sources, of the following account : Between the Arctic Circle and the Tropic of Cancer repose all the principal carboniferous formations of our planet. Some detached coaT deposits, it is true, exist above and below these limits, but they appear, so far as we know, to be of limited extent. Many of these southern coal-fields are of doubtful geological age ; a few are supposed to approximate to the class of true coals, as they are commonly styled, others are decidedly of the brown coal and tertiary period, while the remainder belong to various intermediate ages, or possess peculiarities which render them of doubtful character. Southward of the Tropic of Cancer the existence of coal corresponding with the European and American hard coal is somewhat uncertain. There seems to be little coal on the South American continent. The discovery said to be made at Ano Baser needs confirmation, and of that in the province of Santa Catharina in Brazil we know little. On the African conti- nent we have had vague accounts of coal in Ethiopia, and at Mozambique, also at Madagas- car, and quite recently we have had intelligence of large quantities of coal in the newly- ceded territory above Port Natal, on the eastern side of Africa, but we believe no geologist has examined these sites. In the Chinese and Burmese empires brown coal only appears to approach the Tropic, but true coal seems to exist in the northern provinces. Southward of the Asiatic continent we are uncertain of the exact character of the coal deposits, such as occur at Sumatra, Java, and Borneo, and neighboring islands. Coal, however, exists in these islands, and is of a fair workable quality. In New South Wales the great coal range on the eastern margin of that continent has sometimes been described as resembling the Newcastle coal in England, and sometimes it is described as of more ancient date. This coal differs essentially from that of any known European formation, but bears a strong resemblance to the Burdwan coal of India. We have not yet arrived at the period when we could pronounce with any approach to certainty on the actual number of *coal basins in the world ; the total number must, how- ever, amount at least to from 250 to 300 principal coal-fields, and many of these are subdi- vided by the disturbed position of the strata into subordinate basins. The basins or coal districts are, however, grouped into a comparatively small number of districts, and even many of these are little known and not at all measured. The greater . 346 COAL. number occur in Western Europe and Eastern North America, while Central and Southern Africa, South America, and a large part of Asia are almost without any trace of true car- boniferous rocks. The remarks, therefore, that will follow chiefly refer to our own and adjacent countries, or of the United States and British North America. The principal coal-fields of Europe, apart from the British Islands, are those of Belgium, France, Spain, (in the Asturias,) Germany, (on the Ruhr and Saare,) Bohemia, Silesia, and Russia, (on the Donetz.) Belgium. — The Belgian coal-field is the most important, and occupies two districts, that of Liege and that of Hainault, the former containing 100,000, and the latter 200,000 acres. In each, the number of coal seams is very considerable, but the beds are thin and so much disturbed as to require special modes of working. The quality of coal is very various, in- cluding one peculiar kind, the Flenu coal, unlike any found in Great Britain, except at Swansea. It burns rapidly with much flame and smoke, not giving out an intense heat, and having a somewhat disagreeable smell. There are nearly fifty seams of this coal in the Mons district. No iron has been found with the coal of Belgium. Mr. Dunn, H. M. Inspector of Collieries, has reported on the coal of Belgium: and first quoting a report which announces that the mines would be exhausted in twenty years, says : “ This announcement comes with appalling force upon the numerous joint-stock companies.. * * * According to the report of M. Briavionne, Belgium is traversing towards a momen- tous crisis ; and I am much inclined to confirm the writer’s opinion that, according to the present plan of carrying on the collieries, notwithstanding the high price received for the coals, yet that coal will not be found workable to profit below the depth of 250 or 260 fathoms, inasmuch as the deeper they go the more destructive and unmanageable will be the effects of the pressure.” — The Government Mining-Engineer' s Report. Belgium is traversed, in a direction from nearly west-south-west to east-north-east, by a large zone of bituminous coal formation. The entire region is generally described under two principal divisions : — 1. The western or Hainault division, comprising a. The two basins known as Levant and Couchant of Mons. That of Charleroi. b. The basin of Namur. 2. The eastern or Liege division. France. — The most important coal-fields of France are those of the basin of Loire, and those of St. Etienne, which are the best known and largest, comprising about 50,000 acres. In this basin are eighteen beds of bituminous coal, and in the immediate neighborhood several smaller basins containing anthracite. Other valuable localities are in Alsace, several in Burgundy worked by very deep pits, and pf considerable extent ; some in Auvergne with coal of various qualities ; some in Languedoc and Provence with good coal ; others at Ar- veyron ; others at Limosin ; and some in Normandy. Besides these, there are several others of smaller dimensions and less extent, whose resources have not been developed. The total area of coal in France has not been ascertained, but it is probably not less than 2,000 square miles. The annual production now exceeds 4,000,000 tons. But the coal of France is of an inferior description, and, therefore, when good and strong coals are required, the supply is obtained from the English coal-fields. The mineral combustibles of France are divided by the government engineers into Anthracite, not yielding coke. Gaseous coal, long flame. Hard coal, short flame. Small coal, long flame. Forging or gaseous coal. Lignite, Stipite, &c. The total of indigenous fuel extracted, according to the State returns, is 47,222,743 metrical quintals of 10-1465 to the English ton. The geological phenomena attendant upon the coal formations in France are, that in some places we have the coals resting on the granite and schists, and in others on the Silu- rian rocks. Taylor gives the details of eighty-eight coal, anthracite, and lignite basins in France. In 1852 only nine of these produced coal to any extent. The total produce of all the coal- fields being 4,816,355 tons, valued at £1,870,072 sterling. Germany. — The Germanic Union — the Zollverein — embraces the following principal coal-beds • — f Saxony. ^ German States. 4 Bavaria. ( Duchy of Flesse. i La Ruhr, in Westphalia. Prussian States. 4 Silesia. ( Saarbriick, and provinces of the Bas Rhin. COAL. 347 The true coal of Prussian Silesia stretches for a distance of seventeen leagues. The most recent information we have been able to obtain as to its production, would appear to give above 850,000 English tons. The coal-fields of Westphalia were described by Sedg- wick and Murchison in 1840. The productive coal-beds are on the right bank of the Rhine, and possess many features in common with the English coal-fields. Bituminous wood, and lignite or brown coal, occur extensively in some districts. The coal basin of Saarbritck, a Rhenish province belonging to Prussia, has thus been described by Humboldt, chiefiy from a communication received from M. Von Dechen : — “ The depth of the coal measures at Mont St. Gilles, Liege, I have estimated at 3,650 feet below the surface, and 3,250 feet below the sea level. The coal basin at Mons lies fully 1,V50 feet deeper. These depressions, however, are trifling when compared with that of the coal strata of the Saar rivers, (Saarbriick.) After repeated trials I have found that the lowest coal strata known in the county of Duttweiler, near Bettingen, north-eastward from Saar-louis, dip 19,406 feet, and 20,656 under the level of the sea.” The coal of the valley of the Glane is bituminous, and of good quality ; it is procur- able at a depth of 112 feet, and the seam is about two feet in thickness : about 50,000 tons annually are produced from this valley. Coal is found in Wurtemburg, but not much worked. In Saxony are extensive mines of bituminous coal ; at Schonfield, near Zivickau, the coal alternates with porphyry. Near Dresden a bituminous coal is also worked, and the coke manufactured from it is used in the metallurgical works at Freiburg. The Hessian States produce little beyond lignite. In Hesse Cassel some bituminous coal is worked, but to a very inconsiderable extent. In the Thuringerwald or Thuringian forest some coal is produced. Hungary and other countries in the east of Europe contain true coal measures of the carboniferous period ; but the resources of these districts are not at present developed. On the banks of the Donetz, in Russia, coal is worked to some extent, and is of excellent quality. Austria. — Coal occurs in Styria, Carinthia, Dalmatia, the Tyrol, Moravia, Lombardy, and Venice ; but 700,000 tons appear to be the maximum annual produce of the empire. The basin of Vienna, in Lower Austria, produces several varieties of coal, which belong to the brown coal of the tertiary period. Bohemia. — In this kingdom coals are abundant ; one coal-field occupies a length of 15 leagues, and a breadth of from 4 to 5 leagues. Between 300,000 and 400,000 tons are produced annually. Sweden. — Anthracite is found in small quantities at Dannemora ; and bituminous coal is worked at Helsingborg, at the entrance of the Baltic. Denmark. — The island of Bornholm and some other islands belonging to Denmark pro- duce coal, but it would appear to belong to the Bovey coal variety. Russia. — The Donetz coal-field is the most important. In that extensive district many good seams, according to Sir R. I. Murchison, of both bituminous and anthracite coal exist. Turkey. — Coal is found bordering on the Carpathian mountains, in Servia, Roumelia, and Bulgaria. The coal of Heraclia, on the south coast of the Black Sea, in Anatolia, has been, since the Crimean war, exciting much attention. Spain. — Spain contains a large quantity of coal, both bituminous and anthracite. The richest beds are in Asturias, and the measures are so broken and altered as to be worked by almost vertical shafts through the beds themselves. In one place upwards of 1 1 distinct seams have been worked, the thickest of which is nearly 14 feet. The exact area is not known, but it has been estimated by a French engineer that about 12,000,000 of tons might be readily extracted from one property, without touching the portion existing at great depths. In several parts of the province the coal is now worked, and the measures seem to resemble those of the coal districts generally. The whole coal area is said to be the largest in Europe, presenting upwards of 100 workable seams, varying from 3 to 12 feet in thickness. The Asturias Mining Company are working many mines in this region, and they are said to produce 400,000 tons annually, or to be capable of doing so. In Catalonia and in the Basque provinces of Biscay there are found anthracite and bituminous coals. In the Balearic islands also coal exists. Portugal. — Beds of lignite and some anthracite are known to exist, but the produc- tion of either is small. Italy. — The principal coal mines of Italy are in Savoy and near Genoa. In the Apen- nines some coal is found, and in the valley of the Po are large deposits of good lignite and a small quantity of good coal is worked in Sardinia. North America. — There are in North America four principal coal areas, compared with which the richest deposits of other countries are comparatively insignificant. These are the great central coal-fields of the Alleghanies ; the coal-fields of Illinois, and the basin of the COAL. S48 Ohio ; that of the basin of the Missouri ; and those of Nova Scotia, New Brunswick, and Cape Breton. Besides, there are many smaller coal areas which, in other countries, might well take rank as of vast national importance, and which even in North America will one day contribute greatly to the riches of various States. The Alleghany or Appalachian coal-field measures 750 miles in length, with a mean breadth of 85 miles, and traverses eight of the principal States in the American Union. Its whole area is estimated at not less than 65,000 square miles, or upwards of 40,000 square acres. The coal is bituminous, and used for gas. Coal has been found in Louisiana, on the Iberville rivers, and on the shores of Lake Bistineau : it is also reported as having been found at Lake Borgne — but this is probably a lignite. In Kentucky both bituminous and cannel coal are worked in seams about 3 or 4 feet thick, the cannel being sometimes associated with the bituminous coal as a portion of the same seam ; and there are in addition valuable bands of iron ore, {the argillaceous car- bonate.) The coal-field of Kentucky extends over about 9,000 square miles. In Western Virginia there are several coal-fields of variable thickness: one, 9^ feet; two others of 5, and others of 3 or 4 feet. On the whole there seem to be at least 40 feet of coal dis- tributed in 13 seams. In the Ohio district the whole coal-field affords on an average at least 6 feet of coal. The Maryland district is less extensive, but is remarkable as contain- ing the best and most useful coal, which is worked now to some extent at Frostbury. There appear to be about 30 feet of good coal in 4 seams, besides many others of less importance. The quality is intermediate between bituminous and anthracite, and is considered well adapted for iron-making. Lastly, in Pennsylvania there are generally from two to five workable beds, yielding on an average 10 feet of workable coal, and amongst them is one bed traceable for no less than 450 miles, consisting of bituminous coal, its thickness being from 12 to 14 feet on the south-eastern border, but gradually diminishing to 5 or 6 feet. Besides the bituminous coal there are in Pennsylvania the largest anthracite deposits in the States, occupying as much as 250,000 acres, and divided into three principal districts. The Illinois coal-field, in the plain of the Mississippi, is only second in importance to the vast area already described. There are four principal divisions traceable, of which the first, or Indian district, contains several seams of bituminous coal, distributed over an area of nearly 8,000 square miles. It is of excellent quality for many purposes ; one kind burn- ing with much light and very freely, approaching cannel coal in some of its properties ; other kinds consist of caking or splint coal. In addition to the Indian coal-field there ap- pears to be as much as 48,000 square miles of coal area in other divisions of the Illinois district, although these are less known and not at present much worked. 30,000 are in the State of Illinois, which supplies coal of excellent quality, and with great facility. The coal is generally bituminous. The third great coal area of the United States is that of the Missouri, which is little known at present, although certainly of great importance. Taylor states that at least one-eighth of the State of Missouri is overlaid by coal meas- ures. 6,000 square miles are assigned to the coal-fields of Missouri. Bituminous coal is stated to have been found in the Arkansas valley, and brown coal and lignite in abundance in the Upper Missouri valley. British America contains coal in the provinces of New Brunswick and Nova Scotia. The former presents 3 coal-fields, occupying in all no less than 8,000 square miles ; the latter exhibits several very distinct localities wdiere the coal abounds. The New Brunswick coal measures include not only shales and sandstones, as is usual with such deposits, but bands of lignite impregnated with various copper ores, and coated by green carbonate of copper. The coal is generally in thin seams lying horizontally. It is chiefly or entirely bituminous. Nova Scotia possesses three coal regions, of which the northern presents a total thick- ness of no less than 14,570 feet of measures, having 70 seams, whose aggregate magnitude is only 44 feet, the thickest beds being less than 4 feet. The Pictou or central district has a thickness of 7,590 feet of strata, but the coal is far more abundant, one seam measuring nearly 30 feet ; and part of the coal being of excellent quality and adapted for steam pur- poses. The southern area is of less importance. Besides the Nova Scotia coal-fields there are three others at Cape Breton, yielding different kinds of coal, of which one, the Sydney coal, is admirably adapted for domestic purposes. There are here 14 seams above 3 feet thick, one being 11, and one 9 feet. Newfoundland Coal-field. — This field is estimated at about 6,000 square miles. Ac- cording to Mr. Jukes, now Director of the Geological Survey in Ireland, the entire western side of the island, along a space of 356 miles in breadth, is occupied by secondary and car- boniferous rocks. The coal on the southwestern point of the island has been traced at inter- vals, along a space of 150 to 200 miles to the north-east. Greenland. — Captain Scoresby discovered a regular coal formation here. At Hasen Island, Bovey or brown coal has been found, and also at Disco Island on the western coast. COAL. 349 Arctic Ocean. — At Byam Martin’s Island coal formations exist ; and at Melville Island several varieties of coal have been discovered, much of it being of an anthracitic or of a semi-anthracitic character. We learn that at Prince Regent’s Inlet indications of coal have been observed. Russian America. — Beyond the icy cape and at Point Barrow, coal was observed on the beach ; and it has been found by digging but a few feet below the surface at Point Franklin. Oregon Territory. — Coal has been discovered and worked in Wallamette valley, nearly 100 miles above Oregon City ; and anthracite has been observed by Sir George Simpson about 30 miles up one of the tributaries of the Columbia River. California. — Colonel Fremont states that a coal formation exists in Upper California, North lat. 41|-°, and West long. 1071°. “The position of this coal formation is in the centre of the Rocky Mountain chain, and its elevation is 6,820 feet above the level of the sea. In some of the coal seams the coal did not appear to be perfectly mineralized, and in others it was compact and remarkably lustrous.” — Fremont'' s Report, 1843. In 1847 a coal mine was discovered near San Luis Obisco, North lat. 35°. There are three coal mines within 300 miles of Monterey. Mexico. — On Salado River coal is worked by an American company. A coal formation 50 miles in breadth crosses the Rio Grande from Texas into Mexico at Loredo, and on the Mexican shore, within 200 yards of the Rio Grande, a remarkable fine vein of coal 8 feet thick occurs. Texas. — Coal is known to exist in Texas, though the country has not been geologically examined. The “ Trinity Coal and Mining Company ” was incorporated by the Texan Con- gress in 1840, who worked both anthracite and a semi-bituminous coal. Kennedy, in his work, “ Texas, its Geography, c&c.,” says, “ Coal, both anthracite and bituminous, abounds from the Trinity River to the Rio Grande.” South America. — In the republic of New Granada, especially at Santa Fe de Bogota, coal occurs ; also in the island of Santa Clara, and brown coal in the province of Panama. Venezuela is said to contain coal, but whether brown or bituminous coal does not appear certain. Peru appears to possess some coal, but a fossil charcoal of considerable value is more abundant. Chili. — The coal of this district has been examined by many American engineers, and by Captains Fitzroy and Beechy and Mr. Darwin. In 1844 upward of 20 coal mines were open in the neighborhood of Conception. At Tulcahnano a new seam of 4^ feet was proved. The coal is described by W. R. Johnson as “in external appearance nearly rela- ted to many of the richest bituminous coals of America and Europe and Mr. Wheel- wright, in his report on the mines and coal of Chili, says, “ in fact, the whole southern country is nothing but a mine of coal.” Brazil does not appear to possess much coal of any value, beyond a few lignites. The West Indian Islands. — Cuba, in the vicinity of Havana, produces a kind of asphaltum much resembling coal, the analysis of which gives, carbon 34*97, volatile matter 63*00, ashes 2*03. At New Havana a similar combustible is found ; but it contains 71*84 of carbon. True coal does not appear to have been found in Jamaica. Sir H. de la Beche, Trans. Geological Society of London, describes three or four thin seams of coal imbedded in shale near the north-eastern extremity of the island. Barbadoes. — Bitumen is found plentifully ; and, on Grove Plantation estate, a good coal is stated to have been found. Trinidad. — The pitch lake of this island is well known. Near it, and, it is believed, extending under it, a true coal of superior quality is worked. For a very satisfactory description of the coal-field of South Staffordshire, the reader is referred to a memoir “ On the Geology of the South Staffordshire Coal-field,” by J. Beete Jukes, published in the “ Records of the School of Mines.” It is not possible in the present work to enter into any further description of the coal- fields of this country. In the selections which have been made, striking types have been chosen, which are sufficiently characteristic to serve the purposes of general illustration. There are many variations from the conditions which have been described, but these are due to disturbances which have taken place either since the formation of the coal, or during the period of the actual deposition of the coal. That coal is derived from the vegetable kingdom, no longer admits of a doubt ; but the class of plants to which more especially we are to look for the origin of coal, is still a mat- ter of much uncertainty ; and the conditions under which the change is brought about are very imperfectly understood, and indeed by many geologists entirely misconceived. The idea generally entertained is, that — already described in part — which supposes a natural basin in which vegetable matter is deposited, the layers, according to circumstances, vary- ing in thickness, which become covered with mud or sand, and were thus entombed ; the decomposition and disintegration breaking up the vegetable structure, goes on for ages. COAL. 350 Microscopic observers assure us that they are enabled to detect ligneous structure in the bituminous coal. Mr. Quecket has given a great number of drawings in proof of this, and he refers the coal to the woody matter of an extinct class of the Conifera. Botanists of eminence, however, assure us that there is no evidence of ligneous structure in any of the examples brought forward in proof of that hypothesis. Sir Charles Lyell, in his excellent Manual of Elementary Geology^ enters largely and with his usual lucid manner into the consideration of the carboniferous plants. There can be no doubt of the existence of the remarkable flora described by him during the period when our beds of fossil fuel were forming. Referring to Sir William Logan as his author- ity, Sir Charles says : “It was observed, that while in the overlying shales or ‘ roof’ of the coal, ferns and trunks of trees abound, without any stigmarice^ and are flattened and com- pressed, those singular plants of the underclay {the stigmarice) very often retain their natu- ral forms of branching freely, sending out their slender leaf-like rootlets, formerly thought to be leaves, through the mud in all directions.” This plant is singularly indicative of the class of plants from which coal has been derived. M. Adolph Brongniart states that the number of species of carboniferous plants amounts to about 600. Bindley informs us that no less than 250 ferns have been obtained from the coal strata. Forty species of fossil plants of the coal period have been referred to the Lepidodendrons. These, with Equisetacece, Colamites^ Asterophyllites^ Sigillaria, of which about thirty-five species are known with their roots, Stigjnarice and Conifera^ make up the remarkable flora which have been preserved to us in our coal series. Trees and humbler plants in great variety are found in the carboniferous sandstones and shales, and in the coal itself, but it does not appear that we have any one evidence of the actual conversion of the woody fibre of these plants into coal ; that is, there is no evidence of the direct conversion of wood into bituminous coal. The trees are almost invariably silicified, or converted into columns of sandstone ; the carbon which constituted the original woody fibre being substituted by silica, or sometimes by carbonate of lime, and sometimes by iron. Sir Charles Lyell has carefully examined the phenomena, now in progress, of the great delta of the Mississippi, and he perceives in them many facts which fully explain, to his mind, the progress of coal deposit. It cannot, however, l)e disguised, that even while he refers the coal to the supposed submerged forests, he does not venture to explain any of those changes, which he evidently believes depend upon some peculiar conditions of climate. Professor John Phillips, who has devoted much study to this subject, says : “ There is no necessity to enlarge upon the proofs of the origin of coal from vegetables, drawn from an examination of its chemical constitution, as compared with the vegetable products, and the composition of the ligneous parts of the plants, and from the unanswerable identity of the carbonaceous substance^ into which a vast multitude of fossil plants have been converted. The chemical constitution of this carbonaceous product of the individual vegetables, is ex- actly analogous to the chemical constitution of coal ; and it is quite probable that hereafter the reason of the variations to which both are subject, whether dependent on the original nature of the plant or produced by unequal exposure to decay after inhumation, or meta- morphic subsequent operations, will be as apparent as that of the general argument arising from a common vegetable origin.” — Manual of Geology. Mr. Jukes says : “ If, therefore, we suppose wood (or vegetable matter) buried under accumulations of more or less porous rock, such as sandstone and shale, so that it might rot and decompose, and some of its elements enter into new combinations, always using up a greater quantity of oxygen and nitrogen than of carbon and hydrogen, or of oxygen and hydrogen than of carbon, we should have the exact conditions for the transformation of vegetable matter into coal.” — The Student's Manual of Geology. Much stress has been laid upon the faet that we have brown coal still retaining all the unmistakable characters of wood, and the apparent passage of this into true coal. Goppert states that the timber in the coal mines of Charlottenbrunn is sometimes con- verted into brown coal. The same conversion was many years ago found in an old gallery of an iron mine at Turrach in Styria. A. Schrotter explains, according to the analysis made by him, this conversion, by the separation of marsh gas and carbonic acid from the ligneous fibre of oak wood. — Bischof. The same authority says : “ This conversion of wood into coal may take place in four •different ways, namely : “1. By the separation of carbonic acid and carburetted hydrogen. 2. “ “ carbonic acid and water. 3. “ “ carburetted hydrogen and water. 4. “ “ carbonic acid, carburetted hydrogen and water.” Quoting the information accumulated by Bischof for the purpose of showing the chemi- cal changes which take place, the following analyses are given ; — COAL. 351 Carbon. Hydrogen. Oxygen. Authority. Oak Wood . - . - - 62*53 6*27 42*20 j Gay-Lussac ( and Thenard. Decayed Oak Wood - - - 53*47 6*16 41‘37 Liebig. Fossil Wood ... - - 57*8 5*8 36*4 Regnault. Turf - - 60*1 6*1 33*8 Vaux. Lignite . . - - - - 72*3 6*3 22*4 Regnault. Coal from Marennen - - 76*7 5*2 18*1 Bischof. Retinite from the brown coal mines of Walchow ... - - 80*3 10*7 9*0 Schrotter. Peat coal - - - - - . 80*7 4*1 15*2 Baer. Coal - - . . - - 82*2 6*5 12*3 Bischof. Such is, in the main, the evidence brought forward in support of the view that coal is the result of the decomposition, upon the place where it is found, of woody fibre. The following remarks by Professor Henry Rogers on the structure of the Appalachian coal ex- hibit some of the difficulties which surround this view : — “ Each bed is made up of innumerable very thin laminee of glossy coal, alternating with equally minute plates of impure coal, containing a small admixture of finely divided earthy matter. These subdivisions, differing in their lustre and feature, are frequently of excessive thinness, the less brilliant leaves sometimes not exceeding the thickness of a sheet of paper. In many of the purer coal-beds these thin partings between more lustrous layers consist of little laminge of pure fibrous charcoal, in which we may discover the peculiar texture of the leaves, fronds, and even the bark of the plants which supplied a part of the vegetable mat- ter of the bed. All these ultimate divisions of a mass of coal will be found to extend over a surprisingly large surface, when we consider their minute thickness. Pursuing any given brilliant layer, whose thickness may not exceed the fourth part of an inch, we may observe it to extend over a superficial space which is wholly incompatible with the idea that it can have been derived from the flattened trunk or limb of any arborescent plant, however com- pressible. When a large block of coal is thus minutely and carefully dissected, it very sel- dom, if ever, gives the slightest evidence of having been produced from the more solid parts of trees, though it may abound in fragments of their fronds and deciduous ex- tremities.” It is not possible, within the space which can be afforded to this article in the present work, to examine further the various views which have been entertained by geologists and chemists of the formation of coal. A brief summary must now suffice. 1. Coal is admitted upon all hands to be of vegetable origin. 2. Many refer coal to some peculiar changes which have taken place in wood ; others to the formation and gradual subsidence of peat bogs, {Unger.) Fuci have also been thought by others to supply the materials for coal-beds. 3. By some the coal is thought to be found upon the spots on which the trees grew and decayed. By others it is supposed that vast masses of vegetable matter were drifted into lakes or deltas, to be there decomposed. 4. Whether the plants grew on the soil — the under clay — upon which the coal is found, or were drifted to it, there must have been long periods during which nothing but vegetable matter was deposited, and then a submergence of this land, and vast accumulations of mud and sand. The number of coal seams in some of our coal-fields, and the thicknesses of the strata above them, have been already given. Henry Rogers and others suppose, that the whole period of the coal measures was characterized by a general slow subsidence of the coasts on which we conceive that the vegetation of the coal grew ; that this vertical depression was, however, interrupted by pauses and gradual upward movements of less frequency and duration, and that these nearly statical conditions of the land, alternated with great paroxysmal displacements of the level, caused by the mighty pulsations of earthquakes. (See Faults.) The difficulties are mainly the facts — 1. That the evidence is not clear that any thing like ligneous structure can be detected in coal. 2. That the woody matter found in coal is never converted into coal, although sometimes it appears as if the bark was so changed. ' 3. That the coal arranges itself always in exact obedience to the underlying surface, as though a semi-fluid mass had been spread out on a previously formed solid bed. 4. The thinning out of true coal to extreme tenuity, as mentioned by Professor Rogers, numerous examples of which appear in this country. 6. The extreme difficulty connected with the subsidence of the surface of the earth to such a depth as that to which the lowest seams of coal extend. L 352 COAL BRASSES. We do not intend to answer any of those difficulties, but to leave the question open for further examination, merely remarking, in conclusion, that there can be no doubt of the vegetable origin of coal ; the only question is, the conditions of change by which bitu- minous coal has been produced from vegetable fibre ; and, that we have not completed all the links in the chain between brown coal and true coal. Ill concluding this notice of mineral fuel, it may be worth while to draw attention to the vast and overwhelming importance of the subject, by a reference both to the absolute and relative value of the material, especially in the British Islands. It may be stated as proba- bly within the true limit, if we take the annual produce of the British coal mines at 66,000,000 tons, the value of which is not less than £16,700,000 sterling at the pits’ mouth, which may be estimated at the place of consumption, and therefore including a certain amount of transport cost necessary to render available the raw material, at not less than £20,000,000. The capital employed in the coal trade is now estimated at £18,500,000, We have, therefore, the following summary, which will not be without interest : Value of the coal annually raised in Great Britain, estimated at the pit mouth £16,700,000 Mean annual value at the place of consumption ... 20,000,000 Capital engaged in the coal trade - 18,500,000 Mean annual value, at the furnace, of iron produced from Brit- ish coal 14,545,000 COAL BRASSES. Iron pyrites^ sulphide of iron^ found in the coal measures. These are employed in Yorkshire and on the Tyne in the manufacture of copperas, the proto- sulphate of iron. For this purpose they are exposed in wide-spread heaps to atmospheric action ; the result is the conversion of the sulphur into sulphuric acid, which, combining with the iron, forms the sulphate of the protoxide of iron, which is dissolved out and recrystallized. The iron ores called Brass, occurring in the coal measures of South Wales, were par- ticularly described by E. Chambers Nicholson and David S. Price, Ph. D., F.C.S., at the meeting of the British Association at Glasgow. Their remarks and analyses were as follows : — “ There are three kinds of ores to which the name brass is applied ; they are considered to be an inferior class of ore, and are even rejected by some iron-masters. One is com- pact, heavy, and black, from the admixture of coaly matter, and exhibits, when broken, a coarsely pisiform fracture. A second is compact and crystalline, not unlike the darkest- colored mountain limestone of South Wales in appearance. The third is similar in struc- ture to the first-named variety ; the granules, consisting of iron pyrites, are mixed with coaly matter, and cemented together by a mineral substance, similar in composition to the foregoing ores. It is from the yellow color of this variety that the name brass has been assigned to the ores by the miners. The ores have respectively the following composition : — I. II. III. i Carbonate of iron Carbonate of manganese Carbonate of lime ------- Carbonate of magnesia ------ Iron pyrites ........ Phosphoric acid ------- Coaly matter - -- -- -- - Clay % 68-71 0-42 9-36 11-80 0-22 0-17 8-87 59*73 0*37 11-80 15-55 trace. 0*23 9-80 2*70 17-74 14-19 12-06 49-72 trace 6-10 99-65 100-18 99-81 “ It is unnecessary to allude to the third variety ; as an iron-making material, its color admits of its being at all times separated from the others. The pyrites which it contains, we may remark, is bisulphuret of iron. “ It is to the ores I. and II. that we would direct attention. The reason of their having hitherto been comparatively disregarded may be attributed either to their having been mis- taken for the so-called brass of coal, or to their being difficult to work in the blast-furnace in the ordinary manner, through the belief that they were similar in construction to the argillaceous ores of the district. It will be seen from the above analyses that they are varieties of spathic iron ore, in which the manganese has been replaced by other bases. If treated judiciously, they would smelt with facility, and afford an iron equal to that produced from the argillaceous ores. From the large amount of lime and magnesia which they con- tain, their employment must be advantageous in an economic point of view. COAL-GAS. 353 “ An interesting feature in these ores is their fusibility during calcination on the large scale. When this process is conducted in heaps, the centre portions are invariably melted. This, considering the almost entire absence of silica, is apparently an unexpected result. The fused mass is entirely magnetic and crystalline. Treated with acids, it dissolves with great evolution of heat. “ The following is its composition : — Protoxide of iron - 38'28 Sesquioxide of iron 32’50 Protoxide of manganese - - 0-38 Lime 12-84 Magnesia 13-87 Phosphoric acid 0-17 Sulphur 0-23 Silicic acid 1*20 Alumina 0-51 99-98 “ From the above analysis, it is probable that the fusibility of the compound is owing to the magnetic oxide of iron acting the part of an acid. When thoroughly calcined and un- fused, the ores retain their original form ; and if exposed to the air for any length of time, crumble to powder from the absorption of water by the alkaline earths.” COAL-GAS. Before proceeding to describe the actual processes now employed for the generation of illuminating gas, it will be advisable to consider briefly the general scientific principles involved in those processes, and especially the chemical relations of the materials employed for the generation and purification of illuminating gas, together with the bearings of chemistry upon the operations of generating, purifying, and burning such gas. The Chemistry of Gas- Manufacture . — The chief materials employed in the manufacture of gas for illuminating purposes are, coal, oil, resin, peat, and wood. These materials, although very dissimilar in appearance, do not essentially differ from each other in their chemical constituents, they may all be regarded as consisting chiefly of the elements, car- bon, hydrogen, and oxygen, and their value for the production of illuminating gas increases with the increase of the proportion of hydrogen, and with the diminution of the relative amount of oxygen. Accordingly we find that oil and resin generally produce gas larger in volume and better in quality than coal, whilst peat and wood, owing to the large proportion of oxygen which they contain, are greatly inferior to coal for the purposes of the gas manu- facturer. The relative proportions of carbon, hydrogen, and oxygen, in the organic part of these substances, is seen from the following comparison : — 1 Percentage of Carbon. Percentage of Hydrogen. Percentage of Oxygen. Cannel (Boghead) .... 80-35 11-21 6-71 Cannel (Wigan) 85-95 6*75 8*14 Coal 88-15 5-26 5*41 Oil 78-90 10-97 10*13 Resin ------- 79*47 9-93 10*59 Peat 60*41 5*57 34-02 Wood 50-00 5-55 44*45 In addition to the three essential constituents above mentioned, most of these materials contain small and variable proportions of sulphur, nitrogen, and inorganic matter, the latter constituting, when the substance is burnt, what we term ash. When these substances are heated to redness, they undergo decomposition, a considerable quantity of inflammable gases and vapors being evolved, whilst a residue, consisting of carbon, or of carbon and ash, remains behind in the solid form. When atmospheric air has free access during this heating operation, the inflammable gases and vapors burn with a more or less bright flame, as in a common fire ; whilst the carbonaceous residue continues afterwards to glow, until nearly the whole of the carbon is consumed. If, however, the application of heat be made without access of air, by inclosing the materials, for instance, in an iron retort provided only with an outlet for the escape of gases, the decomposition goes on in much the same man- ner as before, but the various products formed, being no longer exposed to the simultaneous action of atmospheric oxygen, do not undergo combustion ; the inflammable gases and vapors are evolved through the outlet pipe in an unburnt condition, and the carbonaceous residue also remains unconsumed in the retort. Upon cooling the gases and vapors thus evolved, the latter condense more or less into liquids which separate into two layers, the lower one forming a dense black oily fluid, commonly known as tar, and cont ainin g several solid VoL. HI.— 23 354 COAL-GAS. hydrocarbons partly in solution and partly in suspension ; whilst the other one consists chiefly of an aqueous solution of salts of ammonia, if the organic matters operated upon contained nitrogen. Thus the volatile products of this process of destructive distillation consist of solids, liquids, and gases. These constituents may be thus tabulated : — I. Gaseous. Name. Hydrogen - - - - Chemical Formula. - H Light carburetted hydrogen - C^H" Carbonic oxide - - - . CO Olefiant gas - . Propylene - C®H® Butylene - - C®H® Carbonic acid - - - . CO"' Sulphuretted hydrogen . SH Nitrogen - - N Aqueous layer II. Liquid. Name. —Water - . - . Chemical Formula. - HO Oily layer : — Bisulphide of carbon - CS^ i( Benzol .... . Ci2H« Toluol - - . . . C'^H® (( Cumol .... . C16Hi3 Ci Cymol .... - C20HM C( Aniline .... . C*"H’N Picoline .... . C’^H’N C( Leucoline - . C^“H^N Carbolic acid . . - . CisH'^O'* <( Other hydrocarbons - . CnHn^ <( u a . CnHn 4- 2 a u - CnHn— 6 In aqueous layer :- III. Solid. Name. —Carbonate of ammonia Chemical Formula. - NH'OCO" Hydrosulphate of sulphide of ammonium - NH^S-hHS <( Sulphite of ammonia . - NH'OSO* Chloride of ammonium . - NH^Cl In oily layer : — Paraffine .... . - C10H42 Naphthaline - - C20H8 (( PdVanaphthaline - - C30H12 (( Pyrene .... . - C30H6 i( Chrysene - - - (J30H10 In practice, there is not such a perfect separation of the products as is represented in the above table : thus a small proportion of the gases dissolves in the liquid products, whilst most of the liquids, and even some of the solids, diffuse themselves in the form of vapor, to a certain extent, into the gases ; and the solids are in most cases almost com- pletely dissolved in the liquids. The relative proportions also in which these products occur greatly depend upon the temperature employed in the destructive distillation, and the length of time during which the volatile products are exposed to it ; a low temperature and short exposure favoring the formation of solids and liquids, whilst a higher heat and longer exposure determine the production of a larger proportion of gases at the expense of the solids and liquids. The usual process of gas-making consists in exposing coal or cannel to a bright-red heat, in close vessels of convenient size and shape, until all, or the greater part, of the volatile matter is expelled. Coke is the material left in the retort, and the matters volatilized con- sist of condensible vapors, and of permanent gases more or less saturated with these vapors. By a simple process of refrigeration nearly the whole of the vapors may be readily condensed, thus separating the gases more or less perfectly from the liquid and solid pro- ducts of the distillation. But this preliminary process of purification leaves the gases still in a state totally'unfitted for use in the production of artificial light. They still retain con- stituents, which are either noxious in themselves, or generate noxious compounds when they are burnt, such as sulphuretted hydrogen, sulphide of ammonium, carbonate of ammo- nia, and bisulphide of carbon. They also contain carbonic acid, which greatly diminishes the amount of light yielded by the illuminating gases with which it is mixed. ♦ Here n means an even number, as 2, 4, 6, &c. COAL-GAS. 355 Besides these injurious ingredients, which may be conveniently included in the term impurities^ there are others wMch do not contribute any thing to the illuminating power of the mixture, and which may be denominated diluents. We can thus classify the constitu- ents of coal-gas as follows : — Illuminating Ingredients. Diluents. Impurities. Olefiant gas. Propylene. Butylene. Hydrocarbon vapors of the formulae CnHn and CnII(n - 6). Vapors of hydrocarbons of the formula CnH(n - 12.) A Hydrogen. Light carburetted hydro- gen. Carbonic oxide. Sulphuretted hydrogen. Hydrosulphate of sulphide of ammonium. Carbonate of ammonia. Carbonic acid. Vapor of bisulphide of car- bon. Nitrogen. Oxygen. Aqueous vapor. As the intelligent manufacture of gas for illuminating purposes requires a knowledge of the leading properties of the compounds included under the three heads just mentioned, we will now proceed briefly to describe them. I. Illuminating Ingredients. Olefiant Gas. — This gas has been proved by Berthelot to exist in coal-gas, and it is probably always a constituent of the illuminating gases from resin, oil, peat, and wood. It is occasionally, though rarely, met with in nature, as a product of the action of volcanic heat upon coal-bearing strata ; it never occurs, however, in coal strata under ordinary cir- cumstances, and no trace of it has ever been met with amongst the gases issuing from the coal strata of this country, and which have been investigated by Graham, Playfair, and others. Oleflant gas can be prepared nearly pure by heating in a glass retort a mixture of 1 part by weight of alcohol, and 6 parts of oil of vitriol. The gas must be passed through solution of caustic soda, to remove sulphurous and carbonic acids with which it is generally contaminated. Oleflant gas is colorless, and possesses a peculiar and slightly unpleasant odor. Its spe- cific gravity is, rather less than that of atmospheric air, being -9784 : 100 cubic inches, at 60° F., and 30 inches barometrical pressure, weigh 30‘3418 grains. It consists of two vol- umes of carbon vapor and four volumes of hydrogen, the six volumes being condensed to two. It contains, in a given bulk, exactly twice as much carbon as is contained in light carburetted hydrogen. Olefiant gas is inflammable, but does not support combustion : when inflamed as it issues from a jet into the atmosphere, it burns with a wlyte flame, emit- ting a very brilliant light without smoke. In burning, it consumes three times its volume of oxygen, and produces twice its volume of carbonic acid. Exposed to a full red heat, as in passing through a red-hot tube, it is rapidly decomposed, carbon being deposited, whilst hydrogen and light carburetted hydrogen are produced ; exposure to a full red heat conse- quently soon entirely destroys its illuminating power. Propylene and Butylene. — The first of these highly illuminating constituents of coal-gas may be obtained by passing the vapor of fusel oil through a red-hot tube, and the second by the electric decomposition of valerate of potash. Both these gases are colorless, possess a slight ethereal odor, and burn with a brilliant white flame. Like olefiant gas, they are rapidly decomposed at a bright-red heat, depositing much carbon, and being converted into the non-illuminating gases — hydrogen and light carburetted hydrogen. Propylene consists of three volumes of carbon vapor and six volumes of hydrogen condensed to two volumes. It therefore contains, in a given volume, one-half more carbon than olefiant gas. Its specific gravity is 1’4511. Butylene consists of four volumes of carbon vapor and eight volumes of hydrogen, the twelve volumes being condensed to two ; it consequently contains, in a given volume, twice as much carbon as olefiant gas. Its specific gravity is 1'9348. Vapors of Hydrocarbons of the Form CnHn. — A considerable number of compounds having this formula are known to exist in coal-tar, and, as many of them are very volatile, they must be diffused as vapors in coal-gas ; but as they have not yet been successfully dis- entangled from each other, no account of their individual properties can be given ; they all, however, contain more carbon in a given volume than butylene, and must therefore contribute, proportionally to their volume, a greater illuminating power than any of the gaseous hydrocarbons. They are all readily decomposed at a bright-red heat, chiefly into carbon and non-illuminating gases. Vapors of Hydrocarbons of the Formula CnH(n - 6). — These consist chiefly of benzol, toluol, curaoi, and cymol, compounds which, being components of the more volatile portion 356 COAL-GAS. of the tar, diffuse themselves into the gaseous products of distillation, contributing in no inconsiderable degree to the total illuminating effect of the gas. The composition of these substances has been already given in the Table ; and it is therefore only necessary here to remark, that benzol vapor contains, in a given volume, three times as much carbon as ole- fiant gas, whilst the vapors of toluol, cumol, and cymol, contain respectively 3i, 4-^, and 5 times the amount of carbon contained in olefiant gas. For a further account of these and the following hydrocarbons, see Coal Naphtha, Destructive Distillation. Vapors of Hydrocarbons of the Formula CnH(n-12. — The only vapor of this compo- sition known to be present in coal-gas is naphthaline, which, although a solid at ordinary temperatures, yet emits a considerable quantity of vapor ; in fact, its presence occasions to a great extent the peculiar odor of coal-gas. Naphthaline is a frequent source of serious annoyance to the gas manufacturer, by con- densing in the street mains and gradually blocking them up, or so narrowing their bore as to prevent the passage of the needful supply of gas. This effect can only be produced, when the gas charged with naphthaline vapor is allowed to leave the holder at a tempera- ture higher than that of the mains through which it subsequently flows ; but as this cannot always be avoided, the prevention of such deposits might perhaps be best effected by pass- ing the gas over a large surface of coal oil before it is led into the mains. The oil would absorb so much of the naphthaline as to prevent any subsequent deposition. The vapor of naphthaline contains, in an equal volume, five times as much carbon as olefiant gas. The amount of light yielded by these illuminating constituents is directly proportionate to the amount of carbon contained in an equal volume of each ; taking, therefore, the illuminat- ing power of olefiant gas as unity, the following numbers exhibit the relative illuminating values of equal volumes of the several luminiferous constituents of gas : — Propylene ... - 1-5 Benzol - - 30 Butylene - - 2-0 Toluol - - 3-5 Amylene - - 2-5 Heptylene - 3-5 Hydride of amyl - - 2-5 Cumol - - - - 4-0 Hydride of hexyl - - 3-0 Cymol - - 6-0 Hexylene - - 3-0 Naphthaline - - 50 II. Diluents. Hydrogen. — This element constitutes one-ninth of the total weight of the waters of our globe, and with one or two unimportant exceptions, enters into the composition of all animal and vegetable substances and of the products derived from them, as peat, coal, oils, bitumen, &c. It is, however, very rarely met with in nature in a free or uncombined state ; having hitherto only been thus found in the gases emitted from volcanoes. Hydrogen gas may be obtained in abundance and nearly pure by passing steam over iron, zinc, and several other metals, in a fine state of division, at a full red heat. Mixed with carbonic oxide and carbonic acid gases, it is also generated in large quantity when steam is passed over charcoal, coke, or other carbonaceous substances at a red heat. In all these cases the watery vapor is decomposed, its hydrogen being liberated, whilst its oxygen unites with the metal or carbon, forming in the first case a solid non-volatile oxide, which encrusts the pure metal, and soon stops further action ; in the second case a gaseous oxide of carbon is generated, and passes off along with the hydrogen, thus leaving the carbon freely exposed to the further action of the watery vapor. When carbon is used, that portion of the steam which is converted into hydrogen and carbonic oxide yields its own volume of each of these gases ; and that portion which forms hydrogen and carbonic acid affords its own volume of hydrogen and half its own- volume of carbonic acid. The amount of watery vapor which undergoes the latter decomposition decreases as the tem- perature at which the operation is conducted increases. At a white heat scarcely a trace of carbonic acid is produced. Hydrogen is the lightest of all known bodies, its specific gravity being only -0691 ; 100 cubic inches, at 60° Fahr., and 30 inches barometric pressure, weigh only 2-13'71 grains. It has a powerful affinity for oxygen, but develops scarcely any light during combustion ; when, however, solid substances, such as lime, magnesia, or platinum, are held in the flame of hydrogen, considerable light is emitted. Burnt in air or oxygen gas, it is entirely con- verted into watery vapor, which condenses upon cold surfaces held above the flame. Light Carhuretted Hydrogen. — This gas consists of carbon and hydrogen in the propor- tion of 6 parts by weight of the former element combined with 2 parts of the latter. Owing to its being copiously generated in marshy swampy places, it is frequently termed marsh gas, and from certain considerations relative to its chemical constitution, it has more recently received the name of hydride of methyl. It enters largely into the composition of coal-gas, and is also a natural product "of the slow decomposition of coal, and of putre- faction in general. Thus it occurs in enormous quantities in the coal strata, and bubbles up from stagnant pools and ditches which contain putrefying organic remains. As thus COAL-GAS. 357 generated, it is mixed with small quantities of carbonic acid and nitrogen ; it can, how- ever, be artificially prepared perfectly pure, but the processes need not be described here. Light carburetted hydrogen when pure is colorless, tasteless, and inodorous ; it is neu- tral to test papers, and nearly insoluble in water ; its specific gravity is -5594, and 100 cubic inches, at 60'’ Fahr., and 30 inches barometric pressure, weigh 1'7'4166 grains. It does not support combustion or respiration, but is inflammable, burning with a blue, or slightly yellow flame, yielding scarcely any light. Mixed with a due proportion of atmos- pheric air or oxygen, and ignited, it explodes with great violence : the products of its com- bustion are water and carbonic acid. When light carburetted hydrogen is exposed to a white heat, it is slowly decomposed, depositing carbon, and yielding twice its volume of hydrogen. Carbonic Oxide. — This gas consists of 6 parts by weight of carbon, and 8 parts of oxygen. It is formed when carbon is consumed in a limited quantity of air or oxygen, and is also generated, as stated above, when steam is passed over ignited coke or charcoal, or when coal tar and steam meet in a red-hot vessel. It is always a constituent of coal-gas. Carbonic oxide is a colorless and inodorous gas, rather lighter than atmospheric air, and having exactly the specific gravity of olefiant gas, *9'72'7 ; it is very sparingly soluble in water, but is very soluble in ammoniacal solution of chloride of copper. Carbonic oxide is inflammable, burning with a beautiful blue flame almost devoid of light ; the product of its combustion is carbonic acid. It is said to be very poisonous. III. Impurities. Sulphuretted Hydrogen. — This gas consists of sixteen parts of sulphur and one part of hydrogen : it may be produced by passing hydrogen along with the vapor of sulphur through a red-hot tube, but it is best prepared pure by decomposing proto-sulphuret of iron with dilute sulphuric acid, and collecting the evolved gas at the pneumatic trough or over mercury. It is always an ingredient in crude coal, peat, or wood-gas. Sulphuretted hydrogen is a colorless gas, of a very nauseous odor, resembling that of putrid eggs; its specific gravity is ri747. It is highly inflammable, burning with a blue flame, destitute of light, and generating a large amount of sulphurous acid : it is chiefly this latter circumstance which renders its presence in coal-gas objectionable. It is readily absorbed by metallic solutions, by hydrated oxide of iron, and by lime both in the wet and dry state, and is easily recognized in coal-gas by exposing a strip of paper impregnated with acetate of lead to a stream of the gas ; if the paper becomes discolored, sulphuretted hydrogen is present. Hydrosulphate of Sulphide of Ammonmm. — This compound is formed by the combina- tion of equal volumes of ammonia and sulphuretted hydrogen. It consists of 14 parts by weight of nitrogen, 15 of hydrogen, and 32 of sulphur. It is always largely produced in the manufacture of coal-gas, but is almost completely condensed and retained in the aque- ous layer of liquid products, contributing principally to the unbearable odor of gas liquor ; a mere trace of this body is therefore present in crude coal-gas. When quite pure it is a colorless crystalline solid, very soluble in water, and volatile at ordinary temperatures. Its vapor, when present in coal-gas, is absorbed and decomposed by hydrate of lime both in the wet and dry state, ammonia being liberated. It is also decomposed by acids, but in this case the ammonia is retained by the acid, whilst sulphuretted hydrogen is evolved. Carbonic Acid. — This gas is met with in nature as a constituent of atmospheric air, and is produced in large quantities during the earlier stages of the formation of coal in the earth’s strata. Thus, in the lignite districts of Germany, it is copiously evolved, and meet- ing with water in its passage to the surface, it is absorbed, and forms those sparkling min- eral springs commonly known as seltzer- water. Carbonic acid is also formed during fermentation, by the combustion of carbon in air, and in the decomposition of water by carbon at a red heat. At ordinary temperatures carbonic acid is a colorless and invisible gas, but it may be liquefied by very intense cold or pressure. It consists of 6 parts, by weight, of carbon united with 16 parts of oxygen, and thus differs from carbonic oxide by containing twice as much oxygen as the latter gas. By passing carbonic acid over ignited coke, charcoal, or other carbonaceous matters, it takes up as much carbon as it already contains, and becomes converted into carbonic oxide ; but it is impossible in this way to convert the whole of the carbonic acid into carbonic oxide unless the process be very frequently repeated. Carbonic acid is pungent, acidulous, and soluble in an equal bulk of water, to which it communicates that briskness which we so much admire in soda-water ; it is considerably heavier than atmospheric air, its specific gravity being 1‘524. This gas is uninflammable, and cannot support combustion or animal life. Its acid properties are not strongly developed, but it unites readily with alkaline bases, forming carbonates : it is upon this property that the removal of carbonic acid from coal-gas depends. On passing coal-gas containing this acid through slaked lime in fine powder, or through milk of lime, the whole of the carbonic acid disappears, having united with the lime. Quick-lime, slaked in such a manner as to be neither dust-dry nor very perceptibly moist, is most effective for the absorption of high per- 358 COAL-GAS. centages of carbonic acid, a layer three inches in thickness not allowing a trace of the acid gas to pass through it. The presence even of a small percentage of carbonic acid in coal-gas is much to be deprecated, on account of the great loss of light which it occasions, 1 per cent, of carbonic acid diminishing the illuminating power of coal-gas to the extent of about 6 per cent. ; the addition which it makes to the carbonic acid produced during combustion is, however, too minute to be of any importance. Carbonate of Ammonia. — During the destructive distillation of coal, a considerable pro- portion of the nitrogen contained in the coal is converted into carbonate of ammonia, the greater part of which condenses in the aqueous layer of liquid products ; but as carbonate of ammonia is very volatile, even at ordinary temperatures, crude coal-gas always contains a small quantity of this compound. It is a volatile, white, crystalline solid, very soluble in water, and possessing a pungent smell like ammonia. Its vapor is decomposed by lime, which unites with carbonic acid, liberating ammonia. The presence of this salt, or of am- monia, in coal-gas, is very undesirable, as it corrodes brass fittings, and is also partially con- verted into nitrous acid during the combustion of the gas. Bisulphide of Carbon. — This compound consists of 6 parts, by weight, of carbon, and 32 parts of sulphur ; it is formed whenever sulphur and carbonaceous matter are brought together at a bright-red heat, and therefore, owing to the presence of sulphur in all varieties of coal, its vapor is generally, and probably always, present in coal-gas. Bisulphide of car- bon is a colorless liquid, of a most insupportable odor, resembling garlic ; it is very volatile, boiling at 108°. It does not mix with water, but dissolves in alcohol and ether ; it is also very soluble in solution of caustic soda or potash in methylic, ethylic, or amylic alcohol. It is very inflammable, and generates during combustion much sulphurous acid : on this account its presence in coal-gas is very injurious, and as there is no known means of remov- ing it on a large scale by any mode of purification, its non-generation in the process of gas- making becomes a problem of great importance. Few attempts have yet been made to solve this difficulty, but Mr. Wright, the eminent engineer of the Western Gas Company, has observed that its formation is greatly hindered, if not entirely prevented, by the em- ployment of a somewhat moderate temperature. In corroboration of this observation it has frequently been noticed that the gas furnished by companies who use a high heat contains a very large quantity of this noxious material, whilst gas generated at lower temperatures, as, for instance, that produced by White’s hydrocarbon process, contains mere traces of this compound. Although no process for the absorption of bisulphide of carbon vapor from coal-gas is sufficiently cheap for employment on a large scale, yet advantage might be taken of its solubility in a solution of caustic potash in fusel oil (a by-product in spirit distilleries) or in methylated spirit of wine, for its removal from the gas supplied to private houses, where the damage done by the sulphurous acid is most annoying. By passing the gas over a considerable surface of this solution, contained in a small private purifier, the bisulphide of carbon vapor is completely removed Bisulphide of carbon vapor can be readily detected in coal-gas by a very simple appa- ratus devised by Mr. Wright :* in this instrument the products of the combustion of a jet of gas are made ^o pass through a small Liebig’s condenser ; if the liquid dropping from this condenser strongly reddens blue litmus-paper, it is highly probable that bisulphide of carbon is present. As a decisive test, 50 or 60 drops of the condensed fluid should be col- lected in a small test-tube, and a few drops of pure nitric acid added : on heating this mix- ture to boiling over a spirit-lamp, and then adding a drop or two of a solution of chloride of barium, the liquid will become more or less milky if bisulphide of carbon has been pres- ent in the gas. It is necessary here to remark, that the absence of sulphuretted hydrogen must be first ascertained by the non-coloration of paper imbued with acetate of lead, and held for some minutes in a stream of the gas. Nitrogen. — This gas is the chief constituent of atmospheric air, 100 cubic feet of air containing rather more than VO cubic feet of this gas. It also enters into the composition of a large number of animal and vegetable substances. All descriptions of coal contain small quantities of this element. When nitrogen is eliminated from combination in contact with oxygen, it usually takes the form of nitrous or nitric acid ; whilst in contact with an excess of hydrogen it generates ammonia. It is in this latter form that it is eliminated from coal in the process of gas-generation. Nitrogen is a colorless, inodorous, and tasteless gas, of specific gravity 0'976. It is in- combustible under ordinary circumstances, and instantaneously extinguishes burning bodies. Under certain conditions, however, nitrogen does undergo combustion, as when it is exposed to a very intense heat in the presence of oxygen. This occurs, for instance, when a small quantity of nitrogen is added to a mixture of hydrogen, with a somewhat larger proportion of oxygen than is requisite to form water, and the mixture then ignited : a loud explosion takes place, and a considerable quantity of nitric acid is formed, owing to combustion of the * This instrument can be had on application to Mr. Wright, 55 and 65a, Millbank Street, Westmin- ster, S. W. COAL-GAS. 359 nitrogen, or, in other words, its union with oxygen gas. This formation of nitric acid pos- sibly occurs also to a limited extent during the burning of coal-gas ; and as the temperature required to form nitric acid is very high, the greater the volume of gas consumed from one burner in a given time, the greater will be the relative quantity of nitric acid produced. The formation of such a corrosive material as nitric acid under these circumstances shows the importance of preventing the admixture of the products of the combustion of coal-gas with the atmosphere of the apartments in which it is consumed. The nitrogen contained in coal-gas is due entirely to the admission of atmospheric air, and not to the elimination of the nitrogen contained in the coal ; for this latter nitrogen appears to be evolved only in combination with hydrogen as ammonia. As nitrogen is incombustible, it is not only a use- less ingredient in coal-gas, but, owing to its abstracting heat from the flame of such gas, it causes a diminution of light, and is thus decidedly injurious. The admixture of this ele- ment ought therefore to be avoided as much as possible. Oxygen . — This element is always present in coal-gas, although in very small quantity if the manufacture be properly conducted. It is never evolved from the coal itself, but it makes its way into the gas through leaky joints, and also to a certain extent through the water in which the holders are immersed. Its presence is highly injurious to the illuminat- ing power of the gas ; and since, when once introduced, it cannot be abstracted by any practicable means, its admixture ought to be carefully guarded against. Oxygen is a colorless, invisible, and inodorous gas, very sparingly soluble in water, and which has hitherto resisted all attempts to liquefy it by cold or pressure. It is evolved from the leaves of plants under the influence of light, and constitutes about one-fifth of the bulk of our atmosphere. By far the largest amount of oxygen however exists in combina- tion with other elements ; thus eight out of every nine tons of water are pure oxygen, and it forms at least one-third of the total weight of the mineral crust of our globe. It is there- fore the most abundant of all elements. Oxygen gas is heavier than atmospheric air; 100 cubic inches, at 60° Fahr. and 30 inches barometric pressure, weighing 34"193 grains, whilst 100 cubic inches of the latter weigh only 31 ‘01 17 grains. The specific gravity of oxygen is 1‘1026. It eminently supports combustion, all combustible bodies when intro- duced into it burning much more vividly than in common air ; indeed it is owing to the presence of this gas in our atmosphere, that common air possesses the property of support- ing combustion. Aqueous vapor . — Water is volatile at all natural temperatures, and therefore its vapor always exists to a greater or less extent diffused in coal-gas, even as delivered to the con- sumer. The percentage amount of aqueous vapor thus present in coal-gas is always small, even when the gas is saturated ; nevertheless the presence of even this small proportion of aqueous vapor diminishes to a certain extent the light produced by the combustion of gas. This effect is no doubt owing to the action of aqueous vapor upon carbon at a high temper- ature, by which action hydrogen, carbonic oxide, and carbonic acid gases are produced. The presence of aqueous vapor therefore tends to reduce the number of particles of carbon floating in the gas flame, and consequently the light is diminished. The following table shows the maximum percentages of aqueous vapor which can be present in gas at different temperatures. As a general rule the gas will contain the maximum amount at the lowest temperature to which it has been exposed in its passage from the retorts to the burners. Temperature. Percentage of aqueous vapor. Temperature. Percentage of aqueous vapor. Temperature. Percentage of aqueous vapor. 32° F. 0-6 42° F. 0-9 52° F. 1-3 33° 0-6 43° 0-9 53° 1-3 34° 0-7 44° 1-0 64° 1-4 35° 0-7 45° 1-0 55° 1-4 36° 0-7 46° 1-0 56° 1-5 37° 0-7 47° M 67° 1-5 38° 0-8 48° M 68° 1-6 39° 0*8 49° 1-1 69° 1-7 40° 0*8 60° 1-2 60° 1-8 41° 0-9 61° 1-2 Aqueous vapor has a specific gravity of *6201, and one cubic foot of it contains one cubic foot of hydrogen and half a cubic foot of oxygen. In contact with ignited carbon, or carbonaceous substances, it is decomposed; producing a mixture of hydrogen, carbonic oxide, and carbonic acid gases. When passed over ignited iron it yields its own volume of nearly pure hydrogen. Having thus described the more important properties of the constituents of coal-gas, 360 COAL-GAS. we are now prepared to discuss the conditions involved in the generation, purification, and combustion of gas. On the generation of illuminating gas . — The production of gas for illuminating pur- poses, whether derived from coal, peat, wood, or oil, depends, as we have seen, upon a re- arrangement of the elements composing the material employed. The nature of this re- arrangement is dependent upon the temperature employed. The lower the heat at which it can be effected, the less the weight of coke or carbonaceous residue left in the retort, and, consequently, the greater the amount of carbon remaining combined with the hydrogen ; the hydro-carbons thus formed being chiefly solids and liquids. On the other hand, the higher the temperature employed, the greater is the weight of carbonaceous residue, and, therefore, the smaller is the amount of carbon contained in the volatilized matters, whilst the proportion of gases in these latter becomes larger as the temperature increases. By employing a very low temperature for the destructive distillation, the production of gas may be almost entirely prevented, whilst by the employment of a very high temperature the three chief constituents of coal might without doubt be completely converted into coke, carbonic oxide, and hydrogen. Now the results produced by both these extremes of tem- perature are valueless to the gas manufacturer, and it is therefore necessary to employ a heat sufficiently high to prevent as much as possible the volatile substances from escaping in the form of condensible vapors, but not high enough to decompose the luminiferous con- stituents of the evolved gas. If coal w^ere a definite and single chemical compound, and could be so exposed to heat as to suddenly raise the temperature of every particle to a uni- form and definite degree, it is highly probable that the results of the distillation would be far less complex than they are in the present mode of gas manufacture ; and it might even be possible to find such a degree of temperature as would convert the whole of the hydrogen into one or more of the higher gaseous compounds of carbon, thus giving results of maximum value to the gas-manufacturer. In the ordinary processes of gas-making, where a charge of several cwts. of coal, often in large lumps, is thrown into an ignited retort, it is impossible to attain any such uniform temperature. The heat is conducted very gradually to the interior of the mass of coal, and therefore various portions of the charge are exposed to very unequal temperatures, especially in the earlier stages of the distillation. The natural consequence of these conditions is the production, on the one hand, of products resulting from excessive temperature, viz. : hydrogen and light carburetted hydrogen, and on the other, of tar, which may be regarded as the consequence of deficient heat. Notwithstanding several attempts, these disadvantages have not yet been successfully overcome, but the importance of a practical process which would secure a tolerably uniform temperature during the whole course of distillation, is seen from the remarkable results obtained with Clegg’s revolving web retort — a form of apparatus undoubtedly the most ingenious yet invented for the pro- duction of gas, and which, although in its present form too complicated for successful prac- tical use, yet embodies, when we consider the early date of its invention, in a remarkable manner, the true scientific principles of gas-making. This retort, of which a description will be found at p. 381, obviated to a great extent the inequality and uncertainty of temper- ature in the ordinary gas retorts, and the result was an increase of from 30 to 40 per cent, in the quantity of gas produced, the quality being also improved, whilst scarcely any tar was formed. But besides the great influence exercised by the temperature to which coal is exposed in the process of gas-making, the length of time., during which the volatile products of decom- position are exposed to that temperature, is a most important circumstance as regards the successful manufacture of gas. If we take into consideration the behavior of the luminif- erous constituents of gas when exposed to a bright red heat, and which has been described above, it will be evident that a second most important condition in the manufacture of gas is the rapid removal of these luminiferous constituents from the destructive influence of the red-hot retort as soon as they are generated : every second during which these gases are al- lowed to remain in their birthplace diminishes their value as illuminating agents. The only method hitherto employed for the rapid removal of the gases from the retorts is White’s process, the mechanical details of which are fully described below. This process consists essentially in transmitting a current of water gas through the retorts in which coal or can- nel gas is being generated. The water gas is produced by transmitting steam through re- torts filled with coke or charcoal, and consists of a mixture of hydrogen, carbonic oxide, and carbonic acid gases. These gases, which are not in themselves luminiferous on com- bustion, necessarily become mixed with the coal or cannel gas, and thus diminish the illu- minating power of the latter whilst they increase its volume. Nevertheless, if the admission of water gas be properly managed, the luminiferous constituents saved from destruction by their rapid removal from the retorts, compensate for the dilution of the gas, so as to render the diluted gas equal in illuminating power to the gas produced from the same coal or can- nel in the ordinary process of manufacture. When cannels yielding very highly luminifer- ous gas are employed, it is desirable to dilute them to a much greater extent, and this can be easily effected by admitting into the coal retort a larger proportion of water gas. In COAL-GAS. 361 some cases the total amount of light yielded by the gas from a given weight of coal when treated according to White’s process is more than double that obtained by the ordinary pro- cess, and in all cases the gain in total amount of light is very large, thus showing the im- portance of removing the gases from the red-hot retorts as rapidly as possible. This re- mark applies especially to gases very rich in luminiferous hydrocarbons, because such gases suffer relatively much more deterioration than those containing a larger proportion of dilu- ents. In addition to these advantages such a dilution of rich cannel gases with any of the non-luminous constituents, hydrogen, carbonic oxide, or light carburetted hydrogen, in- creases the illuminating power of the gas in another way : this is effected by their forming a medium for the solution of the vapors of such hydrocarbons as exist in the liquid or even solid state at the ordinary temperature of the atmosphere, and they thus enable us to con- vert an additional quantity of illuminating materials into the gaseous form, which they retain permanently, unless the temperature fall below the point of saturation. The gain in illuminating power which is thus obtained will be perhaps better seen from the following example : — Suppose 100 cubic inches of olefiant gas were allowed to saturate itself with the vapor of a volatile hydrocarbon, containing three times as much carbon in a given volume of its vapor as that contained in an equal volume of olefiant gas, and that it took up or dissolved 3 cubic inches of this vapor ; then, if we express the value of 1 cubic inch of olefiant gas by unity, the illuminating power of the 103 cubic inches of the mixture of olefiant gas and hydrocarbon vapor will be 109. Now if we mix these 103 cubic inches with 100 cubic inches of hydrogen, the mixture will be able to take up an additional 3 cubic inches of hydrocarbon vapor, and the illuminating power of the 20G cubic inches will then become 118 ; thus the hydrogen produces a gain in illuminating power equal to 9 cubic inches of olefiant gas, or nearly 4 ‘5 per cenl upon the volume of mixed gases. When we consider that coal naphtha contains hydrocarbons of great volatility, and that these are the surplus remaining after the saturation of the gas from which they have condensed, the importance of this function of the non-illuminating class of combustible gases wall be sufficiently evi- dent. It may here be remarked that incombustible gases could not be employed for this purpose, since their cooling influence upon the flame during the subsequent burning of the gas would diminish the light to a greater extent than the hydrocarbon vapor could in- crease it. It is evident that all the three non-illuminating gases, forming the class of diluents, would perform both the offices here assigned to them perfectly well, and therefore we have as yet seen no reason for giving our preference in favor of any one of these diluents ; if, however, we study their behavior during combustion, w'e shall find that where the gas is to be used for illuminating purposes, hydrogen has qualities which give it a very decided pref- erence over the other two. When gas is used for lighting the interior of public buildings and private houses, it is very desirable that it should deteriorate the air as little as possible, or, in other words, it should consume as small a quantity of oxygen and generate as little carbonic acid as possible. The oppressive heat which is so frequently felt in apartments lighted with gas also shows the advantage of the gas generating a minimum amount of heat. The following is a comparison of the properties of the three non-illuminating gases in reference to the points just mentioned: — One cubic foot of light carburetted hydrogen, at 60° Fahr. and 30 inches barometrical pressure, consumes 2 cubic feet of oxygen during its combustion, and generates 1 cubic foot of carbonic acid, yielding a quantity of heat capable of heating 5 lbs. 14 oz. of water from 32° to 212°, or causing a rise of temperature from 60° to 80'8° in a room containing 2,500 cubic feet of air. One cubic foot of carbonic oxide, at the same temperature and pressure, consumes, dur- ing combustion, a cubic foot of oxygen, generates 1 cubic foot of carbonic acid, and affords heat capable of raising the temperature of 1 lb. 14 oz. of water from 32° to 212°, or that of 2,500 cubic feet of air from 60° to 66 ’6°. One cubic foot of hydrogen, at the same temperature and pressure, consumes a cubic foot of oxygen, generates no carbonic acid, and yields heat capable of raising the tempera- ture of 1 lb. 13 oz. of water from 32° to 212°, or that of 2,500 cubic feet of air from 60° to 66-4°. This comparison shows that light carburetted hydrogen is very objectionable as a dilu- ent, not only on account of the carbonic acid which it generates, but also by reason of the very large quantity of oxygen which it consumes, and the very great amount of heat which, in relation to its volume, it evolves on combustion ; the consumption of oxygen being four times, and the absolute thermal effect more than three times as great as that of either of the other gases. The quantity of heat evolved by the combustion of equal volumes of carbonic oxide and hydrogen is nearly, and the amount of oxygen consumed quite, the same ; but the carbonic acid evolved from the first gives a decided preference to hydrogen as the best diluent. The same comparison also shows that when the gas is to be used for heating purposes, 362 COAL-GAS. and the products of combustion are carried away, light carburetted hydrogen is by far the best diluent. The experiments of Dulong on the absolute thermal effects of hydrogen, light carbu- retted hydrogen, and carbonic oxide are taken as the basis of the foregoing calculations. Dulong found that — 1 lb. of hydrogen raised the temperature of 1 lb. of water through 62471° F. 1 lb. of carbonic oxide “ “ “ 4504° F. 1 lb, of light carburetted hydrogen “ “ 24244° F. These considerations indicate the objects that should chiefly be regarded, in the gener- ating department of the manufacture of gas for illuminating purposes. They are — 1st. The extraction of the largest possible amount of illuminating compounds from a given weight of material. 2d. The formation of a due proportion of illuminating and non-illuminating constitu- ents, so that on the one hand the combustion of the gas shall be perfect, and without the production of smoke or unpleasant odor, and on the other, the volume of gas required to obtain a certain amount of light shall not be too large. 3d. The presence of the largest possible proportion of hydrogen amongst the non-illu- minating constituents, to the exclusion of light carburetted hydrogen, and carbonic oxide ; so as to produce the least amount of heat and atmospheric deterioration in the apartments in which the gas is consumed. On the 'purification of illuminating gas. — If we except the insigniflcant quantities of ni- trogen and oxygen, which become mixed with illuminating gas through imperfections in the joints of the apparatus employed, and by the transferring power of the water of the gas- holder, all impurities arise from the presence of the three elements sulphur, oxygen, and nitrogen in the generating material used. The sulphur, uniting with portions of the hydrogen and carbon of the coal, generates with the first-named element sulphuretted hydrogen, and with the second, bisulphide of carbon. It is also probable that volatile organic compounds of sulphur are produced by the union of this element with carbon and hydrogen simultaneously, although we have as yet no positive evidence of their presence in illuminating gas. The oxygen, uniting with another portion of carbon, forms carbonic acid, whilst the nitrogen unites with hydrogen to form ammonia, which, by combination with sulphuretted hydrogen, produces hydrosulphate of sulphide of ammonium, and, with carbonic acid and water, carbonate of ammonia. With the exception of bisulphide of carbon and the organic sulphur compounds just mentioned, the removal of all these impurities is not difficult. Slaked lime, either in the form of moist powder, or suspended in water as milk of lime, absorbs the whole of them ; whilst it has no perceptible effect upon the other constituents of the gas. By this process of purification the sulphuretted hydrogen and caustic lime are converted into sulphide of calcium and water ; the former, being non-volatile, does not mix with the gas. Hydrosulphate of sulphide of ammonium is in like manner converted into sulphide of calcium, water, and ammonia ; part of the latter is retained by the moisture present in the purifying material, but the re- mainder mixes with the gas, from which, however, it can be removed by contact with a large surface of water. Carbonic acid unites .with caustic lime with great energy, forming car- bonate of lime, a perfectly non-volatile material ; and thus the acid gas is effectually re- tained. Carbonate of ammonia is under similar circumstances decomposed, carbonate of lime being formed and ammonia liberated ; the last, as before, being only partially retained by the moisture present, and requiring, when “dry-lime” is used, a subsequent application of water for its complete removal. Although in the wet lime purifying process a given weight of lime can remove a much larger volume of impurities, yet the dry lime process pos- sesses so many manipulatory advantages that it is now all but universally employed where lime is used as the purifying agent. The maximum amount of sulphuretted hydrogen or of carbonic acid which can be absorbed by 1 lb. of quick-lime, in the so-called dry and wet states respectively, is seen from the following table ; — Cubic feet of Cubic feet of Sulphuretted hydrogen. Carbonic acid. 1 lb. of quick-lime used as dry lime absorbs - - 6’78 - - * - 3’39 1 lb. of quick-lime used as wet lime absorbs - - 6’78 ... 6'78 In practice, however, the absorption actually effected is, even under the most favorable circumstances, considerably less than here indicated. As a substitute for lime in the puri- fication of gas a mixture of hydrated peroxide of iron and sulphate of lime has lately come into extensive use. This material is prepared in the first place by mixing slaked lime with hydrated peroxide of iron, the composition being rendered more porous by the addition of a certain proportion of sawdust. This mixture is now in a condition to remove those im- purities from coal-gas which are abstracted by lime. The peroxide of iron absorbs sul- phuretted hydrogen and sulphide of ammonium and becomes converted into sulphide of iron. COAXi-GAS. 363 The slaked lime absorbs carbonic acid and carbonate of ammonia until it is converted into subcarbonate of lime. When the absorbing powers of the mixture are nearly exhausted, the covers of the purifiers are removed and the mixture is exposed to the air. The follow- ing change is then said to take place. The sulphide of iron rapidly absorbs oxygen and be- comes converted first into sulphate of protoxide of iron, and finally into sulphate of perox- ide, which latter is decomposed by the carbonate of lime, carbonic acid being evolved as gas, whilst sulphate of lime and peroxide of iron are produced ; the mixture is thus again rendered available for the process of purification ; the peroxide of iron acts as before, but in the place of quick -lime we have now sulphate of lime, which is quite effectual for the removal of carbonate of ammonia, with which it forms carbonate of lime and sulphate of ammonia ; but the mixture is incapable of removing free carbonic acid, and it is therefore necessary to provide a separate dry lime-purifier for the removal of this gas. When the purifying material is again saturated with the noxious gases, another exposure to atmos- pheric oxygen restores it again to its active condition, the only permanent effect upon it being the accumulation of sulphate of ammonia within its pores. If this latter salt be oc- casionally dissolved out with water, the mixture may be used over and over again to an almost unlimited extent. It has been found that this process can be much simplified, and Mr. Hills, who has brought gas purification to great perfection, recommends that hydrated peroxide of iron should be merely mixed with a considerable bulk of saAvdust and placed in the purifiers. After the gas has passed through this mixture for 18 hours, it is shut off and replaced by a current of air forced through by a fanner for 3 hours. The sulphide of iron is thus oxidized, sulphur being separated and hydrated peroxide of iron regenerated : and the purifying material being now revivified, the gas may be passed through it again as be- fore. In this way it is only found necessary to remove the material once a month in order to separate the lowest stratum of about an inch in thickness, which has become clogged up with tar. A proportional quantity of fresh mixture of hydrated peroxide of iron and sawdust having been added, the whole is again returned to the purifier. It is difficult to conceive a more simple and inexpensive process of purification than this. It does not, how- ever, remove carbonic acid. Several other materials have been proposed for the separation of sulphuretted hydrogen from coal-gas, such as sulphate of lead, and chloride of manganese, but they possess no peculiar advantages and have never been extensively adopted. It has been already mentioned that, in addition to sulphuretted hydrogen and carbonic acid, which are readily removed by the processes just described, there also exist in coal-gas, as impurities, variable quantities of bisulphide of carbon and probably sulphuretted hydro- carbons. Now all these sulphur compounds produce sulphurous acid during the combus- tion of the gas, and where the quantities of these impurities are considerable, as is the case with much of the gas nov/ manufactured, the atmosphere of the apartments in which such gas is used becomes so strongly impregnated with sulphurous acid, as to be highly olFensive to the senses and very destructive to art decorations, bindings of books, &c. It becomes, therefore, a matter of considerable importance to prevent, as far as possible, the occurrence of these injurious constituents ; in fact, until this is effected, gas will never be more than very partially adopted as a means of illumination in dwelling-houses. When once gener- ated with coal-gas all attempts to remove these constituents have hitherto proved ineffect- ual, and there seems little ground for hope that any practical process will be devised for their abstraction. Attention may, therefore, more profitably be directed to the conditions which tend to diminish the amount generated in the retorts, or altogether to prevent their formation. Mr. Wright, who has paid considerable attention to 'this problem, finds that the employment of a moderate heat for the generation of the gas has the effect of greatly re- ducing the relative quantity of these noxious ingredients, and thus, by simply avoiding ex- cessive heat in the retorts, and rejecting the last portions of gas, he has, to a great extent, prevented their formation. Unfortunately, however, this remedy is not likely to find favor among.st gas-manufacturers in general, inasmuch as it considerably reduces the yield of gas. A few well-directed chemical experiments could scarcely fail to discover the conditions necessary for the non-production of these sulphuretted compounds. Probably the proper admixture of salt or lime with the coals before carbonization would have the desired effect. The subject is one of so much importance to the future of gas illumination, that it ought not to be suffered to rest in its present unsatisfactory condition. On the consumption of gas.—^\iQ proper consumption or burning of illuminating gas depends upon certain physical and chemical conditions, the due observance of which is of great importance in the development of a maximum amount of light. The production of artificial light depends upon the fact that, at certain high temperatures, all matter becomes luminous. The higher the temperature the greater is the intensity of the light emitted. The heat required to render matter luminous in its three states of aggregation differs greatly. Thus solids are sometimes luminous at comparatively low temperatures, as phosphorus and phosphoric acids. Usually, however, solids require a temperature of 600° or 700° F. to render them luminous in the dark, and must be heated to 1000° F. before their luminos- 364 COAL-GAS. ity becomes visible in daylight. Liquids require about the same temperature. But to ren- der gases luminous, they might be exposed to an immensely higher temperature ; even the intense heat generated by the oxyhydrogen blowpipe scarcely suffices to render the aqueous vapor produced visibly luminous, although solids, such as lime, emit light of the most daz- zling splendor when they are heated in this flame. Hence those gases and vapors only can illuminate which produce, or deposit, solid or liquid matter during their combustion. This dependence of light upon the production of solid matter is strikingly seen in the case of phosphorus, which when burnt in chlorine produces a light scarcely visible, but when con- sumed in air or oxygen emits light of intense brilliancy. In the former case the vapor of chloride of phosphorus is produced, in the latter, solid phosphoric acid. Several gases and vapors possess this property of depositing solid matter during com- bustion, but a few of the combinations of carbon and hydrogen are the only ones capable of practical application : these latter compounds evolve during combustion only the same products as those generated in the respiratory process of animals, viz. : carbonic acid and water. The solid particles of carbon which they deposit in the interior of the flame, and which are the source of light, are entirely consumed on arriving at its outer boundary ; their use as sources of artificial light, under proper regulations, is therefore quite compat- ible with the most stringent sanitary rules. The constituents of purified coal-gas have already been divided into illuminating and non-illuminating gases ; amongst the latter will be found light carburetted hydrogen, which, although usually regarded as an illuminating gas, has been proved by the experiments of Frankland to produce, under ordinary circumstances, no more light than hydrogen or car- bonic oxide, and therefore for all practical purposes it must be regarded as entirely desti- tute of illuminating power. This is owing chiefly to the temperature required for the de- position of its carbon being higher than that attained in an ordinary gas-burner ; for Frank- land has proved that, if the temperature of the light carburetted hydrogen flame be increased by previously heating the gas and air nearly to redness, then the flame becomes luminous to a considerable degree. It is not improbable that when gas is consumed in very large burners this necessary temperature is attained, and the light carburetted hydrogen con- tributes considerably to the aggregate illuminating effect ; a view which is, to a certain ex- tent, confirmed by the fact, that a relatively much larger amount of light is obtained from coal-gas wdien the latter is consumed in a large flame than when it is allowed to burn in a small flame. Omitting light carburetted hydrogen and carbonic oxide, the remaining carboniferous constituents of coal-gas yield, during combustion from suitable burners, an amount of light directly proportionate to the quantity of carbon which they contain in a given volume. In order to understand the nature of the combustion of a gas flame, it is necessary to remember that the flame is freely permeable to the air, and that, according to the well- known laws of gaseous mixture, the amount of air which mixes wdth the ignited gases will be increased, first, by an increase of the velocity with which the gas issues from the orifice of the burner ; and secondly, by the velocity of the current of air immediately surrounding the flame. It is well known that a highly luminiferous gas may be deprived of all illumina- ting power either by being made to issue from the burner with great velocity, or by being burnt in a very rapid current of air produced by a very tall glass chimney. The foregoing considerations indicate the conditions best adapted for obtaining the max- imum illuminating effect from coal-gas. The chief condition is the supply of just such a volume of air to the gas flame as shall prevent any particles of carbon from escaping uncon- sumed. Any excess of air over this quantity must diminish the number of particles of car- bon deposited within the flame, and consequently impair the illuminating effect. Another condition is the attainment of the highest possible temperature within the flame. The first of these conditions has been more or less perfectly obtained in the differ- ent gas-burners now in use. The second has been hitherto almost entirely neglected : the means by which it may be attained will be discussed after the burners at present in general use have been described. The chief buimers now in use are the bat’s-wing, fish-tail, argand, bude argand, Win- field’s argand. Guise’s argand, and Leslie’s argand. The hafs-wing consists of a fine slit in an iron nipple, giving a flat fan-like flame. The fish-tail consists of a similar nipple perforated by two holes, drilled so that the jets of gas are inclined towards each other at an angle of about 60°. A flat film of flame is thus produced, somewhat resembling the tail of a fish. This form of burner is especially adapted for the consumption of cannel and other highly illuminating gases. The argand consists of a hollow annulus, {see fig. 161,) from the upper surface of which the gas issues through a number of small apertures, which are made to vary in diameter from V 32 of an inch to 7 so of an inch, according to the richness of the gas; the most highly illuminating gases requiring the smallest apertures. The distances of the orifices for coal- COAL-GAS. 365 gas should be *16 to ’18 inch, and for rich cannel gas *13 inch. If the argand ring has ten orifices, the diameter of the central opening should be = Vio of an inch ; if 25 orifices, it should be 1 inch for coal gas ; but for oil gas, with 10 orifices, the central opening should have a diameter of ^ an inch, and for 20 orifices, 1 inch. The pin holes should be of equal size, otherwise the larger ones will cause smoke, as in an argand flame with an uneven wick. The bude burner consists of 2 or 3 concentric argand rings perforated in the manner just described. It is well adapted for producing a large body of very intense light with a comparatively moderate consumption of gas. Winfield's argand. — The chief distinction between this and the ordinary argand burner consists in the introduction of a metallic button above the annulus, so as to cause the internal current of air to impinge against the flame. A peculiarity in the shape of the glass chimney, as seen in the figure, produces the same effect upon the outer current of air. Seey?^. 162. Guise's argand contains 26 holes in a ring, the inner diameter of which is *6 inch, and the outer diameter 1*9 inch. Like the Winfield burner, it has a metal button ^ an inch in diameter, and 1 inch above the annulus. The glass chimney, which is cylin- drical, is 2 inches in diameter, and 6 inches long. Leslie's argand consists, as is seen in the figure, {fig. 164,) of a series of fine tubes arranged 163 162 164 in a circle, by which a more uniform admixture of air with the gas is effected. A sufScient current of air for all these argand burners can only be obtained by the use of a glass chim- ney, the rapidity of the current depending upon the height of the chimney. In the Les- lie’s argand the height of the chimney is especially adapted to the amount of light re- quired, and in order to consume gas economically, this point must be attended to in all argand burners. The following experiments made with different burners, by three eminent experiment- ers, upon the gas from three different kinds of coal, show the relative values of these burners for the gases produced from the chief varieties of coal used for the manufac- ture of gas in this country. Table I. — Results of Experiments on Newcastle Cannel Gas, by Mr. A. Wright. 1 Foot per Hour. Foot per Hour. 2 Feet per Hour. ! 2-J- Feet ' per Hour. 3 Feet per Hour. 3^ Feet per Hour. 4 Feet per Hour. 4 ^ Feet per Hour. Scotch Fish-tail, No. 1 ; — One foot = candles - - 4-75 5-02 “ = grains of sperm 585-0 602-0 Scotch Fish-tail, No. 2: — One foot = candles - - 5-05 5-7T 5-95 5-84 5-.53 “• = grains of sperm 606-0 690-0 714-0 700-0 563-0 Guise’s Argand : — One foot = candles - - . 1-08 1-85 3-12 4-85 495 5-77 6-74 “ = grains of sperm ■ 129-0 222-0 374-0 582-0 594-0 692-0 808-0 161 366 COAL-GAS. COAL-GAS. 867 Table III. contains the results of Mr. Barlow’s experiments on gas produced from a mix- ture of Felton, Felling, and Dean’s Primrose, all first-class Newcastle gas-coals, largely used in London. The burners employed in these experiments were the following: — 1st. A No. 3 fish-tail, or union jet. 2d. A No. 6 bat’s-wing. 3d. A common argand, with 15 large holes in a ring '85 inch diameter, and a cylin- drical chimiley glass 1 inches high. 4th. A Platow’s registered argand, with large holes in a ring, '9 inch, with inside and outside cone, and cylindrical chimney glass 8 '5 inches high. 5th. A Biznner’s patent No. 3 argand, with 28 medium-sized holes in a ring '75 inch diameter, and cylindrical chimney glass 8 '65 inches high. 6th. A Winfield’s registered argand, with 58 medium-sized holes in 2 rings of 29 holes in each, the mean diameter being 1 inch, with deflecting button inside and gauge below, bellied chimney glass 8 inches high. 7th. A Leslie’s patent argand, with 28 jets in a ring '95 inch diameter, and chimney glass 3 '5 inches high. 8th. A Guise’s registered shadowless argand, with 26 large holes in a ring '85 inch diameter, and deflecting button, cylindrical chimney glass 6'1 inches high, and glass reflect- ing cone to outside gallery. On an average of numerous trials the annexed results were obtained : — Table III. Burner. Bate of Consumption per Hour in Cubic Feet. Value of Cubic Foot in Grains of Sperm. Standard Candles per Cubic Foot. No. 2 4'9 289'0 2'4 “ 3 6'5 343 '0 2'85 “ 5 5 '5 374'0 3'11 “ 6 5'5 337'0 2'8 “ 8 5 '5 350'0 2'91 “ 1 5'5 27 6 '0 2'3 “ 2 5'0 290'0 2'41 . “ 3 5'5 341 '0 2'84 “ 4 6'5 348*0 2'9 “ 5 5'5 380'0 3'16 “ 6 5'5 335'0 2'79 “ 7 4'1 369.0 3*07 “ 8 5'5 364'0 3-03 It has been stated that one of the conditions necessary for the pro- duction of the maximum illuminating power from a gas flame, is the attainment of the highest possible temperature, and that this condition has been almost entirely neglected in the burners hitherto in use. Dr. Frankland has, however, proved, by some hitherto unpublished experi- ments, that this condition may be easily secured by employing the waste heat radiating from the gas flame, for heating the air previous to its employment for the combustion of the gas ; and that the increased tem- perature thus obtained has the effect of greatly increasing the illuminat- ing power of a given volume of the gas. Fig. 165 shows the burner contrived by Dr. Frankland for this purpose, a is a common argand burner, or better, a Leslie’s argand, furnished with the usual gallery and glass chimney 6, c ; the latter must be 4 to 6 inches longer than usual, c? c? is a circular disc of plate glass, perforated in the centre, and fixed upon the stem of the burner about 1-^ inches below the gallery by the collar and screw e. ffiso. second glass chimney somewhat conical, ground at its lower edge so as to rest air-tight, or nearly so, upon the plate d d; and of such a diameter as to leave an annular space \ inch broad between the two cylinders at g g. The cylinder / should be of such a length as to reach the level of the apex of the flame. The action of this burner will now be sufficiently evident. When lighted, atmos- pheric air can only reach the flame by passing downwards through the space between the cylinders / and c ; it thus comes into contact with the intensely heated walls of c, and has its temperature raised to about 500° or 600° before it reaches the gas flame. The passage of this heated air over the upper portion of the argand burner, also raises the temperature of the gas considerably before it issues from the burner. 165 /I e d O 368 COAL-GAS. Thus the gases taking part in the combustion are highly heated before inflammation, and the temperature of the flame is consequently elevated in a corresponding degree. Experi- ments with this burner prove a great increase in light, due chiefly to the higher temperature of the radiating particles of cax’bon ; but, no doubt, partly also to the heat being sufficiently high to cause a deposition of carbon from the light carburetted hydrogen ; thus rendering this latter gas a contributor to the total illuminating effect ; whilst, when burnt in the ordi- nary manner, it merely performs the functions of a diluent. The following are the results of Dr. Frankland’s experiments with this burner : I. Argand burner wnthout external cylinder. II. Same burner with ex- ternal cylinder. Rate of Consumption per Hour. f 3*3 cubic feet Light in Sperm Candl burning 120 grs. per 13'0 candles. 4 3-7 tt 15-5 4-2 (f 17-0 ii '2-2 (( 13-0 U 2-6 a 15-5 u - 2-7 “ 16-7 u 3-0 “ 19-7 a 3-3 u 21-7 These results show that the new burner, when compared with the ordinary argand, saves on an average 49 per cent, of gas, when yielding an equal amount of light ; and also that it produces a gain of 67 per cent, in light for equal consumptions. Faraday's ventilating hurner . — This admirable contrivance, the invention of Mr. Fara- day, completely removes all the products of combustion, and prevents their admixture with the atmosphere of the apartments in which the gas is consumed. The burner consists of an ordinary argand, 166, a, fitted with the usual gallery and chimney hh. A second wider and taller cylinder, c c, rests upon the outer edge of the gallery which closes at bot- tom the annular space, d d, between the two glass cylinders. c c is closed at top with a double mica cap e. f is the tube convey- ing the gas to the argand ; g g a wider tube 1;^ inches in diameter, communicating at one extremity with the annular space between the two glass cylinders, and at the other, either with a flue or the open air. The products of combustion from the gas flame are thus com- pelled to take the direction indicated by the arrows, and are therefore prevented from con- taminating the air of the apartment in which the gas is consumed, h is a ground glass globe enclosing the whole arrangement, and having only an opening below for the admission of air to the flame. In order to dispense with the descending tube, to wffiich there are some objections, Mr. Rutter has constructed a ven- tilating burner in which the ordinary glass chimney is made to terminate in a metal tube, through which the products of combustion are conveyed away. Mr. Dixon has also con- structed a modification of Faraday’s burner, the peculiarity of wffiich consists in the use of a separate tube bringing air to the flame from the same place, outside the building, to which the products of the burner are conveyed ; this contrivance is said to prevent downward draughts through the escape pipe, and a consequently unsteady flame. Faraday’s burner is in use at Buckingham Palace, Windsor Castle, the House of Lords, and in many public buildings. On the Estimation of the Value op Illuminating Gas. There are two methods in use for estimating the illuminating value of gas, viz. : — 1st. The photometric method. 2d. Chemical analysis. The photometric method consists in comparing the intensity of the light emitted by a gas flame, consuming a known volume of gas, with that yielded by some other source of light taken as a standard. The standard employed is usually a spermaceti candle, burning at the rate of 120 grains of sperm per hour. A spermaceti candle of six to the pound usually burns at a somewhat quicker rate than this ; but in all cases the consumption of sperm by the candle during the course of each experiment ought to be carefully ascertained by weighing, and the results obtained corrected to the 120-grain standard. Thus, suppose that during an experiment the consumption of spei-m was at the rate of 130 gi’ains per COAL-GAS. 369 hour, and that the gas flame being tested gave a light equal to 20 such candles, and it is re- quired to know the light of this flame in standard 120-grain candles, then — 120 : 130 : : 20 : 21-7; or, 20 candles burning at the rate of 130 grains per hour, are equal to 21*'7 candles burning at the rate of 120 grains per hour. There are two methods of estimating the comparative intensity of the light of the gas and candle flames, both founded upon the optical law that the intensity of light diminishes in the inverse ratio of the square of the distance from its source. Thus, if a sheet of writ- ing paper be held at the distance of one foot from a candle, so that its surface is perpen- dicular to a line joining the centre of the sheet and the flame, it will be illuminated with a light four times as intense as that which would fall upon a sheet of paper held in the same position at a distance of 2 feet ; whilst at a distance of 3 feet the light would have but 7o of the intensity it possessed at 1 foot. One method of estimating the comparative intensity of the gas and candle flames, consists in placing the two lights and an opaque rod nearly in a straight line, and in such a way as to cause each light to project a shadow of the rod upon a white screen placed at a distance of about 1 foot behind the rod. The two shadows must now be rendered of equal intensity by moving the candle either nearer to the rod or further from it. The shadows will be of equal intensity when the light falling upon the white screen from both sources is equal ; and if now the respective distances of the candle and gas flame from the screen be measured, then the square of the distance of the gas flame divided by the square of the distance of the candle will give the illuminating power of the gas ill candles. Thus, if equally intense shadows fall upon the screen when the candle is 3 feet distant and the gas flame 12 feet, the illuminating power of the gas flame will be — 12" 144 — r = =16 candles. 3"* 9 This method of estimating the illuminating power of a gas flame, known as the shadow test^ is very easy of execution, and would appear from the description to be capable of yield- ing results of considerable accuracy ; nevertheless, an unexpected difficulty arises from the great difference in color of the two shadows; that of the gas being of a bluish brown, whilst that of the candle is of a yellow brown tinge. This difference of tint renders it exceedingly difficult for the observer to ascertain when the two shadows possess equal intensity ; and, consequently, the limits of error attending determinations by this test are probably, even in the hands of an experienced operator, never less than 5 per cent., and frequently even as much as 10 per cent. The shadow test has, therefore, been all but superseded by the Bunsen'' s Photometer^ which consists of a graduated metal or wooden rod about 8 or 10 feet long, and sufficiently strong to be inflexible. At one extremity of this rod is placed the gas flame, and at the opposite end the standard candle. A stand which slides easily along the rod supports a small circular paper screen, at the same height as the two flames, and at right angles to the rod. This screen consists of colorless, moderately thin writing paper, ' saturated with a solution of spermaceti in spirit of turpentine, except a spot in the centre, about the size of a shilling, which is to be left untouched by the solution. The spirit of turpentine soon evaporates, and the paper is now ready for use. Being more transparent in the portion which has been saturated with the spermaceti solution, it becomes a delicate test of equality of light when placed between two luminous bodies ; for if the light of one of the bodies impinge with greater intensity upon one side of the screen than the other light does upon the opposite side, the difference in the transparency of the two portions of the screen will become distinctly visible ; the spot in the centre appearing comparatively opaque on the less illuminated side. When the screen is brought into such a position between the two sources of light as to render the central spot nearly or quite invisible on both sides, the illuminating effect of both lights at that point may be regarded as equal ; and all that now remains to be done is to measure the respective distances of the candle and gas from the screen, and di- vide the square of the distance of the gas by the square of that of the candle : the quotient expresses the illuminating power of the gas in candles. One of the most convenient forms of this instrument has been contrived by Mr. Wright, and may be had at 55 Millbank Street, Westminster. It consists of the following parts: — 1. A wooden rod exactly 100 inches long {Jig. IGY) from the centres of sockets at its ends A B. 2. An upright pillar c. 3. A candle holder n. 4. A mahogany slide e, having a metal socket f on its top, to hold the circular frame G, and a small pointer in its front. 5. A circular metal frame g, made to hold a prepared paper. 6. A blackened conical screen h, diminishing in size from its centre, where it opens with a hinge towards its ends, with two holes in front. The long rod is graduated, in accordance with the laws of distribution of light, from its VoL. III.— 24 sro COAL-GAS. centre each way into squares of distances in divisions numbered respectively 1, 2, 3, &c., to 36 ; to measure smaller differences than those amounting to 1 candle in value, each major division to 9 is subdivided into 10 parts, each, of course, representing Vio of an in- crement. From thence to 20 the subdivisions indicate i. Beyond that point no subdivi- sions are made, because the major divisions become so small that, practically, such divisions would be useless. The manner of fitting the apparatus together will be understood by reference to the annexed sketch. 167 The pillar c is screwed to one end of the shelf, and an experimental meter l placed at the other. This latter instrument is for measuring the quantity of gas passing to the. burner, and indicating the rate of consumption by observations of one minute, which is accomplished by the construction of its index dial. This dial has two circles upon its face, with a pointer to each ; the outer circle divided into four, and the inner into six* parts ; and each of these again divided into tenths. Every major division of the outer circle is a cubic foot ; and every major division of the inner circle is Vso of a cubic foot ; so that the major divisions on the inner circle each bear the same proportion to a cubic foot that a minute does to an hour. If, therefore, the number of these divisions and tenths of divisions, which the hand passes over in a minute, is ob- served, it will evidently only be necessary to read them off as feet and tenths of a foot to obtain the hourly rate of consumption. Thus, suppose the pointer passes from the upper figure 6 to the fifth minor division be- yond the figure 4, it would read off as 4Vio and ^eoo of a cubic foot in Veo of an hour. Multiplying these quantities by 60, we have Vco Vcoo x 60 = “’'‘’“/eoo = 4-|- cubic feet and Voo X 60 = 1 ; so that 4|^ feet and 1 hour are obtained by simply reading off the divisions which had been passed as feet and tenths. A pillar j, having a pressure gauge and two cocks at k, one with a micrometer move- ment, screws on to the top of the meter, and is intended for receiving burners when experi- menting. The graduated rod is supported in an exactly horizontal position by the pillars c and j, and screwed together by its binding screws. The candle socket n is screwed on to the top of c, and the mahogany slide c placed on the rod, with its pointer to the scale, carrying the frame g, containing a prepared paper, and covered by the cone h. The prepared paper is made by coating white blotting-paper with sperm, so as to render it semi-transparent, leaving a small spot in the centre plain, and therefore opaque. See g in the figure. All that now remains to render the apparatus ready for experimenting, is to put a piece of candle into the socket, and consume the gas through a proper burner over the meter, taking care that the centres of the candle-flame, paper, and gas flame, are in one horizontal line, and adopting the precautions previously laid down. Unfortunately, the determination of the exact point of equality of the two lights, is by no means easy, even after considerable practice ; and th# maximum amount of error to which even the practised operator is liable in such estimations of illuminating power, can- not be set down at less than 6 per cent. It is scarcely necessary to add, that all photometric experiments must be conducted in an apartment from which all light from other sources is excluded, and the walls of which are rendered as absorbent as possible, by being coated with a mixture of lampblack and size, or by being hung with black lustreless calico. Analytical Method of Estimating the Value of Illuminating Gas. — Frankland has shown that the resources of chemical analysis place in our hands a method for the determi- nation of the illuminating value of gas considerably more accurate than the photometric processes just described, although the execution of the necessary operations requires more skill, and is usually much more troublesome. As the determination of the illuminating power of a sample of gas by the analytical method necessitates most of the operations re- quired for the performance of a complete analysis of coal-gas, we shall here include in our description of the former process the additional details necessary for the latter. COAL-GAS. 371 1. Collection of the Sample of Gas . — In all analytical operations upon gases, it is of the utmost importance that the latter should be preserved from all admixture with atmos- pheric air. This can only be done, either by collecting the samples of gas over mercury, or by enclosing them in hermetically sealed tubes. When the sample of gas is collected at the place where the analysis is to be made, the former plan is usually most convenient ; but when the sample has to be obtained from a locality at some distance from the operator’s laboratory, the latter plan is usually adopted. To collect a sample of gas over mercury, attach one end of a piece of vulcanized India-rubber tube to the gas-pipe, and insert into the other extremity a piece of glass tube bent, as shown at a, fig. 168, allow the gas to stream through these tubes for two or three minutes, and then suddenly plunge the open extremity of the glass tube beneath the surface of the mercury in the trough C. Then fill the small glass jar b completely with mer- cury, taking care to remove all air-bubbles from its sides by means of a piece of iron w'ire, and closing its mouth firmly with the thumb, invert it in the trough c, intro- ducing the end of the bent tube a into its open extrem- ity, in such a way as to bring the mouth of a above the level of the surface of the mercury in c. The gas will then flow into b, until the level of the mercury in b is somewhat lower than that of the metal in the trough. If now, the tube a being removed, a small cup be filled with mercury and brought beneath B, the latter may be removed from the trough, and will be thus preserved from any appre- ciable atmospheric intermixture for several months. To collect samples of gas in hermetically sealed tubes, proceed as follows : Take a piece of glass tube about | of an inch internal diameter, and 1 foot long ; draw it out at both ends before the blowpipe, as shown in fig. 169 ; attach one extremity a, fig. 170, to a vul- canized India-rubber tube, communicating with a source of the gas, and the opposite ex- tremity B to a similar flexible tube about three feet long, and which is allowed to hang down perpendicularly from b. After the gas has streamed through this system of tubes for about three minutes, so as to ensure the complete expulsion of atmospheric air, the flame of a mouth blowpipe is directed against the narrow portion of the glass tube at c, so as to fuse it off. With as much expedition as possible the same operation is performed at the opposite extremity of the tube c?, which is thus hermetically sealed, and assumes the appear- ance shown in fig. 171. 168 The gas having been thus carefully collected, the necessary analytical operations must be conducted over mercury in a small wooden pneumatic trough, with plate glass sides, the construction of which is shown in fig. 172. a is a piece of hard well-seasoned wood, 12 inches long and 3 inches broad, hollowed out, as shown in the figure ; the cavity is 8f inches long. If inches broad, and If inches deep. The bottom of this cavity is rounded, with the exception of a portion at one end, where a surface, 1 inch broad, and 1| inches long, is made perfectly flat, a piece of vulcanized India-rubber, Vio of an inch thick, being firmly cemented upon it. Two end pieces b b, f of an inch thick, 3f inches broad, and 6 inches high, are fixed to the block a ; these serve below as supports for a, and above as the ends of a wider trough, which is formed by the pieces of plate glass c c, cemented into a and B B. The glass plates c c are 10| inches long, and 1|- inches high ; they are slightly 372 COAL-GAS. inclined, so that their lower edges are about 2f inches, and their upper edges 2| inches apart. This trough stands upon a wooden slab d d, upon which it is held in its place by two strips of wood e e. An upright column f, which is screwed into d, carries the inclined stand g, which serves to support the eudiometer during the transference of gas. A is a circular inclined slot in b, which allows of the convenient inclination of the eudiome- ter in the stand g. i is an indentation in which the lower end of the eudiometer rests, so as to prevent its falling into the deeper portion of the trough a. When in use, the trough is filled with quicksilver to within an inch of the upper edge of the glass plates c C, about 30 to 35 lbs. of the metal being necessary for this purpose. The eudiometers, or measuring tubes, should be accurately calibrated and graduated into cubic inches and tenths of a cubic inch, the tenths being subdivided by the eye into hun- dredths, when the volume of gas is read off ; this latter division is readily attained by a little practice. At each determination of volume, it is necessary that the gas should either be perfectly dry, or quite saturated with moisture. The first condition is attained by plac- ing in the gas, for half an hour, a small ball of fused chloride of calcium, attached to a pla- tinum wire the second condition, by introducing a minute drop of water into the head of the eudiometer, before filling it with quicksilver. The determinations of volume must either be made when the mercury is at the same level inside and outside the eudiometer, or, as is more frequently done, the difference of level must be accurately measured and allowed for in the subsequent reduction to a standard pressure. The height of the barome- ter and the temperature of the surrounding atmosphere must also be observed each time the volume of gas is measured, and proper corrections made for pressure, temperature, and also the tension of aqueous vapor, if the gas be moist. As tables and rules for these cor- rections are given in most treatises on chemistry, they need not be repeated here. These troublesome corrections and calculations can be avoided, by employing an instru- ment lately invented by Dr. Frankland and Mr. Ward, and which not only does away with the necessity for a room devoted exclusively to gaseous manipulations, but greatly shortens and simplifies the whole operation. This instrument, which is represented by fff. 173, con- sists of the tripod a, furnished with the usual levelling screws, and carrying the vertical pillar B B, to which is attached, on the one side, the movable mercury trough c, with its rack and pinion a a, and on the other, the glass cylinder n n, Avith its contents. This cylin- der is 36 inches long, and 4 inches internal diameter ; its lower extremity is firmly cemented into an iron collar c, the under surfiice of which can be screwed perfectly Avater-tight upon the bracket-plate d by the interposition of a vulcanized caoutchouc ring. The circular iron plate d is perforated with three apertures, into which the caps 6, c, c, are screAved, and * These balls, which should be of the size of a large pea, are required constantly in operations upon gases; they are readily prepared, when the substance of which they are formed is fusible by heat, as chloride of calcium or caustic potash, by melting these materials in a crucible and then pouring them into a small bullet-mould in Avhich the curved end of a platinum wire has been placed; when quite cold the ball attached to the wire is readily removed from the mould. Coke bullets are made by tilling the mould containing the platinum wire with a mixture of tAA'o parts of coke and one of coal, both finely powdered, and then exposing the mould and its contents to a heat gradually increased to redness, for a quarter of an hour. COAL-GAS. 373 which communicate below the plate with the t piece e e. This latter is furnished with a double-way cock /, and a single-way cock g, by means of which the tubes cemented into the sockets c, e, e, can be made to communicate with each other, or with the exit pipe h at pleasure. F, G, H, are three glass tubes, which are firmly cemented into the caps e, c, e. p and h are each from 15 to 20 millimetres internal diameter, and are selected of as nearly the same bore as possible, to avoid a difference of capillary action. The tube g is somewhat wider, and may be continued to any convenient height above the cylinder, h is accurately gradu- ated with a millimetre scale, and is furnished at top with a small funnel i, into the neck of which a glass stopper, about 2 millimetres in diameter, is carefully ground. The tube f ter- minates at its upper extremity in the capillary tube k, which is carefully cemented into the small steel stopcock 1. p has also fused into it at m, two platinum wires, for the passage of the elec- tric spark. After this tube has been firmly cemented into the cap e, its internal volume is accurately divided into 10 perfectly equal parts, which is effected without difficulty by first filling it with mercury from the supply tube g, up to its junc- tion with the capillary attachment, and then allowing the mercury to run off through the nozzle h until the highest point of its convex sur- face stands at the division 10, pre- viously made so as exactly to coin- cide with the zero of the millimetre scale on h ; the weight of the mer- cury thus run off is carefully deter- mined, and the tube is again filled as before, and divided into 10 equal parts, by allowing the mercury to run off in successive tenths of the entire weight, and marking the height of the convexity after each abstraction of metal. By using the proper precautions with regard to temperature, &c., an exceedingly accurate calibration can, in this way, be accomplished. The absorption tube i is sup- ported by the clamp n, and con- nected with the capillary tube k, by the stopcock and junction piece 1 1', p, as shown in the figure. When the instrument is thus far complete, it is requisite to ascertain the height of each of the nine upper divisions on the tube, above the lowest or tenth division. This is very accurately effected in a few minutes by carefully levelling the instrument, filling the tube G with mercury, opening the cock Z, and the stoppered funnel Z, and placing the cock f in such a position as to cause the tubes f n to communicate with the supply tube g. On now slightly turning the cock g, the mercury will slowly rise in each of the tubes f and n ; when its convex surface exactly coincides with the ninth division on f, the influx of metal is stopped, and its height in ii accurately observed ; as the tenth division on f corresponds with the zero of the scale upon h, it is obvious that the number thus read off is the height of the ninth division above that zero point. A similar observation for each of the other divisions upon f completes the instrument.^ Before using the apparatus, the large cylinder d d is filled with water, and the internal , walls of the tubes f and ii are, once for all, moistened with distilled water, by the introduc- tion of a few drops into each, through the stopcock Z, and the stoppered funnel i. The three tubes being then placed in communication with each other, mercury is poured into G until it rises into the cup e, the stopper of which is then firmly closed. When the mercury begins to flow from Z, that cock is also closed. The tubes f and h are now apparently filled with mercury, but a minute and imperceptible film of air still exists between the metal and ♦ This instrument may be obtained from Mr. Oertling, philosophical instrument-maker, Store Street Tottenham Court Koad. 374 COAL-GAS. glass ; this is effectually got rid of by connecting r and h with the exit tube A, and allow- ing the mercury to flow out, until a vacuum of several inches in length has been produced in both tubes ; on allowing the instrument to remain thus for an hour, the whole of the film of air above mentioned will diffuse itself into the vacuum, to be filled up from the supply tube G. These bubbles are of course easily expelled on momentarily opening the cock 1 and the stopper i whilst g is full of mercury. The absorption tube i being then filled with quicksilver, and attached to 1 by the screw clamp, the instrument is ready for use. In illustration of the manner of using the apparatus, a complete description of an analysis of coal-gas by this instrument will be given below. For the analysis of purified coal-gas by means of the mercury trough and eudiometer, the following operations are necessary : — I. Estimation of Cakbonic Acid. A few cubic inches of the gas are introduced into a short eudiometer, moistened as above described ; the volume is accurately noted, with the proper corrections, and a bullet of caustic potash is then passed up through the mercury into the gas : it is allowed to remain for at least one hour ; the volume of the gas, being again ascertained and subtracted from the first volume, gives the amount of carbonic acid which has been absorbed by the potash. II. Estimation of Oxygen. This gas can be very accurately estimated by Liebig’s method, which depends upon the rapid absorption of oxygen by an alkaline solution of pyrogallic acid. To apply this solu- tion, a small test tube is filled with quicksilver, and inverted in the mercury trough ; a few drops of a saturated solution of pyrogallic acid in water are thrown up into this tube by means of a pipette, and then a similar quantity of a strong solution of potash ; a coke bul- let attached to a platinum wire is introduced into this liquid, and allowed to saturate itself ; it is then withdrawn, and conveyed carefully below the surface of the mercury into the eudiometer containing the residual gas of experiment No. 1 ; every trace of oxygen will be absorbed in a few minutes, when the bullet must be removed, and the volume being again measured, the diminution from the last reading will represent the amount of oxygen origi- nally present in the gas. It is essential that the coke bullet, after saturation with the alka- line solution of pyrogallic acid, should not come in contact with the air before its introduc- tion into the gas. III. Estimation of the Luminiferous Constituents. Various methods have been employed for the estimation of the so-called olefiant gas (luminiferous constituents) contained in coal-gas. The one which has been most generally employed, depends upon the property which is possessed by olefiant gas, and most hydro- carbons, of combining with chlorine, and condensing to an oily liquid : hydrogen and light carburetted hydrogen are both acted upon in a similar manner when a ray even of diffused light is allowed to have access to the mixture ; but the condensation of the olefiant gas and hydrocarbons takes place in perfect darkness, and advantage is therefore taken of this cir- cumstance to observe the amount of condensation which takes place when the mixture is excluded from light. The volume, which disappears during this action of the chlorine, is regarded as indicating the quantity of olefiant gas present in the mixture. There are many sources of error inseparably connected with this method of operating, which render the results unworthy of the slightest confidence ; the same remark applies also to the employ- ment of bromine in the place of chlorine ; in addition to the circumstance that these deter- minations must be made over water, which allows a constant diffusion of atmospheric air into the gas, and vice versd^ there is also formed in each case a volatile liquid, the tension of the vapor of which increases the volume of the residual gas ; and this increase admits of neither calculation nor determination. The only material by which the estimation of the luminiferous constituents can be accurately effected is anhydrous sulphuric acid, which im- mediately condenses the luminiferous constituents of coal-gas, but has no action upon the other ingredients, even when exposed to sunlight. The estimation is conducted as follows : A coke bullet prepared as described above, and attached to a platinum wire, being rendered thoroughly dry by slightly heating it, for a few minutes, is quickly immersed in a saturated solution of anhydrous sulphuric acid, in Nordhausen sulphuric acid, and allowed to remain in the liquid for one minute ; it is then withdrawn, leaving as little superfluous acid adher- ing to it as possible, quickly plunged beneath the quicksilver in the trough, and introduced into the same portion of dry gas, from which the carbonic acid and oxygen have been with- drawn by experiments I. and II. ; here it is allowed to remain for about two hours, in order to ensure the complete absorption of every trace of hydrocarbons. The residual volume of gas cannot, however, yet be determined, owing to the presence of some sulphurous acid ‘ derived from the decomposition of a portion of the sulphuric acid : this is absorbed in a few minutes by the introduction of a moist bullet of peroxide of manganese, which is readily made by converting powdered peroxide of manganese into a stiff paste with water, rolling it into the shape of a small bullet, and then inserting a bent platinum wire, in such COAL-GAS. 875 a manner as to prevent its being readily drawn out ; the ball should then be put in a warm place, and allowed slowly to diy, it will then become hard, and possess considerable cohe- sion, even after being moistened with a drop of water, previous to its introduction into the gas. After half an hour, the bullet of peroxide of manganese may be withdrawn, and re- placed by one of caustic potash, to remove the watery vapor introduced with the previous one ; at the end of another half hour, this bullet may be removed, and the volume of the gas at once read off. The difference between this and the previous reading, gives the volume of the luminiferous constituents contained in the gas. This method is very accu- rate ; in two analyses of the same gas, the percentage of luminferous constituents seldom varies more than 01 or 0‘2 per cent. IV. Estimation of thf Non-Luminiferous Constituents. These are light carburetted hydrogen, hydrogen, carbonic oxide, and nitrogen. The percentages of these gases are ascertained in a graduated eudiometer, about 2 feet in length, and f of an inch internal diameter; the thickness of the glass being not more than 7io of an inch. This eudiometer is furnished at its closed end with two platinum wires, fused into the glass, for the transmission of the electric spark. A drop of water, about the size of a pin’s head, is introduced into the upper part of the eudiometer before it is filled with mer- cury and inverted into the mercurial trough : this small quantity of water serves to saturate with aqueous vapor the gases subsequently introduced. About a cubic inch of the residual gas from the last determination is passed into the eudiometer, and its volume accurately read off ; about 4 cubic inches of pure oxygen are now introduced, and the volume (moist) again determined. The oxygen is best prepared at the moment when it is wanted, by heating over a spirit or gas flame a little chlorate of potash, in a very small glass retort, allowing of course sufficient time for every trace of atmospheric air to be expelled from the retort before passing the gas into the eudiometer. The open end of the eudiometer must now be , pressed firmly upon the thick piece of india-rubber placed at the bottom of the trough, and an electric spark passed through the mixture ; if the above projiortions have been observed the explosion will be but slight, which is essential if nitrogen be present in the gas, as this element will otherwise be partially converted into nitric acid, and thus vitiate the results. By using a large excess of oxygen, all danger of the bursting of the eudiometer by the force of the explosion is also avoided. The volume after explosion being again determined, a bullet of caustic potash is introduced into the gas, and allowed to remain so long as any diminution of volume takes place ; this bullet absorbs the carbonic acid that has been pro- duced by the combustion of the light carburetted hydrogen and carbonic oxide, and also renders the residual gas perfectly dry ; the volume read off after this absorption, when de- ducted from the previous reading, gives the volume of carbonic acid generated by the com- bustion of the gas. The residual gas now contains only nitrogen and the excess of oxygen employed. The former is determined by first ascertaining the amount of oxygen present, and then deduct- ing that number from the volume of both gases ; for this purpose a quantity of dry hydro- gen, at least three times as great as the residual gas, is introduced, and the volume of the mixture determined ; the explosion is then made as before, and the volume (moist) again recorded ; one-third of the contraction caused by this explosion represents the volume of oxygen, and this deducted from the volume of residual gas, after absorption of carbonic acid, gives the amount of nitrogen. The behavior of the other three non-luminous gases on explosion with oxygen enables us readily to find their respective amounts by three simple equations, founded upon the quantity of oxygen consumed, and the amount of carbonic acid generated by the three gases in question. Hydrogen consumes half its own volume of oxygen, and generates no carbonic acid ; light carburetted hydrogen consumes twice its volume of oxygen, and gen- erates its own volume of carbonic acid ; whilst carbonic oxide consumes half its volume of oxygen, and generates its own volume of carbonic acid. If, therefore, we represent the volume of the mixed gases by A, the amount of oxygen consumed by B, and the quantity of carbonic acid generated by C, and further, the volumes of hydrogen, light carburetted hydrogen, and carbonic oxide respectively by x, y, and z, we have the following equations : x-f-y-t-z = A ■ix-h2y-l-iz = B y + z = C Prom which the following values for x, y, and z are derived : — x = A — C 2B — A 3 z-C 3 876 COAL-GAS. V. Estimation of the Yalue op the Luminiferous Constituents. We have now given methods for ascertaining the respective quantities of all the ingre- dients contained in any specimen of coal-gas, but the results of the above analytical opera- tions afford us no clue to its illuminating power. They give us, it is true, the amount of illuminating hydrocarbons contained in a given volume of the gas, but it will be evident, from what has already been said respecting the luminiferous powers of these hydrocarbons, that the greater the amount of carbon contained in a given volume, the greater will be the quantity of light produced on their combustion ; and therefore, as the number of volumes of carbon vapor contained in one volume of the mixed constituents, condensible by anhy- drous sulphuric acid, has been found to vary from 2-54 to 4-36 volumes, it is clear that this amount of carbon vapor must be accurately determined for each specimen of gas, if we wish to ascertain the value of that gas as an illuminating agent. Fortunately this is easily effected ; for if we ascertain the amount of carbonic acid generated by 100 volumes of the gas in its original condition, knowing from the preceding analytical processes the percentage of illuminating hydrocarbons, and also the amount of carbonic acid generated by the non- luminiferous gases, we have all the data for calculating the illuminating value of the gas. For this purpose a known volume of the original gas (about one cubic inch) is introduced into the explosion eudiometer, and mixed with about five times its volume of oxygen, the electric spark is passed, and the volume of carbonic acid generated by the explosion ascer- tained as above directed. If we now designate the percentage of hydrocarbons absorbed by anhydrous sulphuric acid by A, the volume of carbonic acid generated by 100 volumes of the original gas by B, the carbonic acid formed by the combustion of the non-luminous constituents remaining after the absorption of hydrocarbons from the above quantity of original gas by C, and the volume of carbonic acid generated by the combustion of the luminiferous compounds (hydrocarbons) by x, we have the following equation : — x = B — C and therefore the amount of carbonic acid generated by one volume of the hydrocarbons is represented by B — C A But as one volume of carbon vapor generates one volume of carbonic acid, this formula also expresses the quantity of carbon vapor in one volume of the illuminating constituents. For the purpose of comparison, however, it is more convenient to represent the value of these hydrocarbons in their equivalent volume of olefiant gas, one volume of which con- tains two volumes of carbon vapor ; for this purpose the last expression need only be changed to B — C 2 A Thus, if a sample of gas contain 10 per cent, of hydrocarbons, of which one volume contains three volumes of carbon vapor, the quantity of olefiant gas to which this 10 per cent, is equivalent, will be 15. By the application of this method we obtain an exact chemical standard of comparison for the illuminating value of all descriptions of gas ; and by a comparison of the arbitrary numbers thus obtained, with the practical results yielded by the same gases when tested by the photometer, much valuable and useful information is gained. Analysis of Coal-Gas with Frankland and Ward\s Apparahis. — Introduce a few cubic inches of the gas into the tube i, fig. 173, and transfer it for measurement into f, by open- ing the cocks 1 1 ' and placing the tube f in communication with the exit pipe the trans- ference being assisted, if needful, by elevating the trough c. When the gas, followed by a few drops of mercury, has passed completely into f, the cock I is shut, and f turned, so as to connect f and h with h. Mercury is allowed to flow out until a vacuum of two or three inches in length is formed in h, and the metal in f is just below one of the divisions ; the cock f is then reversed, and mercury very gradually admitted from g, until the highest point in f exactly corresponds with one of the divisions upon that tube ; we will assume it to be the sixth division. This adjustment of mercury and tiie subsequent readings can be very accurately made by means of a small horizontal telescope placed at a distance of about six feet from the cylinder, and sliding upon a vertical rod. The height of the mercury in h must now be accurately determined, and if from the number thus read off, the height of the sixth division above the zero of the scale on h be deducted, the remainder will express the true volume of the gas. As the temperature is maintained constant during the entire analy- sis, no correction on that score has to be made ; the atmospheric pressure being altogether excluded from exerting any influence upon the volumes or pressures, no barometrical obser- vations are requisite ; and as the tension of aqueous vapor in f is exactly balanced by that in H, the instrument is in this respect also self-correcting. Two or three drops of a strong COAL-GAS. 377 solution of caustic potash are now introduced into i by means of a bent pipette, and mer- cury being allowed to flow into f and h by opening the cock g, the gas returns into i through 1 1', and there coming into contact with an extensive surface of caustic potash solu- tion, any carbonic acid that may be present will be absorbed in two or three minutes, and the gas being passed back again into ii for remeasurement, taking care to shut I before the caustic potash solution reaches I \ the observed diminution in volume gives the amount of carbonic acid present. The amount of oyxgen is determined in like manner by passing up into i a few drops of a saturated solution of pyrogallic acid, which forms with the potash already present pyro- gallate of potash. The gas being then brought back into i, oxygen, if present, will be absorbed in a few minutes. Its amount is of course ascertained by remeasuring the gas in F. The next step in the operation consists in estimating the amount of olefiant gas and illuminating hydrocarbons. For this purpose, whilst the gas, thus deprived of oxygen and carbonic acid, is contained in f, the tube i must be removed, thoroughly cleansed and dried, and being filled with mercury, must be again attached to /. The gas must now be trans- ferred from F to I, and a coke bullet, prepared as above described, being passed up into i, must be allowed to remain in the gas for one hour. After its removal, a few drops of a strong solution of bichromate of potash must be admitted into i in order to absorb the sul- phurous acid and vapors of anhydrous sulphuric acid resulting from the previous operation. The gas is now ready for measurement ; it is therefore passed into f, and its volume deter- mined ; the diminution which has occurred since the last reading represents the volume of olefiant gas and illuminating hydrocarbons that were present in the gas. It now only remains to determine the respective amounts of light carburetted hydrogen, carbonic oxide, hydrogen, and nitrogen present in the residual gas. This is effected as fol- lows : — As much of the residual gas as will occupy about inches of its length at atmos- pheric pressure is retained in f, and its volume accurately determined ; the remainder is passed into J, and the latter tube removed, cleansed, filled with mercury, and reattached. A quantity of oxygen equal to about three-and-a-half times that of the combustible gas is now added to the latter, and the volume again determined ; then the mixture having been expanded to about the sixth division, an electric spark is passed through it by means of the wires at m. The contraction resulting from the explosion having been noted, two or three drops of caustic potash solution are passed into j, and the gas is then transferred into the same tube. In two minutes the carbonic acid generated by the explosion is perfectly ab- sorbed, and its volume is determined by a fresh measurement of the residual gas. The lat- ter must now be exploded with three times its volume of hydrogen, and the contraction on explosion noted. These operations furnish all the data necessary for ascertaining the rela- tive amounts of light carburetted hydrogen, carbonic oxide, hydrogen, and nitrogen, accord- ing to the mode of calculation given above. Finally, the value of the luminiferous constituents is obtained as before, by exploding about a cubic inch of the original specimen of gas with from four to five times its volume of oxygen, and noting the amount of carbonic acid produced. I. Apparatus used in the Generation of Coal-Gas. Retorts. — The use of this portion of the apparatus is to expose the coal to a high tem- perature, to exclude atmospheric air, and to deliver the gaseous and vaporous products of distillation into the refrigeratory portion of the apparatus. The materials composing the retorts should therefore possess the following properties : — 1st, high conducting power for heat ; 2d, rigidity and indestructibility at a high temperature ; and 3d, impermeability to gaseous matter. The materials hitherto used in the construction of retorts are cast-iron, wrought-iron, and earthenware; but none of these materials possess the above qualifica- tions in the high degree that could be wished. Thus cast-iron, though a good conductor of heat, is not perfectly rigid and indestructible. At high temperatures it becomes slightly viscous, and at the same time undergoes rapid oxidation. Wrought-iron is a still better conductor of heat, but its qualities of indestructibility and rigidity are even lower than those of cast-iron ; whilst earthenware, though rigid and indestructible by oxidation, is a very bad conductor of heat, and is moreover very liable to crack from changes of tempera- ture. V ery various forms of retort have been employed at different times in order to secure, as far as possible, the conditions just enumerated. Cast-Iron Retorts. — The chief forms of the cast-iron retorts are : First, the cylindrical, fig. 174, used in the Manchester Gas Works, 12 inches diameter, and 6 to 9 feet long; Second, the elliptical, 18 inches by 12 inches, by 6 to 9 feet, fig. 175 ; Third, the car 378 COAL-GAS. shape, fg. 176, now little used, 2 feet by 9 inches, and of the same length as before ; Fourth, the D-shaped retort. Jig. 177, 20 inches wide and 14 inches high. This form of retort is at present far more extensively used than any of the others. Fig. 17 8 shows a bed of 5 D-shaped iron retorts. The length is 7| feet, and the trans- verse area, from one foot to a foot and a half square. The arrows show the direction of the flame and draught. The charge of coals is most conveniently introduced in a tray of sheet-iron, made some- what like a grocer’s scoop, adapted to the size of the retort, which is pushed home to its further end, inverted so as to turn out the contents, and then immediately withdrawn. All these retorts are set horizontally in the furnace, and they have a flanch cast upon their open end, to which a mouthpiece a a, jig. 179, can be securely bolted. The mouth- piece is provided with a socket b, for the reception of the standpipe., and also with an arrangement by which a lid c C can be screwed gas-tight upon the front of the mouthpiece, as soon as the charge of coal has been introduced. By applying a luting of lime mortar to that part of the lid which comes into contact with the mouthpiece, a perfectly tight joint is obtained. Sometimes iron retorts are made of double the above length, passing completely through the furnace, and being furnished with a lid and standpipe at each end. Such is the con- struction of Mr. Croll’s and of Lowe’s reciprocating retorts. These retorts are charged from each end alternately, and there is an arrangement of valves by means of which the gas evolved from the coal recently introduced is made to pass over the incandescent coke of the previous charge, at the opposite end of the retort. It is highly probable that some advantage is derived from this arrangement during the very early stage of the distillation of the fresh coal ; but on the whole, for reasons stated above, the principle is undoubtedly bad, for although it enables the manufacturer to produce a larger volume of gas, the quality is so much inferior as to reduce the total illuminating effect obtainable from a given weight of coal. Wrought-Iron Retorts. — Mr. King, the eminent engineer of the Liverpool Gas Works, has for many years successfully used retorts of wrought-iron. They are made of thick boiler plates, riveted together, and are of the D shape, 5^ feet wide, 6 feet long, and 18 inches high at the crown of the arch. About 1 ton of coal can be worked off in these retorts in 24 hours. Occasionally the bottoms are of cast-iron, which materially prevents the great amount of warping to which wrought-iron is subject when exposed to high temperatures. Earthenware., or Clay Retorts . — These are usually of the D shape, although they are occasionally made circular or elliptical. Their dimensions are about the same as those of the cast-iron retorts commonly used, but their walls are necessarily thicker, varying from 2^ to 4 inches in thickness ; this, added to the circumstance that clay is a very bad conductor of heat, undoubtedly causes the expenditure of a larger amount of fuel in heating these retorts ; nevertheless, this disadvantage is, perhaps, less than might be supposed, since iron retorts soon become coated outside with a thick layer of oxide of iron, which also greatly hinders the free communication of heat to the iron beneath. Moreover, the lower price and much greater durability of clay retorts, are causing their almost universal adoption in gas works, especially since the removal of pressure by exhausters greatly reduces the amount of leakage to which clay retorts are liable. The following is an extract relating to clay retorts, from the “Reports of Juries” of the great Exhibition of 1851 : — “ The use of fire-clay is not of very ancient date, and has greatly increased within the last few years. It is found in England almost exclusively in the coal measures, and COAL-GAS. 379 from different districts the quality is found to differ considerably. The so-called “ Stour- bridge clay ” is the best known, and will be alluded to presently ; but other kinds are almost, if not quite, as well adapted for the higher purposes of manufacture, being equally free from alkaline earths and iron, the presence of which renders the clay fusible when the heat is intense. The proportions of silica and alumina in these clays vary considerably, the former amounting sometimes to little more than 50 per cent., while in others it reaches be- yond 70, the miscellaneous ingredients ranging from less than ^ to upwards of 7 per cent, “ The works of Messrs. Cowen & Co. are among the most extensive in England, and they obtain their raw material from no less than nine different seams, admitting of great and useful mixture of clay for various purposes. “ After being removed from the mine, the clay is tempered by exposure to the weather, in some cases for years, and is then prepared with extreme care. The objects chiefly made are fire-bricks and gas retorts — the latter being now much used, and preferred to iron for dura- bility. “ These retorts were first made by the present exhibitors in ten pieces, (this being twenty years ago,) and since then the number of pieces has been reduced successively to four, three, and two pieces, till in 1844 they were enabled to patent a process for making them in one piece, and at the present time they are thus manufactured of dimensions as much as 10 feet long by 3 feet wide in the inside, which is, however, more than double the size of the largest exhibited by them. 180 380 COAL-GAS. “ Gas retorts of very fair quality are shown by Mr. Ramsay of Newcastle, who has also succeeded extremely well in the manufacture of fire-bricks. The retorts show a little more iron than is desirable, but the exhibitor has been considered worthy of honorable mention. Retorts of less creditable appearance are exhibited by Messrs. Hickman & Co. of Stour- bridge, and Mr. A. Potter of Newcastle. The surface of both these retorts is cracked and undulating. When we consider the high and long-continued temperature to which these objects are exposed, the absolute necessity of attending to every detail in mixing the clay and moulding the retort will be at once recognized, and the apparently slight defects of some of those sent for exhibition require to be noticed as of real importance. “ Next to England, the finest specimens of fire-clay goods on a large scale are from Bel- gium : the gas retort sent from France is not remarkable for excellence.” Fig. 180 is an elevation of Mr. Wright’s plan for a range of long clay retorts. Fig. 181 shows the plans and sections of the setting for these retorts. 181 COAL-GAS. 381 .Retorts, or rather ovens, of fire-brick, the invention of Mr. Spinney, have been long used successfully at Exeter, Cheltenham, and other places. They appear to be very durable, and to require little outlay for repairs, but a very large expenditure of fuel is required for heating them. They are of the D shape, Y feet long, 3 feet 2 inches wide, and 14 inches high at the crown of the arch. Each retort receives a charge of 5 or 6 cwt. of Newcastle or Wesh coal every 12 hours, and produces gas at the rate of 9,000 cubic feet per ton of Welsh, and 10,000 to 12,000 per ton of Newcastle coal. Clegg's Revolving Web Retort . — This retorf, the invention of Mr. Clegg, sen., makes the nearest approach to a truly philosophical apparatus for the generation of gas ; in it the coal is exposed to a sudden and uniform heat, in a thin stratum, by which means the gases are liberated at once, and under the conditions most favorable for the production of a maxi- mum amount of illuminating constituents. Very little tar is produced from this retort. Fig. 182 represents a section of this retort, which is of the D shape, with a very low and flat arch. It is made of wrought-iron boiler plates riveted together, e is a hopper for holding the coal to be carbonized ; f is a discharging disc ; g is the retort ; n is a web on to which «the coal is discharged by the disc f ; 1 1 are revolving drums carrying the wrought-iron web h ; l l are the flues from a lateral furnace by which the retort is heated ; M is the exit pipe for the coke, its lower extremity is either closed by an air-tight door, or is made to dip into water. 182 All the coal must be reduced to fragments about the size of coffee berries, and a 24 hours’ charge must be placed at once in the hopper, and secured by a luted cover. The dis- charging disc has 6 spurs, and is made to revolve uniformly with the drum below it at the rate of 4 revolutions per hour. The diameter of the hexagonal drums is so regulated, that the coal, which fiills upon the web from the discharging disc, will at one revolution have passed the entire length of the retort. The passage through the retort occupies 15 min- utes, which is quite sufficient to expel the whole of the gas from the coal. In each revolu- tion of the disc and drum, 745 cubic inches of coal (or 21 lbs.) are distributed over a heated surface of 2,016 square inches. 18 cwt. of coal is carbonized in one of these retorts in 24 hours, and the production of gas is equal to 12,000 cubic feet per ton of Newcastle coal. The quality of the gas is also considerably superior to that obtained from the same coal in the ordinary retorts. Although the first cost of these retorts and accompanying machinery is considerably greater than that of the retorts in ordinary use, yet the destructible parts can be replaced at about the same cost as that required to replace the latter. The coke produced is greater in quantity, but inferior in quality, owing to its more minute state of division. The minor advantages attendant upon this form are, that it occupies less space, requires much less man- ual labor, and enables the retort-house to be kept perfectly clean, wholesome, and free from suffocating vapor. If the principle of this plan could be combined with less complication of details, it would no doubt come into extensive use. 382 COAL-GAS. II. The Refrigeratory Apparatus. From the moment that the gas leaves the retorts, it is subjected to cooling influences which gradually reduce its temperature, until on leaving the so-called condenser its temper- ature ought to be only a few degrees higher than that of the atmosphere, except in winter, when it is advisable to maintain a heat, relatively to the external air, greater than in sum- mer. The gas leaves the retort by the standpipes a a a, jig. 1 83, which are of cast-iron, 6 inches in diameter at their lower extremity, and slightly tapering upwards. Some of the least volatile products of decomposition condense in these pipes, but their prox- imity to the furnaces, and the constant rush of heated gas and vapor through them, prevent more than a very slight amount of refrigeration. They conduct to the hydraulic main., which is shown atB, 183. It consists of a cylinder running the entire length of the retort house, and fixed at a sufficient height above the mouths of the retorts to pro- tect it from the flame issuing from the latter during the times of charging and drawing. The diameter varies from 12 to 18 inches, and the recurved extremi- ties of the standpipes {the dip'pipes) c C c c, pass through it by gas-tight joints, and dip, to the extent of 3 or 4 inches, into the condensed liquids contained in the hydraulic main. The use of this portion of the apparatus is to cut off the communication in the reverse direc- tion between the gas beyond the stand- pipes and the retorts, so as to prevent the former rushing back down the standpipe during the time that the lid of the retort is removed. Being maintained half full of tar it effectually seals the lower ends of the dip-pipes, and prevents any 184 COAL-GAS. 383 return of gas towards the retorts. The condensed products, consisting chiefly of tar, make their exit from the hydraulic main by the pipe d, which leads them to the tar well. From the hydraulic main the gas passes to the condenser, the office of which, as its name implies, is to effect the condensation of all those vapors which could not be retained by the gas at the ordinary atmospheric temperature.' The condenser has received a variety of lonns, but the one which appears to unite in the highest degree simplicity and efficiency, is the invention of Mr. Wright, of the Western and Great Central Gas Companies.. Its con- struction is shown in fig. 184. a a a a are 5 double concentric cast-iron cylinders, through which the gas is made to circulate in succession by means of the tiepipes b b b b, whilst the inner cylinders being open above and below, a current of air, set in motion by their heated walls, rushes through them, thus securing both an internal and external refrigeratory action. It will be also seen by a reference to the figure, that the heated gas enters these cylinders at the top, taking an opposite direction to that pursued by the external and internal currents of air, and thus securing the most perfect refrigeration, by bringing the gas constantly in proximity to air of increasing coldness. Each cylinder is furnished at bottom with a tar receptacle c, for the collection of the condensed products, which are carried to the tar well by a pipe not shown in the figure. The details of construction are sufficiently seen from the drawing, and require no further description. In some country works the condenser is used. The extent of surface which the gas requires for its refrigeration before it is admitted into the washing-lime apparatus, depends upon the temperature of the milk of lime, and the quantity of gas generated in a certain time. It may be assumed as a determination sufficiently exact, that 10 square feet of surface of the condenser can cool a cubic foot of gas per minute to the temperature of the cooling water. For example, suppose a furnace or arch with 5 retorts of 150 pounds of coal each, to produce in 5 hours 3,000 cubic feet of gas, or 10 cubic feet per minute, there would be required, for the cooling surface of the condenser, 100 square feet = 10 x 10. Suppose 100,000 cubic feet of gas to be produced in 24 hours, for which 8 or 9 such arches must be employed, the condensing surface must contain from 800 to 900 square feet. After the action of the condenser, the gas still retains, chiefly in mechanical suspension, a certain quantity of tarry matter, besides a slight percentage of ammonia. To free it ifom these, it is passed through a sambber d, {fig. 184,) which consists of a tall cylinder filled with bricks, paving stones, or coke, and having an arrangement by which a stream of water can be admitted at top and removed at bottom. The chief use of the water is to remove ammonia from the gas, but as it also dissolves some of the luminiferous hydrocarbons, its use is objected to by Mr. Wright, and dry scrubbers are now used at the Western Gas Works. It is also considered by the same gentleman, that the detention of a certain per- centage of ammonia by the gas, is rather an advantage than otherwise, as it serves in part to neutralize the sulphurous acid which is inevitably produced by the combustion even of the best gas. It must, however, be borne in mind, that the presence of ammonia in gas gives rise to the formation of nitric acid during its combustion. The Exhauster . — The passage of the gas through the liquid of the hydraulic main, and the other portions of apparatus between the retorts and gas-holder, causes a very consider- able amount of pressure to be thrown back upon the retorts, — an effect which is productive of mischief in two ways ; in the first place, if there be any fissure or flaw in the retorts, or leakage in the joints, the escape and consequent loss of gas is greatly augmented ; and in the second place, it has been ascertained by Mr. Grafton, of Cambridge, that pressure in the retorts causes the decomposition of the illuminating hydrocarbons with greatly increased rapidity. It is, therefore, very desirable to remove nearly the whole of this pressure by mechanical means, and this is now done in all well-arranged works, by the use of an appa- ratus termed an exhauster. Several forms of exhausters are in use, but it will be necessary only to describe that of Mr. J. T. Beale, which has been found by experience to be very effective and economical. It is shown in section in fig. 185. The axle a is reduced at each end, and passes into two cylindrical boxes bored to a larger diameter than the axle at those parts ; and in the annular space between the axle and the box antifriction rollers are intro- duced, their diameter being equal to the width of the annular space ; the box at one end is fitted wfith a stuffing-box, through which the axle passes for the application of the driving power. Upon motion being given to the axle, the sliding pistons b b are carried with it. These sliding pistons are furnished at their ends with cylindrical pins which project and fit into cylindrical holes bored in the guide blocks c C, which fit into annular recesses n in the end plates, and keep the slides in contact with the cylinder. The slides are fitted with me- tallic packing e, to allow of wear. The axle continuing to revolve, as one slide reaches the outlet and ceases to exhaust, the other comes into action, and the exhaustion is unceasing. Thus the pressure upon the retorts (which is indicated by a gauge) is reduced to about half an inch of water. In order to judge of the degree of purity of the gas after its transmission through the lime machine, a slender siphon tube provided with a stopcock may have the one end in- 384 COAL-GAS. serted in its cover, and the other dipped into a vessel containing a solution of acetate of lead. Whenever the solution has been rendered turbid by the precipitation of black sul- 185 phuret of lead, it should be renewed. The saturated and fetid milk of lime is evaporated in oblong cast-iron troughs placed in the ash-pit of the furnaces, and the dried lime is partly employed for luting the apparatus, and partly disposed of for a mortar or manure. III. Apparatus used in the Puripication of Coal-Gas. Figs. 186 and 187 represent the form of a dry purifier, combined with a washer or scrubber, lately patented by Mr. Lees of Manchester. Fig. 186 is an elevation, partly in section of this apparatus, and jig. 187 is another elevation, also partly in section, of the same, a is a hopper, into which the dry lime is fed ; 6 is a damper, or sliding door, by which the supply of lime can be regulated ; c is a sheet metal tube, containing the worm or screw d, the axis of which is supported at one end by the stuffing-box e, and at the other end by the bearing /. A slow revolving motion is given to the worm d from the driving shaft g, by means of the bevel wheels A, upright shaft i, worm and worm wheel A:, fixed on the axis of the worm. The lime in the hopper a, is Icept in motion by the screw n, which is turned slowly round by the worm g^ the worm wheel o and bevel wheels jr>, one of which is fixed on the screw n. The tube c is open at c', to admit the dry lime from the hopper o, and the worm or screw d is furnished with cross pieces d' to agitate the lime, which is gradually moved from the hopper to the other end of the tube c, by the revolving of the worm. Below the tube c is another tube l\ ?/ is a siphon, by which the washing fluid is supplied and con- ducted to the chamber s, which then flows down the tube I to the chamber r, keeping the level indicated by j b. z are two paddles, fixed upon the circular perforated plates, which are set to an angle, and secured to the shaft m\ and are revolved speedily by the strap and pulleys X. These agitators serve to increase the action of the washing fluid contained in the tube A, by which the gas is washed previous to passing through the dry lime purifier. The mode of operation is as follows : — The gas to be purified is admitted through the pipe 9 ^, to the chamber r, from whence it passes along the tube A, as shown by the arrows, to the chamber s ; it then rises into the chamber t and enters the tube c, along which it passes in the direction shown by the arrows whence it may be conveyed, through the pipe w, to the gasometer. COAL-GAS. 385 It will be apparent, as the gas passes along the tube /, containing the agitators rn, which are caused to revolve speedily by the motion given by the straps and speed pulleys rr, that the washing fluid, which is passing regularly through the siphon ?/, and running into the chamber s, and along the tube /, into the chamber r, keeping the level as shown by j 6, is caused to be re- volved into a centrifugal motion round the tube /, by the two paddles 2 r, placed upon the circular perforated plates, secured upon the shaft which are set to an angle, thereby causing a counter-motion from left to right of the tube and causing the washing fluid to be wrought into a complete spray amongst the gas, whereby the heavier parts of the impurities are carried away more effectually than by any other washers in use. The gas then enters the chamber t through the tube c, passes along the coils or threads of the worm or screw c?, and as the cross pieces d are set to an angle, as shown in fig. 187, the lime is raised from the lower to the upper part of the tube c, and then drops down to the gas that is making its way towards the openings d ; consequently, the lime and the gas become most intimately mixed, whereby the lime is made to absorb a much greater pro- portion of the impurities contained in the gas than is effected by the dry lime purifiers usually employed, in which the lime is supported on stationary trays. The lime dropping into the tube c from the hopper a, is worked gradually towards the chamber into which it drops. The speed of the screw or worm 7 Imperial f - 8 0 - - - 47 Chartered J Western - - - 3*0 - - 22 Manchester gas - - - - 4*0 - - - 82 Notwithstanding the great economy and convenience attending the use of gas, and, in a sanitary point of view, the high position which, as an illuminating agent, coal-gas of proper composition occupies, its use in dwelling-houses is still extensively objected to. The objec- tions are partly well founded and partly groundless. As is evident from the foregoing table, even the worst gases produce, for a given amount of light, less carbonic acid and heat than either lamps or candles. But then, where gas is used, the consumer is never satisfied with a' light equal in brilliancy only to that of lamps or candles, and consequently, when three or four times the amount of light is produced from a gas of bad composition, the heat and atmospheric deterioration greatly exceed the corresponding effects produced by the other means of illumination. There is nevertheless a real objection to the employment of gas-light in apartments, founded upon the production of sulphurous acid during its combus- tion : this sulphurous acid is derived from bisulphuret of carbon, and the organic sulphur compounds, which have already been referred to as incapable of removal from the gas by the present methods of purification. These impurities, which are encountered in almost all coal-gas now used, are the princi- pal if not the only source of the unpleasant symptoms experienced by many sensitive per- sons in rooms lighted with gas. It is also owing to the sulphurous acid generated during the combustion of these impurities that the use of gas is found to injure the bindings of books, and impair or destroy the delicate colors of tapestry. Therefore the production of gas free from these noxious sulphur compounds is at the present moment a problem of the highest importance to the gas manufacturer, and one which demands his earnest attention. The high sanitary position which gas takes, with regard to the production of a minimum amount of carbonic acid and heat for a given amount of light, ought to stimulate the manu- facturer to perfect the process, by removing all sulphur compounds, and attaining the most desirable composition, so that this economical, and, if pure, agreeable and sanitary light, may contribute to our domestic comfort to a much greater extent than it has hitherto done. Hydrocarbon Gas. * This title has been given to illuminating gas manufactured according to a patent granted some years ago to Mr. White of Manchester. The process of manufacture consists essen- tially in the generation of non-illuminating combustible gases by the action of steam upon 890 COAL-GAS. charcoal, coke, or other deoxidizing substances, in a separate retort, and the introduction of these gases, technically called water-gas, into the retort in which the illuminating gases are being generated, and in such a manner that these latter gases shall be swept out of the retort as rapidly as possible, so as to remove them from the destructive influence of a high temperature. The retorts used for the hydrocarbon-gas process may be of various shapes and sizes. The settings are similar to those for the ordinary retorts, and any number which is neces- sary may be placed in an oven. They difler only from the ordinary retorts by having a horizontal partition, or diaphragm, cast in the centre, dividing the retort into two cham- bers, and extending to within 12 inches of the back. This diaphragm is found in practice to strengthen the sides of the retorts, and thus to add to their durability. The water-gas retorts may be cast from the same pattern as the cannel retorts, and may be set in exactly the same manner. Figs. 193a and 194 represent a setting of two retorts in one oven, and 193a show the same in elevation, transverse section, and longitudinal section. The retorts here shown have an internal cubical capacity of about 16 feet, and the bed of two is capable of producing about 10,000 cubic feet per diem of hydrocarbon gas. The temperature at which the retorts are worked is about the average. The water-gas is generated in the retort a in the following manner ; — The upper and lower chambers are well filled with coke or char- coal, and a very fine stream, or rapid drops, of water flowing from the tap enters the upper chamber through the siphon pipe, falling into a small steam-generating tube, which is placed inside to receive it, and instantly converts it into steam. The steam, in passing backwards along the upper chamber, and forwards along the lower one, becomes to a great extent de- composed into hydrogen, carbonic oxide, and carbonic acid gases. The water-gas generated in the retort a, as described above, enters the lower chamber of the retort b, through the connecting pipe c c,*cast on the mouthpiece. In the chambers of this retort the illuminat- ing gas is generated, either from coal, cannel, resin, or other suitable material, and being rapidly carried forward by the current of water-gas, its illuminating principles are preserved from the destruction caused by prolonged contact with the incandescent surfaces in the retort, whilst at the same time its volume is increased. When very rich cannels or other COAL-GAS. 391 materials are used, two, three, or even four water-gas retorts are made to discharge their gas into the can- nel retort. The hydrocarbon process has hitherto been applied only to resin, coals, and cannels. The following is a brief summary of the results of a series of experiments made by Dr. Frankland on the manufacture of hydrocarbon resin gas: Each hundred weight of resin was dis- solved by heat in 7^ gallons of the resin oil of a former working, and the liquid, whilst still hot, was run into one of the retorts, by means of a siphon tube, in a stream about the thickness of a crowquill, whilst water-gas, generated in the second retort, was admitted as described above. The mixed gases were then made to stream through ^the usual form of condensing apparatus, and were afterwards compelled to pass successively through wet and dry lime purifiers before they reached the gas-holder. In order to secure a uniform mixture of the gas pro- duced in each experiment, it was allowed to remain at rest in the gas- holder for at least twelve hours be- fore a specimen was withdrawn for analysis. In the following tables both the practical and analytical results are given. I. Practical Results. Average evolu- tion of Gas per hour. Materials Consumed. Products Obtained. Eesin. Coal. Char- coal. Lime. Water. Eesin Oil. Gas. Gas per cwt. of Eesin. Cubic ft. Cwt. qr. lb. Cwt. qr. lb. lb. lb. Gals. Cb. ft. 1st Experiment 930 2 1 17i 1 2 10 20 73 10-7 3,340 1,388 2d “ 1,000 2 1 18 1 2 12 20 77 7-8 3,800 1,576 3d “ - 2 0 17 1 2 12 28 85 4'5 4,157 1,932 4th “ ■ 2 0 7 1 2 10 28 62i 8-75 3,090 1,520 Average production of gas per ton of resin - - . 32,080 cubic feet. Average production of resin oil per ton of resin - - 'JO'S gallons. Illuminating power of average gas before purification, as ascertained by shadow test, •7 5 cubic feet per hour = light of one short six spermaceti candle. II. Analytical Results. Composition of Gas before Purification. Actual Amount in Cubic Feet. 1st Exp. 2d Exp. 3d Exp. 4th Exp. 1st Exp. 2d Exp. 3d Exp. 4th Exp. Average. Hydrocarbons - 25S-7 269-0 305-7 254-0 7-75 7-08 7-41 8-22 7-62 Light carbd. hydrogen - 587-5 1527-7 895-9 961-0 17-58 40-20 21-71 31-09 27-64 Hydrogen - 1315-3 1274-8 1976-2 1297-8 39-38 33-54 47-90 42-06 40-72 Carbonic oxide - 967-9 319-2 753-3 463-5 28-98 8-40 18-26 15-04 17-67 Carbonic acid - • 210-6 409-5 1949 113-7 6-31 10-78 4-72 3-59 6-35 3340-0 3800-2 4126-0 ! 3090-0 i 100-00 100-00 100-00 100-00 100-00 Percentage Amount. Amount of carbon vapor contained in 1 volume of hydrocarbons = 2*8 volumes. 392 COAL-GAS. Composition of Gas aftee Pukification. 1st Exp. 2d Exp. 3d Exp. 4th Exp. Average. Hydrocarbons - 8-27 7 ’94 7’78 8’53 8’13 Light carburetted hydrogen - 18’76 45 ’06 22’79 32’25 29’71 Hydrogen - - - - - 42’03 37’59 60’27 43’62 43’38 Carbonic oxide - 30’93 9’41 19’16 16’60 18-78 lOO’OO lOO’OO lOO’OO lOO’OO lOO’OO Specific gravity of average gas before purification = ’65886. “ “ “ after “ =: ’69133. Yalue of Hydrocaebons expressed in their equiva- lent Volume of Olefiant Gas. Value of Actual Amount. Value of Percentage Amount in Purified Gas. 1st Experiment Cubic Feet. 862’2 Cubic Feet. 11-68 2d Experiment - - - 376’6 11-12 3d Experiment - - - 428-0 10-89 4th Experiment • * ■ 11-94 This process is especially adapted for the manufacture of gas on a small scale, as in private houses or small manufactories. The necessary operations involve little trouble and unpleasant effluvia. Dr. Frankland has also investigated the hydrocarbon process as applied to coals and cannels, and the following is a tabulated summary of his experimental results. Summary of Experimental Besults. Name of Coal. Cubic feet of Gas per ton. Illuminating power per ton in Sperm Candles. Gain per ton by White’s process. Gain per cent, by White’s process. By old process. By IVhite'B procees. By old process. By White’s process. Quantity of gas in cubic feet. Illuminat- ing power in sperm candles. Quantity of Gas. Illumi- nating power. Wigan Cannel, Ince Hall - Wigan do., Balcarres - Boghead Cannel Ditto, 2d experiment - Lesmabago Cannel Metbill Cannel - - - Newcastle do., Eamsey 10,900 10,440 13,240 10,620 9,560 10,300 16,120 15,500 38,160 51,720 29,180 26,400 15,020 4,816 4,156 11,340 7,620 5,316 5,026 6,448 5,920 21,368 20,688 13,934 11,088 5,646 5,220 5,060 24,920 38,480 18,560 16,840 4,720 1,632 1,764 9,988 9,308 6,314 5,772 620 47- 9 48- 5 198-2 290-6 174-8 176-2 45-8 33-9 42-4 87-8 81-8 82-8 108-1 12-3 Table, showing the quantity of Coal or Cannel requisite for producing light equal to 1,000 Sperm Candles, each burning 10 hours at the rate of 120 grs. per hour. Name of Coal. Weight of Coal. By old process. By White’s process. lbs. lbs. Wigan Cannel (Ince Hall) ... 465-1 347-4 Wigan Cannel (Balcarres) 639-0 878-4 Boghead Cannel 197-5 104-8 Lesmahago Cannel - 293-9 160-7 Methill Cannel ..... 421-4 202-0 Newcastle Cannel 445-7 396-7 Newcastle Coal (Felton) .... 746-7 COAL-GAS. . 893 Table Showing the quantity of Gas requisite for producing light equal to 1000 Sperm Candles^ each burning 10 hours at the rate of 120 grs. per hour. Name of Gas. Eate of Consumption per hour. Quantity of Gas. Wigan Cannel (Ince Hall) ... Ditto by White’s process - Wigan Cannel (Balcarres) Ditto by White’s process - Boghead Cannel Ditto by White’s process - Ditto ditto, 2d experiment Lesmahago Cannel .... Ditto by White’s process - Methill Cannel Ditto by White’s process - Newcastle Cannel (Ramsay) . . - Ditto by White’s process - Newcastle Coal (Felton) ... Resin Gas by White’s process Manchester Gas (June, 1851) 02 r City Company’s Gas (July 15, 1851) - 1 Great Central Company’s Gas, do. o ^ -< Chartered Company’s Gas do. Imperial Company’s Gas - do. ^ (Western Company’s Gas - do. Cubic Feet. 5 5 5 5 3 3 5 4 4 5 5 5 5 5 j calculated ) ( from analysis J ditto ditto 5 5 ( calculated ) ) from analysis f ditto ditto ditto ditto Cubic Feet. 2263 2500 2512 2618 1168 1786 2500 1394 2094 1798 2381 2049 2660 3356 8012 3448 3846 3546 3320 4099 1538 Dr. Frankland thus sums up the advantages which he conceives to result from the appli- cation of the hydrocarbon process to coals and cannels : — 1. It greatly increases the produce in gas from a given weight of coal or cannel, the increase being from 46 to 290 per cent., according to the nature of the material operated upon. 2. It greatly increases the total illuminating power afforded by a given weight of coal, the increase amounting to from 12 to 108 per cent., being greatest when coals affording highly illuminating gases are used. * 3. It diminishes the quantity of tar formed, by converting a portion of it into gases pos- sessing a considerable illuminating power. 4. It enables us profitably to reduce the illuminating power of the gases produced from such materials as Boghead and Lesmahago cannels, &c., so as to fit them for burning with- out smoke and loss of light. Mr. Barlow has also experimented upon this process of gas-making, and finds that a very considerable gain in total illuminating power results from its use. Mr. Clegg’s investigation of this process showed, that whilst Wigan Cannel produces by the ordinary process of gas-making about 10,000 cubic feet of 20 candle gas per ton, 16.000 cubic feet of 20 candle gas, or 26,000 cubic feet of 12 candle gas can be made from the same quantity of material by the hydrocarbon process. Also that, by the applica- tion of the same process to Lesmahago Cannel, 36,000 cubic feet of 20 candle gas, or 58.000 cubic feet of 12 candle gas per ton, can be obtained ; whilst Boghead Cannel yields 62.000 cubic feet of 20 candle gas, or 75,000 cubic feet of 12 candle gas. The following table presents in a condensed form Mr. Clegg’s results as to comparative cost : — Name op Coal. Cost of 1000 feet of 20 candle gas by old process. Cost of 1000 feet of 20 candle gas by hy- drocarbon process. Cost of 1000 feet of 12 candle gas by hy- drocarbon process. Wigan Cannel at 14s. per s. d. s, d. s. d. ton .... 1 9^ 1 sf 0 Ilf Lesmahago Cannel at 18s. per ton ... 2 6i 0 Ilf 0 9f Boghead Cannel at 20s. per ton .... 2 H 0 11 0 9f 394 , COAL-GAS. Wood Gas. Attempts were first made in France towards the close of the last century to manufac- ture an illuminating gas from wood. The Thermolamp of Lebon, a wood-gas apparatus, then and for some time afterwards excited considerable attention, especially in the districts of Germany, Sweden, and Russia, where coals are scarce. This mode of illumination proved, however, to be a complete failure, owing to the very feeble illuminating power of the gas produced, and as at this time the production of gas from coal was rapidly becoming better known, any thing like a regular manufacture of wood-gas never in any case gained a footing. Subsequent trials only confirmed the failure of Lebon, so that it was universally considered impossible to produce a practically useful gas from wood by the usual process of gas-manufacture. In the year 1849, Professor Pettenkofer of Munich had occasion to repeat these experiments, and he found that the gases evolved from wood at the tempera- ture at which it carbonizes, consist almost entirely of carbonic acid, carbonic oxide, and light carburetted hydrogen ; olefiant gas and the illuminating hydrocarbons being entirely absent. Such gas was therefore totally unfitted for illuminating purposes. The temperature of boiling quicksilver, at which coal is not in the slightest degree de- composed, is quite sufficient to carbonize wood completely. If small pieces of wood be placed in a glass retort half filled with mercury, and the latter be heated to boiling, a black lustrous charcoal is left in the retort, whilst gas of the following composition is evolved : — Carbonic acid 57*4 Carbonic oxide 35 ‘6 Light carburetted hydrogen 7’0 100-0 If, however, the gases and vapors produced by the above experiment be heated to a con- siderably higher temperature than that at which the wmod is carbonized. Professor Petten- kofer found that a very different result is obtained ; the volume of permanent gas is con- siderably augmented, whilst such an amount of illuminating hydrocarbons is produced as to render the gas actually richer in these constituents than coal-gas. Analyses of various samples of such superheated gas gave the following results : — Carbonic acid 18 to 25 per cent. Carbonic oxide 40 “ 50 “ Light carburetted hydrogen - - - - - - 8“12 “ Hydrogen 14 “17“ Olefiant gas and hydrocarbons 6 “ 7 “ The illuminating value of the hydrocarbons was found to be one-half greater than that of an equal volume of olefiant gas. Varieties of w'ood differing so much in character as pine and beech were found to yield equally good gas. These observations prove that wood-gas is indubitably entitled to rank amongst illuminating agents. With regard to the apparatus employed, various forms have been contrived so as to communicate the necessary temperature to the escaping vapors : it has been however at length found that the ordinary form of retort furnishes the necessary conditions, provided it be not filled more than one- third with the charge of wood. 120 lbs. of the latter, thoroughly dried, constitute the charge for one retort. In 1^ hours the distillation is com- plete, the result being, after absorption of carbonic acid, 650 cubic feet of gas, which is perfectly free from all sulphur and ammonia compounds, and possesses, according to the numerous experiments of Liebig and Steinheil, an illuminating power greater than coal-gas in the proportion of 6 : 5. The following analyses show the composition of wood-gas when made on a manufactur- ing scale. No. 1 is a sample of gas before purification from the works at the Munich Rail- way Station, and No. 2 is purified gas, as supplied to the town of Bayreuth : — No. 1. Olefiant Gas. No. 2. Olefiant Gas. Hydrocarbons - 6-91 = 9.74 7-70 = 11-93 Light carburetted hydrogen - 11.06 - - 9-45 Hydrogen - - - . - 15-07 - - 18-43 Carbonic oxide ... - 40-59 . - 61-79 Carbonic acid ... - 25-72 . - 2-21 Nitrogen .... 99-35 - -42 100-00 The specific gravity of the purified wood-gas is about ‘700, and this, coupled with the large percentage of carbonic oxide which it contains, renders it necessary to employ burn- COOHIKEAL. 395 ers with much larger perforations than those used for coal-gas ; in fact, if wood-gas be con- sumed at the rate of from 3 to 4 cubic feet per hour from a coal-gas burner, it yields scarcely any light at all, whereas if consumed from a fish-tail burner with wide apertures, its illuminating power exceeds, as just stated, that of coal-gas. Although the relative cost of wood and coal will prevent the adoption of Professor Pet- tenkofer’s ingenious process in this country, yet, as it can also be applied with like results to peat, there is a high probability that it might be employed with great advantage in Ire- land. Its rapid adoption in many German and Swiss towns proves the practicability of the process in districts where wood is cheap. — E. F. COAL NAPHTHA. See Naphtha (Coal.) COBALT BLUE, or THENARD’S BLUE, is prepared by precipitating a solution of sulphate or nitrate of cobalt by phosphate of potash, and adding to the resulting gelatinous deposit from three to four times its volume of freshly deposited alumina, obtained by the addition of carbonate of soda to a solution of common alum. This mixture, after being well dried and calcined in a crucible, affords, when properly ground, a beautiful blue pig- ment. COCHINEAL. In order to ascertain the value of cochineal for dyeing, we must have recourse to comparative experiments. We are indebted to MM. Robiquet and Anthon for two methods of determining the quality of cochineals, according to the quantity of carmine they contain. The process of M. Robiquet consists in decolorizing equal volumes of decoc- tion of different cochineals by chlorine. By using a graduated tube, the quality of the cochineal is judged of by the quantity of chlorine employed for decolorizing the decoction. The process of M. Anthon is founded on the property which the hydrate of alumina pos- sesses of precipitating the carmine from the decoction so as to decolorize it entirely. The first process, which is very good in the hands of a skilful chemist, does not appear to us to be a convenient method for the consumer ; in the first place, it is difficult to procure per- fectly identical solutions ; in the next place, it is impossible to keep them a long time with- out alteration. We know that chlorine dissolved in water reacts, even in diffused light, on this liquid ; decomposes it, appropriates its elements, and gives rise to some compounds which possess an action quite different from that of the chlorine solution in its primitive state. The second process seems to us to be preferable, as the proof liquor may be kept a long while without alteration. A graduated tube is also used ; each division rqpresents one- hundredth of the coloring matter. Thus the quantity of proof liquor added exactly repre- sents the quantity in hundredths of coloring matter contained in the decoction of cochineal which has been submitted to examination. The following remarks from a practical dyer are valuable : — “ The coloring matter of cochineal being soluble in water, I have used this solvent for. exhausting the different kinds which I have submitted to examination in the colorimeter. I operated in the following manner : — I took a grain of each of the cochineals to be tried, dried at 122° Fahr. ; I submitted them five consecutive times to the action of 200 grains of distilled water at water-bath heat, each time for an hour ; for every 200 grains of distilled water I added two drops of a concentrated solution of acid sulphate of alumina and of pot- ash. This addition is necessary to obtain the decoctions of the different cochineals exactly of the same tint, in order to be able to compare the intensity of the tints in the color- imeter.* “ In order to estimate a cochineal in the colorimeter, two solutions, obtained as de- scribed above, are taken ; some of these solutions are introduced into the colorimetric tubes as far as zero of the scale, which is equivalent to 100 parts of the superior scale ; these tubes are placed in the box, and the tint of the liquids enclosed is compared by look- ing at the two tubes through the eye-hole ; the box being placed so that the light falls ex- actly on the extremity where the tubes are. If a difference of tint is observed between the two liquors, water is added to the darkest (which is always that of the cochineal taken as type) until the tubes appear of the same tint.f “ The number of parts of liquor which are contained in the tube to which water has been added is then read off; this number, compared with the volume of the liquor con- tained in the other tube, a volume which has hot been changed, and is equal to 100, indi- cates the relation between the coloring power and the relative quality of the two cochineals. And if, for example, 60 parts of water must be added to the liquor of good cochineal, to bring it to the same tint as the other, the relation of volume of the liquids contained in the tubes will be in the case as 160 is to 100, and the relative quality of the cochineals will be represented by the same relation, since the quality of the samples tried is in proportion to their coloring power.” — {Napier.) * Care must be taken not to add to the water, which serves to extract the coloring matter from the different cochineals, more than the requisite quantity of acid sulphate of alumina and solution of potash, because a stronger dose would precipitate a part of the coloring matter in the state of lake. t For diluting the liquors the same water must always be used which has served to extract the color- ing matter of the cochineals under examination, otherwise the darkest decoction would pass into violet, as water was added to it, to bring back the tint to the degree of intensity as that of the decoction to which it is compared. COCK-METAL. 396 The exports from Guatemala consist principally of cochineal, the staple and almost the only article of exportation for a number of years past. It is chiefly produced in Old Gua- temala, nine leagues distant from Guatemala, and also in Amatellan, about six leagues dis- tant. The raising of this insect is subject to so many accidents and contingencies that it is excessively precarious, and, above all, the weather has a great effect upon it. Taking all this into consideration, it is suiprising that attention has not been directed to the cultivation and production of other articles suited to the climate and soil of Guatemala, and less liable to destruction by unseasonable rains and atmospheric changes than cochineal. It is reason- ably to be feared that, if a longer time be suffered to pass, the cochineal of this country cannot compete with that of Teneriffe, and other parts of the world, where it is now begin- ning to be cultivated with success ; and, should this happen, it would tend to diminish the trade of this country with England. COCK-METAL. An inferior metal ; a mixture of copper and lead used for making cocks. See Alloy. COCOA-NUT OIL. Cocoa-nut oil is obtained by two processes, — one is by pressure, the other by boiling the bruised nut and skimming off the oil as it forms on the surface. It is a white solid having a peculiar odor. It fuses a little above 70° Fahr. ; becomes readily rancid, and dissolves easily in alcohol. It consists of a solid fat called cocin or cocinine^ (a combination of glycerine and cocinic, or coco-stearic acid,) -t- 2HO ; or, according to Richardson, C*-H^"0®-f Aq, and of a liquid fat or oleine. Cocoa-nut oil is used in the manufacture of soap and candles. COD-LIVER OIL. The oil obtained from the livers of several varieties of the Gadidoe family ; especially from the torsk, Brosmius brosme. It is administered medicinally : it acts mainly as a nutritive body, and the old idea that its medicinal value depended on the iodine it contained is now proved to be false, since it holds no iodine in composition. Since the demand for cod-liver oil has been large, it has been extensively adulterated with other fish oils. CODILLA OF FLAX. The coarsest parts of the fibre sorted out by itslf. See Flax. COIR. The outer coating of the cocoa-nut, often weighing one or two pounds, when stripped off longitudinally, furnishes the fibres called by the native name of Coir^ and used for small cables and rigging. In England these fibres are used in matting and for coarse brush work. In Price & Co.’s works they are advantageously employed, placed between iron trays and on the sur- face of the cocoa-nut and other concrete oils and fats, and subjected to great pressure ; the liquid oil flows out, leaving solid fats behind. From the abundance, cheapness, and durability of this substance, it is likely to come into more general use, and it is even now very seri- ously proposed as a material for constructing Ocean Telegraphs, from its lightness and power of resisting sea-water. The qualities of coir for many purposes have been established for ages in the East Indies. Dr. Gilchrist thus describes the properties of coir ropes : — “ They are particularly elastic and buoyant, floating on the surface of the sea ; therefore, when, owing to the strength of the current, a boat misses a ship, it is usual to veer out a quantity of coir, having previously fastened an oar, or small cask, &c., to its end. Thus the boat may be easily enabled to haul up to the ship’s stern. Were a coir hawser,” he adds, “ kept on board every ship in the British Marine, how many lives would probably be saved.” It is stated that fresh water rots coir in a very short time, corroding it in a surprising degree, whereas salt water absolutely strengthens it, seeming to increase the elasticity. Coir is therefore unfit for running rigging, especially for vessels subject to low latitudes, it being easily snapped in frosty weather. Nothing can equal the ease with which a ship rides at anchor, when her cables are of coir. As the surges approach the bows, the vessel gradually recedes in consequence of the cable yielding to their force ; but as soon as they have passed, it contracts again, drawing the vessel gradually back to her first position: the lightness of the material adds to this effect, for the cable would float if the anchor did not keep it down. At the present time the forces exerted upon cables and the angles assumed under different circumstances, in paying out submarine telegraphic cables, have been the subject of practical attention and theoretical investigation. Some of the greatest authorities have assumed that the forces exerted, between the bottom of the sea and the ship’s stern, had reference only to forms or waves of the cables, representing some curve between the vertical and horizontal line, but always concave to the water surface. For a curve to exist, in the opposite direction, was named only as a condition, without evidence of any practical kind to show that it really existed, or called for any attention to investigate it. So long since, however, as 1825, Dr. Gilchrist, among others, had described this very opposite curve of the coir, viz. — of being, when in action as a cable, curved with a concave surface toward the bottom of the sea ; a fact well known to the experienced sailors of England, as well as to the natives who employ these coir cables so extensively on the East Indian coast. “ A hempen cable always makes a curve doivnwards, between the vessel and the anchor, but a coir cable makes the curve upwards. Therefore, if a right line were drawn from the COKE. 397 hawse-hole, to the ring of the anchor, it would be something like the axis of a parabolic spindle, of which the cables would form, or nearly so, the two elliptic segments.” In the employment of materials for ocean telegraphs, especially for deep-sea purposes, the use of iron and the proposal for using coir and other light substances, have caused the telegraphic means to be spoken of as “ heavy ” or “ light ” cables. Dr. Allan, of Edin- burgh, proposes the abundant use of coir to make a light cable^ say half the weight of the lightest hitherto made, the Atlantic cable. He states that a deep-sea cable may be com- pounded to weigh not more than 10 cwt. per mile : while the cheapness, durability in salt water, lightness, and abundant supply, will give it advantages over gutta percha and other substances used to form the bulk of the lightest cables hitherto employed. When cocoa-nuts are sawed into two equal parts across the grain of the coir coating, they form excellent table brushes, causing wood planks to assume a very high polish by friction. If the shell should be left, the edges should be perfectly smooth, and then they will not scratch. It is a good mode to strip off the coir, and, after soaking it in water, to beat it with a heavy wooden mall until the pieces become pliant, when they should be firmly bound together with an iron ring ; the ends being levelled, the implement is fit for use ; a little beeswax, rubbed occasionally upon them, adds greatly to the lustre of the furniture ; of course, the polish is mainly due to strength and rapid action producing the friction upon the wood, and other articles of furniture. In India, the coarse bark of the nuts is extensively used to cleanse houses, and washing the decks of vessels. Coarse stuff, matting, and bagging are made of the fibres, as well as ropes, sails, and cables. The general preparation is simple ; the fibrous husks or coats which envelop the cocoa- nuts, after being for some time soaked in water, become soft ; they are then beaten to sepa- rate other substances with which they are mixed, which fall away like saw-dust, the strings or fibres being left ; this is spun into long yarns, woven into sail-cloth, and twisted into cables, even for large vessels. Cordage thus made is considered preferable, in many re- spects, to that brought from Europe, especially the advantage of floating in water. On burning the ligneous envelope of the cocoanut, an empyreumatic oil is obtained by the inhabitants of the island of Sumatra, and used by them for staining the teeth ; and a light velvet-like carbon which is found useful in painting. COKE. (Eng. and Fr. ; Ahgeschwefelte^ Germ.) It is necessary to distinguish between what is called gas-coke and oven-coke. The word coke applies, properly, to the latter alone ; for, in a manufacturing sense, the former is merely cinder. The production of good coke requires a combination of qualities in coal not very frequently met with ; and hence first-rate coking coals can be procured only from certain districts. The essential requisites are, first, the presence of very little earthy or incombustible ash ; and, secondly, the more or less infusibility of that ash. The presence of any of the salts of lime is above all objec- tionable ; after which may be classed silica and alumina ; for the whole of these have a strong tendency to produce a vitrification, or slag, upon the bars of the furnace in which the coke is burnt ; and in this way the bars are speedily corroded or burnt out ; whilst the resulting clinker impedes or destroys the draught, by fusing over the interstices of the bars or air-passages. Iron pyrites is a common obstacle to the coke maker : but it is found in practice, that a protracted application of heat in the oven dissipates the whole of the sul- phur from the iron, with the production of bisulphuret of carbon and metallic carburet of iron, the latter of which alone remains in the coke, and, unless silica be present, has no great disposition to vitrify after oxidation. Where the iron pyrites exists in large quantities, it is separated by the coal-washing machines, some of which will be described in a general article. — See Washing Machines. One object, therefore, gained by the oven-coke manu- facturer over the gas maker, is the expulsion of the sulphuret of carbon, and consequent purification of the residuary coke. Another, and a still more important consequence of a long-sustained and high heat is, the condensation and contraction of the coke into a smaller volume, which, therefore, permits the introduction of a much greater weight into the same space — an advantage of vast importance in blast furances, and, above all, in locomotive engines, as the repeated introduction of fresh charges of coal fuel is thus prevented. Part of this condensation is due to the weight of the superincumbent mass of coal thrown into the coke-oven, by which (when the coal first begins to cake or fuse together) the particles are forced towards each other, and the cavernous character of cinder got rid of: but the chief contraction arises, as we have said, from the natural quality of carbon, which, like alumina, goes on contracting, the longer and higher the heat to which it is exposed. Hence, good coke cannot be made in a short time, and that used in locomotive engines is com- monly from 48 to 96, or even 120 hours in the process of manufacture. The prospects of improvement in coke-making point rather to alterations in the oven than in the process. Formerly it was not thought possible to utilize the heat evolved by the gaseous constituents of the coal ; but now, as an example of the incorrectness of this idea, it may be stated that at the Felling Chemical Works, 200 tons of salt per week are made by the waste heat alone, and it is also employed in partially heating the blast for one 398 COKE. of the furnaces. There appears no valid reason why sets of coke-ovens might not be so arranged as mutually to compensate for each other, and produce upon one particular flue a constant and uniform effect. Contrivances of this kind have been projected, — but hitherto, we may suppose, without uniform success, as many of our large coke-makers still continue the old mode of working. Mr. Ebenezer Rogers, of Abercam, in Monmouthshire, has lately introduced a new method of coking, which he thus describes : — “ A short time ago a plan was mentioned to the writer as having been used in West- phalia, by which wood was charred in small kilns : as the form of kiln described was quite new to him, it led him to some reflection as to the principles on which it acted, which were found to be so simple and effective, that he determined to apply them on a large scale for coking coal. The result has been that in the course of a few months the original idea has been so satisfactorily matured and developed, that instead of coking 6 tons of coal in an oven costing £80, 150 tons of coal are now being coked at once in a kiln costing less than the former single oven. Figs. 195 and 196 are a side elevation and plan of one of the new coking kilns to a small scale ; Jig. 197 is an enlarged transverse section. “ D D are the walls of the kiln, which are provided with horizontal flues, e, f, which open into the side or bottom of the mass of coal. Connected with each of these flues are the vertical chimneys gh. The dotted lines 1 1 , fg. 196, represent a movable railway, by which the coal may be brought into the kiln and the coke removed from it. In filling the kiln with coal, care is taken to preserve transverse passages or flues for the air and gases between the corresponding flues e f in the opposite walls. This is effected by building or constructing the passages at the time with the larger pieces of coal, or else by means of channels or flues permanently formed in the bed of the kiln. When the coal is of differ- ent sizes, it is also advantageous to let the size of the pieces diminish towards the top of the mass. The surface of the coal, when filled in, is covered with small coal, ashes, and other suitable material. “ When the kiln is filled, the openings k at the ends are built up with bricks, as shown dotted ; the kiln is not covered by an arch, but left entirely open at the top. The aper- tures of the flues f and the chimneys g are then closed, as shown in ^fig. 197, and the coal is ignited through the flues e ; the air then enters the flues e and pa*sses through the coal, and then ascends the chimneys n, as shown by the arrows. When the current of air has proceeded in this direction for some hours, the flues e and chimneys ii are closed, and f and G are opened, which reverses the direction of the current of air through the mass. This alternation of the current is repeated as often as may be required. At the same time COKE. 399 air descends through the upper surface of the mass of coal. When the mass is well ignited, which takes place in from 24 to 36 hours, the external apertures of the flues e and f are closed, and the chimneys g and h opened : the air now enters through the upper surface of the coal only, and descends through the mass of the coal, the products of combustion pass- ing up the chimneys. “ The coking gradually ascends from the bottom of the mass to the top, and can be easily regulated or equalized by opening or closing wholly or partially the apertures of the flues or chimneys. The top surface of the coal being kept cool by the descending current of air, the workman is enabled to walk over it during the operation ; he inserts from time to time at different parts of the surface an iron bar, which is easily pushed down until it reaches the mass of coke, by which its further descent is prevented. In this way the work- man gauges the depth at which the coking process is taking place, and if he finds it to have progressed higher at one part than at another, he closes the chimneys communicating with that part, and thus retards the process there. This gauging of the surface is carried on without difficulty until the coking process has arrived close to the top. The gases and tarry vapors produced by the distillation or combustion descend through the interstices of the incandescent mass below, and there deposit a portion of the carbon contained in them, the residual gases passing up the chimneys. The coke at the lower part of the kiln is effect- ually protected from the action of the air, by being surrounded and enveloped in the gases and vapors which descend through it, and are non-supporters of combustion. “ When the mass of coal has been coked up to the top, which takes place in about seven days, it is quenched with water, the walls closing the end openings k are taken down, and the coke is removed. When a portion has been removed, a movable railway is laid in the kiln, so as to facilitate the removal of the remainder of the coke. “ The flues e and f may enter at the bottom of the kiln, or at the sides above the bot- tom, as in^^. 197 ; in the latter case the space below, up to the level of the bottom of the flues, may be filled with small coal, which becomes coked by the radiated heat from the incandescent mass above. The transverse passages through the mass are then constructed upon this bed of Small coal with the larger lumps of coal, as before mentioned. The flues and chimneys need not necessarily be horizontal and vertical ; and instead of connecting a separate chimney with each transverse flue, flues may be constructed longitudinally in the walls of the kiln, so as to connect two or more of the transverse flues, which are then regu- lated by dampers, conveying the gaseous products from them into chimneys of any conve- nient height ; the arrangement first described, however, and shown in the drawings, is pre- ferred. The gaseous products may be collected, and tar and ammonia and other chemical compounds manufactured from them by the usual modes. The coking or charring of peat and wood may be effected in a similar manner to that already described with regard to coal. “ The new kilns have proved entirely successful ; they are already in use at some of the largest iron works in the kingdom, and are being erected at a number of other works. The great saving in first cost of oven, economy in working and maintenance, increased yield, and improved quality of coke, will probably soon cause this mode of coking to supersede the others now in use. The kilns are most advantageously made about 14 feet in width, and 90 feet in length, and 7 feet 6 inches in height; this size of kiln contains about 150 tons of coal.” From the long experience of this gentleman, we are induced to quote yet further from his memoir : — “ The process of coking converts the coal into a porous mass ; but this is done during the melting of the coal, at which moment the gases in liberating themselves form very minute bubbles ; but the practical result is the same as in wood coal, allowing a large sur- face of carbon in a small space to be acted upon by the blast. As a general rule, coke made rapidly has larger pores and is lighter than coke made slowly ; it accordingly bears less blast, and crumbles too easily in the furnace. “ The proeess of coking in the ordinary ovens may be thus explained : When the oven is filled with a proper charge, the coal is fired at the surface by the radiated heat from the roof ; enough air is admitted to consume the gases given off by the coal, and thus a high temperature is maintained in the roof of the oven. The coal is by this means melted ; and those portions of it which, under the influenee of a high temperature, can of themselves form gaseous compounds, are now given off, forming at the moment of their liberation small bubbles or cells ; the coke now left is quite safe from waste, unless a further supply of air is allowed to have access to it. At this stage of the process, the coke assumes a pentagonal or five-sided shape, and columnar structure. When the coke is left exposed to heat for some time after it is formed, it becomes harder and works better, from being less liable to crush in the furnace and decrepitate on exposure to the blast. “ It has been often remarked as a strange fact, that the hotter the oven the better the yield of coke ; hence all the arrangements of flues to keep up the temperature of the ovens. This fact is however the result of laws well known to chemists When the coal is melted as 400 COLLIDINE. above mentioned, the hydrogen in the coal takes up two atoms of carbon for each two atoms of hydrogen, forming bicarburetted hydrogen gas, ;) this at once escapes, but it has to pass upwards through the red-hot coke above, which is at a higher temperature than the melted coal below. Now when bicarburetted hydrogen gas is exposed to a bright- red heat, it is decomposed, forming carburetted hydrogen gas, (CH^,) and depositing one atom, or one-half of its carbon, in a solid form. Consequently in the process of coking, if the oven is in good working order and the coke hot enough, the liberated carbon is detained in its passage upwards, and either absorbed by the coke, or crystallized per se upon it. This is simply illustrated by passing ordinary illuminating gas through a tube heated to a bright-red heat ; the tube will soon become coated internally, and ultimately filled with a carbonaceous deposit produced by the decomposition of the bicarburetted hydrogen con- tained in the gas. “ It is found that some coal which is too dry or not sufficiently bituminous to coke when put into the oven by itself in lumps, will coke perfectly if crushed small and well wetted with water and charged in this state. This fact, if followed out, -would lead to an examina- tion of the chemical nature of the eflect produced by the water, and would point the way to further improvements.” “ Charred Ooal^’’' as it is called, must be regarded as a species of coke. It has been largely employed in lieu of charcoal in the manufacture of tin plates. This preparation is also a discovery of Mr. Ebenezer Rogers, who thus describes its manufaeture : — The preparation of the “ charred coal ” is simple. The coal is first reduced very small, and washed by any of the ordinary means ; it is then spread over the bottom of a rever- beratory furnace to a depth of about four inches ; the bottom of the furnace is first raised to a red heat. When the small coal is thrown over the bottom, a great volume of gases is given off, and much ebullition takes place : this ends in the production of a slight spongy mass, which is turned over in the furnace and drawn in one hour and a half. To com- pletely clear off the sulphur, water is now freely sprinkled over the mass until all smell of the sulphuretted hydrogen produced ceases. Charred coal has been hitherto produced on the floor of a coke-oven, whilst red-hot, after drawing the charge of coke. See Tin Plate Manufacture. A process has for some time been gaining ground in France known as the “ Systhne Appolt^'^ from its being introduced by two brothers of that name. The coking furnaces employed are vertical, and they are in compartments. The authors have published a de- scription of their process and a statement of its results, “ Carbonisation de la Houille Sys- ieme Appolt, deer it par les Auteurs, MM. Appolt Fr'eres Paris, 1858, to which we must refer our readers. COLLIDINE. C‘®H"N. A volatile base discovered by Anderson in bone oil, and sub- sequently found in shale naphtha, in the basic fluid obtained by acting on cinchonine with potash, and in common coal naphtha. Its density is 0'921, and its boiling point, 354°. — C. G. W. COLORING MATTERS. The color of any object, either natural or artificial, owes its origin to the effect produced on it by the rays of light. This effect is either due to the mass or substance of the body itself, as may be seen in the colors of metals and many shells, or it arises from the presence of some foreign substance or substances not absolutely essential to it, and which may in many cases be separated and removed from it. It is in speaking of these foreign substances, Avhich are often found coloring natural objects, or which are employed in the arts for the purpose of imparting colors to various materials, that we generally make use of the term coloring matter. By chemists, however, the term is only applied to organic bodies and not to mineral substances, such as oxide of iron, cin- nabar, ultramarine, &c., which, though they are employed as pigments in the arts, differ very widely in their properties from one another and from coloring matters in the narrower sense of the word. Coloring matters may be defined to be substances produced in animal or vegetable organisms, or easily formed there by processes occurring in nature, (such as oxidation or fermentation,) and which are either themselves colored or give colored com- pounds with bases or with animal or vegetable fibre. According to this definition, bodies like carbazotic acid and murexide, which are formed by complicated processes such as never occur in nature, are excluded, though they resemble true coloring matters in many of their properties, such as that of giving intensely colored compound bases. Whether, however, even after accepting the above definition, coloring matters can be considered as constituting a natural class of organic bodies, such as the fats, resins, &c., must still remain doubtful, though modern research tends to prove that these substances are related to one another by other properties besides the accidental one of color, and Avill probably be found eventually to belong in reality to one natural class. Coloring matters occur in all the organs of plants, in the root, wood, bark, leaves, flow- ers, and fruit ; in the skin, hair, feathers, blood, and various secretions of animals ; in insects, for example, in various species of coccus ; and in mollusca, such as the murex. Indeed, there are very few plants or animals whose organs do not produce some kind of COLOKING MATTERS. 401 coloring matter. It is remarkable, however, that the colors which are most frequently pre- sented to our view, sueh as those of the leaves and flowers of plants and the blood of ani- mals, are produced by coloring matters with which we are but very little acquainted, the coloring matters used in the arts, and which have been examined with most care, being derived chiefly from less conspicuous organs, such as the roots and stems of plants. In almost all cases the preparation of coloring matters in a state of purity presents great diffi- culties, so that it may even be said that very few are known in that state. Some coloring matters bear a great resemblance to the so-called extractive matters, oth- ers to resins. Hence they have been divided into extractive and resinous coloring matters. These resemblances are however of no great importance. The principal coloring matters possess such peculiar properties that they must be considered as bodies altogether sui generis. As regards their most prominent physical characteristic, coloring matters are divided into three principal classes, viz., the red, yellow, and blue, the last class comprising the smallest number. Only one true green coloring matter occurs in nature, viz., chlorophyll, the substance to which the green color of leaves is owing.* Black and brown coloring matters are also uncommon, the black and brown colors obtained in the arts from animals or vegetables being (with the exception of sepia and a few others) compounds of coloring matters with bases. The colors of natural objects are often due to the presence of more than one coloring matter. This may easily be seen in the petals of some flowers. If, for instance, the petals of the orange-colored variety of the Tropoeolum magus be treated with boiling water, a coloring matter is extracted which imparts to the water a purple color. The petals now appear yellow, and if they be treated with boiling spirits of wine, a yellow coloring matter is extracted, and they then become white. When the purple coloring mat- ter is absent, the flowers are yellow ; when, on the contrary, it is present in greater abun- dance, they assume different shades of brown. Precisely the same phenomena are observed in treating the petals of the brown Calceolaria successively with boiling water and spirits of wine. In many cases coloring matters exhibit, when in an uncombined state, an entirely different color from what they do when they enter into a state of combination. The color- ing matter of litmus, for instance, is, when uneombined, red, but its eompounds with allm- lies are blue. The alkaline compounds of alizarine are of a rich violet color, while the substance itself is reddish-yellow. Many yellow coloring matters become brown by the action of alkalies, and the blue coloring matters of flowers generally turn green when ex- posed to the same influence. The classification of coloring matters, according to color, is therefore purely artificial. The terms red, yellow, and blue coloring matter, merely signify that the substance itself possesses one of these colors, or that most of its compounds are respectively red, yellow, or blue. In almost all cases, even when the color is not entirely changed by eombination with other bodies, its intensity is much increased thereby, sub- stances of a pale yellow color becoming of a deep yellow, and so on. Coloring matters consist, like most other organic substances, either of carbon, hydrogen, and oxygen, or of those elements in addition to nitrogen. The exact relative proportions of these constituents, however, is known in very few cases, and in still fewer instances have the chemical formulae of the compounds been established with any approach to certainty. This proceeds on the one hand from the small quantities of these substances usually present ill the organs of plants and animals, and the difficulty of obtaining sufficient quantities for examination in a state of purity, and on the other hand from the circumstance of their pos- sessing a very complex chemical constitution and high atomic weight. Only a small number of coloring matters are capable of assuming a crystalline form ; the greater number, especially the so-called resinous ones, being perfectly amorphous. Among those which have been obtained in a crystalline form, may be mentioned alizarine, indigo-blue, quercitrine, morine, luteoline, chrysophan, and rutine. It is probable, how- ever, that when improved methods have been discovered of preparing coloring matters, and of separating them from the impurities with which they are so often associated, many which are now supposed to be amorphous will be found to be capable of crystallizing. Very little is known concerning the action of light on coloring matters and their com- pounds. It is well known that these bodies, when exposed to the rays of the sun, especially when deposited in thin layers on or in fabrics made of animal or vegetable materials, lose much of the intensity of their color, and sometimes even disappear entirely — that is, they are converted into colorless bodies. But whether this process depends on a physical action induced by the light, or whether, as is more probable, it consists in promoting the decom- posing action of oxygen and moisture on them, is uncertain. The most stable coloring mat- ters, such as indigo-blue and alizarine in its compounds, are not insensible to the action of light. Others, such as carthamine from safflower, disappear rapidly when exposed to its influence. Colors produced by a mixture of two coloring matters are often found to resist * Another green coloring ntatter, derived from different species of Rhamnus, has lately been de- scribed under the name of “ Chinese Green.” It is stated to be a peculiar substance, not, as might be supposed, a mixture of a blue and a yellow coloring matter. VoL. III.— 26 402 COLOEmG MATTERS. the action of light better than those obtained from one alone. In one case, viz., that of Tyrian purple, the action of light seems to be absolutely essential to the formation of the coloring matter. The leaves of plants also remain colorless if the plants are grown in dark- ness, though in this case the formation of the green coloring matter is probably not due to the direct chemical action of the light. The action of heat on coloring matters varies very much according to the nature of the latter and the method of applying the heat. A moderate degree of heat often changes the hue of a coloring matter and its compounds, the original color being restored on cooling — an effect which is probably due to physical causes. Sometimes this effect is, without doubt, owing to the loss of water. Alizarine, for instance, crystallized from alcohol, when heated to 212° F., loses its water of crystallization, its color changing at the same time from red- dish-yellow to red. At a still higher temperature most coloring matters are entirely decom- posed, the products of decomposition being those usually afforded by organic matters, such as water, carbonic acid, carburetted hydrogen, empyreumatic oils, and, if the substance con- tains nitrogen, ammonia, or organic bases such as aniline. A few coloring matters, as, for example, alizarine, rubiacine, indigo-blue, and indigo-red, if carefully heated, may be vola- tilized without change, and yield beautifully crystallized sublimates, though a portion of the substance is sometimes decomposed, giving carbon and empyreumatic products. Coloring matters, like most other organic substances, undergo decomposition with more or less facility when exposed to the action of oxygen ; and the process may, indeed, be more easily traced, in their case, as it is always accompanied by a change of hue. Its effects may be daily observed in the colors of natural objects belonging to the organic world. Flowers, in many cases, lose a portion of their color before fading. The leaves of plants, before they fall, lose their green color and become red or yellow. The color of venous blood changes, when exposed to the air, from dark red to light red. .When exposed to the action of oxygen, blue and red coloring matters generally become yellow or brown ; but the process seldom ends here : it continues until the color is quite destroyed ; that is, until the substance is converted into a colorless compound. This may be easily seen when a fabric, dyed of some fugitive color, is exposed to the air. The intensity of the color diminishes, in the first instance ; it then changes in hue, and, finally, disappears entirely. Indeed, the whole process of bleaching in the air depends on the concurrent action of oxygen, light, and moisture. The precise nature of the chemical changes which coloring matters undergo, during this process of oxidation, is unknown. No doubt it consists, generally speaking, in the removal of a portion of their carbon and hydrogen, in the shape of carbonic acid and water, and the conversion of the chief mass of the substance into a more stable compound, capable of resisting the further action of oxygen. But this statement conveys very little information to the chemist, who, in order to ascertain the nature of a process of decompo- sition, requires to know exactly all its products, and to compare their composition with that of the substances from which they are derived. The indeterminate and uninteresting nature of the bodies into which most coloring matters are converted by oxidation, has probably deterred chemists from their examination. The action of oxygen on coloring matters varies according to their nature and the manner in which the oxygen is applied, and it is the de- gree of resistance which they are capable of opposing to its action that chiefly determines the stability of the colors produced by their means in the arts. Indigo-blue shows no ten- dency to be decomposed by gaseous oxygen at ordinary temperatures ; it is only when the latter is presented in a concentrated form, as in nitric or chromic acid, or in a nascent state, as in a solution of ferridcyanide of potassium containing caustic potash, that it undergoes decomposition. When, however, indigo-blue enters into combination with sulphuric acid, it is decomposed by means of oxygen with as much facility as some of the least stable of this class of bodies. Some coloring matters are capable of resisting the action of oxygen even in its most concentrated form. Of this kind are rubianine and rubiacine, which, when treated with boiling nitric acid, merely dissolve in the liquid, and crystallize out again when the latter is allowed to cool. The action of atmospheric oxygen on coloring matters is gen- erally promoted by alkalies, a«d retarded in the presence of acids. A watery solution of hematine, when mixed with an excess of caustic alkali, becomes of a beautiful purple ; but the color, when exposed to the air, almost immediately turns brown, the hematine being then completely changed. It is almost needless to observe, that the bodies into which coloring matters are converted by oxidation, are incapable, under any circumstances, of returning to their original state. The action of reducing agents, that is, of bodies having a great affinity for oxygen, on some coloring matters, is very peculiar. If indigo-blue, suspended in water, be placed in contact with protoxide of iron, protoxide of tin, or an alkaline sulphuret, sulphite or phos- phite, or grape sugar, or, in short, any easily oxidlzable body, an excess of some alkali or alkaline earth being present at the same time, it dissolves, forming a pale yellow solution without a trace of blue. This solution contains, in combination with the alkali or alkaline earth, a perfectly white substance, to which the name of reduced indigo has been applied. When an excess of acid is added to the solution, it is precipitated in white flocks. By ex- COLORING MATTERS. 403 posure to the air, either by itself or in a state of solution, reduced indigo rapidiy attracts oxygen, and is reconverted into indigo-blue. Hence the surface of the solutions, if left to stand in uncovered vessels, becomes covered with a blue film of regenerated indigo-blue. It was for a long time supposed that reduced indigo was simply deoxidized indigo-blue, and that the process consisted merely in the indigo-blue parting with a portion of its oxygen, which was taken up again on exposure to the air. It has, however, been discovered, that in every case water is decomposed during the process of reduction which indigo-blue under- goes, the oxygen of the water combining with the reducing agent, and the hydrogen uniting with the indigo-blue, water being again formed when reduced indigo comes in contact with oxygen. Reduced indigo is therefore not a body containing less oxygen than indigo-blue, but is a compound of the latter with hydrogen. There are several red coloring matters which possess the same property, that of being converted into colorless compounds by the simultaneous action of reducing agents and alkalies, and of returning to their original state when exposed to the action of oxygen. There can be little doubt that the process consists, in all cases, in the coloring matter combining with hydrogen and parting with it again when the hydruret comes in contact with oxygen. The action of chlorine on coloring matters is very similar to that of oxygen, though, in general, chlorine acts more energetically. The first effect produced by chlorine, whether it be applied as free chlorine, or in a state of combination with an alkali, or alkaline earth as an hypochlorite, usually consists in a change of color. Blue and red coloring matters gen- erally become yellow. By the continued action of chlorine, all trace of color disappears, and the final result is the formation of a perfectly white substance, which is usually more easily soluble in water and other menstrua than that from which it was formed. Since it is most commonly by means of chlorine or its compounds that coloring matters are destroyed or got rid of in the arts, as in bleaohing fabrics and discharging colors, the process of de- composition which they undergo by means of chlorine has attracted a good deal of atten- tion, and the nature of the chemical changes, which take place in the course of it, has often been made a subject of dispute, though the matter is one possessing more of a theoretical than a practical interest. It is a well-known fact, that many organic bodies are decomposed when they are brought into contact, in a dry state, with dry chlorine gas. The decompo- sition consists in the elimination of a portion of the hydrogen of the substance and its sub- stitution by chlorine. When water is present at the same time, the decomposition is, how- ever, not so simple. It is well known that chlorine decomposes water, combining with the hydrogen of the latter and setting its oxygen at liberty, and it has been asserted, that in the bleaching of coloring matters by means of chlorine when moisture is usually present, this always takes place in the first instance, and that it is in fact the oxygen which effects their destruc- tion, not the chlorine. This appears, indeed, to be the case occasionally. Rubian, for instance, the body from which alizarine is derived, gives, when decomposed with chloride of lime, phthalic acid, a beautifully crystallized substance, containing no chlorine, which is also produced by the action of nitric acid on rubian, and is, therefore, truly a product of oxidation. In many cases, however, it is certain that the chlorine itself also enters into the composition of the new bodies produced by its action on coloring matters. When, for instance, chlorine acts on indigo-blue, chlorisatine is formed, which is indigo-blue, in which one atom of hydrogen is replaced by one of chlorine, plus two atoms of oxygen, the latter being derived from the decomposition of water. The behavior of coloring matters towards water and other solvents is very various. Some coloring matters, such as those of logwood and brazilwood, are very easily soluble in water. Others, such as the coloring matters of madder and quercitron-bark, are only spar- ingly soluble in water. Many, especially the so-called resinous ones, are insoluble in water, but more or less soluble in alcohol and ether, or alkaline liquids. A few, such as indigo- blue, are almost insoluble in all menstrua, and can only be made to dissolve by converting them, by means of reducing agents, into other bodies soluble in alkalies. Those which are soluble in water, are, generally speaking, of the greatest importance in the arts, since they admit of more ready application when tliey possess this property. The behavior of coloring matters towards acids, is often very characteristic. Most coloring matters are completely decomposed by nitric, chloric, manganic, and chromic acids, in consequence of the large proportion of oxygen which these acids contain. With many coloring matters the decomposition takes place even at the ordinary temperature ; with oth- ers, it only commences when the acid is warmed, especially if the latter be applied in a state of considerable dilution. Concentrated sulphuric acid also destroys most coloring matters, especially if the acid be heated. It seems to act by depriving them of the elements of water, and thereby converting them into substances containing more carbon than before, as may be inferred from the dark, almost black color which they acquire. At the same time the acid generally loses a portion of its oxygen, since sulphurous acid is almost always evolved on heating. Some coloring matters, such as alizarine, are not decomposed by con- centrated sulphurie acid even when the latter is raised to the boiling point ; they merely dis- solve, forming solutions of various colors, from which they are precipitated unchanged, on COLORmG MATTERS. 404 the addition of water, when they are insoluble, or not easily soluble in the latter. Others, again, like indigo-blue, dissolve in concentrated or fuming sulphuric acid, without being de- composed, and at the same time enter into combination with the acid, forming true double acids, which are easily soluble in water, and combine as such with bases. Many coloring matters undergo a change of color when exposed to the action of acids, the original color being restored by the addition of an excess of alkali, and this property is made use of for the detection of acids and alkalies. The color of an infusion of litmus, for instance, is changed by acids from blue to red, and the blue color is restored by alkalies. An infusion of the petals of the purple dahlia or of the violet becomes red on the addition of acids, and this red color changes again to purple or blue with alkalies, an excess of alkali making it green. The yellow color of rutine becomes deeper with strong acids. In most cases, this alteration of color depends on a very simple chemical change. Litmus, for example, in the state in which it occurs in commerce, consists of a red coloring matter in combination with ammonia, the compound being blue. By the addition of an acid, the ammonia is removed, and the uncombined red coloring matter makes its appearance. Ammonia and most alkalies remove the excess of acid, and, by combining with the red coloring matter, restore the blue color. When a coloring matter, like alizarine, is only sparingly soluble in water, its solu- bility is generally diminished in the presence of a strong acid. Hence, by adding acid to the watery solution, a portion of the coloring matter is usually precipitated. It is very sel- dom that coloring matters are really found to enter into combination with acids. Indeed, only one, viz., berberine, is capable of acting the part of a true base, and forming definite compounds with acids. Some acids, such as sulphurous and hydrosulphuric acids, do cer- tainly seem to combine with some coloring matters and form -with them compounds, in which the color is completely disguised, and apparently destroyed. If a red rose be sus- pended in an atmosphere of sulphurous acid, it becomes white, but the red color may be restored by neutralizing the acid with some alkali. On this property of sulphurous acid depends the process of bleaching woollen fabrics by means of burning sulphur. In this case the coloring matter is not destroyed, but only disguised by its combination with the acid. Most coloring matters are capable of combining with bases. Indeed, their affinity for the latter is generally so marked, that they may be considered as belonging to the class of weak acids. Like all other weak acids, they form, Avith bases, compounds of a very indefi- nite composition, so much so that the same compound, prepared on two different occasions, is often found to be differently constituted. Hence the great difficulty experienced by chemists in determining the atomic weight of coloring matters. There are very few of the latter for which several formulce, all equally probable, may not be given, if the compounds Avith bases be employed for their determination. The compounds of coloring matters with bases liardly ever crystallize. Those wdth alkalies are mostly soluble in Avater and amor- phous ; those Avuth the alkaline earths, lime and baryta, are sometimes soluble, sometimes insoluble ; those with the earths and metallic oxides are almost alAA^ays insoluble in water. The compounds with alkalies are obtained by dissolving the coloring matter in water, to which a little alkali is added, and evaporating to dryness — an operation Avhich must be care- fully conducted if the coloring matter is one easily affected by oxygen. The insoluble com- pounds, Avith earths and metallic oxides, are obtained either by double decomposition of a soluble compound with a soluble salt of the respective base, or by adding to a solution of the coloring matter, in water or any other menstruum, a salt of the base containing some weak acid, such as acetic acid. It is remarkable, that of all bases, none show so much affinity for coloring matters as alumina, peroxide of iron, and peroxide of tin, bodies Avhich occupy an intermediate position betAveen acids and bases. If a solution of any coloring matter be agitated with a sufficient quantity of the hydrates of any of these bases, the solu- tion becomes decolorized, the Avhole of the coloring matter combining with the base and forming a colored compound. It is accordingly these bases that are chiefly employed in dyeing, for the purpose of fixing coloring matters on particular portions of the fabric to be dyed. When used for this purpose, they are called mordants. Their compounds with coloring matters are denominated lakes.^ and are employed as pigments by painters. The colors of the compounds usually differ, either in kind or degree, from those of the coloring matters themselves. Red coloring matters often form blue compounds, yellow ones some- times give red or purple compounds. The compounds with peroxide of iron are usually distinguished by the intensity of their color. When a coloring matter gives with alumina and oxide of tin red compounds, its compound Avith peroxide of iron is usually purple or black ; and when the former are yellow, the latter is commonly olive or brown. Almost all the compounds of coloring matters with bases are decomposed by strong acids, such as sul- phuric, muriatic, nitric, oxalic, and tartaric acids, and even acetic acid is not without effect on some of these compounds. The compounds with earths and metallic oxides are also decomposed, sometimes, by alkalies. A solution of soap is sufficient to produce this effect in many cases, and dyes are therefore often tested by means of a solution of soap, in order to ascertain the degree of permanence which they possess. COLORING MATTERS. 405 No property is so characteristic of coloring matters, as a class, as their behavior towards bodies of a porous nature, such as charcoal. If a watery solution of a coloring matter be agitated with charcoal, animal charcoal being best adapted for the purpose, the coloring matter is in general entirely removed from the solution and absorbed by the charcoal. The combination which takes place under these circumstances is probably not due to any chemi- cal j^ifmity, but is rather an effect of the so-called attraction of surface, which we often see exerted by bodies of a porous nature, such as charcoal and spongy platinum, and which enables the latter to absorb such large quantities of gases of various kinds. That the com- pound is indeed more of a physical than a chemical nature, seems to be proved by the cir- cumstance that sometimes the coloring matter is separated from its combination with the charcoal by means of boiling alcohol, an agent which can hardly be supposed to exert a stronger chemical affinity than water. It is this property of coloring matters which is made use of by chemists to decolorize solutions, and by sugar manufacturers to purify their sugar. The attraction manifested by coloring matters for animal or vegetable fibre, is probably also a phenomenon of the same nature, caused by the porous condition of the latter, and the powerful affinity of the so-called mordants for coloring matters, may, perhaps, be in part accounted for by their state of mechanical division being different from that of other bases. Coloring matters, however, vary much from one another in their behavior towards animal or vegetable fibre. Some, such as indigo-blue, and the coloring matters of safflower and turmeric, are capable of combining directly with the latter and imparting to them colors of great intensity. Others are only slightly attracted by them, and consequently impart only feeble tints ; they therefore require, when they are employed in the arts for the purpose of dyeing, the interposition of an earthy or metallic base. To the first class Bancroft applied the term substantive coloring matters, to the second that of adjective coloring matters. One of the most interesting questions connected with the history of coloring matters, is that in regard to the original state in which these substances exist in the animal and vege- table organisms from which they are derived. It has been known for a long time that many dye-stuffs, such as indigo and archil, do not exist ready-formed in the plants from which they are obtained, and that a long and often difficult process of preparation is required in order to eliminate them. The plants which yield indigo exhibit, while they are growing, no trace of blue color. The coloring matter only makes its appearance after the juice of the plant has undergone a process of fermentation. The lichens employed in the preparation of archil and litmus are colorless, or at most light brown, but by steeping them in liquids con- taining ammonia and lime, a coloring matter of an intense red is gradually generated, which remains dissolved in the alkaline liquid. Other phenomena of a similar nature might be mentioned, as, for instance, the formation of the so-called Tyrian purple from the juice of a shell-fish, and new ones are from time to time being discovered. In order to explain these phenomena, various hypotheses have been resorted to. It was supposed, for instance, that the indigoferae contained white or reduced indigo, and hence were devoid of color, and that the process of preparing indigo-blue consisted simply in oxidizing the white indigo, which was for this reason denominated indigogene by some chemists. The same assumption was made in regard to other coloring matters, all of which were supposed to exist originally in a deoxidized and colorless state. In regard to indigo, however, the hypothesis is disproved at once by the fact, that reduced indigo is only soluble in alkaline liquids, and that the juice of the indigo-bearing plants is always acid. In regard to the other coloring matters it seems also to be quite untenable. The first person to throw some light on this obscure department of organic chemistry was Robiquet. This distinguished chemist succeeded in obtaining from lichens in their colorless state a beautifully crystallized, colorless substance soluble in water, having a sweet taste, and consisting of carbon, hydrogen, and oxygen. This substance he denominated orcine. By the combined action of ammonia and oxygen, he found it to be converted into a red coloring matter, containing nitrogen, and insoluble in water, which was in fact identical with the coloring matter of archil. This beautiful dis- covery furnished chemists with a simple explanation for the curious phenomena observed in the formation of this and other coloring matters, and it was soon followed by others. Heeren and Kane obtained from various lichens other colorless substances of similar prop- erties, and it was shown by Schunck that orcine is not even the first link in the chain, but is itself formed from another body, lecanorme^ which, by the action of alkalies, yields orcine and carbonic acid, just as sugar by fermentation gives alcohol and carbonic acid. In like manner, it was discovered by Erdmann that the coloring matter of logwood is formed by the simultaneous action of oxygen and alkalies from a crystallized colorless substance, hoematoxyline^ which is the original substance existing in the wood of the tree, and is like the others, not itself, strictly speaking, a coloring matter, but a substance which gives rise to the formation of one. There is, however, another class of phenomena connected with the formation of color- ing matters, entirely different from that just referred to. It was discovered by Robiquet, that if madder be treated for some time with sulphuric acid, and the acid be afterwards completely removed, the madder is found to have acquired a much greater tinctorial power 406 COLZA. than before. This fact was explained by some chemists by supposing that the sulphuric acid had combined with or destroyed some substance or substances contained in the mad- der, which had previously hindered the coloring matter from exerting its full power in dye- ing, such as lime, sugar, woody fibre, &c. By others it was suspected that an actual forma- tion of coloring matter took place during the process, and this suspicion has been verified by recent researches. Schunck succeeded in preparing from madder a substance resembling gum, very soluble in water, amorphous, and having a very bitter taste, like madder itself, and to which he gave the name of rubian. This substance, though not colorless, is inca- pable of combining with mordants, like most coloring matters. When, however, it is acted on by strong acids, such as sulphuric or muriatic acid, it is completely decomposed, and gives rise to a number of products, the most important of which is alizarine, one of the coloring matters of madder itself. Among the other products are a yellow crystallized coloring matter, rubianine, two amorphous red coloring matters resembling resins, rubi- retine and verantme, and lastly, grape sugar. When subjected to fermentation, the same products are formed, with the exception of rubianine, which is replaced by a yellow color- ing matter of similar properties. This process of decomposition evidently belongs to that numerous class called by some chemists “ catalytic,” in which the decomposing agent does not act, as far as we know, in virtue of its chemical affinities. It is evident, then, that when madder is acted on by sulphuric acid, an actual formation of coloring matter takes place, and it is even probable that the whole of the coloring matter found in madder in its usual state was originally formed from rubian, by a process of slow fermentation, the portion of the latter still remaining undecomposed being that which is acted on when acids are applied to madder. From the Isatis linctoria, or common woad plant, Schunck, in like manner, extracted an amorphous substance, easily soluble in water, called by him indican, and which, by the action of strong acids, is decomposed into indigo-blue, indigo-red, sugar, and other products, among which are also several resinous coloring matters. Looking at them from this point of view, coloring matters may be divided into two classes, viz., first, such as are formed from other substances, not themselves coloring matters, by the action of oxygen and alkalies ; and, secondly, such as are formed from other substances by means either of fer- ments or strong acids, without the intervention of oxygen. To the first class belong the coloring matters of archil, litmus, and logwood ; they yield comparatively fugitive dyes, and are usually decomposed by allowing the very process to which they owe their formation to continue. To the second class belong indigo-blue, indigo-red, and alizarine, bodies which show a remarkable degree of stability for organic compounds. More extended research will probably show that many other coloring matters are formed either in one manner or the other, which will probably afford us the means of arriving at a rational .mode of classifying these bodies, and of distinguishing them as a class from others. — E. S. COLZA. Colza oil is now extensively used for burning in lamps and for lubricating machinery. The Carcel, Moderator, and other lamps, are contrived to give a continuous supply of oil to the wick, and by a rapid draught of air brilliant combustion of the oil is maintained without smoke. In the lighthouses of France and England it has been employed with satisfaction, so as to replace the use of sperm oil ; the preference has been given on the grounds of greater brilliancy, a steadier flame, the wick being less charred, and the advantage of economy in price. The Corporation of the Trinity House and the late Mr. Hume took great interest in the question of the relative merits of colza, rape, and seed oils, as compared with sperm oil, and in 1845 referred the investigation of the power and qualities of the light from this de- scription of oil, to Professor Faraday. He reported “ that he was much struck with the steadiness of the flame, burning 12 or 14 hours without being touched;” “taking above 100 experiments, the light came out as one-and-a-half for the seed oil to one of the sperm ; the quantity of oil being used in the same proportion ;” and he concludes by stating his “ confidence in the results.” The advantages then were, less trouble, for the lamps with sperm had to be retrimmed, and the same lamp with seed oil gave more light, and the cost then was as 3s. 9c?. per gal- lon seed oil, against 6s. 4c?. imperial gallon of sperm. Those interested should consult returns, ordered by the House of Commons, — “ Light- houses, on the motion of Mr. Hume, ‘ On the Stibstitution of Rape Seed Oil for Sperm Oil, and the Saving accruing therefrom' \lth Feb., 1857 ; Ko. 75; \^th March, 1857, 196 and 196 I.” In the Supplementary Returns laid before the House of Commons by the Commissioners of the Northern Lights, there is the following report of Alan Stevenson, Esq., their En- gineer : — “ In the last annual report on the state of the lighthouses, I directed the attention of the Board to the propriety of making trial, at several stations, of the patent culza or rape seed oil, as prepared by Messrs. Briggs and Garford, of Bishopsgate street. These trials have now been made during the months of January and February, at three catoptric and « COMB. 407 three dioptric lights, and the results have from time to time been made known to me by the light-keepers, according to instructions issued to them, as occasion seemed to require. The substantial agreement of all the reports as to the qualities of the oil renders it needless to enter into any details as to the slight varying circumstances of each case ; and I have therefore great satisfaction in briefly stating, as follows, the very favorable conclusion at which I have arrived : — “ 1. The culz^ oil possesses the advantage of remaining fluid at temperatures which thicken the spermaceti oil. ■ “ 2. Tlie culzi\ oil burns both in the Fresnel lamp and the single argand burner, with a thick wick, during seventeen hours, without requiring any coaling of the wick, or any adjustment of the damper ; and the flame seems to be more steady and free from flickering than that from spermaceti oil. “ 3. There seems (most probably owing to the greater steadiness of the flame) to be less breakage of glass chimneys with the culza than with the spermaceti oil.” The above firm, who from thirty years’ experience in the trade were enabled to induce the Trinity Corporation to give this oil a fair and extended trial, state, that “ for manufac- turing purposes it is equally useful ; it is admitted by practical men to be the best known oil for machinery — equal to Gallipoli ; and technically it possesses more ‘ body,’ though perfectly free from gummy matter.” On this point, the following letter has due weight : — Admiralty^ 9/A December^ 1845. — Messrs. Briggs and Garford : — Referring to your letter of the 1st of August last, I have to acquaint you, in pursuance of the directions of the Lords Commissioners of the Admiralty, that the officers of Woolwich yard have tried your vegetable oil, and find it to be equal to the best Gallipoli. “ It is very hardy ; and while sperm, Gallipoli, nut, or lard oils are rendered useless by the slightest exposure to frost, the patent oil will, with ordinary care, retain its brilliancy : this has been acknowledged as a very important quality to railway and steamboat com- panies.” It should be here stated, that the terms rape oils, seed oils, colza, or culza, are all now blended together ; and, however much this may be regretted, yet it does not seem easy to keep distinctness in the general usages of oil, for the customs returns class all under one head, — ^rape oil. A number of British and colonial seed-bearing plants appear to be now employed for the sake of their oils, although, on account of the mucilaginous matter contained in many of the oils, they are far inferior to the colza, which they are employed to adulterate. — T. J. P. COMB. The name of an instrument which is employed to disentangle, and lay parallel and smooth the hairs of man, horses, and other animals. They are made of thin plates, either plain or curved, of wood, horn, tortoise-shell, ivory, bone, or metal, cut upon one or both sides or edges with a series of somewhat long teeth, not far apart. Two saws mounted on the same spindle are used in cutting the teeth of combs, which may be considered as a species of grooving process ; one saw is in this case larger in' diam- eter than the other, and cuts one tooth to its full depth, whilst the smaller saw, separated by a washer as thick as the required teeth, cuts the succeeding tooth part-way down. A few years back, Messrs. Pow and Lyne invented an ingenious machine for sawing box- w6od or ivory combs. The plate of ivory or box-wood is fixed in a clamp suspended on two pivots parallel with the saw spindle, which has only one saw. By the revolution of the handle, a cam first depresses the ivory on the revolving saw, cuts one notch, and quickly raises it again ; the handle, in completing its circuit, shifts the slide that carries the sus- pended clamp to the right, by means of a screw and ratchet movement. The teeth are cut with great exactness, and as quickly as the handle can be turned ; they vary from about thirty to eighty teeth in one inch, and such is the delicacy of some of the saws, that even 100 teeth may be cut in one inch of ivory. The saw runs through a cleft in a small piece of ivory, fixed vertically or radially to the saw, to act as the ordinary stops, and prevent its flexure or displacement sideways. Two combs are usually laid one over the other and cut at once ; occasionally the machine has two saws, and cuts four combs at once. In the manufacture of tortoise-shell combs, very much ingenuity is displayed in solder- ing the back of a large comb to that piece which is formed into teeth. The two parts are filed to correspond ; they are surrounded by pieces of linen, and inserted between metal moulds, connected at their extremities by metal screws and nuts ; the interval betw'cen the halves of the mould being occasionally curved to the sweep required in the comb ; some- times also the outer faces of the mould are curved to the particular form of those combs in which the back is curled round, so as to form an angle with the teeth. Thus arranged it is placed in boiling water. The joints, when properly made, cannot be deteeted, either by the want of transparency or polish. Much skill is employed in turning to economical account the flexibility of tortoise-shell in its heated state : for example, the teeth of the larger de- scriptions of comb are parted, or cut one out of the other with a thin frame saw ; then the shell, equal in size to two combs with their teeth interlaced, is bent like an arch in the - COMBINING NUMBERS— CHEMICAL COMBINATION. 408 direction of the length of the teeth. The shell is then flattened, the points are separated with a narrow chisel or pricker, and the two combs are finished, whilst flat, with coarse single-cut files, and triangular scrapers ; and lastly, they are warmed, and bent on the knee over a wooden mould by means of a strap passed round the foot, in the manner a shoemaker fixes a shoe-last. Smaller combs of horn and tortoise-shell are parted whilst flat, by an ingenious machine with two chisel-formed cutters, placed obliquely, so that every cut pro- duces one tooth, the repetition of which completes the formation of the comb. Mr. Rogers’s comb-cutting machine is described in the 2'ravsactions of the Society of AW.s, vol. xlix., part 2, page 150. It has been since remodelled and improved by Mr. Kelly. This is an example of slender chisel-like punches. The punch or chisel is in two parts, slightly inclined and curved at the ends to agree in form with the outline of one tooth of the comb, the cutter is attached to the end of a jointed arm, moved up and down by a crank, so as to penetrate almost through the material, and the uncut portion is so very thin that it splits through at each stroke, and leaves the tw'o combs detached. The comb-maker’s double saw is called a “ staddaf and has two blades contrived so as to give with great facility and exactness the intervals between the teeth of combs, from the coarsest to those having from forty to forty-five teeth to the inch. The gage-saw or gage- vid is used to make the teeth square and of one depth. The saw is frequently made with a loose back, like that of ordinary hack-saws, but much wider, so that for teeth i i f inch long, it may shield all the blade except f f inch of its wddth respectively, and the saw is applied until the back prevents its further progress. Sometimes the blade has teeth on both edges, and is fixed between two parallel slips of steel connected beyond the ends of the saw blade by two small thumb-screws. After the teeth of combs are cut, they are smoothed and polished with files, and by rubbing them .with pumice stone and tripoli. — Holtzapffel. COMBINING NUMBERS AND CHEMICAL COMBINATION.— Constancy of compo- sition is one of the most essential characters of chemical compounds ; by which is meant that any particular body, under whatever circumstances it may have been produced, consists invariably of the same elements in identically the same proportion ; the converse of this is not, however, necessarily true, that the same elements in the same proportion always pro- duce the same body. But not only is there a fixity in the proportion of the constituents of a compound, but also, if any one of the elements be taken, it is found to unite with the other elements in a proportion which is either invariable, or changes only by some very simple multiple. The numbers expressing the combining proportions of the elements are only relative. In England it is usual to take hydrogen as the starting point, and to call that number the combining number of any other element which expresses the proportion in which it unites with one part by weight of hydrogen ; and these numbers are now becoming adopted on the Continent, although in France the combining numbers are still referred to oxygen, which is taken as 100. It is obvious that, whichever system is used, the numbers have the same value relatively to each other. These combining numbers would have but little value if they expressed nothing more than the proportion in which the elements combine with that body arbitrarily fixed as the standard ; but they also represent the proportions in which they unite among themselves in the event of union taking place. Thus, not only do 8 parts of oxygen unite with one of hydrogen, but also 8 parts of oxygen unite with 39 of potassium, 23 of sodium, 100 of mercury, 108 of silver, Ac. It is in virtue of this law that the combining proportions of many of the elements have been ascertained. Some of them do not combine with hydro- gen at all, and in such cases the quantity which unites with 8 parts of oxygen, or 16 of sul- phur, &c., has to be ascertained. — H. M. W. COMBUSTION. (Eng. and Fr. ; Verbrennung, Germ.) The phenomena of the de- velopment of light and heat from any body, as from charcoal combining with the oxygen of the air, from phosphorus combining with iodine, and from some of the metals combining with chlorine. Combustion may be exerted with very various degrees of energy. We have a low combustion often established in masses of vegetable matter ; as in hay-stacks, or in heaps of damp sawdust. In these cases, the changes going on are the same in character, only varying in degree, as those presented by an ordinary fire, or by a burning taper, — oxygen is combining with carbon to form carbonic acid. The heat thus produced, (the process has been termed by Liebig Eremacausis,) increasing in force, gives rise eventually to visible combustion, COOLING FLUIDS. See Refrigeration op Worts. COPPER. — Mechanical Preparation of the Copper Ores in Cornwall. — The ore receives a first sorting, the object of which is to separate all the pieces larger than a wal- nut ; after which the whole is sorted into lots, according to their relative richness. The fragments of poor ore are sometimes pounded in stamps, so that the metallic portions may be separated by washing. Tlie rich ore is either broken into small bits, with a flat beater, or by means of a crush- ing-mill. The ore to be broken by the bucking-iron is placed upon plates of cast-iron. COPPER. 409 each about 16 inches square and inches thick. These plates are set towards the edge of a small mound about a yard high, constructed with dry stones rammed with earth. The upper surface of this mound is a little inclined from behind forwards. The work is per- formed by women, each furnished with a bucking-iron : the ore is placed in front of them beyond the plates ; they break it, and strew it at their feet, whence it is removed and dis- posed of as may be subsequently required. The crushing-mill has of late years been brought to a great degree of perfection, and is almost universally made use of for pulverizing certain descriptions of ore. For a descrip- tion of this apparatus, see Grinding and Crushing Machinery. Stamping-mills are less frequently employed than crushers for the reduction of copper ores. At the Devon Great Consols Mines, the concentration of the crushed copper ores is effected in the following manner ; — From the crushing-mill the stuff is carried by a stream of water into a series of revolving separating sieves, where it is divided into fragments of 720 inch, 7 i 2 inch, and Vio inch diameter, besides the coarser particles which escape at the lower end of the sieves. The slimes flow over a small water-wheel called a separator^ in the buckets of which the coarser portions settle, and are from thence washed out by means of jets of water into a round buddle, whilst the finer particles are retained in suspension, and ai’e carried off into a series of slime-pits, where they are allowed to settle. The work produced by the round buddle is of three sorts ; that nearest the circumfer- ence is the least charged with iron pyrites, or. any other heavy material, but still contains a certain portion of ore ; this is again huddled, when a portion of its tail is thrown away, and after submitting the remainder to a huddling operation, and separating the wasie^ it is jigged in a fine sieve, and rendered merchantable. The other portions of the first buddle are rebuddled, and after separating the waste, the orey matters are introduced into sizing cisterns, from which the finer particles are made to flow over into a buddle, from whence a considerable portion goes directly to market. That which requires further manipulation is again huddled until thoroughly cleansed. The coarser portions of the stuff introduced into the sizing cisterns pass downward with a cur- rent of water into the tye^ and after repeated projections against the stream, the orey mat- ter is separated, leaving a residue of mundic in a nearly pure state. The stuff falling from the lower extremities of the separating sieves is received into bins and subsequently cleansed, each of the three sizes is jigged, and in proportion as the worthless matters are separated, they are scraped off and removed. Those portions of the stuff that require further treatment are taken from the sieves, washed down from behind the hutches, and treated by tyes, until all the valuable portions have been extracted. In this way, vein stuff that originally contained but 1^ per cent, of copper, is so con- centrated as to afford a metallic yield of 10 per cent., whilst, by means of sizing-sieves, dressing-wheels, jigging-machines, and round-buddies, &c., from 40 to 50 tons of stuff are elaborated per day of 9 hours, at a cost of 12s. per ton of dressed ore. Captain Richards, the agent of these mines, has also introduced considerable improve- ments in the slime-dressing department. The proper sizing of slime is as necessary as in the case of rougher work, and in order to effect this, he has arranged a slirae-pit, which answers this purpose exceedingly well. This pit has the form of an inverted cone, and receives the slimes from the slime-separator, in an equally divided stream. The surface of this apparatus being perfectly level, and the water passing through it at a very slow rate, all the Vciluable matters are deposited at the bottom. If slime be valuable in the mass, it can evidently be more economically treated by a direct subdivision into fine and coarser work ; since a stream of water, acting on a mixture of this kind, will necessarily carry off an undue proportion of the former in freeing the latter from the waste with which it is con- taminated. The ordinary slime-pit is of a rectangular form, with vertical sides, and flat bottom. Tlie water enters it at one of the ends by a narrow channel, and leaves it at the other. A strong central current is thus produced through the pit, which not only carries with it a portion of valuable slime, but also produces eddies and creates currents tov^ards the edges of the pit, and thus retains matters which should, have been rejected. The slime-pits at Devon Consols are connected with sets of Brunton’s machines, which are thus kept regu- larly supplied by means of a launder from the apex of the inverted cone, through which the flow is regulated by means of a plug-valve and screw. A wagon cistern is placed under each frame for receiving the work, which is removed when necessary, and placed in a packing-kieve. This is packed by machinery, set in motion by a small water-wheel. The waste resulting from this operation is either entirely rejected, or partially reworked on Brunton’s machines, whilst the orey matters contained in the kieve are removed by a wagon to the orehouse, where they are discharged. Napier'a Process for Smelting Copper Ores . — As the copper ores of this country often contain small portions of other metals, such as tin, antimony, arsenic, &c., which are found to deteriorate the copper, Mr. Napier’s process has in view to remove these metals, and at the same time to shorten the operations of the smelting process. 410 COPPER. The first two operations, that of calcining and fusing the ore, are the same as the ordi- nary process ; but the product of this last fusion — viz., the coarse metal — is again fused with a little sulphate of soda and coal mixed. And whenever this becomes solid, after tap- ping the furnace, it is thrown into a pit of water, where it immediately falls into an impal- pable powder ; the water boils, and then contains caustic soda and sulphide of sodium, dissolving from the powder those metals that deteriorate the copper, the lye is let off, and the powder washed by allowing water to run through it. The powder is then put into a cal- cining furnace, and calcined until all sulphur is driven off, which is easily done from the finely divided state of the mass. This calcined powder is now removed to a fusing furnace, and mixed with ores containing no sulphur, such as carbonates and oxides, and a little ground coal, and the whole fused ; the result of this fusion is metallic copper and sharp slag — that is, a scoria containing much protosilicate of iron, which is used as a flux in the first fusion of the calcined ore, so that any small trace of copper which the slag may con- tain is thus recovered. The copper got from this fusion is refined in the ordinary way, and is very pure. When the copper ores contain tin to the extent of from ^ per cent, to 2 per cent., which many of them are found to do, Mr. Napier proposes to extract this tin, and make it valuable by a process which has also been the subject of a patent. The ore is first ground and calcined, till the amount of sulphur is a little under one-fourth of the copper present, the ore is then fused with a little coal. The result of this fusion, besides the scoria, is a regulus composed of sulphur, copper, and iron, and under this is a coarse alloy of copper, tin, and iron, called white metal. This alloy is ground fine, and calcined to oxidize the metals, which are then fused in an iron pot with caustic soda, which combines with the tin and leaves the copper. The oxide of copper is now fused with the regulus. The .stannate of soda is dissolved in water, and the tin precipitated by slaked lime, which is dried and fused with carbonaceous matters and a little sand, and metallic tin obtained ; the caustic soda solution is evaporated to dryness and used over again. This process is well adapted for very poor copper ores that are mixed with tin, or poor tin ores mixed with copper. The Process of Extracting Copper from Ores^ at the Mines in the Riotinto District^ Prov- ince of Huelva^ Spain^ by what is termed “ Artificial Cementation''' (Translated from the newspaper “ Minero Espahol ” for January 23, 1858.) This method, which was first applied here by Don Felipe Prieto, a mine proprietor of Seville, in the year 1845, is the only one employed in the present day in the copper mines of that district. The operation begins with the calcination of the ores, previously reduced to small pieces ; piles or heaps of these ores (sometimes in the form of cones) are made on beds of stubble fire-wood of about a yard thick ; each pile is made up with from 400 to 500 tons of mineral, and allowed to burn for six months ; the smoke destroying all vegetation within its reach. The ores, after being thus burnt or calcined, are thrown into wooden troughs let into the ground, about 6 yards long, 4 wide, and 1^ deep, called “ dissolvers.” In each of these troughs, or cisterns, are plaeed about twelve tons of caleined ore, and the trough is then filled with water ; wliich water is, after remaining in contact with the ores for forty- eight hours, drained off into a similar trough placed at a lower level, and called a “ depos- itor.” The ores remaining in the dissolver are covered by a second quantity of water, left on, this time, for three days ; and the process repeated four times successively, the water being always drained off into the same depositor. From the depositors the water flows on to another set of troughs called “ pilones,” into which is placed a quantity of pig iron, broken into pieces of about the size of bricks, and piled loosely together that the vitriol in the water may better act on its whole surface. Each of these troughs {pilones) will hold from 12 to 18 tons of pig iron, (wrought iron an- swers the purpose as well, but it is much more expensive ;) and, as experience has demon- strated that a slow continuous movement in the water hastens the process, a man is employed for the purpose of agitating it, until all the copper suspended in the vitriol water is depos- ited, which, in summer, is effected in about 2 days, and in from 3 to 5 days in winter. After the water has been renewed four or five times, and the agitation proeess repeated, the scales of copper deposited on the iron, as well as that in the form of coarse grains of sand found in the bottom of the trough, are collected together, washed, and melted, Avhen it is found to produce from 65 to 70 per cent, of pure copper. From the remains of the first washings of tlie above copper scales, &c., another quality is obtained, worth about 50 per cent, for copper, which is mixed with the after washings, yielding about 10 per cent, of copper, and passed on to the smelting furnace. The method is very defective. Minerals containing 5 per cent, of copper, treated by this system of reduction, will scarcely give a produce of 2 per cent, of that metal. It is, however, the only known method that can be profitably employed in the Riotinto district. COPPER. 411 [ Note by the Translator. — The average produce of the copper ores of the Riotinto dis- trict by this process is under 1^ per cent. The following quantities, put into English meas- ure, are taken from the returns of the Government mines at Riotinto, published in the “ Re vista Minera — Year. Quantity of Ores raised. Quantity of Copper produced. Produce per Cent, Tons. Tons. 1854 38,915 720-9 1-85 1855 ... 37,123 834-5 2-24 1856 37,866 740-5 1-98 Average - 37,968 765.3 *2-0 of 4 years. The produce of some of the mines of the district is under 1 per cent. A quantity of the richest of the copper ores produced by the mines in the Riotinto district in the year 1857 has been shipped from Huelva, a port near Seville, for Newcastle, in England ; and it has been reported here that the value of the sulphur saved in the process of reduction has contributed largely towards paying the smelting expenses. — S. H.] The Process of Extracting Copper from the Water that Drains out of th^ Mine at Rio- tinto., called the '•'‘System of Natural Cementation f {Precipitation.) (Translated from the “ Minero Espafiol” for January 28, 1858.) The mine worked by the Spanish Government at Riotinto is formed in a mass of iron pyrites containing copper ; and its immense labyrinth of excavations are known to extend over a length of 500 j^ards and a width of 100 yards, (and probably to a much greater ox- tent ;) the earliest of which workings must date back to very remote times ; for in the dif- ferent excavations are still to be found the impressions of hands, evidently guided by the science of the ancients, middle ages, and of more modern times. The sixth, or lowest level in the mine, where all the operations of the present day are carried on is 80 yards deep, (from the top of the hill in which the lode is found,) and it is from this level that the mine is (naturally) drained by an adit. From the roof, at the ex- treme end of a gallery at this level, flows, from an unknown source, a stream of water rich in copper, which, together with the drainage from other points of the mine, is directed through a channel to the adit “ San Roque,” that empties its waters at the foot of the hill, where the copper is extracted. An able engineer has thus explained the phenomena of “natural cementation”: — “ The natural ventilation through the open excavations of this mine, combined with the humidity of the ground, produces a natural decomposition of the materials composing the lode or vein, and thereby forming sulphates of iron and copper, which the water is continually dis- solving and carrying off, thus forming the substance of this ‘ natural cementation.’ ” This said adit “ San Roque,” which empties its waters on the south side of the hill, has placed in it two wooden launders, or channels, about 12 inches wide and 15 inches deep, and (in the year 1853) 400 yards long ; in the bottom of these launders are placed pieces of pig iron, and to this iron adhere the particles of copper which the slowly flowing water con- tained in solution. In ten days the iron becomes coated with copper, so pure as to be worth 80 per cent, for fine copper, and so strongly formed in scales as to resist to a certain extent the action of a file, and give a strong metallic sound on being struck with a hammer. At the expiration of ten days or earlier, the scales of copper so formed on the iron are removed, that the surface of the iron may be again exposed to the action of the mineral water ; and the process repeated to the entire extinction of the iron. The copper thus ob- tained passes at once to the refining furnace. Since 1853 it has been discovered that the water escaping from the launders in the adit, 400 yards long, still contained copper, and they have been lengthened to nearly 1,000 yards with good effect. [Note by the Translator. — The “ Revista Mmera,” (a mining review,) published by the engineers of the Government School of Mines, in Madrid, gives returns of the Government mines at Riotinto for the year 1856 ; wherein it is stated that the quantity of copper taken out of this mineral water, by “ natural cementation,” amounted, for the year, to 206| tons. — S. H.] • But this average of 2 per cent, for the 4 years contains and includes the copper produced from the water which drains out of the mine, and which copper, for the year 1856, amounted to 206i tons; de- ducting this quantity from the return, 740^ tons, for that year, and the produce would be only 143 per cent, for the ores. 412 COPPER. The following processes for the humid treatment of copper ores are described by Messrs. Phillips-and Darlington : — * Linz Cojyper Process. — “ At Linz on the Rhine, and some other localities in Germany, the poorer sulphides of copper, containing from 2 to 6 per cent, of that metal, are treated by the following process : — “The ores coming directly from the mine, and T^ithout any preliminary dressing, are first roasted in a double-soled furnace, and then taken to a series of tanks sunk in the ground, and lined with basalt. These tanks are also provided with a double bottom, like- wise formed of basalt, so arranged as to make a sort of permeable diaphragm, and on this is placed the roasted ore, taking care that the coarser fragments are charged first, whilst the finer particles are laid upon them. “ The cavity thus formed between the bottom of the tank and the diaphragm, or false bottom, is connected, by means of proper flues, with a series of oblong retorts, through each of which a current of air is made to pass from a ventilator, or a pair of large bellows, set in motion by steam or water power, “ In order to use this apparatus, a quantity of ore is roasted in the reverberatory fur- nace, and subsequently placed in the tanks, taking care that the first layer shall be in a coarser state of division than those w'hich succeed it. “ The retorts — which are formed of fire tiles, and about 6 inches in height by 1 foot in width and 6 feet in length — are now brought to a red heat, charged with blende, and the blast applied. “ The snlphurous acid thus formed is forced by the draught through the flues, where it becomes mixed with nitrous fumes, obtained from a mixture of nitrate of soda and sul- phuric acid, and ultimately passes into the chambers beneath the diaphragms on which are laitl the roasted ores, which must be previously damped by the addition of a little water, of which a small quantity is also placed in the bottoms of the tanks. The sulphuric acid thus generated attacks the oxide of copper formed during the preliminary roasting, giving rise to the production of sulphate of copper, which percolates through the basaltic diaphragm into the reservoir beneath. “ The liquors which thus accumulate are from time to time distributed over the surface of the ore, and the operation repeated until the greater portion of the copper has been ex- tracted, when, by shifting the damper, the gases are conducted into another tank similarly arranged. The liquors from the first basin arc now pumped into the second, and the opera- tion continued until the ores which it contains have ceased to be acted on by the acid. When sufficiently saturated, the liquors arc drawn off into convenient troughs, and the cop- per precipitated by means of scrap iron. The sulphate of iron thus formed is subsequently crystallized out, and packed into casks for sale. “ On removing the attacked ores from the tank, the finer or upper portions are thrown away as entirely exhausted, nearly the whole of the copper having been removed from them, whilst the coarser fragments are crushed and re-roasted, and finally form the upper stratum in a subsequent operation. “ It has been found that, by operating in this way, ores yielding only 1 per cent, of cop- per may be treated with considerable advantage, since the sulphate of iron produced, and the increased value of the roasted blende, are alone sufficient to cover the expenses of the operation. “ By this process, 3 cwt. of coal are said to be required to roast one ton of ore, whilst the same quantity of blende is roasted by an expenditure of 4 cwts. of fuel.” Treatment of Copper Ores hy Hydrochloric Acid. — “ At a short distance from the vil- lage of Twista, in the Waldeck, several considerable bands of sandstone, more or less im- pregnated with green carbonate of copper, have been long known to exist. Although vary- ing considerably in its produce, this ore, on the average, yields 2 per cent, of copper, and was formerly raised and smelted in large quantities ; but this method of treatment not hav- ing apparently produced satisfactory results, the operations were ultimately abandoned. “ The insoluble nature of the granular quartzitic gangue with which the copper is asso- ciated, suggested, some two years since, to Mr. Rhodius, of the Linz Mctallurgic Works, the possibility of treating these ores by means of hydrochloric acid, and a large establishment for this purpose has ultimately been the result. “ These works consist of a crushing mill, for the reduction of the cupreous sandstone to a small size, 16 dissolving tubs, and a considerable number of tanks and reservoirs for the reception of the copper liquors and the precipitation of the metal by means of scrap iron. Each of the 16 dissolving tubs is 13 feet in diameter, and 4 feet in depth, and fuimished with a large wooden revolving agitator, set in motion by a run of overhead shafting in con- nection with a powerful water-wheel. This arrangement admits of the daily treatment of 20 tons of ore, and the consequent production of from 7 to 8 cwts. of copper. Each oper- ation is completed in 24 hours, the liquor being removed from the tanks to the precipitating trough by the aid of wooden pumps. The ore is sloped and brought into the works at 4s. per ton. * Kecords of Mining and Metallurgy, p. 182. COPPER. 413 “ The acid employed at Twista is obtained from the alkali works in the neighborhood of Frankfort, contains 16 per cent, of real acid, and costs, delivered at the works, 2.s‘, per 100 lbs. Each ton of sandstone treated requires 400 lbs. of acid, which is diluted with water down to 10 per cent, before being added to the ore. Every ton of copper precipi- tated requires IJ ton of scrap iron at £4 5s. per ton. “ These works yielded during the last year 120 tons of metallic copper, and afforded a net profit of nearly 50 per cent. The residues from the washing vats, run off after the opera- tion, contain but Vio per cent, of copper. “ It is probable that this extremely simple process of treating the poorer carbonates and oxides of copper ma,y be practicable in many other localities ; but in order to be enabled to do so with advantage, it is necessary that the ore should be obtainable in large quantities at a cheap rate, and that it should contain but little lime or any other substance than the ores of copper soluble in dilute hydrochloric acid. It is also essential that the mine should be in the vicinity of alkali works, in order that a supply of acid may be obtained at a cheap rate, and also that scrap iron be procurable in sufficient quantities and at a moderate price.” Assa^ of Copper Ores. The ores of this metal are exceeding numerous, but may be comprehended under three classes : — The first class includes those ores which contain, with the exception of iron, no metal except copper, and are free from arsenic and sulphur. The second class comprehends those ores which contain no other metal than copper and iron, but in which a greater or less proportion of sulphur is present. The third class consists of such ores as contain other metals in addition to iron and cop- per, together with sulphur or arsenic, or both. The apparatus best adapted for the assay of copper ores is a wind furnace, about 1 6 inches in depth, and of which the width may be 8 inches, and the length 10 inches. This must be supplied with good hard coke, broken into fragments of about the size of a small orange. Ores of the First Class . — When these are moderately rich, their assay offers no diffi- culty, and usually affords satisfactory results. The sample, after being ground in a mortar and well mixed to insure uniformity of composition, is intimately blended with three times its weight of black flux. The whole is now introduced into a crucible, of which it should not occupy above one-third the capacity, in order to avoid loss from the subsequent swell- ing of the pasty mass when heated ; and on the top is uniformly spread a thin layer of car- bonate of soda. The crucible and its contents are now placed in the furnace, previously heated to red- ness, and the pot is allowed to remain uncovered until the ore and flux have become re- duced to a state of tranquil fusion. This will take place in the course of about a quarter of an hour, and the crucible is then closed by a cover, and the damper opened so as to subject the assay, during another quarter of an hour, to the highest temperature of the furnace. The crucible is then removed from the fire, and the metallic button obtained, either by I’apid pouring into a mould, or by allowing the pot to cool, and then break- ing it. The metallic prilV thus obtained, may subsequently, if necessary, be refined accord- ing to the Cornish process, to be hereafter described. Ores of the Second Class . — The most common ores of this class are copper pyrites and other sulphides. Fusion for Regulus . — This process consists in fusing the ores with fluxes capable of removing a portion of its sulphur, and eliminating siliceous and earthy impurities. These conditions are well fulfilled by a mixture of nitre and borax, since, with a proper propor- tion of these reagents, all the ores belonging to this class are fused with the formation of a vitreous slag and a well-formed button of regulus. When the contents of the crucible have been completely fused, they must be rapidly poured into an iron or bell-metal mould of a conical form. The separation of the regulus from the scoriaa must be carefully effected by the use of a small chisel-edged hammer, a sheet of paper being placed under the button to prevent loss. Roasting . — To obtain the pure metal from the sulphides of copper, it is necessary that the sulphur, &c., should be removed by roasting before reducing the copper present to the metallic state. When rich ores, producing from 20 to 35 per cent, of metallic copper, are operated on, the roasting and subsequent reduction may be made directly on the mineral. When, how- ever, poor ores, such as those of Cornwall, containing from 6 to 10 per cent., are to be treated, it is far better to commence by obtaining a button of regulus as above. The calcination of the rich ore or regulus is conducted in the same crucible in which the subsequent fusion with reducing agents is to take place ; and at the commencement of COPPER. 414 the operation care must be taken not to cause the agglutination of the ore, or pulverized button, by the application of too high a temperature. In order to succeed in effecting this object, the ore or regulusSnust be first finely powdered in an iron mortar, and then put into an earthen crucible, which is to be placed in a sloping position on the ignited coke with which the furnace is filled, the draught at the same time being partially cut off by the damper. A moderate heat is thus obtained, and the mixture is continually stirred by means of a slight iron rod, so that each particle may in its turn be exposed to the oxidizing influences of the atmosphere. When a large portion of the sulphur, &c., has been driven off, the contents of the crucible become less fusible, and may without inconvenience be heated to redness. At this stage, it is often found advantageous to heat the partially roasted mass to full redness, since by this means the sulphides and sulphates become reduced to the state of oxides by their mutual reaction on each other. As soon as the smell of sulphur can no longer be observed, and the roasting process is consequently in an advanced state, the heat should for some minutes be increased to white- ness, in order to decompose the sulphates, after which the crucible may be withdrawn and allowed to cool. Reduction . — To obtain the copper from the roasted ore or matt, it may be mixed with one-fourth its weight of lime, from 10 to 20 per cent, (according to the produce of the ore) of finely powdered charcoal, from 1 to l^- times its weight of soda ash or pearl ash, and a little borax. When this has been well mixed, it is placed in the crucible in which the roasting of the ore, or regulus, has been conducted, and covered with a thin stratum of fused borax. In lieu of powdered charcoal, from 15 to 20 per cent, of crude tartar is sometimes em- ployed. The crucible is now placed in the fire and strongly heated for about a quarter of an hour, at the expiration of which time the bubbling of the assay will have ceased, and it must then be closed by an earthen cover, and for a short time heated nearly to white- ness. The prill may be obtained either by rapidly pouring into a suitable mould or by allow- ing the pot to cool and then breaking it. If required, the resulting button may be refined by the Cornish method. Ores of the Third Class . — Minerals belonging to this class must be treated like those of the second, excepting that the preliminary roasting should, from their greater fusibility, be conducted at a lower temperature. The button obtained from the calcined ore, or regulus, will in this case consist of an alloy of copper and other metals instead of, as in the former instances, being nearly pure copper. If an ore contains lead, the roasting must at first be conducted with the greatest pre- caution, since it is extremely difficult so to moderate the heat as to cause at the same time the elimination of the arsenic and sulphur, and avoid the agglutination of the mass. The assay of ores belonging to this class should in all cases be commenced by a fusion for matt. The refining of the button obtained from such assays may be effected either by the Cor- nish method, or by the humid process, to be hereafter described. Coryiish Method of conducting an Assay . — A portion of the pounded and sifted ore is first burnt on a shovel, and examined as to its supposed richness and the amount of sul- phur, arsenic, and other impurities it may contain. A little practiee in this operation will enable the operator to judge with considerable accuracy of the quantity of nitre necessary in order to obtain a good regulus. Two hundred grains of the mixed ore are now weighed out and carefully mixed with a flux consisting of nitre, borax, lime, and fluor-spar, and th-e fusion for matt or regulus is begun. The quantity of nitre used will of course vary with the amount of sulphur and ar- senic present ; but the other ingredients ai’e commonly employed in the following propor- tions: — Borax, 5 dwts. : lime, 1^ ladlefuls; fluor spar, 1 ladleful.* After being placed in the crucible, the whole is generally covered by a thin stratum of common salt. After re- maining in the fire for about a quarter of an hour, the fusion will be found complete, and the contents of the pot may be poured into a suitable iron mould. The button or regulus is now examined, in order to determine whether a suitable proportion of nitre has been used. If the right quantity has been employed, the button, when broken, should present a granular fraeture, and yield from “ 8 to 10 for 20 ” for copper, i. c., from 40 to 60 per cent. However rank a sample may be, it should never be mixed with above 9 or 9^ dwts. of nitre ; and if the amount of sulphur be small, 3 dwts. are often sufficient. The gray sulphides, the red and black oxides, and carbonates, have sulphur added to them for the purpose of obtaining a regulus. Highly sulphurized samples, requiring above 9-^ dwts. of nitre, are sometimes treated in a different way. * The ladle used for this purpose is three-quarters of an inch in diameter and half an inch in depth. COPPER. 415 In this case the ores are first carefully roasted, and afterwards fused with about 5 dwts. of nitre, 9 dwts. of tartar, and 3 dwts. of borax. The roasting of the regulus thus obtained is performed in a smaller crucible than that used in the fusion for matt. During the first quarter of an hour, a very low temperature is sufficient. The heat is then increased to full redness, and the assay allowed to remain on the fire for a further period of about 20 minutes. During the first 15 minutes it should be kept constantly stirred Avith a slender iron rod ; but afterwards an occasional stirring will be found sufficient. When nearly the whole of the sulphur and arsenic has been expelled, the temperature must be raised nearly to whiteness during a few minutes, and the assay then withdrawn and allowed to cool. The fusion for copper is effected in the same crucible in which the roasting has been carried on. The quantity of flux to be used for this purpose varies m accordance with the weight of the button of regulus obtained. A mixture of 2 dwts. of nitre, dwts. of tartar, and 1^ dwts. of borax, is sufficient for the reduction of a calcined regulus that, previous to roast- ing, weighed from 45 to 50 grains. In the case of a button weighing from 90 to 100 grains, dwts. of nitre, 9 dwts. of tartar, and 2 dwts. of borax, should be employed. These quantities are, however, seldom weighed, since a little practice renders it easy to guess, with a sufficient degree of accuracy, the necessary amounts. The prill of copper thus obtained is seldom fine, and consequently requires purifica- tion. A crucible is heated to redness in the furnace, the metallic button is taken from the mould and thrown into it, and some refining flux and salt are placed in a scoop for imme- diate use.* In a few minutes the fusion of the prill is effected. The crucible is noAV taken from the fire by a pair of tongs, the contents of the scoop introduced, and a gentle agita- tion given to it ; an appearance similar to the brightening of silver on the cupel now takes place, and the crucible is returned to the fire for about four minutes. The crucible is now removed, and its contents rapidly poured into a mould. The but- ton thus obtained will consist of pure copper, and present a slight depression on its upper surface. The slags from the reducing and refining operations are subsequently fused with a couple of spoonfuls of crude tartar, and the prill thus obtained weighed with the larger button. Humid Method of assaying Copper Ores . — In some localities, and particularly in the United States of America, the assay of copper ores is performed by the humid process. The whole of the ores belonging to the three different classes may be estimated in this way: A weighed quantity of the pulverized ore is introduced into a long-necked flask of hard German glass, and slightly moistened with water. Nitric acid is now added, and the flask exposed to the heat of a sand bath. A little hydrochloric acid is subsequently introduced, and the attack continued until the residue, if any remains, appears to be free from all metallic stains. The contents of the flask must be transferred to a porcelain evaporating dish, and evap- orated to dryness, taking care, by means of frequent stirring, to prevent the mass from spirting. The whole must now be removed from the sand bath and allowed to cool, a little hydrochloric acid subsequently added, and, afterwards, some distilled water. The contents of the basin must then be made to boil, and, whilst still hot, filtered into a beaker. A piece of bright Avrought iron, about tAvo inches in length, three-quarters of an inch in Avidth, and a quarter of an inch in thickness, is now introduced, and the liquor gently heated on the sand bath until the whole of the copper has been throAvn doAvn. The liquor is now re- moved by means of a glass siphon, and the metallic copper freed from all adhering chlo- rides, by means of repeated Avashings Avith hot Avater, and then dried in a water bath, and AA-eighed. In case the mineral operated on should contain tin or antimony, very minute traces only of these metals Avill be found Avith the precipitated copper. When lead is present, it is best to add a few drops of sulphuric acid during the process of the attack ; by this means the lead Avill be precipitated as sulphate of lead, and be removed by filtration. The results obtained by this process are somewhat higher than afforded by the fire assay. — J. A. P. Copper, Nitrate of, prepared by dissolving copper in moderately strong nitric acid, and evaporating to crystallization. Its formula is CuO,NO^. This salt is used to produce a tine green in fireworks. Copper, Sulphate of, called in commerce Blue Vitriol. Blue Stone. Blue Cop- peras. — This salt is frequently prepared by roasting copper pyrites with free access of air. It is also obtained by heating old copper with sulphur, by Avhich a subsulphide of copper is * The refinine: flux consists of tAVO parts of nitre and one of white tartar fused together, and subse- quently pounded. COPYING. 416 produced ; this is converted into sulphate, by roasting in contact with air. Large quan- tities of sulphate of copper are obtained in the process of silver refining. See Pyrites and Silver. COPYING. A new and important quality of writing-inks was introduced by the inde- fatigable James Watt, in 1780, who in that year took out a patent for copying letters and other written documents by pressure. The modus operandi being to have mixed with the ink some saccharine or gummy matter, which should prevent its entire absorption into the paper, and thus render the writing capable of having a copy taken from it when pressed against a damp sheet of common tissue paper. But although this process was very imper- fect, the writing generally being much besmeared by the damping, and the copies, in many cases, only capable of being read with great difficulty, it was not for seventy-seven years after the invention of Watt that any improvement in such inks was attempted. The firm of Underw’ood and Burt patented a method of taking copies by the action of a' chemically prepared paper, in a chemical ink, by which, not only are far superior copies taken, and the original not at all damaged, but many copies may be taken at one time from a single document. Printed matter may also be copied at the same time, on the same beautiful principle. We give the specification of Mr. Underw'ood : — “But while the means employed for producing the desired effects may be varied, I pre- fer the following for general use : — I damp the paper, parchment, or other material w'hich I desire to copy upon, with a solution of 200 grains of the yellow or neutral chromate of potash dissolved in 1 gallon of distilled w-ater, and either use it immediately, or dry it and subsequently damp it with W'ater as it is required for use. I then prepare the material which I use for producing the characters or marks, and which may be called copying ink, by simply dissolving (in a water bath) pure extract of logw^ood in distilled water ; or, for printing, I use a varnish or other similar material soluble in water, and dust or throw over it powdered extract of logwood. If I desire to take twenty copies from an original, I use about six pounds of the pure extract of logwood to a gallon of distilled wmter ; but a larger number of copies may be taken by dusting or throwing over the original, before the ink has thoroughly dried, a powffier composed of five parts of powffiered extract of logwood, one part of powdered gum arabic, and one part of powdered tragacanth. When I desire to print from an original, in producing which I have used ink prepared as before described, I proceed by damping six sheets of paper, prepared as before described, and having taken off all superfluous moisture with good blotting paper, I place the original upon the upper sheet and press the whole for about half a minute in a copying press ; I then remove the original, and in its place put six other sheets of the prepared paper in a damp state, and subject the whole to pressure for about a quarter of an hour. I then take five other pre- pared sheets in a damp state, and having laid the original upon them, press them together for about two minutes, then replace the original by three other prepared and damped sheets, and press the whole together for about a quarter of an hour. The extract of logwood so acts upon the neutral chromate of potash that I thus obtain twenty good clear fac-similes of the original matter or design.” They have also produced an Indian ink on the same principle, which, when used in the preparation of architectural plans, maps, &c., rvili give one or more clear copies of even the finest lines. The only point to be observed in the taking of such copies, is that as they are done to a scale, they must be kept pressed in close contact with the original, till they are perfectly dry, because if not they will shrink in drying, and the scale be spoilt. The most complete information on this subject, and that of inks generally, is to be found in a memoir read before the Society of Arts, on the 16th December, by Mr. John Under- wood. COQUILLA NUTS. These nuts are produced in the Brazils by the Attalca funifera. They are suitable for a great variety of small ornamental works, and are manufactured into the knobs of umbrellas and parasols. CORDAGE; — {Cordage^ Fr. ; TauwerTc^ Germ.) Cordage may be, and is, made of a great variety of materials. In Europe, however, it is mostly formed of hemp, although now, much cordage is made of Coir. See Coir. Professor Robinson proposed the following rule for determining the strength of cordage. Square the circumference of a rope in inches ; one-fifth of the product will be the number of tons’ w’eight which it will bear: this is, however, uncertain. COROMANDEL WOOD. The wood of the Di/ospyros hirsuta. CORROSIVE SUBLIMATE, Mercury, Chloride of, or Protochloride, {Deutochlorure clc mercure, Fr. ; Aetzendes quecksilber siiblimat. Germ.,) is made by subliming a mix- ture of 2^ parts of sulphate of oxide of mercury, and one part of sea-salt, in a stone- ware cucurbit. The sublimate rises in vapor, and encrusts the globular glass capital with a white mass of small prismatic needles. Its specific gravity is 6*225. Its taste is acrid, stypto-metallic, and exceedingly unpleasant. It is soluble in 16 parts of water, at the ordinary temperature, and in less than three times its weight. It dissolves in 2^ times its weight of cold alcohol. It is a very deadly poison. Raw white of eggs swal- COTTON MANUFACTURE. 417 lowed in profusion is the best antidote. A solution of corrosive sublimate has been lono* employed for preserving soft anatomical preparations. By this means the corpse of Colonel Norland was embalmed, in order to be brought from the seat of war to Paris. His features remained unaltered, only his skin was brown, and his body was so hard as to sound like a piece of wood when struck with a hammer. In the work upon the dry rot, published by Mr. Knowles, secretary of the committee of inspectors of the navy, in 1821, corrosive sublimate is enumerated among the chemical substances which had been prescribed for preventing the dry rot in timber ; and it is well known that Sir H. Davy had, several years before that date, used and recommended to the Admiralty and Navy Board corrosive sublimate as an anti-dry-rot application. It has been since extensively employed by a joint-stock company for the same purpose, under the title of Kyan’s patent. The preservative liquid known as Goadhy's solution, which is employed for preserving wood and anatomical preparations, is composed as follows : — Bay salt, 4 oz. ; alum, 2 oz. ; corrosive sublimate, 2 grains ; water, 2 pints. The composition of corrosive sublimate is — Mercury - - 100' 73-86 Chlorine - - 35-5 26-14 135-5 100-00 H. M. N. See Mercury. i CORRUGATED IRON. A process has been introduced for giving strength to sheet iron, by bending it into folds or wrinkles ; the iron so treated is thus named. The iron shed at the London Terminus of the Eastern Counties Railway, constructed of corrugated iron, has been described by Mr. W. Evill, jun. The entire length is 216 feet, and consists of three roofs, the centre of 36 feet span, rising 9 feet, and the side-roofs 20 feet 6 inches, with a rise of four feet. The corrugated wrought-iron is composed of sheets No. 16 wire gauge, or ’/14 of an inch in thickness ; the weight per foot is 3 lbs. ; the whole weight of the centre roof of 10,235 superficial feet being scarcely 13f tons, and the side roofs, of 5,405 square feet, weigh 7^ tons. The whole roof was erected by Messrs. Walker and Sons, Bermondsey, the holders of Palmer’s patent, at a charge of £6 10s. per 100 superficial feet, including fixing, and the whole roofs cost £1,365, and might now be erected for half the cost, the patent having ex- pired, and increased facilities existing. Many corrugated roofs have been erected ; one at St. Katherine’s Dock. At the en- trance of the London Docks there is one 40 feet span and 225 feet long. On the London, Birmingham, Great Western, and other railways they have been employed. Iron appears to have great strength given to it by this change of form ; a single sheet, so thin as to be unable to bear its own vertical position, will bear 700 lbs. after corrugation without bending. Cast-iron has been corrugated. Mr. Palmer has patented this form, and at Swansea a bridge of three arches, one of 50 and two of 48 feet span, has been erected. COTTON AND COTTON MANUFACTURE. Fig, 198 is F. A. Calvert’s patent, toothed roller cotton gin. a is a perspective view, 6 is a sectional view, a is the box to hold seed cotton ready to be ginned ; b is the top of the hopper ; c is the fluted guard ; n is the fine-toothed roller ; e the brush ; f is the discharge pipe ; and g is a suitable block on which the machine stands. N. B. — Over the handle in fig. a there is shown an arrow, indicating the direction of the motion. The handle should not be driven less than fifty turns per minute. The seed cotton should be fed into the hopper in small portions, and regularly throughout its whole length ; at the same time care should be taken that a large quantity does not collect, as it will retard the operation. This gin is made from six inches to five feet wide ; two persons can drive, with ease, a gin of this kind three feet wide, producing 200 lbs. of cleaned cotton per day, at the speed above stated. When driven by steam or water power at the rate of 200 revolutions per minute, it will clean 400 lbs. each foot in length per day. It is well adapted for all classes of cotton, particularly fast seed cotton, which has been valued at one penny per pound more when done on this gin than when done on the saw gin. It will be seen that there is no band or belt employed, hence the machine requires small power com- pared with other machines for like purposes. After the cotton wool is thus separated from the seeds, it is packed in large canvas bags, commonly with the aid of a screw or hydraulic press, into a very dense bale, for the convenience of transport. Each of the American bags contains about 500 lbs. of cotton wool. When this cotton is delivered to the manufacturer, it is so foul and flocky, that he must clean and disentangle it with the utmost care, before he can subject it to the carding operation. VoL. III.— 27 418 COTTON MANUFACTUKE. 198 h Fig. 199, the scutcher or opening machine, though usually preceded by the willow, is often the first machine in a mill through which the cotton is passed, and serves, as its name implies, to open the matted locks of cotton and separate its fibres, and at the same time to remove a large percentage of the seed and dirt which may have been packed with it. The cotton is placed upon the travelling creeper marked a, which is made of a number of narrow slips, or laths, of wood, screwed to three endless bands of leather, the pivots of which are marked b and c. Motion is given to the roller e, by a wheel on the end of the feed roller, thus causing the creeper to advance, carrying with it the cotton to the feeding rollers d ; these revolving slowly pass the cotton to the second smaller pair of fiuted rollers, which serve it to the beater. The top feeding rollers are weighted by levers and weights e c, and hold the cotton sufficiently tight for the beater to act upon it. The beater is placed inside the machine at /, and extends quite across its breadth, its shaft or axis being shown with the speed fully upon it at g. The form of the beater varies, but we give the following as an example : — On a shaft are placed four or five spiders, each having three or four arms ; to the ends of these arms are attached steel blades, which pass along the whole length of the beater ; two of the arms being shorter than the other arms of the spider, allow two of the blades to contain a double row 200 COTTON MANUFACTURE. 419 of spikes in eacli, the points of the spikes being at the same distance from the axis as the other two blades: As the beater revolves about 800 turns per minute, the blades and spikes strike the cotton with considerable force as it is passed from the feeding rollers, and thus free it from many of its impurities. Immediately under the feed rollers and beater, are placed a number of wedge-shaped bars, which form a semi-circular grid, through the narrow openings of which the dirt and seeds fall to the floor, their removal being effected through the doors in the framing. To prevent the cotton passing with the dirt through the grid, a current of air to draw the cot- ton from the beater to the cage, is produced by an exhaust fan (its axis being shown at h) receiving its motion from a pulley on the beater shaft. The projection i on the framing forms a pipe, through which the fan draws the air from the beater, passing on its way through a large revolving cage or cylinder, the periphery of which is formed of sheets of perforated metal, or wire gauze. Its axis is shown at k. From the cage the cotton is delivered by a second travelling creeper and falls into a receptacle, from which it is weighed and made ready for the operations of the lap machine. Figs. 201, 202, represent skeletons of the old cards, to facilitate the comprehension of these complex machines. Fig. 201 is a plan ; f is the main cylinder ; m m is the doffer knife or comb ; g, the carded fleece hemmed in by the funnel a, pressed between the rollers 201 202 6, and then falling in narrow fillets into its can. Fig. 202, k l are the feed rollers ; a b, the main cylinder ; c d, the tops ; e f, the doffer card ; m n, the doffer knife ; o«oeoia o 3 cO(Mi— I Olir-Xr^OiCOrttrlHG^ ^ O Ci '"I •~* W ®* rlT tN" cf o' r~T (ji" CCT o' Oi »-H >o' o” (MlM— • 01 00 kC 5 r— 01 1-1 01 01 0000 0000 kC 5 00 01 CO of of (TT CO*' CO C» kC5 rH 01 01 CO CO CO 00 £- 1 — ( 1(0 CO CO CO CO « ^ ® s CO V o 3 kffl ^ CO 1 ^ CO 01 CO 00 00 CO CO 10 CO CM (35 (05 o CO CO CO (35 CM 05 (35 CO CO 00 00 05 O CO It o o 03 kO M la o ko tH 1 ^ lit 00 000 O O CO O rf (35 o o o c kC^ k(0 cf tf O kO co^ 1-T CM o o o o CM kO CM CM CM O^ Tjc^ of kcf CO 1 -H CCl' (oT CO^ tf tf 000 000 05 I— ^ _C^ j>r < 3 T kcf o o o o 05 CO o o Ci ^, but long enough to make them useless as disinfectants when used so strong. Vinea^ir is the best of the purely acid disinfectants ; wood vinegar the best of the vinegars, because it unites to the acidity a little kreasote. Vinegar is a very old and well-established agent ; it has been used in the case of plague and various pestilences from time immemo- rLoI. It is used to preserve eatables of various kinds. For fumigation, no acid vapor used fs pleasant except vinegar, and in cases where the impurity is not of the most violent kind, it may be used with great advantage. Even this, however, acts on some bright surfaces, a disadvantage attending most fumigations. Sulphurous Acid^ or the fumes of burning sulphur, may be treated under this head, although in reality it does not act as a mere acid combining with a base and doing no more. It certainly unites with bases so that it has the advantage of an acid, but it also decomposes by precipitating its sulphur, as when it meets sulphuretted hydrogen. It therefore acts as an oxidizer in some cases, but it is generally believed, from its desire to obtain oxygen, that it acts by being oxidized, thus showing the peculiar characteristics of a deoxidizer. We can certainly believe that bodies may be disinfected both by oxidation and deoxidation. The solutions of sulphurous acid act as a restraint on oxidation, and preserve like vinegar. Its compounds with bases, such as its salts of soda, potash, &c., preserve also like vinegar, salt- petre, &c. ; probably from their affinity for oxygen, taking what comes into the liquid before the organic matter can obtain it. But it is not probable that this rivalry exists to a great extent ; the presence of the sulphurous acid in all probability puts some of the particles of oxygen in the organic matter in a state of tension or inclination to combine with it, so that the tension of the particles which are inclined to combine with the oxygen of the air is removed. Sulphur fumes are amongst the most ancient disinfectants held sacred in early times from their wonderful efficacy, and still surpassed by none. With sulphur the shepherd purified or disinfected his flocks, and with sulphur Ulysses disinfected the suitors which he had slain in his house. No acid fumigation is less injurious generally, vinegar excepted, to the lungs or furniture, and its great efficiency marks it out as the most desirable, although much laid aside in modern times. The amount arising from burning coal must have a great effect in disinfecting the putrid air of our streets, and rendering coal-burning towns in some respects less unpleasant ; this is one of the advantages which that substance brings along with it, besides, it must be confessed, greater evils. It is curious that this compound of sulphur should be one of the most efficient agents in destroying sulphuretted hydrogen, another compound of sulphur. Sulphurous acid prevents decomposition, and also preserves the valuable principle of a manure, so that it belongs partly to the class of disinfectants, and partly to antiseptics. The peculiar actions of sulphurous acid and kreasote have been united in that called “ McDougall’s Disinfecting Powder.” Since in towns and farms, when disinfectants are used, it is desirable not to use liquids, these two have been united into a powder, which assists also in removing moisture, as water is often a great cause of discomfort and disease in stables and cowhouses. When they are used in this manner, the acids are united with lime and magnesia. When the floors of stables are sanded with the powder, it becomes mixed with the manure, which does not lose ammonia, and is found afterwards much more valuable for land. The cattle are also freed from a great amount of illness, because the air of the stable is purified. When faeces of any kind cannot be at once removed by water, as by the water-closet system, the use of this is invaluable ; but it is well to know that the instant removal of impurity by water is generally best for houses, however difficult the after problem may be when the river is polluted. In stables and cowhouses this is not the case, and it is then that a disinfecting powder becomes so valuable, although it is true that so many towns are unfortunately so badly supplied with water-closets that disinfectants are still much wanted for the middens. The inventors have proposed to disinfect sewers, as well as sewage, by the same sub- stances ; not, however, in the state of a powder. They apply the acids to the sewage water in the sewers themselves, and so cause the impure water to pass disinfected through the town ; by this means the towns and sewers are purified together. When the sewage water is taken out of the town it can be dealt with either by precipitation or otherwise. As it will cease to be a nuisance, covered passages for it will not require to be made. Lime is used for precipitating sewage water, and acts as a disinfectant as far as the removal of the precipitate extends, and also by absorbing sulphuretted hydrogen, which, however, it allows again to pass off gradually. The other substances proposed for sewers have chiefly relation to the precipitation, and do not so readily come under this article. Charcoal has been mentioned ; alum has been proposed, and it certainly does act as a disin- fectant and precipitant None of these substances have been tried on a great scale except- ing lime. \ \ 454 DISTILLATION. Absence oj Air is an antiseptic of great value. The process of preserving meat, called Appert’s process, is by putting it in tin vessels with water, boiling off a good deaKof steam, to drive out the air, and then closing the aperture with solder. Schroeder and 0.6 Dusch prevented putrefaction for months by allowing no air to approach the meat without passing through cotton ; so also veils are found to be a protection against some miasmas. or compounds of acids with bases, are valuable antiseptics ; some of them are also disinfect- ants, that is, they remove the state of putrefaction after it has begun. An antiseptic pi^e- vents it, but does not necessarily remove it. Common salt is well known as a preserver of flesh ; nitrate of potash, or saltpetre, is a still more powerful one. Some of these salts act- in a manner not noticed when treating of the preceding substances, viz., by removing the ) water. Meat, treated with these salts, gives out its moisture, and a strong solution of brine is formed. Chloride of calcium prevents, to some extent, the putrefaction of wood. Alum, or the sulphate of alumina, is not a very efficient preserver ; but chloride of aluminum seems to have been found more valuable. It is sometimes injected into animals by the carotid artery and jugular vein. Meat usually keeps a fortnight : if well packed, cleaned, and washed with a solution of chloride of aluminum, it will keep three months. But in reality the salts of the heavier metals are of more activity as disinfectants. It has been supposed that their efficiency arose from their inclination to unite with sulphur and phosphorus, and there is no doubt that this is one of their valuable properties, by which ’ they are capable of removing a large portion of the impure smell of bodies ; but they have also an inclination to combine with organic substances, and by this means they prevent them from undergoing the changes to which they are most prone. The actual relative value of solutions it is not easy to tell. Most experiments have been made on solutions not suffi- ciently definite in quantity. Salts of mercury have been found highly antiseptic. Such a salt is used for preserving wood ; the process is known as that of Kyan’s, or kyanizing. A solution of corrosive sublimate, containing about cent, of the salt, is pressed into the wood either by a forcing pump or by means of a vacuum. The albumen is the substance most apt to go into putrefaction, and when in that condition it conveys the action to the wood. It is no doubt by its action on the albumen that the mercury chiefly acts. Thin pieces of pine wood, saturated for four weeks in a solution of 1 to 25 water, with the fol- lowing salts, were found, after two years, to be preserved in this order : — 1. Wood alone, brown and crumbling. 2. Alum, like No. 1. 3. Sulphate of manganese, like 1. 4. Chlo- ride of zinc, like 1. 5. Nitrate of lead, somewhat firmer. 6. Sulphate of copper, less brown, firm.. 7. Corrosive sublimate, reddish yellow and still firmer. In an experiment, in which linen was buried with similar salts, the linen was quite consumed, even the specimen with corrosive sublimate. Other experiments showed salts of copper and mercury to pro- tect best. — Gmelin. Nevertheless, all these metallic salts are found true preservers under other conditions. Chloride of manganese, a substance frequently thrown away, may be used, as Gay-Lussac and Mr. Young have shown, with great advantage, and Mr. Boucherie has shown the value of the acetate of iron. Mr. Boucherie’s process is very peculiar. He feeds the tree, when living, with the acetate of iron, by pouring it into a trough dug around the root. The tree, when cut down, has its pores filled with the salt, and the albumen in the sap is pre- vented from decomposing. For preservation of vegetable and animal substances, see Putrefaction, Prevention of. The chloride of zinc of Sir William Burnett is also a valuable disinfectant, and has more power than it would seem to possess from the experiments quoted above. Wood, cords, and canvas, have been preserved by it under water for many years. It has the advantage also of being so soluble as to take up less room than most other salts, although liquids gen- erally are inconvenient as disinfectants in many places. Nitrate of lead is a disinfectant of a similar kind ; it lays hold of sulphur, and the base unites with organic compounds. All these metals are too expensive for general use, and can only be applied to the preservation of valuable materials. Even iron is much too dear to be used as a disinfectant for materials to be thrown on the fields as manure. All are apt to be very acid, a state to be avoided in a disinfectant, unless when it is applied to sub- stances in a very dilute state, or in an active putrid state, and giving out ammonia. — R. A. S. See also Sanitary Economy. DISTILLATION. Distillation consists in the conversion of any substance into vapor, in a vessel so arranged that the vapors are condensed again and collected in a ve^’sel apart. The word is derived from the Latin dis and stillo^ I drop, meaning originally to drop or fall in drops, and is very applicable to the process, since the condensation generally takes place dropwise. It is distinguished from sublimation by the confinement of the latter term to cases of distillation in which the product is solid, or, in fact, where a solid is vaporized, and con- densed without visible liquefaction. The operation may simply consist in raising the temperature of a mixture sufficiently to / f DISTILLATION. 455 evaporate/ the volatile ingredients ; or it may involve the decomposition of the substance heated, ^nd the condensation of the products of decomposition, when it is termed destruc- tive di^illation ; in most cases of destructive distillation the bodies operated upon are solid^ and the products liquid or gaseous ; it is then called dry distillation. In consequence of the diversity of temperatures at which various bodies pass into vapor, an/5 also according to the scale on which the operation has to be carried out, an almost end- leiss variety of apparatus may be employed. ! Whatever be the variety of form, it consists essentially of three parts : — the retort or still., the condenser., and the receiver. On the small scale., in the chemical laboratory., distillation is performed in the simplest way, by means of the common glass retort a, and receiver 6, as in jig. 221. The great advantages of the glass retort are that it admits of constant observation of the materials within, that it is acted upon or injured by but few substances, and may be cleaned generally with facility. Its great disadvantage is its brittleness. 221 The retort may be either simple, as in jig. 222, or tubulated, as in jig. 221, (ds modifications are employed in the distillation of other liquids. In «'ome cases, unusually effectual condensing arrangements are required, as in the manupcture of Ether, Chloroform, Bisulphide of Carbon, and Bichloride of Carbon. In others higher temperatures are necessary, as in the distillation of sulphuric acid. ^hen the liquids to be distilled are acid, or otherwise corrosive, great care has to be tg^icen especially that the worm or other condenser is of a material not acted upon by the gfcid. See Acetic Acid and Sulphuric Acid. / The term distillation is sometimes applied to cases of the volatilization and subsequent j condensation of the metals either in their preparation or purification, f In cases like mercury, potassium, and sodium, where they are condensed in the liquid j state, or visibly pass through this state before volatilization, this term is quite appropriate ; [ but where the fusing and vaporizing points nearly coincide, as in the case of arsenic, the j term sublimation would be more suitable. \ Nevertheless it is difficult to draw a precise line of demarcation between the two terms ; 1 for in the cases of zinc, cadmium, &c., the metals being melted before volatilization, and ( condensed likewise in the liquid state, the term is certainly correct. ) For the details of construction of the distillatory apparatus, we must refer to the articles on these several metals. DistUlatio per descensum is a term improperly applied to certain cases of distillation where the vapor is dense, and may be collected by descending through a tube which has an opening in the top of the distillatory vessels, and descends through the body of the vessel in which the operation of evaporation is going on, being collected below. This is clearly merely due to the fact of the vapor being even at a high temperature I more dense than atmospheric air, and might be performed with any body forming a dense / vapor, such as mercury, iodine, zinc, &c. \ It has, however, practically been confined to the English process of refining zinc. See ( Zinc. The two most remarkable cases in which the process of destructive distillation is carried out on a manufacturing scale, are the dry distillation of wood, for the manufacture of wood charcoal, acetic acid, and pyroxilic spirit, (which see ;) and of coal, for the purpose of obtaining coal-gas, and coke. This process will be found fully described in the article on Coal-Gas. Dhtillation of Essential Oils or Essences. — The separation of volatile flavoring oils from plants, &c., by distillation with water, will be fully treated under another head. See Perfumery, Essences. Fractional Distillation. — A process for the separation of volatile organic substances (such as oils) is very extensively employed in our naphtha works under this name. If we have two volatile bodies together, but differing appreciably in their boiling points, we find, on submitting them to distillation in a retort, through the tubulature of which a thermometer is fixed, so that its bulb dips into the liquid, that the temperature remains constant (or nearly so) at the point at which the more volatile constituent of the mixture boils, and the distillate consists chiefly of this more volatile ingredient ; and only after nearly the whole of it has passed over, the temperature rises to the point at which the less volatile body boils. Before this point has been reached, the receiver is changed, and the second distillate collected apart. By submitting the first product to repeated redistilla- tion, as long as its boiling point remains constant, the more volatile constituent of the mix- ture is ultimately obtained in a state of absolute purity. See Naphtha. This method may in fact be adopted when the mixture contains several bodies ; and by changing the receiver with each distinct rise of temperature, and repeating the process sev- eral times, a fractional separation of the constituents of the mixture may be effected. — H. M. W. DISTILLATION, DESTRUCTIVE. Organic matters may be divided into two groups, founded on their capability of withstanding high temperatures without undergoing molecular changes. Bodies that distil unchanged form the one, and those which break up into new and simpler forms, the other. The manner in which heat acts upon organic substances dif- fers not only with the nature of the matters operated upon, but also with the temperature employed. We shall study the subject under the following heads : — 1. Apparatus for Destructive Distillation. 2. Destructive Distillation of Vegetable Matters. 3. Destructive Distillation of Animal Matters. 4. Destructive Distillation of Acids. 6. Destructive Distillation of Bases. 6. General Remarks. 1. Apparatus for Destructive Distillation. — Destructive distillation on a large scale is 464 DISTILLATION^’, DESTKUCTIYE. most conveniently performed in the cast-iron retorts used in gas works. Where quantities of materials not exceeding fifteen or twenty pounds are to be operated oif, for the purpose of research, a more handy apparatus can be made from one of the stout cast-iron pots sold at the iron wharves. They are semi-cylindrical, and have a broad flange round the edge. The cover should be made to fit in the manner of a saucepan lid. The aperture by wliich the products of distillation are to be carried away should be of good size, and the exit pipe must not rise too high above the top of the pot before it turns down again. This is ^'ery essential in order to prevent the less volatile portion of the distillate from condensing and falling back. The exit tube should conduct the products to a receiver of considerable capacity, and of such a form as to enable the solid and fluid portions of the distillate to be easily got at for the purpose of examination. From the last vessel another tube should con- duct the more volatile products to a good worm supplied with an ample stream of cold water. If it be intended to examine the gaseous substances yielded by the substances under examination, the exit pipe of the worm must be connected with another apparatus, the nature of which must depend on the class of bodies which are expected to come over. If the most volatile portions are expected to be basic, it will be proper to allow them to stream through one or more Woulfe’s bottles half filled with dilute hydrochloric acid. Any very volatile hydrocarbons of the Cnllu family which escape may be arrested by means of bro- mine water contained in another Woulfe’s bottle. The pressure in the Woulfe’s bottles must be prevented from becoming too great, or the leakage between the flange of the pot and its cover will be very considerable. The luting may consist of finely sifted Stourbri^e clay, worked up with a little horse dung. A few heavy weights should be placed on various parts of the lid of the pot, so as to keep it close, and render the leakage as little as pos- sible. For the destructive distillation of small quantities of substances, I have been accus- tomed for a long time to employ a small still made from a glue-pot, and having a copper head made to fit it. The luting for all temperatures not reaching above 70° may be a mix- ture of f linseed and ^ almond meal, made into a mass of the consistence of putty. For the apparatus employed in the destructive distillation of wood, coal, bones, &c., on the large scale, the various articles in this work on the products obtained from those substances must be consulted. 2. Destructive Distillation of Vegetable Matters. — The principal vegetable matters which are distilled on the large scale are wood and coal. We shall consider these sepa- rately. Destructive Distillation of Wood. — The products obtained in the ordinary process of working, are acetic acid, wood spirit or methylic alcohol, acetone, pyroxanthine, xylite, lig- nine, paraffine, kreosote, or phenic acid, oxyphenic acid, pittacal, several homologues of benzole, with ammonia, and methylamine. There are also several other bodies of which the true nature is imperfectly known. The greater part of the above substances are fully described in separate articles in this work. See Acetic Acid, Paraffine, &c. Peat appears to yield products almost identical with those from wood. Destructive Distillation of Coal. — The number of substances yielded by the distillation of coal is astonishing. It is very remarkable that the fluid hydrocarbons produced at a low temperature are very different to those distilling when a more powerful heat is employed. The principal fluid hydrocarbons produced by the distillation and subsequent rectification of ordinary gas tar are benzole and its homologues. But if the distillate is procured at as low a temperature as possible, or Boghead coal be employed, the naphtha is lighter, and the hydrocarbons which make its chief bulk belong to other series. See Naphtha. 8. Destructive Distillation of Animal Matters. — Bones are the principal animal sub- stances distilled on the large scale. The naphthas which come over are excessively foetid, and are very troublesome to render clean enough for use. The products contained in bone oil will be described in the article Naphtha. Horn and wool have recently been examined with reference to the basic products yielded on distilling them with potash. Horn under these circumstances yields ammonia and amylamine. Wool I find to afford ammonia, pyr- rol, butylamine, and amylamine. My experiments on feathers, made some years ago, although not carried so far as those on wool, appear to indicate a very similar decompo- sition. The products yielded by animal matters, when distilled per are very different to those obtained when a powerful alkali is added previous to the application of heat. If feathers or wool be distilled alone, a disgustingly foetid gas is evolved containing a large quantity of sulphur. Part of the sulphur is in the state of sulphide of carbon. But if an alkali be added previous to the distillation, the sulphur is retained, and the odor evolved, although powerful, is by no means offensive. During the whole period of the distillation of ordinary organic matters containing nitrogen, pyrrol is given off, and may be recognized by the reaction afforded with a slip of deal wood dipped in hydrochloric acid. An interest- ing experiment, showing the formation of pyrrol from animal matters, may at any time be made with a lock of hair, or the feather of a quill. For this purpose the nitrogenous animal / DISTILLATION, DESTRITCTIYE. 465 matter is to placed at the bottom of a test tube, and a little filtering paper is to be placed half-way the tube, to prevent the water formed during the experiment from returning and fracturing the glass. The end of the tube is now to be cautiously heated with a spirit ' lamp, an rough an electro-magnet ; the latter attracts an armature of soft iron and liberates the ball, vf\'hich falls, and in falling it encounters a crutch, or lever, attached to the seconds’ hand, ^md thrusts it this way or that, as the case may be ; but so as to bring it to sixty seconds on tlhe dial, and thus to set the clock right. r Intermediate between the one method of sending a signal every second to regulate k\ clock, and the other method of sending it once a' day, we have the following arrangement of Bain’s i for sending it once an hour. Fig. 252 shows the arrangement, with part of the dial removed, to show the position of the electro-magnet. The armature is below ; it carries a vertical stem, terminating above in a fork. Its ordinary position is shown by the dot- ted lines. The minute hand (partly removed from the cut) carries a pin on its back surface. When the hand is near to sixty minutes, and an electric current is sent through the magnet, the armature is attracted upwards and the fork takes the position shown by the full lines at the top of the dial, and, in doing so, it encounters the pin and forces the hand into the vertical position, and sets the clock to true time, pro- viding the signal comes from a standard clock, or is sent by hand at true time. A dial of moderate char- acter keeps so near to time, that once or twice a day would be, for all common purposes, often enough to correct it. Fig. 253 is an arrangement of Bain’s, by which a principal clock, showing seconds, sends electric currents at minute intervals to other clocks, and causes the hand to move minute by minute, a is a voltaic battery ; b is the principal clock, which may be an electric clock or not, at pleasure ; g and h are two out of many subordinate clocks. The seconds’ hand of the principal clock completes a voltaic circle twice (for the case of two clocks) during the minute ; at the 30 seconds for the clock g, and at the 60 seconds for the clock ii. The clock H shows time in leaps from one minute to the next ; and the clock g from one half minute to the next half minute. As many more contacts per minute may be provided for the seconds’ hand of the prime clock as there are subordinate clocks. 253 Next akin to the time signals above described, and which act automatically upon clocks, either to drive the clock-train or to correct the clock errors, are mere time signals, which are extensively distributed throughout the country by the ordinary telegraph wires, and are looked for at the various telegraph stations, in order to compare the office dials with Green- wich mean time, and to make the necessary correction ; they are also redistributed by hand the moment they appear, through sub-districts branching from junction stations. Large 5 ^ ELECTRICITY. 485 black balls, Moisted in conspicuous stations, are also dropped daily by electric currents in various places, for the general information of the public, or of the captains of ships. — C. V. w/ ELECTRICITY for Blasting in Mines and Quarries. Professor Hare was the first who entertiiined this idea, but Mr, Martin Roberts devised the following process : — In order not to hf called upon to make afresh a new apparatus for each explosion, Mr. Roberts invented carjtridges, which may be constructed beforehand. With this view, two copper wires are prpcured, about a tenth of an inch in diameter, and three yards in length, well covered with silk or cotton tarred, so that their insulation may be very good. They are twisted together (fg. 254) for a length of six inches, care being taken to leave their lower extremities free, lor a length of about half an inch, (separating them about half an inch,) from which the ; insulating envelope is removed, in order to stretch between them a fine iron wire, after hav- ing taken tlie precaution of cleaning them well. The upper extremities of the two copper ■ wires are likewise separated, in order to allow of their being placed respectively in commu- nication with the conductors, that abut upon the poles of a pile. The body of the car- j tridges is in a tin tube, three inches long and three-quarters of an inch in diameter, the 1 solderings of which are very well made, in order that it may be perfectly impermeable to I water. A glass tube might equally well be employed, were it not for its /ragility, which has I caused a tin tube to be preferred. The system of copper wires is introduced into the tube, ( fixing them by means of a stem that traverses it at such a height that the fine iron wire is 1 situated in the middle of the tin tube, so arranged that the ends of the copper wire do not j anywhere touch the sides of the tube, (fg. 255.) The cork is firmly fixed at the upper ' extremity of the tube with a good cement. Mr. Roberts recommends for this operation, a j cement composed of one part of beeswax and two parts of resin ; the tube is then filled with powder by its other extremity, which is likewise stopped with a cork, which is cement- 254 256 ed in the same manner. Fig. 256 indicates the manner in which the car- tridge is placed in the hole, after having carefully expelled all dust and moisture ; care must be taken that the cartridge is situated in the middle of the charge of powder that is introduced into the hole. Above the powder is placed a plug of straw or tow, so as to allow between it and the powder a small space filled with air ; and above the plug is poured dry sand, until the hole is filled with it. The two ends of the copper wires that come out of the cartridge are made to communicate with the poles of the pile, by means of conductors of sufficient length, that one may be protected from all dangers arising from the explosion of the mine. M. Ruhmkorff, and after him, M. Verdu, have successfully tried to substitute the induc- tion spark for the incandescence of a wire, in order to bring about the ignition of the pow- der. This process, besides the considerable economy that it presents — since, instead of from fifteen to twenty Bunsen’s pairs, necessary for causing the ignition of the wire, it requires but a single one for producing the induction spark — possesses the advantages of being less - 486 ELECTRIC LIGHT. susceptible of derangement. Only it was necessary to contrive a plan to br ing about the ignition of the powder ; in fact, it happens, that when by the effect of the It'ngth of the conductors that abut upon the mine, the circuit presents too great a resistance, the induc- tion spark is able to pass through the powder without inflaming it, M. Rubrnkorn'^has con- ceived the happy idea of seeking for a medium, which, more easily inflammable by the spark, may bring about the ignition of the powder in all possible conditions. He found it in Statham’s fusees, which are prepared by taking two ends of copper wire covered '^ith ordinary gutta percha ; they are twisted, {Jig, 257,) and the ends are bent so as to mhke them enter into an envelope of vulcanized (sulphured) guttapercha, which has been cut axud drawn off from a copper wire that had been for a long time covered with it. Upon this envelope a sloping cut, a, 6, is formed ; and after having maintained the extremities of tho copper wires at about the eighth of an inch from each other, their points are covered with fulminate of mercury, in order to render the ignition of the powder more easy. The cut is filled with powder, and the whole is wrapped round with a piece of caoutchouc tube, c, c?, or else it is placed in a cartridge filled with powder. In the Statham fusees, it is the sulphide (sulphuret) of copper adhering to the wire, pro- duced by the action of the vulcanized gutta percha which is removed from the copper wire that it covered, wljich, by being inflamed under the action of the induction spark, brings about an explosion. But it is necessary to take care when the fusee has been prepared, as we have pointed out, to try it in order to regulate the extent of the solution of continuity. It might, in fact, happen that while still belonging to the same envelope of a copper wire, the sheath of a vulcanized gutta percha with which the fusee is furnished, may be more or less impregnated with sulphide of copper ; now, if the sulphide of copper is in too great quantity, it becomes too good a conductor, and prevents the spark being produced ; if, on the contrary, it is not in a sufficiently large quantity, it does not sufficiently faciliate the discharge. The first trials on a large scale of the application of the process that we just described, were made with Ruhmkorff’s induction apparatus, by the Spanish colonel, Verdu, in the workshops of M. Herkman, manufacturer of gutta percha covered wire, at La Villette, near Paris. Experiments were made successively upon lengths of wire of 400, 600, 1,000, 5,000, and up to 26,000 metres, (of 3-28 feet ;) and the success was always complete, whether with a circuit composed of two wires, or replacing one of the wires by the earth ; two ordinary Bunsen’s pairs were sufficient for producing the induction spark with Ruhm- korff’s apparatus. Since his first researches with M. Ruhmkorff, M. Verdu has applied him- self to fresh researches in Spain ; and he was satisfied, by many trials, that of all explosive substances, not any one was nearly so sensitive as fulminate of mercury ; only, in order to avoid the danger that arises from the facility of explosion of this compound, he takes the precaution of introducing the extremity of the fusees into a small gutta percha tube, closed at the end. After having filled with powder this species of little box, and having closed it hermetically, the fusees may be carried about, may be handled, may be allowed to fall, and even squeezed rather hard, without danger. The elastic and leather-like nature of gutta percha, which has been carefully softened a little at the fire, preserves the fulminate from all chance of accident. We may add, that with a simple Bunsen’s pair, and by means of Ruhmkorff’s induction apparatus, M. Verdu has succeeded in producing the simultaneous explosion of six small mines, interposed in the same circuit at 320 yards from the appa- ratus. He has not been beyond this limit ; but he has sought for the means of acting indi- rectly upon a great number of mines, by distributing them into groups of five, and by interposing each of these groups in a special circuit. The fusees of each group are made to communicate by a single wire, one of the extremities of which is buried in the ground, and whose other extremity is near to the apparatus. On touching the induction apparatus ^ successively with each of the free ends that are held in the hand, which requires scarcely a second of time, if there are four wires, that is to say, four groups and consequently twenty mines, twenty explosions are obtained simultaneously at considerable distances. There are no limits either to the distance at which the explosion may take place, or to the number'of mines that may thus be made to explode. ELECTRIC LIGHT. Various attempts have been made, from time to time, to employ electricity as an illuminating power ; but hitherto without the desired success. The voltaic battery has been employed as the source of electricity, and in nearly all the arrangements, the beautiful arc of light produced between the poles, from the points of the hardest char- coal, has been the illuminating source. One of the great difficulties in applying this agent arises from the circumstance that there is a transference of the charcoal from one pole to the other, and consequently an alteration in the distance between them. This gives rise to considerable variations in the intensity and color of the light, and great want of steadiness. Various arrangements, many of them exceedingly ingenious, have been devised to over- come these difficulties. The most simple of the apparatus which has been devised is that of Mr. Staite, which has been modified by M. Archereau. Two metal columns or stems, to which any desired -ELECTRIC LIGHT. 487 form can hfe given, are connected together by three cross pieces, so as to form one solid frame ; op/e of these cross pieces is metallic ; it is the one which occupies the upper part of the apijparatus ; the others must be of wood. These latter serve as supports and points of attachipfent to a long bobbin placed parallel to the two columns and between them, and which must ^e made of tolerably thick wire, in order that the current, in traversing it without meMng it, may act upon a soft iron rod placed in the interior of the bobbin. This iron rod is fsoldered to a brass stem of the same calibre, and of the same length, carrying at its free esttremity a small pulley. On the opposite side the iron carries a small brass tube, with blinding screws, into which is introduced, one of the carbons, when the entire rod has been ■placed in the interior of the bobbin. Then a cord fixed to the lower cross piece, and roll- /ing over a pulley of large diameter, is able to serve as a support to the movable iron rod, running in the groove of the little pulley. For this purpose, it only requires that a coun- terpoise placed at the end of the cord shall be enabled to be in equilibrio with it. The metal cross piece which occupies the upper part of the apparatus, carries a small brass tube, which descends perpendicularly in front of the carbon that is carried by the electro-mag- netic stem, and into which is also introduced a carbon crayon. By means of a very simple adjustment, this tube may besides be easily regulated, both for its height and for its direc- tion ; and consequently the two carbons may be placed very exactly above one another. .The apparatus being adjusted, we place one of the two metal columns of the apparatus in connection with one of the poles of the pile, and cause the other pole to abut upon the cop- per wire of the bobbin, (one end of which is soldered upon its socket.) The current then passes from the bobbin to the lower carbon by the rod itself that supports it, and passing over the interval separating the two carbons, it arrives at the other pole of the pile by the upper cross piece of the apparatus and the metal column, to which one of the conducting wires is attached. So long as the current is passing and producing light, the bobbin reacts upon the iron of the electro-magnet rod, which carries the lower carbon and attracts it on account of the magnetic reaction that solenoids exercise over a movable iron in their interior. It is this which gives to the carbons a separation sufficient for the luminous effect. But immediately the current ceases to pass, or is weakened, in consequence of the con- sumption of the carbons, this attraction ceases, and the movable carbon, acted on by the counterpoise, is found to be drawn on and raised until the current passes again ; equilibrium is again established between the two forces, and the carbons may be employed again. Thus, in proportion as the light tends to decrease, the counterpoise reacts ; and this it is that always maintains the intensity of the light equal. M. Breton has an apparatus which differs somewhat from the above, and M. Foucault has also devised a very ingenious modification. M. Duboscq has made by far the most successful arrangement, for a description of which we are indebted to De la Rive's Treatise on Electricity., translated by C. V. Walker. The two carbons, between which the light is developed, burn in contact with the air, and shorten at each instant ; a mechanism is consequently necessary, which brings them near to each other, proportionally to the progress of the combustion ; and since the positive carbon suffers a more rapid combustion than the negative, it must travel more rapidly in face of this latter ; and this in a relation which varies with the thickness and the nature of the car- bon. The mechanism must satisfy all these exigencies. The two carbons are unceasingly solicited towards each other^ the lower carbon by a spiral spring, that causes it to rise, and the upper carbon by its weight, which causes it to descend. The same axis is common to them. The galvanic current is produced by a Bunsen’s pile of from 40 to 50 elements : it arrives at the two carbons, as in apparatus already known, passing through a hollow electro- magnet, concealed in the column of the instrument. When the two carbons are in contact, the circuit is closed, the electro-magnet attracts a soft iron, placed at the extremity of a lever, which is in gear with an endless screw. An antagonist spring tends always to unwind the screw as soon as a separation is produced between the two carbons ; if it is a little con- siderable, the current no longer passes, the action of the spring becomes predominant, the screw is unwound, and the carbons approach each other until, the current again commenc- ing to pass between the two carbons, the motion that drew them towards each other is relaxed in proportion to the return of the predominance of the electricity over the spring ; the combustion of the carbons again increases their distance, and with it the superior action of the spring ; hence follows again the predominance of the spring, and so on. These are alternatives of action and reaction, in which at one time the spring, at another time the electricity, has the predominance. On an axis, common to the two carbons, are two pul- leys : one, the diameter of which may be varied at pleasure, communicates by a cord with the rod that carries the lower carbon, which corresponds with the positive pole of the pile ; the other, of invariable diameter, is in connection with the upper or negative carbon. The diameter of the pulley, capable of varying proportionately to the using of the carbon, with which it is in communication, may be increased from three to five. The object of this arrangement is to preserve the luminous point at a convenient level, whatever may be the 488 ELECTRIC LIGHT. , thickness or the nature of the carbons. It is only necessary to know that, at iicach change of kind or volume of the carbon, the diameter of the pulley must be made to \tary. This variation results from that of a movable drum, communicating with six levers, articulated near the centre of the sphere ; the movable extremity of the six arms of the leve*” carries a small pin, which slides in cylindrical slits. These slits are oblique in respect of the sphere ; they form inclined planes. A spiral spring always rests upon the extremity of the levers ; so that, if the inclined planes are turned towards the right, the six levers btsnd m 258 towards the centre, and diminish the diameter. If, on the contrary, they are turned towards the left, the diameter increases, and with it the velocity of the translation of the carbon, which communicates with the pulley. We may notice, in passing, that this apparatus is marvellously adapted to the production of all the experiments of optics, even the most deli- cate ; and that, in this respect, it advantageously supplies the place of solar light. As it is quite impossible to describe accurately the minute arrangements of this instrument, the let- ters of reference have not been used in the text. ^ _ — 1 y ELECTEO-METALLURGY. 489 Dr. Richardson informs us, that although Mr. Grove calculated, some years ago, that for acid, zinc, ], as already fuescribed ; and rn, the other metal of the voltaic pair, is suspended in the copper solutidh and connected with the zinc z by the wire w. The electric current now passes ; zinc '^is consumed, as in jig. 259, but copper is now deposited on the metal m front and baqK, and on as much of the wire w as may be in the liquid ; or, if Mr. Spencer’s precau- tioh is taken of varnishing the wire and the back of the metal w, all the copper that is lib- erated will be accumulated on the face of m. If salt and water or very weak acid water is Contained in the porous tube jo, and the zinc z does not considerably exceed in size the metal m, the conditions will be complied with for depositing copper in a compact reguliue form. It is obvious that, with this arrangement, m may be a mould or other form in metal, and jthat a copy of it may be obtained in copper. Fusible metal, consisting of 8 parts of bis- f muth, 4 of tin, 5 of lead, and 1 of antimony ; or 8 parts bismuth, 3 tin, and 5 lead, is I much used for taking moulds of medals. The ingredients a»e well melted together and 1 mixed ; a quantity sufficient for the object in view is poured upon a slab or board and stirred ( together till about to set ; the film of dross is then quickly cleared from the surface with a I card, and the cold metal is either projected upon the bright metal, or being previously fitted in a block of wood, is applied with a sudden blow. Moulds of wax or stearine variously combined, or more recently and better in many cases, moulds of gutta percha, are applicable to many purposes. But, as none of these latter materials conduct electricity, it is necessary to provide them with a conducteous surface. Plumbago or black lead is almost universally i ‘ employed for this purpose ; it is rubbed over the surface of the mould with a piece of wool on a soft brush, care being taken to continue it as far as to the conducting wire, by which the mould is connected with the zinc. With moulds of solid metal, the deposit of copper commences throughout the entire surface at once ; but, with moulds having only a film of plumbago for a conductor, the action commences at the wire, and extends itself gradually until it has been developed on all parts of the surface. The nature of the electro-chemical decompositions that are due to the passage of voltaic currents through liquids, especially through liquids in which metal is in certain forms con- tained, can be best understood by studying the arrangement that is most commonly used in the arts, wherein the voltaic apparatus, from which the electric current is obtained, is dis- tinct and separate from the vessel in which the electro-metallurgical operations are being brought about. Such an arrangement is shown in Jig. 261, where a is a Daniell’s cell, as 261 * in j^g. 259 ; and b a trough filled with an acid solution of sulphate of copper; ttt is a metal rod, on which the moulds are hung ; and c a metal rod, upon which plates of copper are hung facing the moulds ; the copper-plates are connected by the wire s with the copper of the battery cell, and the moulds by the wire x with the zinc rod. The voltaic current is generated in the cell a, and its direction is from the zinc rod, through the solutions to the copper of the cell ; thence by the wire z to the plates of copper c ; through the sulphate solution to the moulds rn . ; and thence by the wire x to the zinc rod. In this arrangement, no shelf is necessary in the trough b for crystals of sulphate of copper to keep up the strength of the solution ; for the nature of the electro-chemical decompositions is such, that in proportion as copper is abstracted and deposited upon the moulds other copper is dissolved into the solution from the plates c. Water is the prime subject of decomposi- tion. It is a compound body, consisting of the gases oxygen and hydrogen, and may be represented by Jig. 262, where the arrows show the direction in which the current, by the wire /), enters the trough b of jig. 261 by the plate of copper c, and passes through the 492 ELECTRO-METALLURGY. water in the direction shown, and leaves it after traversing the mould by the wire n. Two alom8 of water o h and o' h', as bracketed 1 and 2, are shown to exist before the electric ^ current passes ; and two atoms, one of water h o', t^bracketed l " 1',) and one of oxide of copper o c, exist after the; action. On the one hand, an atom of copper c has come into the solution ; and, on the other hand, the atom of hydroge n h', belonging to the second atom of water, is set free and t-ises in the form of gas. The explanation is to show that oxygen is liberated where the current enters, and combines there in its nascent state with copper : it would not have combined, for instance, with gold or platinum. We might easily extend this symbolical figure, and show how that, when free sulphuric acid is in the solution, the; oxide of copper on its formation combines with this acid to produce the sulphate of copper- required ; and how, when free sulphate of copper is present, the hydrogen, instead of being freed in the form of gas, combines with oxygen of the oxide of copper, and liberates the metal which in its nascent »state is deposited on the mould, and produces the electrotype copy of the same. One battery cell is sufficient for working in this way in copper ; it is increased in size in proportion to the size of the object operated upon. And, although for small objects, such as medals, a vertical arrangement will act very well ; for large objects it has been often found of great advantage to adopt a horizontal arrangement, placing the mould beneath the copper-plate. The varying density of a still solution in the vertical arrange- ment is not without its effect upon the nature of the deposit, both on its character and its relative thickness. This has been in some instances obviated, and the advantage of the vertical method retained by keeping the solution in motion, either by stirring or by a con- tinuous flow of liquid. We have described principally Daniell’s battery as the generating cell in electro-metal- lurgical operations ; but Mr. Smee’s more simple arrangement of platinized silver and zinc, excited with diluted sulphuric acid, has been found in practice more economical and con- venient. Fig. 263 is a Smee’s cell ; a vessel of wood, glass, or earthenware contains diluted sul- phuric acid, one in eight or ten, a platinized silver plate s, sustained by a piece of wood w, with a plate of zinc z z on each side, so as to turn to useful account both sides of the silver plate. The zinc plates are connected by the binding screw b. Platinization consists in applying platinum in fine powder to the metallic surface. When hydrogen is liberated by ordinary electric action upon a surface so prepared, it has no tendency to adhere or cling to it ; but it at once rises, and in fact gets out of the way, so that it never, by its presence or lingering, interferes with the prompt and ready continuance of the electric action ; and in this way the amount of supply is well kept up. Platinization is itself another illustration of working in metal by electricity. A few crystals of chloride of platinum are dissolved in diluted sulphuric acid. A voltaic current is made to enter this solution by a plate of platinum, and to come out by a silver plate. Two or three Daniell’s or Smee’s cells are necessary for the operation. The chloride of platinum is decomposed, and the metal is deposited upon the silver plate ; not, however, in the reguline compact form, as in the case of copper, but in a state of black powder in no way coherent. This affords also an illustra- tion of the different behavior of metals under analogous circumstances. Copper is of all metals the most manageable ; platinum is among the more unmanageable. Mr. C. V. Walker has, with great advantage, substituted graphite for silver. The material is obtained from gas retorts, and is cut into plates a quarter of an inch thick, or thicker, when plates of a large size are cut. He platinizes these plates in the usual way as above described, and deposits copper on their upper parts, also by electrotype process, and solders a copper slip to the electrotype copper, in order to make the necessary connection. With the exception of silver and gold, copper is the metal which has been most exten- sively worked by these processes. Si-:als are copied by obtaining impressions in sealing-wax, pressing a warm wire into the edge for a connection ; rubbing black-lead over the wax to make the surface conducteous ; fiistening a slip of zinc to the other end of the wire ; wrapping the zinc in brown paper, and putting the whole into a tumbler containing sulphate of copper, a little salt-water hav- ing been poured into the brown paper cell. Plaster of Paris Medallions may be saturated with wax or stearine, and then treated, if small, like seals ; if large, in a distinct trough, as in Jig. 261. In this case the copy is in intaglio, and may be used as a mould for obtaining the fac-simile of the cast. More commonly, the cast is saturated with warm water, and a mould of it taken in wax, stearine, or gutta percha. This is treated with black-lead, and in other respects the same as seals. 1 ELECTRO-METALLURGY. 493 WooD-cua's are treated with black-lead, and a copper reverse is deposited upon them. This is used /as a mould to obtain electrotype duplicates, or as a die for striking off dupli- cates. ^ ' Stereotype Plates are obtained in copper by taking a plaster copy of the type, treat- ing it plaster fashion, depositing a thin plate of copper upon it, and giving strength by back^g up with melted lead. Qld Brasses may be copied by the intervention of plaster. Embossed cards or paper may be copied by first saturating with wax and then using bl^ck-lead. / Fruit may be copied by the intervention of moulds, or may be covered with copper. Leaves, twigs, and branches may have copper deposited upon them. The same for STATUETTES, BUSTS, and STATUES. ; Leaves and flowers are furnished with a conducting surface by dipping them into a solu- tion of phosphorus in bisulphuret of carbon, and then into a solution of nitrate of silver, ^ilver is thus released in a metallic state upon their surface. ; Plaster busts, &c., have been copied in copper, by first depositing copper on the plas- ter prepared for this operation ; when thick enough, the original bust is destroyed, the cop- per shell is filled with sulphate of copper, as in jig. 261, and copper is deposited on its inner surface till of sufficient thickness ; the outer shell is then removed. Tubes and vessels of capacity do not appear to have been profitably multiplied by elec- Itrotype. ' Plates have been prepared for the engraver to work on by depositing copper on pol- ished copper-plates, and removing the deposits when thick enough. 1 For the multiplication of engraved copper-plates, the electrotype process has been • very extensively adopted. A reverse of the plate is first obtained by the deposition of cop- ,'per ; this serves as a mould, from which many copies of the original plate are obtained by (depositing copper upon it, and then separating the two. The mode practised by the Duke of Leuchtenberg is to print from an engraved plate on very thin paper with a mixture of resin of Damara, red oxide of iron, and essence of turpentine. While the impression is wet, the paper face downwards is pressed upon a polished plate of eopper. When dry the paper is washed away, and the impression remains. An electrotype copy from this is ob- tained in intaglio, and is fit for the use of the printer. Galvanography is a picture drawn originally in varnish on the smooth plate, and then treated in a similar way to the above. The PLATES on rollers used by calico printers have been multiplied like engraved plates. Glyphography is a name given by Mr. Palmer to his process. He blackens a fair cop- per-plate with sulphuret of potassium, covering it uniformly with a coating of wax and other things, then draws the design through the wax with fine tools. From the plate thus prepared, an electrotype is taken in the usual way, and is backed up and mounted as an electro-glyphic cast to print from as from a wood block. For a stereo-glyphic cast to work from as a stereotype plate, a plaster copy is taken of the original drawing, the high lights are cut out, and then an electrotype copy is made. Electro -TINT is done by drawing with wax or varnish any design on a fair copper-plate, and making an electrotype copy for the printer’s use. Fern-leaves, &c,, are copied by being laid on a sheet of soft gutta percha, pressed into the surface by a smooth plate to which pressure is applied, and then removed in order to subject the gutta percha mould to the electrotype process. This is Nature Printing, which see. MM. Auer and Worring have copied lace, embroidery, flowers, leaves of trees, entire plants, fossils, insects, &c., in their natural relief, by laying the objects upon a plate of cop- per, after having soaked them in spirits of wine and turpentine so as to fix them. A plate of clean lead is laid over, and, on being pressed, an intaglio copy is produced on it of the object. From this an electrotype is obtained. Undercut medallions, &c., are copied in elastic moulds made of treacle and glue in the proportions of 1 to 4. Masks and busts may also be obtained in such moulds. Electro-cloth was made by saturating the fibre of canvas or felt, making it conducte- ous in the usual way ; it was proposed in place of tarpaulins as a water-tight cover. Retorts and crucibles, &c., of glass or porcelain, have been successfully coated with electrotype copper by first varnishing or otherwise preparing the surface to retain the black- lead, and then treating them as usual. Soldering copper surfaces has been accomplished by galvanic agency. The ends to be united are placed together in the solution of sulphate of copper, and connected with the battery as for ordinary deposition. Parts not included in the process are protected off by varnish ; copper is then deposited so as to unite the separate pieces into one. Iron may be coated with copper. But here a new feature comes into view. Sul- phuric acid leaves the copper of the sulphate, combines with iron, and deposits copper on i I- — 494 ELECTKO-METALLUKGY. ^ its surface without the aid of the voltaic apparatus. The iron surface is im^perfectly cov- ered with copper ; no firm perfect deposit occurs. In order to obtain solid depV'Osits of cop- per on iron, it is necessary to use a solution that has no ordinary chemical reati'jtion upon iron. Cyanide of copper is used, which may be obtained by dissolving sulphate o\,f copper in cyanide of potassium. This solution requires to be raised to and retained at a te^mpera- ture not greatly below 200°, in order to give good results. j Electro-zincing is applied to surfaces of iron, in order to protect them from corrol^ion. A solution is made of sulphate of zinc, which is placed in a trough b, fig. 261. Tw(^> or three battery cells are required. The iron to be zinced is connected with the zinc end jOf the battery, and a plate of zinc with the copper end. ' \ Voltaic brass does not appear to have been obtained in a solid distinct form, but ha'^s been successfully produced as a coating upon a copper surface. Separate solutions ane made of sulphate of copper and of sulphate of zinc in cyanide of potassium. The twc^ solutions are then mixed, and placed in a decomposing trough. Two or three cells of i\ battery are used, and a brass plate connected with the copper end. An electrotype copper' medal or other prepared surface is connected with the zinc. Brilliant and perfect brass, soon appears, and will deposit slowly for some hours ; but after a while the character of the solution changes, and copper appears in place of brass. This hasty glance at the leading applications of this art will give an idea of its utility. , It also comes into play in cases where least suspected. Pins were tinned by electrotype long before the art was known. Brass pins are thrown into solution of tin in cream of tartar, and are unchanged ; but when a lump of tin is thrown among them, a voltaic pair is formed, and tin is deposited on all the heap. Any stray pins detached from the mass, escape the influence. Space would fail us were we to go through the list of crystalline and of simple bodies formed by these processes ; as for instance, octahedral crystals of protoxide of cop- per ; tetrahedral crystals of proto-chloride of copper ; octahedral crystals of sulphide of silver ; crystals of subnitrate of copper ; bibasic carbonate of copper, and others too nu- merous to name, have all been formed by slow voltaic actions. The alkaline metals, potas- sium, sodium, &c., were first obtained by Davy in the galvanic way ; magnesium, barium, aluminium, calcium, &c., are obtained by M. Bunsen by operating upon the chlorides of these metals either in solution or in a state of fusion. Electro-etching is produced at the place where the current enters the decomposing trough, as at the copper-plates c of fig. 261. A plate of copper is prepared as if for the graver ; its face is then covered with an etching ground of asphalte, wax, black pitch, and Burgundy pitch ; and its back with varnish. The design is then traced through the etching ground with a fine point ; the plate is then placed in the trough b, containing either sul- phate of copper or simply diluted sulphuric acid, and connected with the copper of the battery. After a few minutes it is removed, and the fine lines are stopped out with var- nish ; it is then replaced, and again, after a few minutes, is removed, and the darker shades are stopped out ; the parts still exposed are again subjected to the action, and the etching is complete. When the ground is removed, the design will be found etched upon the cop- per-plate, ready for the printer. Daguerreotype etching is a delicate operation, and requires much care. The solution employed by Professor Grove was hydrochloric acid and water in equal parts, and a battery of two or three cells. Platinized silver is used in face of the daguerreotype, instead of copper. The result comes out in about half a minute. An oxychloride of silver is formed, and the mercury of the plate remains untouched. A Photo-galvano-graphic Company has been formed in London for carrying out the process of Paul Pretsch. He makes solutions of bichromate of potash in glue water, or in solution of gelatine, instead of in pure water. He then treats the glass or plate with these, and in the usual way takes a picture. He washes the gelatine picture with water, or solu- tion of borax or carbonate of soda, which leaves the picture in relief ; when developed, he washes with spirits of wine, and obtains a sunk design. The surfaces thus prepared, or moulds made from them in one or other of the modes already described, are placed in a galvano-plastic apparatus for obtaining an engraved plate from which to print. See Photo- graphic Engraving. The Duke of Leuchtenberg prepares a plate for etching by leaving the design on the ground, and removing the ground for the blank parts. When his electrotype operation is complete, the design is in relief instead of being in intaglio, as in ordinary etching. Metallo-chromes consist of thin films of oxide of lead, deposited sometimes on pol- ished plates of platinum, but most commonly on polished steel plates. The colors are most brilliant and varied. Nobili is the author of the process. A saturated solution of acetate of lead is prepared and placed in a horizontal trough. Three or four battery cells are required. A steel plate is laid in the acetate of lead with its polished surface upward, and is connected with the copper of the battery. If a wire is con- nected with the zinc end of the battery, and held over the steel plate in the solution, a ELECTKO-METALLUEGY. 496 series of circles in brilliant colors arises from the spot immediately beneath the wire, and expands and/spreads, like the circles when a stone is thrown into a pond. Silver-blond is the first color*; then fawn-color, followed by the various shades of violet, and indigoes and blues ; laie, bluish lake, green and orange, greenish violet, and passing through reddish yellow to rose-lake, which is the last color in the series. A/3Cording to the shape of the metal by which the current enters — be it a point, a slip, a cross, a concave, or a convex disc — so is the form of the colored figure varied. And if, in ^ddition to this, a pattern in card or gutta percha is cut out and interposed between the two surfaces, the action is intercepted by the portions not removed, and the design is pro- duced on the steel plate, in colors, that may be greatly varied, according to the duration of tjie experiment. The different colors are due to the different thicknesses of the thin films f the pairs of plates in the voltaic pile, which permits us to increase the speed of rotation at will. We know the magnetic power of the current is not sensibly augmented by increas- ling the number of the pairs of plates, but the counter current is considerably weakened by its being forced to pass through a great many layers of liquid. In fact, on using twelve voltaic pairs, each half a square foot, instead of four copper troughs, each with a surface two square feet, which I had hitherto used, the speed of rotation rose at least 250 or 300 revolutions in a minute.” Mechanical force, whether obtained in the form of man-power, horse-power, steam-power, or electrical-power, is the result of a change of form in matter. In the animal, it is the result of muscular and nervous energy, which is maintained by the due supply of food to the stomach. In the steam-engine, it is the result of vapor pressure, which is kept up by the constant addition of fuel to the fires under the boilers. In the magnetic machine, it is the result of currents circulating through wires, and these currents are directly dependent upon the chemical change of zinc or of some other metal in the battery. Then, Animal power depends on food. * Steam power depends on coal. Electrical power depends on zinc. An equivalent of coal is consumed in the furnace — that is, it unites its carbon with oxygen to form carbonic acid, and its hydrogen with oxygen to form water, and during this change of state the quantity of heat developed has a constant relation to the chemical action going on. ' Mr. Joule has proved by a series of most satisfactory experiments, that “ the quantity of heat capable of increasing the temperature of a pound o-f water by one degree of Fahren- heit’s scale is equal to, and may be converted into, a mechanical force capable of raising 838 lbs. to the perpendicular height of one foot.'” Mr. J. Scott Russell has shown that in the Cornish boilers, at Huel Towan and the United Mines, the combustion of one pound of Welsh coal evaporates of water, from its initial temperature, 10'58° and 10-48'’ respectively. “ But,” says Mr. Joule, “ we have shown that one degree is equal to 838 lbs. raised to the height of one foot. Therefore the heat evolved by the combustion of one pound of coal is equivalent to the mechanical force capable of raising 9,584,206 lbs. to the height of one foot, or to about ten times the duty of the best Cornish engines.” Such are the conditions under which heat is employed as a motive power. An equiva- lent of zinc is acted on by the acid in the cells of the battery, and is oxidized thereby. In this process of oxidation a given quantity of electricity is set in motion ; but the quantity available for use, falls very far below the whole amount developed by the oxidation of the zinc. The electricity, or electrical disturbance, is generated on the surface of the zinc ; it passes through the acidulated fluid to the copper plate or platinum plate, and in thus pass- ing from one medium to another, it has to overcome certain mechanical resistances, and thus a portion of the force is lost. This takes place in every cell of the voltaic arrange- ment, and consequently the proportion of zinc which is consumed, to produce any final mechanical result, is considerably greater than it should be theoretically. J oule gives as the results of his experiments, the mechanical force of the current pro- duced in a Daniell’s battery as equal to 1,106,160 lbs. raised one foot high, per pound of zinc, and that produced in a Grove’s battery as equal to 1,843,600 lbs. raised one foot high, per pound of zinc. VoL. III.— 32 498 • ELECTRO-PLATING AND GILDING. It need scarcely be stated, that this is infinitely above what can be practi’cally obtained. A great number of experiments, made by the Author some years since, enab?^ed him to de- termine, as the mean average result of the currents produced by several formas of battery power, that one grain of zinc, consumed in the battery, would exert a force equai\ to lifting 86 lbs. one foot high. Mr. Joule and Dr. Scoresby thus sum up a series of expeirimental results : “ Upon the whole, we feel ourselves justified in fixing the maximum available duty of an electro-magnetic engine, worked by a Daniell’s battery, at 80 lbs. raised a fooi^ high, for each grain of zinc consumed.” This is about one-half the theoretical maximum ^duty. In the Cornish engines, doing the best duty, one grain of coal raised 143 lbs. one foot ihigh. The difference in the cost of zinc and coal need scarcely be remarked on. The present price of the metal is £35 per ton, and coal can be obtained, including carriage to the len- gines, at less than £1 per ton; and the carbon element does two-thirds more work than can possibly be obtained from the metallic one. By improving the battery arrangements, operators may eventually succeed in getting’ a greater available electrical force. But it must not be forgotten, that the development of any physical force observes a constant law. Whether in burning coal in the furnace, or zinc or iron in the battery, the chemical equivalent represents the theoretical mechanical power. Therefore the atomic weight of the carbon atom being 6, and that of the zinc atom being 32, it is not practicable, under the best possible arrangements, to obtain any thing like the same mechanical power from zinc which can be obtained from coal. Zinc burns at an elevated temperature ; in burning a pound of zinc there should be obtained, as heat, the same amount of mechanical power which is obtained as electricity in the battery. The heat being more easily applied as a prime mover, it would be far more economical to burn zinc under a boiler, and to use it for generating steam-power, than to consume zinc in a voltaic battery for generating electro-magnetical power. ELECTRO-PLATING AND GILDING IRON. Professor Wood, of Springfield, Mass., in a paper which he has communicated to the Scientific American^ recommends the follow- ing as useful recipes for the electro-metallurgist. He says : “ I iDclieve it is the first time that a solution for plating direct on iron, steel, or Britannia metal, has been published. In most of the experiments I have used Smee’s battery ; but for depositing brass I prefer a battery fitted up as Grove’s, using artificial graphite — obtained from the inside of broken coal-gas retorts — in the place of platinum. With one large cell, (the zinc cylinder being 8x3 inches, and excited with a mixture of one part sulphuric acid and twelve parts water, the graphite being excited with commercial nitric acid,) I have plated six gross of polished iron buckles per hour with brass. I have also coated type and stereotype plates with brass, and* find it more durable than copper-facing.” To Prepare Cyanide of Silver. — 1. Dissolve 1 oz. of pure silver in 2 oz. of nitric acid and 2 o?. of hot water, after which add 1 quart of hot water. 2. Dissolve 5 oz. of the cyanide of potassium in 1 quart of water. To the first preparation add by degrees a small portion of the second preparation, until the whole of the silver is precipitated, which may be known by stirring the mixture and allowing it to settle. Then drop into the clear liquid a very small quantity of the second preparation from the end of a glass rod ; if the clear liquid is rendered turbid, it is a proof that the whole of the silver is not separated ; if, on the other hand, the liquid is not altered, it is a proof that the silver is separated. The clear liquid is now to be poured off, and the precipitate, which is the cyanide of silver, washed at least four times in hot water. The precipitate may now be dried and bottled for use. To Prepare Cyanide of Gold. — Dissolve 1 oz. of fine gold in 1’4 oz. of nitric acid and 2 oz. of muriatic acid ; after it is dissolved, add 1 quart of hot water, and precipitate with the second preparation, proceeding the same as for the cyanide of silver. To Prepare Cyan- ides of Copper and Zinc. — For copper, dissolve 1 oz. of sulphate of copper in 1 pint of hot water. For zinc, dissolve 1 oz. of the sulphate of zinc in 1 pint of hot water, and proceed the same as for cyanide of silver. The electro-plater, to insure success in plating upon all metals and metallic alloys, must have two solutions of silver ; the first to whiten or fix the silver to such metals as iron, steel, Britannia metal, and German silver; the second to finish the work, as any amount of silver can be deposited in a reguline state from the second solu- tion. First, or Whitening Solution. — Dissolve 2| lbs. (troy) of cyanide of potassium, 8 oz. carbonate of soda, and 5 oz. cyanide of silver in one gallon of rain or distilled water. This solution should be used with a compound battery, of three to ten pairs, according to the size of the work to be plated. Second, or Finishing Solution. — Dissolve 4^ oz. (troy) of cyanide of potassium, and 1^ oz. of cyanide of silver, in 1 gallon of rain or distilled water. This solution should be used with one large cell of Smee’s battery, observing that the silver plate is placed as near the surface of the articles to be plated as possible. — N. B. By using the first, or whitening solution, you may insure the adhesion of silver to all kinds of brass, bronze, red cock metal, type metal, &c., without the use of mercury, which is so injurious to the human system. To Prepare a Solution of Gold. — Dissolve 4 oz. (troy) of cyanide of potassium, and 1 oz. of cyanide of gold, in 1 gallon of rain or dis- tilled water. This solution is to be used warm, (about 90" Fahr.,) with a battery of at least 1 ^ -/5 / ELECTRO-TELEGRAPHY. 499 two cells. G®ld can be deposited of various shades to suit the artist, by adding to the solu- tion of gold; 4 small quantity of the cyanides of silver, copper, or zinc, and a few drops of the hydro-slulphuret of ammonia. ELECTRO-SORTING APPARATUS. M. Frornent has devised an apparatus for the separation of iron from matters by which it may be accompanied. The apparatus consists of a Wheel carrying on its circumference eighteen electro-magnets. The iron ore reduced and jiulverized is spread continually upon one of the extremities of a cloth drawn along with it, and passed under the electro-magnets in motion. The iron in the ore, which has of course been brought into a magnetic state by any of the processes by which this may be effected, is separated by the magnets, and the impurities carried onward. See De la Rive's Electricity. I ELECTRO-TELEGRAPHY. It would far exceed our limits were we to attempt the most hurried sketch of the history of this art ; we shall therefore content ourselves with illustrating the leading doctrines that have been realized in the telegraph systems which are most in favor at the time in which we write. : Locked up, as it were, in all bodies, is a large store of electric force, the equilibrium of Which is disturbed in a greater or less degree by a variety of causes, some extremely simple, dthers more complex ; and, according as one or other cause is in operation, the conditions lender which the electric force is manifested vary ; some conditions being very unfavorable, a^d others very favorable to the object in view. Friction is a well-known means of producing electric effects. Amber (in Greek, elec- tron) was the first substance on which they were noticed in a special manner, and hence the name. Light bodies, such as gold leaf, or feathers, are attracted by rubbed amber ; the leaf gold is quickly repelled, again, the feathers not so readily. In due course it was dis- covered that this difference of behavior is due to the gold conducting electricity, and the feathers not so ; the one allowing the force to diffuse itself about it, the other receiving and retaining it only in or near the points of contact ; if the former property were universal, it would be impossible to collect electricity ; if the latter, it would be impossible to get rid of it. Conduction is well illustrated and turned to useful account in the iron and copper wires, by which distant telegraph stations are connected with each other ; insidation., by the glass or porcelain articles with which the said conducting wires are suspended to the poles above ground, and by the gutta percha with which the subterranean or submarine wires are covered. The rapidity with which electric force traverses conductors depends upon the circum- stances under which the conductors are placed ; in one case, as in that of wire suspended in the air, the electric force has little else to do than to travel onward and be discharged from the far end of the wire ; in the other case, as in that of buried wire, it has to disturb the electric equilibrium of the gutta percha as it travels onward, and thus suffers consid- erable retardation. The greatest recorded velocity of a signal through a suspended copper telegraph wire, is 1,752,800 miles per second, by M. Hipp ; the lowest velocity through a buried copper wire, 750 miles per second by Faraday. Intermediate velocities are recorded, for which the nature of the wire or the conditions under which it was placed were different. Wheatstone found the velocity of electricity under different conditions from the above to be 288,000 miles per second. His wire was copper, and was wound on a frame. The elec- tricity that was employed by Mr. Wheatstone in these experiments was obtained from the friction of glass against an amalgam of tin. The various velocities are due partly to the conditions under which the conducting wire is placed, and partly, no doubt, to the varied properties of electricity from various sources. And the very different methods of reading off the velocities in this and in other cases may have an influence over the respective values. Electricity is obtained from other sources than friction with so much greater facility, and in forms so much more applicable and manageable for telegraphic purposes, that frictional electricity has not been applied in real practice. It must not, however, be passed over in this place, because one of the earliest telegraphs, perhaps the very first in which a long length of wire was actually used, was actuated by this form of electricity. In 1816, Mr, Ronalds estab- lished, in the grounds attached to his residence at Hammersmith, eight miles of wire sus- pended by silk to dry wood, besides 175 yards of buried wire in glass tubes embedded in pitch and enclosed in troughs of wood. He obtained his electricity from a common elec- trical machine, and his signals from the motion of light bodies, balls of elder pith, produced under circumstances analogous to those to which we have already referred. At the far end of his telegraph wire two pith balls were suspended close together. Electricity applied at the home end of the wire at once diffused itself throughout the conducting system, includ- ing the pair of light balls. Just as we have seen gold leaf recede after having approached rubbed amber, and acquired an electric charge, so the pith balls, each being charged with electricity, derived from the same source, recede from each other ; and this in obedience to the fundamental laws of static electricity, for which we must refer readers to treatises on the subject. Here, then, we have one solitary signal. The manner in which Mr. Ronalds 4 "■ -.I . ._rr.n-a _ . ^ 500 ELEOTPwO-TELEGRAPHY. turned it into language was ingenious. He pressed time into his service, and by combining time and motion he obtained a language. He provided a clock movement at^each station ; the clocks were so regulated as to be synchronous in their movements ; each c?)f them car- ried, in lieu of a hand, a light disc, having the letters of the alphabet and othef\ signals en- graved on it. The disc was hidden by a screen, in which was one opening. It lif obvious that if the clocks were started together, and had uniform rates, the same letter at tfiie same time would be visible through the opening in each screen ; and letter by letter woui’d pass seriatim and simultaneously before the respective openings. If absolute uniformity is; diffi- cult for long periods, it is practicable for shorter. The sender of a message watched the opening of his screen ; the moment the letter approached that he desired to telegraph;, he charged the wire with electricity, and the balls at the far station moved ; the letter then visible there corresponded with the one at the home station, and was read off. The sender watched till the next letter he required came round, and so on. Let us now pass on to some of the leading features of electro-telegraphy, as it has been realized of late years, and to a description of some of the telegraph instruments that are most in use. Chemical action is the most fertile source of electricity. If a silver fork and a steel knife are connected together by a piece of wire, and the fork is thrust into a piece of meat, say a hot mutton chop, the moment an incision is made in the meat with the knife, elec- tricity will pass along the wire, and continue to do so while the above disposition of things remains. Upon the proper test being applied, the electricity is readily detected. This is the current form of electricity. The amount of force in circulation in this particular com- bination is not very great, and its power of travelling to a distance is not very high, but still it is quite capable of producing good signals, on a delicate arrangement of the needle instrument, (of which more hereafter,) with which in England we are so familiar. The amount of electricity obtained by means of chemical action, is increased to the required extent by a judicious selection of metals, and of the liquid or liquids in which they are immersed. Zinc is invariably used as one of the metals ; it is represented by the iron of the knife in the above experiment. Copper, silver, and platinum or graphite, (gas car- bon,) is selected for the other metal. When the two metals are immersed in a same liquid, a mixture of sulphuric acid with salt-water, or fresh, is employed. When two liquids are used, they are separated by a porous partition ; the zinc is usually placed in the sulphuric acid solution, and the other metal in a solution varying with the nature of the arrangements proposed. Zinc is naturally soluble in the acid solution in question ; and would therefore waste away and be consumed at the expense also of the acid, unless precautions were taken to make it resist the ordinary action of the solvent. When zinc is dissolved in mercury it is not attacked, under ordinary circumstances, by sulphuric acid solution. Hence the plates of zinc employed in all good voltaic combinations, as they are called, into which this acid, in a free state, enters, are protected by being well amalgamated ; that is, they are dipped in a strong acid mixture and well washed ; and are then dipped into a mercury bath, and are placed aside to drain. The operation is generally repeated a second time ; and, in the best arrangements, the further precaution is taken of standing the zinc plate, while in the acid water, in some loose mercury, placed either in the bottom of the' containing vessel, or in a gutta percha cell : by the latter arrangement, mercury is economized. In single liquid arrangements, it is desirable to select a metal that is not attacked by the acid. Copper has been extensively used, and is very valuable ; but it possesses the defect of being slowly attackable. The waste, however, that it suffers in itself from this cause, is of small mo- ment compared with certain secondary results, which terminate in the consumption of the acid and the zinc, and the destruction of the functions of the apparatus. Gold and platinum are free from these defects, but are too costly. Silver is to a great extent free from them, and has been much and successfully used, especially when platinized ; that is, having its surface covered with finely divided powder of platinum. The corrosion from gas retorts, cut into plates, and similarly treated, forms with amalgamated zinc one of the cheapest and most effective combinations. A single pair of plates, no matter what their character, is unable to produce a force that can overcome the resistance of a wire of any length, and produce an available result at a distant station ; and hence a series of pairs is employed in the telegraphic arrangements. E { fig. 268) represents a common mode of arranging a series of pairs of plates. It con- sists of a wooden trough made water-tight, and divided into water-tight cells. The metals are eonnected in pairs by copper bands ; each pair is placed astride over a partition, and all the zincs face one way. "When the plates (copper-zinc) are placed in, and the cells are filled up with pure white sand, and the acid water poured in, we have the very portable battery that was originally used by Mr. Cooke, and is still much employed in England. "When bat- teries of a higher class are employed, the cells are distinct pots or jars ; and great precau- tions are taken to prevent any conducting communication existing between the neighboring cells, save by means of the copper band. In the trough form there is a leakage and loss of force from cell to cell. The c or copper is the positive end of such a series, and the z ELECTRO-TELEGRAPHY. 501 or zinc, the neg^ative ; and both are in a condition to discharge, either each to the other, by means of a wjire led from one to the other, or each to the earth, one by a wire leading to the earth at/tlie place where the battery stands, and the other by a long wire (say a tele- graph wirey leading to the earth at a distant place. The resistance to be overcome is, in the fornver case, less ; and the current of force in circulation is proportionately greater. Under Whatever circumstances a wire takes part in promoting the discharge of an apparatus of thi^ kind, the whole of the said wire is in a condition to indicate the presence of the force I that is pervading it ; and as the force may be presented to the wire in either of two directions, that is to say, the copper or , the zinc, namely, the positive or the negative end of fthe battery, may be pre- sented to the given end of the telegraph wire, the rela- tive condition of the wire wiU be modified according- ly./ Not only can the direc- tion of this current force be inverted at pleasure, but it can be maintained for any length of time, great or small, and in either direc- tion. This is accomplished by various mechanical ar- rangements, which are the keys, commutators, or han- dles of the various telegraph instruments, (of which more hereafter,) and are often the only part presenting any complexity about them. In jig. 268, the source of elec- tricity, E, we have already described ; the test-instru- ment for the abnormal state of the wire, that is to say, the telegraph proper, is the part A. The complex part, consisting of springs, cylin- ders, and studs, shown be- low A, is nothing more than the necessary mechanical arrangement for directing at pleasure the current from the bat- tery E, in either direction through the wire, and through the part a. By following the let- ters in the order here given, the course of the current may be traced from its leaving, say the positive or copper end of the battery, till its return to the zinc or negative end ; c c' n w u A z' 6 B z. If a companion instrument were in any part of the circuit of the wire w w, it would correspond in its signals with the home instrument, fig. 268. One of the properties possessed by a wire, during the act of discharging a voltaic bat- tery, is to deflect a magnetized needle. If the two are parallel in the normal state of the wire, the needle is deflected this way or that, when the wire is in the abnormal state ; and if the needle is very delicate, and a large enough amount of electricity is circulating through the wire, the needle reaches the maximum deflection of 90°. This is an extreme case, and cannot be approached in practice. Indeed, the deflection of any ordinary needle, under the action of an ordinary telegraph wire, would not be appreciable. But, as every foot of the M wire has the same amount of reaction, we have merely so to arrange things that many feet — a long length of the wire — shall be made to react upon the needle at the same time, and thus the efect is multiplied in proportion to the length of wire so concentrated. Tliis is managed by covering a considerable quantity of fine wire with silk or cotton, and winding it on a frame a, {jig. 268,) suspending the needle within the frame. Such an instrument is called, from its properties, a multiplier. It is seen at a glance that the wire of the multi- plier is an addition over and above the length of the actual telegraph wire required for reaching the distant station, and thus it practically increases the distance to be 'traversed : its smallness adds to this. The multipliers commonly used add a resistance equal to six or seven miles of telegraph wire. I 'III'’ 268 i 502 ELECTRO-TELEGKAPHY. Let us now turn to the face of the instrument. Here we have a dial^ and an index, which is on the same axis as the magnetized needle above described, capable’ of being de- flected to the right or left, and limited in its motion by ivory pins. We have a handle 269 ' for working the mechanical part so con- nected that, as it moves to the right, it directs a current into the wire such that the needle moves to the right, and vice versa. An alphabet is constructed from the combination of these two elementary motions, one or more of either or both kinds of deflection being used for the va- rious letters, as shown on the engraved dial. This is Cooke and Wheatstone’s sin- gle needle instrument, fig. 269. The form and character of their double needle instrument is shown in fig. 270. It is precisely a duplicate of the former ; two handles, and their respective springs, studs, and cylinders, two multipliers, and two magnetized needles, with their external in- dexes, and two telegraph wires. One bat- tery, however, is sufficient. One or more of either or both kinds of deflection of either or both needles, according to the code engraved on the dial, constitutes the alphabet. This instrument is very exten- sively employed ; messages are sent by it with extreme rapidity. Another property possessed by a wire conveying a current, is that of converting i / ELECTRO-TELEGRAPHY. 503 soft iron, for tSie time, into a magnet. The attractive power, which can thus be given to, and withdrawn from, the soft iron at pleasure, is turned to useful account, either in produc- ing direct ipechanical action, or in liberating the detents of a clock movement. Here also the effect -of the solitary wire is inappreciable, and many convolutions around the iron are iiecessay-y in order to obtain a useful result. simplest application of this principle is shown in fig. 271. Here are two brass reels, /filled with cotton-covered copper wire, in one length. They are hollow, and a U- shaped bar of iron passes through them, presenting its ends at the 271 face turned toward us in the draw- ing. This bar becomes magnetic — forms what is called an electro- magnet — every time and as long as an electrical current circulates ir^ the wire ; and its ends be- come respectively north and south proles. A narrow plate of iron, a^ armature., as it is termed, is mounted on pivots in front of the ends or poles of the magnet ; it mrries a vertical stem upon which tihe hammer is fixed. Every time the iron bar is magnetic the arma- ture is attracted, and the hammer strikes the bell. The spring or contact-maker for introducing the current of electricity into the cir- cuit, is shown in front on the right-hand side. This is Mr. Walker’s bell for signalling railway trains from station to sta- tion. The language consists of one or more blows. One, two, and three blows, are the signals for common purposes ; half a dozen blows is the limit. The acknowledgment of a signal is its repetition. By a simple arrangement of an index, that moves in fellowship with the hammer, the eye, as well as the ear, may read the bell-signals. Fig. 272 shows another application of the direct action of an electro-magnet in produc- ing telegraph signals. It is Morse’s printing telegraph, very generally used in America, and used to no small extent in Europe. The coils of wire are shown at m, the armature at ii, fixed at one end of the lever jt), which is itself carried on centres at c. The range of mo- tion here is small in order to produce rapid utterance ; it is regulated by the screws d and i. The reaction of the spiral spring fi restores the lever to its normal position each time the magnetism ceases. The signals consist of dots or dashes, variously combined, made by the pointed screw t upon the slip of paper p, running from the drum at the right in the direc- tion of the arrows ; a few such signals are shown upon the end of the paper slip. We have described the telegraph proper, which is seen to be extremely simple. The only parts at all complex are, as with the needle instruments already described, the mechanical parts, namely, the train of wheels for carrying on the paper band, and the key or contact-maker, not shown in the figure. The amount of pressure required from the point t in order to J, 504 ELECTRO-TELEGRAPHY. produce a mark, is such that it cannot conveniently be produced by the magn etic attraction derived from a current of electricity that has come from a far distant statioriV in order to circulate in the coils of wire m. This difficulty does not prevail in the signiid-bells, fg. 2V1, which are, at most, not required to be more than eight or ten miles apart, ano\in which also momentum can be and is accumulated so as to conspire in producing the finaJ result. Morse has, therefore, had recourse to a rdag^ as he calls it. This, in principle, is pretty much the same thing as the instrument itself; but it has no heavy work to do, no max”ks to make ; it has merely to act the part of a contact-maker or key ; it can hence be made very delicate, so as to act weU by such currents as would not produce any motion in the in^^tru- ment itself. The batteries which furnish the electricity for doing the actual printing work in Morse’s telegraph, are in the same station with the instrument itself. The office of t\ie relay is to receive the signals from afar, and to make the necessary connections with the local battery and instrument so as to print off the signals on the paper in the usual way. It is obvious that the motions of the instrument and the relay are sympathetic, and that what a trained eye can read off from the one, a trained ear can read off from the othe r. The relays are constructed with much finer wire than is required for the instrument itsel f, so that the current circulating in them, although very low in force, is multiplied by a very high number, and becomes equal to the delicate duty required of it. Fig. 2V3 is another illustration of the direct application of the electro-magnet without adventitious aid. It represents a detent of McCallum’s Globotype for recording signals. The long tube contains small glass balls, which are retained therein by a detent attached to the armature of an electro-magnet. Every time the armature is attracted, one ball is liber- ated and runs down into a grooved dial, where it remains for inspection. One or more tubes and detents are used, according to the nature of the signal required. As applied to the signal-bell, (j%. 271,) three tubes are used — one charged with black balls, for indicating the number of bell strokes made ; one with white balls, for indicating the bell-signals sent ; one with spotted balls, for marking off the time in quar- ters of hours or intervals of less length. The balls, when liberated, all run into the same dial, and arrange them- selves seriatim. We may here refer to the case of another bell or alarum, in which the magnetic attraction derived from the current that arrives, is not equal to the mechanical work of striking a blow and sounding a bell, but which is able to raise a detent, that had restrained a train of wheels, and so allow the mechanism of the latter to do the work required. This arrangement is shown in Cooke and Wheat- stone’s alarum, fig. 274 ; t is the bell ; m m is the double- headed hammer, which is in fact the pendulum, attached to the pallets /, which work in a scape-wheel hidden in the figure, and in gear in the usual way with a coiled spring in the box b, by the train r 4 , ri, rs, r^. The electro-mag- netic part here, as in other instruments, is simple enough ; a 0 is a lever moving on a centre above /, having at one end an armature «, facing the poles of the electro-magnet e ; and at the other end c, a hook which faces the wheel r, and by catching in a notch on its circumference, keeps the train at rest. But when a current circulates through the coils «, the armature is attracted, the hook is raised, the train is liberated, and the pendulum-hammer vibrates and strikes a succession of blows, r is a support carrying a small spring, which reacts on the lever, and restores it to its normal position when the magnetism ceases. This alarum is used for calling the attention of telegraph clerks. It requires a little attention to keep up the proper adjustment between the spring on the one hand, and the magnetic attraction on the other. ELECTEO-TELEGRAPHY. t ( 505 The telegraph originally adopted and still largely used by the French Administration, is somewhat ajKin to the alarum just described. It has a train of wheels, a scape-wheel with four teeth, ^aiid a pair of pallets. There is, however, no pendulum ; but the pallets are con- nected wKh the armature of an electro-magnet, in such a manner that, for each attraction or repij/’ision of the armature, the scape-wheel is liberated half a tooth ; for an attraction and a, repulsion, a whole tooth ; so that four successive currents, producing of course four cons^Ajutive attractions and repulsions, produce a whole revolution of the scape-wheel. The axis iof the latter projects through the dial of the instrument, {fig. 2V5,) and carries an arm I 275 a or 6, {fig. 276,) which, following the motion of the wheel, is able to assume eight distinct positions. The apparatus is generally double, as shown in the figure ; and the signals are made up of the various combinations of the eight positions of each of the two arms. The arm is half black, the other half white. The position of the black portion is read off; the white portion is merely a counterpoise. When only one half of the dial, or one index, is in use, the combinations are shown by producing with the one index successively the posi- tions of the two, whose combination makes the signal, always giving first the position of the left hand index, then that of the right. The handles shown in front are the contact- makers, and are so constructed that the position of the arm on the dial coincides with the position given to the handle. Fig. 276 is a front view of the two arms ; part of the dial is supposed to be removed, so as to ex- pose the four-toothed wheel already men- tioned,, and the pallets x and z\ which, in their movement to and fro, allow of the semi-tooth advances of the wheel. In these various applications of the elec- tro-magnet, the armature has been of soft iron, and the only action of the electro-mag- net has been to attract it. It has been withdrawn from the magnet after the elec- tricity has ceased to circulate, either by its own gravity, by a counterpoise, or by a reacting spring. We now come to a telegraph that is well known and much used — Henley’s mag- neto-electric telegraph, in which there is no reacting spring ; and in which the movement or signal is produced by the joint action of attraction and repulsion, and the return to its normal state by the same joint action. Each pole of Henley’s electro-magnet has a double instead of the single termination, that we have been considering in all preceding cases. A piece of soft iron, like a crescent, is screwed upon each of the poles ; the horns or cusps of the respective crescents are facing and near to each other ; and a magnetized steel needle is balanced between them. This arrangement is somewhat like the following ( ] ). So long as no current is circulating in the coils of the electi'o-magnet, the crescents are impas- sive soft iron, and no one point of either of them has more tendency than any other point to attract either end of the magnetized needle that is between them. But while a current is circulating, one of the crescents is endowed with north magnetic polarity, which is espe- cially developed at its horns, and the other with south polarity. Suppose the horns of the 276 506 ELEOTEO-TELEGRAPHY. right-hand crescent are north poles, those of the left south poles, and the tt^p end of the needle is north. Four forces will conspire to move the needle to the left. ItL’ top will be attracted by the left-hand crescent and repelled by the right ; its bottom will be iVepelled by the left, and attracted by the right. When this current ceases to circulate, tl/.e simple attraction between the magnetized needle and the solt iron of the crescent tends ti'> retain it in a deflected position. This tendency is increased by a little residual magnetism, tdiat is apt to remain in the best iron, notwithstanding every care in its preparation. In o”rder, therefore, to restore the needle to its normal position, a short quick current in the re\^erse direction is given. These instruments are single or double. Only one kind of deflec^tion of the needle is available for actual signals, the other motion being merely the return to t’he normal state. The single needle alphabet is composed of deflections of a short or a lo ng duration ; these are produced by holding on the current for an instant or for more than skn instant ; and the various combinations of short and long correspond to Morse’s dot and dash system. The double needle alphabet consists of combinations of the deflection of eith 3 r or both needles. Fig. 277 shows Henley’s instrument, and, in completing the description of it, we have 277 to describe another source of electric current to which no allusion has been hitherto made. The electricity here employed is obtained neither by friction nor by chemical action, but by means of magnetism and motion. If a piece of metal is moved in the presence of a mag- net, or a magnet is moved in presence of a piece of metal, a current of electricity is gen- erated in the metal. The results are multiplied when the metal is a coil of covered wire ; so that we have here the converse of the electro-magnet ; in the one case electricity had produced magnetism, in the other magnetism produces electricity ; hence the name mag- neto-electric telegraph. We have here a powerful set of steel magnets a a, all the north ends pointing in one direction, and bound together with a plate of iron, and all the south ends similarly arranged in the other direction. Facing each end, but not quite in front when at rest, is an electro-magnet proper, b b, consisting of the U-shaped iron rod and the coil of covered wire, as described in fg. 271. Each electro-magnet is mounted upon an axis, c is a short lever or key ; on depressing this, the electro-magnet moves from its nor- mal position in a region of lesser magnetic force, into a new position in the region of great- est magnetic force, and thus is the double condition, enunciated above, complied with ; the copper wire is moved in the presence of a magnet, and this under the most favorable con- ditions ; and the U iron, rising from a feeble to a strong magnet, its lines of magnetic force move in presence of the copper wire. Just as a current, coming from a long distance, had to be received in Morse’s arrangement {Jig. 272) in an electro-magnet of a long coil of fine wire, so as to be much multiplied in order to do its work, so here a magneto-electric cur- rent, that has to be se^it to a long distance, must be generated in a long coil of very fine wire in order to have electro-motive force sufficient to overcome the resistance opposed to it. In like manner the electro-magnets of the instrument d, in which it is received at the far-off station, have the same multiplying characteristics. The magneto-electric current exists only during the motion of the electro-magnet in front of the steel magnets, and this motion must be rather brisk, or the change of place is slow and the current feeble ; but the current ceases with the motion. The needle, however, remains deflected from causes to which we have already referred, and if the hand is gently raised, so that the coils return slowly to their normal position, the needle will remain deflected ; but, if the hand is so removed that the coils return quickly from the region of greatest to one of lesser magnetic force, a reverse current of lesser force than the original is generated, which releases the needle from its deflected position and restores it to its normal place, ready for making the next signal. In a recent form of this instrument Mr. Henley has obviated the necessity of moving the electro-magnets, still retaining the same fundamental principles. He uses a set of large U-.shaped permanent magnets, and places the electro-magnet in the space be- tween the branches of the permanent magnet, and so that the four poles of the two mag- .. iZ— — =■ ^ : ! ELECTRO-TELEGRAPHY. 507 nets, the pejrraanent and the electro, shall be flush with each other, or in the same plane. A couple of ihon armatures are mounted on a disc in front of the magnets. The disc has a motion Qji\ a centre ; the armatures are curved or crescent-shaped. Their form is so ad- justed to the relative positions of the poles of the respective magnets, that, in their normal or ordinary position, one crescent connects the N. pole of the magnet with one, say the pole of the electro-magnet, and the other crescent connects the S. pole of the per- manent magnet with the lower pole of* the electro-magnet. On pressing a key tlie disc mo\tes, and the armatures so change in position that the N. pole of the magnet is connected with the lower ^ and the S. pole with the upper poles of the electro-magnet. By this art*angement the polarity of the electro-magnet is reversed at pleasure, and in its transition from being a magnet with poles in one direction, to becoming a magnet with poles in t’ne reverse direction, an electric current is generated in the wire with which it is wound, and the direction of the current is this way or that, according as the transition is from this direc- tion of polarity to that. This form of magneto-electric machine allows of larger electro- magnetic coils being used, and gives the manipulator comparatively very little weight to ijnove in signalling. 1 AVe have shown how an electric current generates magnetism, and how magnetism gen- jbrates another electric current ; it would follow logically that one electric current should therefore generate another electric current ; for the magnetism produced by a current circu- lating in one wire, must have all the properties of magnetism, and among them that of pro- ducing another current in another wire ; and so it is. A few convolutions of a large-sized Avire are coiled round an iron rod ; and outside the larger wire is a very great length of jfiner wire. The current from the battery is called the primary current in this arrange- iment ; and the moment it begins to circulate in the large wire, it magnetizes the iron and {generates a current, called secondary^ in the fine wire, which is able to penetrate to a vei'y great distance. When the primary current ceases, magnetization ceases, the lines of mag- netic force disappear, and a reverse secondary current is produced. This was the method proposed for obtaining the secondary current for traversing the Atlantic Ocean from Ireland to Newfoundland. The large wire is not necessarily first coiled on ; in the coils for the Transatlantic telegraph it was coiled outside. Nor is the presence of iron essential to ob- taining secondary currents. It will have been noticed in all the arrangements which have hitherto been described, that the signals are produced by motions, — that the electric current, on reaching the I’ar station, is multiplied by being directed through many convolutions of wire, and is made to act upon either a piece of soft iron or a piece of magnetized steel, and to move them, the motion being turned to account directly, or by the intervention of mechanism. We have yet another property of electricity, that has been very successfully applied to the produc- tion of telegraphic signals by Mr. Bain, in his electro-chemical telegraph. If a current of electricity is led into a compound fluid body, say into water, by one wire and out of it by another wire, the body is decomposed into its constituent elements, one of which, the oxy- gen in the case in question, makes its appearance at one wire, and the other, the hydrogen, makes its appearance at the other wire. The same holds good with bodies of a more complex charac- 2 1 8 ter in solution in water. The compound selected by Mr. Bain is cyanide of potassium. With a so- lution of this, he saturates a long ribbon of paper, y/. . ^ similar to that employed in Morse’s telegraph. He causes the paper b {Jig. 278) to pass over a drum L///^ J of brass R, between the metal of r and an iron ( 0 ^ 1 point or stylus p. The electric current enters the / ll I apparatus by the point p, passes through the solu- // / • tion of cyanide of potassium, with which the paper B is saturated, and out by the spring p', which is in metallic contact with the drum r. Decomposition takes place, and the well-known cyanide of iron (Prussian blue) is formed at the point of contact of the iron stylus p with the paper, the iron of the compound being supplied by the stylus itself. The paper is carried on by ordinary mechanism ; and a dot and dash alphabet is formed, according to the duration of contacts at the sending station. There is a single wire and a double wire code ; and the signals appear as deep blue marks upon the paper. Supplies of paper saturated with the solution are kept in reserve. This is unques- tionably a telegraph of extreme simplicity. It has been employed with much success. Mr. Whitehouse prepared for the Atlantic Telegraph a system in wliich motion and chemical action each play their part. The secondary currents that he employed were not able to produce the chemical decomposition that he requires for his signals. He therefore received them in a very sensitive relay, either an electro-magnet or a multiplier. The relay was a contact-maker, and connected the necessary number of local batteries with the print- 608 ELECTRO-TELEGRAPHY. ing apparatus, which consists of a ribbon of paper, saturated with a chemical s?tlution, and passing between a drum and a steel point. We should exceed our limits, were we to attempt the description of some of ''^'the many other forms that have been proposed. The above are good illustrations of the leadi.'ng prin- ciples, and are all in successful use. Some telegraphs will print in ordinary charaicters ; this result is only attained by much complexity ; and its value is more than questionable, it being as easy to learn a new code as a new alphabet ; and telegraph clerks read their 'sig- nals as readily as they read ordinary writing or printing, and they acquire their knowledge in a very short time. Hence, probably, it is that telegraphs to print in ordinary charactesrs are but little known in real practice ; nevertheless, some very promising instruments of tl.ie class have been produced, by House, and especially one more recently by Hughes, both cvf the United States. The following table has been drawn out as an illustration of the codes of some of the chief instruments that have been the subject of this article. It shows the^ number and nature of the signals (deflections, dots, dashes) for producing the name of the; great discoverer of electro-magnetism, which is the foundation of electro-telegraphy. The figures on the right are the number of marks or signs in printing, and in each kind of tele- graph. The Rheo-electro-static system of telegraphy was first described by M. Botto, in 1848. It is applicable to some but not to all forms of telegraph. It has been applied on the South- Eastern Railway to the signal-bells, {fg. 268,) for the purpose of reducing the amount of battery power required under other circumstances to be maintained. The wire, by which a pair of bells are connected, is in its normal state in permanent connection with the similar pole, say the positive, of batteries of equal power at the respective stations, so that two currents of equal power are opposed to and balanced against each other. Under these cir- cumstances, the wire is in a null, or rheo-electro-static state ; neither current circulates. If the connection of one of the batteries is reversed, so that its negative pole is presented to the wire, then the currents of both batteries are in the same direction, and they circulate as one current, equal in value to the combined force of the two batteries. The application is obvious ; that, whereas, under the ordinary system, a whole battery, of force sufficient to traverse the distance and do effective work, must be at each station, under this system only half such battery is necessary at each station, for producing the same effective work. Also, if a little more battery power is placed at each station than is necessary for the actual work required, signals of higher power are obtained under common circumstances ; and also the equilibrium of the two opposed currents may be disturbed at any place between the two stations, and signals may be made by merely making a connection between the line wire and the earth ; because the negative pole at each station is fitted up in permanent connec- tion with the earth ; and, as the positive poles are in like connection with the line wire, each battery current is made to circulate through its own signal-bell every time the earth and line wire are placed in connection. By this means the guard of a train can make sig- nals of distress to the nearest station without the aid of portable apparatus. Considerable care is required to obtain good communication with the earth on the open railway for mak- ing distress signals, or otherwise the discharge is imperfect, and no signal is made. Fish- jointed rails are very valuable for this purpose ; in their absence, especially at embank- ments, metal must be buried for the purpose at intervals in the moist earth, and a wire attached for use. Contact springs on the telegraph poles are proposed. H' f 1, — ^ — - / ELECTRO-TELEGRAPHY. 509 (' Telegraph wires are suspended to poles by insulators of earthenware, glass, or porce- lain ; the /Tfiiaterial and shape varying according to the experience of the engineer and the leno-th of ' line to be insulated. In very short lengths, the battery power required for over- comino- the resistance is not great ; it will therefore not overcome the resistance of an insu- lator (^f moderate quality, and escape to the pole glnd thence to the earth; but the bat- 279 tery power required to overcome the resist- ^ X / N ance of very long lengths of wire is equally able to overcome the resistances presented f ) by; inferior insulators, and to escape in con- J siderable quantities at every pole ; so that the force which reaches the far station would ( ) not be equal to its work. It is for these long lines that the greatest ingenuity has been f ) expended in constructing insulators. Fine porcelain is most in favor, from its present- \ K ' J ing a very smooth surface, and being less ' hygrometric than glass ; and it is distorted .. 280 inlto most mysterious-looking shapes in order _ _ to present as great a distance, and one as n^ch sheltered as possible, between the part |||^ with which the line wire is in contact, and H I m tae part that is in contact with the pole. ||HB^ j j i J For subterranean and submarine wires li^Bf ’ II Mmmm f-cyr:xz> st|ll greater care is necessary, because they mm K I 1 JMw|||l[f aife in the very bosom of the earth or sea, ImK # j 11^1^1® t(|) which the current will escape, when and III I t where it can, in order to complete the dis- llllllln/li L M |j|l| | I ||i|| charge, 279 represents the cable that |i»j# ^ f'l 1 1 has been lying in the British Channel be- j U m ||| i| tween Dover and Calais, since September, ||^»' ' iK jU |i I ;|to 1851. It contains four No. 16 copper wires; j m III IlM If I llw each wire is doubly covered with gutta per- i||®7 j Iji ^ i II Jm 111 I llw cha. The four wires are then twisted into a |f||K ^ ijl j / i |i| il || |I||| rope, and the rope is thickly covered, first mllj h ^ j l! HS^Im ||||\| |||i with hempen yarn, tarred, and finally with a jj m It'S ml ||| 1 M lip t jacket of ten No. 1 iron wires. The cable i^wf m # i||r M III IIK is shown in perspective and in section. Fig. WM h Ijl i 280 shows the perspective and section of the n li ^1 /M9 1 Irish, a single-wire cable. It consists of a lR|f ji ! li single central conductor, of one No. 16 cop- § i i Mi M per wire, doubly covered with gutta percha, Bwa j / J II ||I||||W then with hempen yarn as before ; and final- Will j mh II ml® ly with a protecting jacket of ten No. 8 iron |||Bm / |p||| |M wires. The Calais cable weighs 7 tons per |||w|M / m ImMmi mile; the Irish, 2 tons per mile. The At- t m j ! |||||iBII lantic Telegraph cable, of whieh nearly 3,000 |f||® I 'Ijl M II \|l miles were prepared, is in section, just the III Mia M |||IW size of a silver threepenny piece. It is a ||i|K u IIMmm |\ single-wire cable ; the wire was a strand of |i||M § l//IU^ K 1 \ wMl| seven No. 22 copper wires, trebly covered ||||||| M l\wH|| with gutta percha, then with yarn, and pro- I|||m m III/////MU |l\ 'tBlI tected with eighteen strands of seven wires ^f|| M ||l\M each, of No. 22 iron wire. It weighs 19 cwt. to the mile. This cable is lost. The iron jacket is in disrepute now for deep-sea cables. Hemp is preferred. Telegraph signals pass with far less rapidity through buried and through submarine wires, than along the ancient aerial wires. The slow travellings mentioned above, were through wires of this kind. We must refer to treatises on Electricity for full details of the conditions presented by a telegraph cable. In practice it is found, that on first sending a signal into a submerged wire, the electricity is delayed on its road, in order to produce a certain electrical condition upon the surface of the gutta percha that is in immediate con- tact with the conducting wire. Nor is this all ; before a second distinctive signal can be sent, it is necessary that the condition produced by the first signal shall be destroyed ; and this is an operation requiring even more time than was consumed in the mere act of pro- ducing it. These two classes of retardation, especially the latter, were largely manifested in the Atlantic cable, and have called forth all the ingenuity of electricians, in order to mitigate or to modify them. — C. V. W. EMAIL OMBRANT. 510 EMAIL OMBRANT. A process which consists in flooding colored but trans}^Darent glazes over designs stamped in the body of earthenware or porcelain. A plane sui face is thus produced, in which the cavities of the stamped design appear as shadows of varii‘'us depths, the parts in highest relief coming nearest the surface of the glaze, and thus h'vaving the effect of the lights of the picture. ^ This process was introduced by the Baron A. Do Trem- blay, of Rubelles, near Melun. < EMBOSSING WOOD. A process which may be regarded either as carving or em'.boss- ing wood, is that patented by Messrs. A. S. Braithwaite & Co. ’ Oak, mahogany, rosewood, horse-chestnut, or other wood, is steeped in water for a bout two hours ; and the cast-iron mould containing the device is heated to redness, or sometfmes to a white heat, and applied against the wood, either by a handle, as a branding-iron, by a lever press, or by a screw press, according to circumstances ; the moulds are made by the iron-founder from plaster casts of the original models or carvings. Had not the wood been saturated with water, it would be ignited, but until the moisture is evaporated, it is only charred ; it gives off volumes of smoke, but no flame. After a short time the iron is returned to the furnace to be reheated, the blackened wood is w ell rubbed with a hard brush to remove the charcoal powder, which being a bad conductor of heat, saves the wood from material discoloration ; and before the reapplication of the hea ted iron, the wood is again soaked in water, but for a shorter time, as it now absorbs moisture with more facility. The rotation of burning, brushing, and wetting, is repeated ten or twenty times, or up- wards, until in fact the wood fills every cavity in the mould, the process being materi; 'ly influenced by the character and condition of the wood itself, and the degrees to which h at and moisture are applied. The water so far checks the destruction of the wood, or even its change of any kind, that the burned surface, simply cleaned by brushing, is often employed, as it may be left either of a very pale or deep brown, according to the tone of color re- quired, so as to match old carvings of any age ; or a very little scraping removes the dis- colored surface. Perforated carvings are burned upon thick blocks of wood, and cut off with the circular saw, EMERALD. Fine emeralds are found in a vein of dolomite, which traverses the horn- blende slate at Muzo, north of Santa Fe de Bogota. A perfect hexagonal crystal from this locality, two inches long, is in the cabinet of the Duke of Devonshire ; it measures across its three diameters 2^ in., 2 Vs in., Ig in., and weighs 8 oz, 18 dwts. : — owing to flaws, it is but partially fit for jewellery. A more splendid specimen, though somewhat smaller, weigh- ing but 6 oz., is in the possession of Mr. Hope ; it cost £500. Emeralds of less beauty, but much larger, occur in Siberia. One specimen in the royal collection measures 14-^ inches long and 12 broad, and weighs 16f lbs. troy ; another is 7 inches long and 4 inches broad, and weighs 6 lbs. troy. — Dana. The emerald is generally believed to derive its color from the presence of a minute quantity of oxide of chrome, the beryl from oxide of iron. This mineral has been recently examined with great care by M. Lewy, from whose com- munication to the Academy of Sciences we abstract the following : — “ M. Lewy visited a mine called Muzo, in New Granada, Mexico, and obtained some fine specimens of emeralds, and of the rocks in which those precious stones are found. He observed that the largest and finest emeralds could be reduced to powder by a slight squeez- ing or rubbing between the fingers when first obtained, but that they acquired hardness after a certain time and repose. It has been commonly stated that the coloring matter of the emerald is chrome, but M. Lewy attributes it to an organic coloring matter, analogous to chloro'phyle. He states that the emerald exposed to heat loses all color ; whereas minerals colored by chrome do not lose their green color by ignition. The green color of the emerald is darkest in those specimens which furnish to analysis most organic matter ; it is completely destroyed by heat, becoming white and opaque. ENAMELS. The following was the process adopted by Henry Bone, R. A., and hrs son, the late Henry Pierce Bone, who have produced the largest enamels ever painted ; and beyond the time and consequent expense there appears no practical limit to the size of enamel paintings. • Preparinf! the Plate. — For small plates, (up to two inches long,) pvre gold is the best material. Silver (quite pure) is also used, but is apt to get a disagreeable yellow color at the edges by repeated firings. For larger sizes, copper is used. The copper should be annealed until quite free from spring, and then cleaned with dilute sulphuric acid, (one part acid, four water,) and shaped in a wooden mould, afterwards used in making the plate so as to produce a convex surface varying according to the size of the plate, taking care that the shaping does not reproduce the spring in the copper, in which case the process must be re- peated. If the plate is not raised in the centre, in the course of repeated firings the cor- ners will rise irregularh", producing undulations over the plate, perfect flatness being next to impossible for large pictures. The copper is then laid fiice downwards on the convex wooden mould used for shaping, and enamel ground fine with water is spread over it with ENGRAVING. 511 a small bone/ spoon ; when covered, a fine cloth doubled is pressed gently on it to absorb the water, ahd then it is smoothed with a steel spatula. This forms the back of the plate, and when lifired this part is finished. The copper is now reversed on a convex board the exact cotinterpart of the other, and covered with white enamel ground fine in the same way as aboWe. The plate is now ready for firing, and after it has been fired and cooled, the sur- face rahst be ground smooth with a flat piece of flint or other hard substance, with silver sand (and water. It must next be covered with a softer and more transparent kind of enamel called flux, ground and spread on in the same way as the first enamel, but this time only on the face of the plate. This is fired as before, and when cool the surface must be again ground smooth, and when glazed in the furnace the plate is finished. For the first coat a white solid enamel is used to prevent the green color from the oxidized copper show- ing through ; the second coat is a softer enamel, to enable the colors used to melt with less heat. Firing . — The plate is placed on a planche of firestone, or well-baked Stourbridge clay, supported on a bed of whiting, thoroughly dried in the furnace, the exact shape of the plate ag originally made, which must be used in all subsequent firings. After the whiting is fofmed in the shape of the plate, it should be notched with a flat knife diagonally across, as| in the accompanying diagram. The use of this is to produce an effect of diagonal bracing while the plate cools, ’ experience has shown that it tends considerably to keep plate in its original shape. When the plate is small, to three inches in length,) it may be annealed for pass- ing into the hot muffle as follows : — The planche bearing thq plate may be placed on another planche heated in the mulffle and placed in the front of the muffle for a few min- utds, until the steam of the plate or the oil of the picture shall have evaporated ; it may then be put in the mouth of the muffle and gradually inserted to the hottest part. After firing, it should be placed on another hot planche and allowed to cool gradually. . Large pictures require a differ- ent arrangement of the furnace. Over the muffle there should be a fixed iron annealing- box, with an iron shelf and door. The bottom should be of cast iron about one inch thick. This should be so arranged that when the muffle attains a white heat, the bottom of the annealing-box should be of a brightish red at the back, and a dull blood-red in front. Large pictures should be placed on the bottom of thd box before the furnace is lit, and the larger the size of the picture, the slower should the furnace be brought to its full heat, so as to allow five or six hours for the largest size, and two or three for smaller plates. When fired, the picture should be returned to the shelf of the annealing-box, and left there till quite cold, for which purpose large plates require at least twelve hours. The colors used are mostly the same as those prepared for jewellers and glass-painters. ENCAUSTIC PAINTING. A mode of painting with heated or burnt wax, which was practised by the ancients. The wax, when melted, was mixed with as much color, finely powdered, as it could imbibe, and then the mass was spread on the wall with a hot spatula. When it became cold the designer cut the lines with a cold pointed tool, and other colors were applied and melted into the former. Many modifications of the process have been employed. Amongst the moderns, the term has been improperly given to some cements, which have nothinj; of an encaustic character about them. (t Planche. & Bed of whiting. ENGRAVING. Engraving on metal plates may be classed under the following heads : Etching., line., mezzotinto., chalk., stipple, and aquatint. Before describing the processes of working these respective kinds, a notice of the instruments used by the engraver is necessary. These, with some modifications, are employed in all the styles. The etching -point, or needle, is a stout piece of steel wire inserted into a handle ; two or three, varying in thickness, are requisite, and they should be frequently and carefully sharpened. This is best done by turning the needle round in the fingers while rubbing it on a hone, and afterwards on a leather strop prepared with putty powder, or on an ordinary razor-strop, to take off any roughness, and to make it perfectly round. The dry-point is a similar instrument, used for delicate lines : it must be sharpened on the hone till a fine conical point is obtained. The graver, or burin, is the principal instrument employed in engraving : several are required, differing from each other in form, from the extreme lozenge shape to the square ; the former being used for cutting fine lines, the latter for broad : the graver fits into a handle about five inches and a half long, and it should be well tempered before using — an opera- tion requiring great care. The angle at the meeting of the two lower sides is called the belly, and the breadth of the end, the face. To sharpen the former, lay one of the flat sides of the graver on the oilstone, keeping the right arm tolerably close to the side, and rub it firmly ; next rub the other in the same way : the face is sharpened by holding it firmly in the hand, with the belly upwards, in a slanting direction ; rub the end rather ENGRAVING. 512 gently on the stone, at an angle of about forty-five degrees, taking care to (^)arry it evenly along until it acquires a very sharp point : this being done, hold the graver a little more upright to square the point, which a very few rubbings will effect. The gralyer for line work must be slightly turned up, to enable the engraver to run it along the plaiste ; other- wise the first indentation he makes on the metal would cause his instrument tc!> become fixed : the graver for stipple should be slightly turned down, to make dots only. i The scraper, which should have three fluted sides, is used for taking off the burr \\e^t by ‘the action of the needles on the metal. The burnisher is employed to soften lines that have been bitten in, or engraved too dark, and to polish the plate, or get rid of any scratches it may accidentally have received. > The dabber used to lay the etching-ground evenly, is made by enclosing a small quantity of fine cotton wool very tightly in a piece of silk, the threads of which should be, as mtuch as possible, of uniform thickness. There are a few other materials which an engraver should have at hand, but they are not of sufficient importance to be mentioned here ; we may, however, point out what, is technically called a bridge, which is nothing more than a thin board for the hand to rest ‘on ; it should be smoothly planed, and of a length and breadth in proportion to the size of the plate ; at each end a small piece of wood should be fastened to raise it above the plate w hen covered with wax. A blind, made of tissue paper stretched upon a frame, ought t ENGRAVING. 515 fore the groun*^ is laid, the engraver proceeds to scrape away, and then burnish the highest lights, after which the next lightest parts are similarly treated, and the process is repeated after this mamner till the work is finished ; the deepest shades are produced from the ground that is left , -untouched. There is, however, no style of engraving for the execution of which it is so difficult to lay down any definite rules, for almost every engraver has his own method of working. Chalk or stipple engraving, for the terms are synonymous, is extremely simple. The plate has first to be covered with the etching-ground, and the subject transferred to it in the ordinary way : the outline is then laid in by means of small dots made with the stipple graver ; all the darker parts are afterwards etched in dots larger and laid closer together. The work is then bitten in with the acid ; and the ground being taken off, the stipple graver must again be taken up to complete the operation ; the light parts and the dark are respectively produced by small and large dots laid in more or less closely together. Stipple is well adapted for, and is often used in, the representation of flesh, when all the other, parts of the subject are executed in line : hence it is very frequently employed in portraiture, and in engravings from sculpture. Chalk engraving is simply the imitation of drawngs in chalk, and is executed like stipple, only that the dots are made with less regu- larity, and less uniformity of size ; in the present day, the two terms are generally considered as eajressing the same kind of work. ^uathit engraving^ which represents a drawing in Indian-ink or bistre even more than does pezzotint, has been almost entirely superseded by lithography, and still more recently by chromo-lithography ; and there seems little probability that it will ever come into fashion again.j This being the case, and as any detailed description of the mode of working would, to be jbf any service, occupy a very considerable space, it will, doubtless, be deemed sufficient to giv« only a brief outline of its character and of the mode of operation ; this we abbreviate from the notice of Mr. Fielding, formerly one of our most able engravers in aquatint. The process consists in pouring over a highly-polished copper plate a liquid composed of resin- ous gum dissolved in spirits of wine, which latter, evaporating, leaves the resin spread all over the plate in minute grains that resist the action of the aqua fortis, which, however, cor- rodes the bare surface of the copper that is left between them : this granulated surface is called a ground. The ground having been obtained, the margin of the plate should be var- nished over, or stopped out, and when dry, the subject to be aquatinted must be transferred to the plate, either by tracing or drawing with a soft black-lead pencil, which may be used on the ground with nearly the same facility as paper ; if the former method be adopted, the tracing must be carefully fastened down to the copper by bits of wax along the upper edge. A piece of thin paper, covered on one side with lamp-black and sweet oil, is placed between the tracing and the ground, with the colored side downwards, and every line of the subject must be passed over with the tracing-point, using a moderate pressure. The tracing being finished and the paper removed, a wall of prepared wax, about three-quarters of an inch high, must be put round the plate, with a large spout at one corner, to allow of the acid running off. The plate is now ready for use ; and the completion of the design ife commenced by stopping out the highest lights on the edges of clouds, water, &c., with a mixture of oxide of bismuth and turpentine varnish, diluting it with spirits of turpentine till of a proper con- sistence to work freely. Next pour on the acid, composed of one part of strong nitrous acid and five parts of water ; let it remain, according to its strength, from half a minute to a minute, then let it run off, wash the plate two or three times with clean water, and dry it carefully with a linen cloth. This process of stopping out and biting in is continued till the work is complete ; each time the aqua fortis is applied a fresh tint is produced, and as each part successively becomes dai’k enough it is stopped out ; in this manner a plate is often finished with one ground bitten in ten or twelve times. We would recommend those who may desire to become thoroughly acquainted with this very interesting yet difficult mode of engraving to consult Fielding’s Art of Engraving. A few remarks explanatory of the method of printing steel or copper plates seem to be inseparable from the subject. The press used for the purpose consists of two cylinders or rollers of wood, supported in a strong wooden frame, and movable at their axes. One of these rollers is placed just above, and the other immediately below, the plane or table upon which the plate to be printed is laid. The upper roller is turned round by means of cogged wheels fixed to its axis. The plate being inked by a printer’s inking-roller, an operation requiring great care, the paper which is intended to receive the impression is placed upon it, and covered with two or three folds of soft woollen stuff like blanketing. These are moved along the table to the spot where the two rollers meet ; and the upper one being turned by the handle fixed to the fly-wheel, the plate passes through it, conveying the im- pression as it moves ; the print is then taken off the plate, which has to undergo the same process of inking for the next and every succeeding impression. proofs of an engraved plate are always taken by the most skilful workmen in a printing establishment ; in the principal houses there are generally employed from two to six men, aocording to the ENGKAVmG. 616 amount of business transacted, whose duty it is to print proof impressions Vnly ; they are called provers. A careful, steady workman is not able to print more than frc>m 180 to 200 good ordinary impressions from a plate, the subject of which occupies about seven inches by ten inches, even in what is considered a long day’s work, that is, about fourteen fiours ; the provey\ from the extreme care required in inking the plate, and from the extra t ime occu- pied in wiping it, and preparing the India-paper, will do from thirty to forty, according as the subject of the plate is light or heavy. This difference in the cost of production,, taking also into account that the proofs are worked off before the plate has become worn, Cven in the least degree, and that very few proofs, compared with the ordinary prints, are generally struck off, is the reason why they are sold at a price so much greater than the latter. Notwithstanding the vast multiplication of engravings within the last few yeans, it is generally admitted, by those best acquainted with the present state of the art, that it is not in a healthy condition. The highest class of pictorial subjects — history, and the highest style of engraving — line, have given place to subjects of less exalted character, and to a mixed style of work, which, however effective for its especial purpose, is not pure art. The pictures by Sir E. Landseer have gained for engravings of such subjects a popularity that has driven almost every thing else out of the field, and have created a taste in the public which is scarcely a matter of national congratulation. We have engravers in the country capable of executing works equal to whatever has been produced elsewhere at any time, but their talents are not called into requisition in such a way as to exhibit the art of en- graving in its highest qualities. Publishers are not willing to risk their capital on works which the public cannot appreciate, and hence their windows are filled with prints, the sub- jects of which, however pleasing and popular, are not of a kind to elevate the taste ; while the conditions under which engravers generally are compelled to work, offer but little in- ducement for the exercise of the powers at their command. Engraving on copper is in the present day but rarely attempted ; formerly nothing else was thought of ; now the demand for engraving is so great that copper, even aided by the electrotype, is insufficient to meet its requirements. In consequence of the comparatively small number of impressions which it yields, a copper-plate will seldom produce more than 500 or 600 good prints ; we have known a steel, with occasionally retouching, produce more than 80,000, when well en- graved, and carefully printed ; very much depends on the printer, both with regard to the excellence of the impression and the durability of the plate. The public demand is for prints both large and cheap, and to obtain this result, the engraver is too often obliged to sacrifice those qualities of his art which under other circumstances his work would exhibit. Such is the state of engraving with us now. There are few, even of the best artists we have, who by their utmost efforts can earn an income equal to that of a tradesman in a small but respectable way of business. This is an evil to be deplored, for it assists to deteriorate the art by forcing the engraver to labor hard for a maintenance, instead of placing him in a position that would enable him to exalt the art and his own reputation at the same time. A process of depositing steel upon an engraved copper-plate has recently been brought over to this country from France. M. Joubert, a French engraver long settled in England, has introduced it here; he has informed us that a copper-plate thus covered may be made to yield almost any number of impressions, for as the steel coating becomes worn it can be entirely taken off, and a new deposit laid on without injury to the engraving, and this may be done several times ; M. Joubert has repeated the experiment with the most satisfactory results. He thus describes his process in a communication made to the Society of Arts, and printed in their journal ; — “If the two wires of a galvanic battery be plunged separately into a solution of iron, having ammonia for its basis, the wire of the positive pole is immediately acted upon, while that of the negative pole receives a deposit of the metal of the solution — this is the princi- ple of the process which we have named ‘ acierage.’ “The operation takes place in this way; — By placing at the positive pole a plate or sheet of iron, and immersing it in a proper iron solution, the metal will be dissolved under the action of the battery, and will form a hydrochlorate of iron, which, being combined with the hydrochlorate of ammonia of the solution, will become a bichloride of ammonia and iron ; on a copper-plate being placed at the opposite pole and likewise immersed, if the solution be properly saturated, a deposit of iron, bright and perfectly smooth, is thrown upon the copper-plate, from this principle : — “Water being composed of hydrogen and oxygen: “ Sal ammoniac being composed of: — “ 1st. Hydrochloric acid, containing chlorine and hydrogen ; “ 2d. Ammonia, containing hydrogen, nitrogen, and oxygen : “ The water is decomposed under the galvanic action, and the oxygen fixes itself on the iron plate, forming an oxide of iron ; the acid hydrochloric of the solution, acting upon this oxide, becomes a hydrochlorate of iron, whilst the hydrogen precipitates itself upon the plate of the negative pole, and, unable to combine with it, comes up to the surface of the solution in bubbles. / / z_ " ENGRAVING ON WOOD. 517 “ My inven^tion has for its object certain means of preparing printing surfaces, whether for intaglio or ' surface printing, so as to give them the property of yielding a considerably greater number of impressions than they are capable of doing in their ordinary or natural state. And the invention consists in covering the printing surfaces, whether intaglio or relief, and whether of copper or other soft metal, with a very thin and uniform coating of iron, by ’means of electro-metallurgical processes. And the invention is applicable whether the device to be printed from be produced by engraving by hand, or by machinery, or by chemica 1 means, and whether the surface printed from be the original, or an electrotype surface produced therefrom. I would remark that I am aware that it has been before pro- posed to coat type and stereotypes with a coating of copper, to enable their surfaces to print 31 larger number of impressions than they otherwise would do ; I therefore lay no claim to the general application of a coating of harder metal on to the surface of a softer one, bat my claim to invention is confined to the application of a coating of iron by means of electricity on to copper and other metallic printing surfaces. “ In carrying out the invention I prefer to use that modification of Grove’s battery known as Bunsen’s, and I do so because it is desirable to have what is called an intensity arrar^gement. The trough I use for containing the solution of iron in which the engraved printing surface is to be immersed in order to be coated, is lined with gutta percha, and it is 45 inches long, 22 inches wide, and 32 inches deep. In proceeding to prepare for work, the timugh, whether of the size above mentioned or otherwise, is filled with water in com- bination with hydrochlorate of ammonia (sal ammoniac) in the proportion of one thousand lbs. by weight of water to one hundred lbs. of hydrochlorate of ammonia. A plate of sheet iron, nearly as long and as deep as the trough, is attached to the positive pole of the bat- tery and immersed in the solution. Another plate of sheet ii’on, about half the size of the other, is attached to the negative pole of the battery, and immersed in the solution, and when the solution has arrived at the proper condition, which will require several days, the plate of iron attached to the negative pole is removed, and the printing surface to be coated is attached to such pole, and then immersed in the bath till the required coating of iron is obtained thereto. If, on immersing the copper plate in the solution, it be not immediately coated with a bright coating of iron all over, the bath is not in a proper condition, and the copper plate is to be removed and the iron plate attached and returned into the solution. The time occupied in obtaining a proper coating of iron to a printing surface varies from a variety of causes, but a workman after some experience and by careful attention will readily know when to remove the plate from the solution ; and it is desirable to state that a copper plate should not be allowed to remain in the bath and attached to the negative pole of the battery after the bright coating of iron begins to show a blackish appearance at the edges. Immediately on taking a copper plate from the bath great care is to be ob- served in washing off the solution from all parts, and this I believe may be most conven- iently done by causing jets of water forcibly to strike against all parts of the surface. The plate is then dried and washed with spirits of turpentine, when it is ready for being printed from in the ordinary manner. “ If an engraved copper plate be prepared by this process, instead of a comparatively limited number of impressions being obtained and the plate wearing out gradually, a very large number can be printed off without any sign of wear in the plate, the iron coating protecting it effectually ; the operation of coating can be repeated as many times as re- quired, so that almost an unlimited number of impressions can be obtained from one plate, and that a copper one. “ This process will be found extremely valuable with regard to electrotype plates and also for photo-galvanic plates, since they can be so protected as to acquire the durability of steel, and more so, for a steel plate will require repairing from time to time, these will not, but simply recoating them whenever it is found necessary ; by these means one electro copper plate has yielded more than 12,000 impressions, and was found quite unimpaired when examined minutely.” — J. D. ENGRAVING ON WOOD. In order to make the whole process of wood engraving clear to the reader, we will describe the production of a wood-cut from the time it leaves the timber-merchant, until it is fit for the hands of the printer. The log of box is cut into transverse slices, of an inch in depth, in order that the face of the cut may be on a level with the surface of the printer’s type, and receive the same amount of pressure ; the block is then allowed to reman some time to dry, and the longer it is allowed to do so the better, as it prevents accidents by warping and splitting, which sometimes happen after the cut is executed if the wood is too green. The slice is ultimately trimmed into a square block, and if the cut be large, it is made in various pieces strongly clamped and screwed together ; and this enables engravers to get large cuts done in an incredibly short space of time, by putting the various pieces into different engravers’ hands, and then screwing the whole to- gether. The upper surface of the wood is carefully prepared so that no inequalities may appear upon it, and it is then consigned to the draughtsman to receive the drawing. He covers the surface with a light coat of flake white mixed with weak gum-water, and the EirVELOPES. 518 thinner this coat the better for the engraver. The French draughtsmen use; an abundance of flake white, but this is liable to make the drawing rub out under the engra ver’s hands, or deceive him as to the depth of the line he is cutting in the wood. The old drajvings of the era of Durer seem to have been carefully drawn with pen and ink on the woo d ; but the modern drawing being very finely drawn with the pencil or silver point is obliterated easily, and there is no mode of “ setting” or securing it. To obviate this danger the wood-en- graver covers the block with paper, and tears out a small piece the size of a shilling to work through, occasionally removing the paper to study the general effect ; in damp an d wintry weather he sometimes wears a shade over the mouth to hinder the breath from settling on the block. It is now his business to produce in relief the whole of the drawing ; with a great variety of tools he cuts away the spaces, however minute, between each of the pencil lines ; and should there be tints washed on the drawing to represent sky and water, he cuts such parts of the block into a series of close lines, which will, as near as he can judge, print the same gradation of tint. Should he find he has not done so completely, he can reenter each line with a broader tool, cutting away a small shaving, thus reducing their width and consequently their color. Should he make some fatal error that cannot be otherwise recti- fied, he can cut out the part in the wood, and wedge a plug of fresh wood in the place, when that part of the block can be reengraved. An error of this sort in a wood-cut is a very troublesome thing ; in copper engraving it is scarcely any trouble ; a blow with a hammer on the back will obliterate the error on the face, and produce a new surface ; but in wood, the surface is cut entirely away except where the lines occur, and it is necessary to cut it deep enough not to touch the paper as it is squeezed through the press upon the lines in printing. To aid the general effect of a cut, it is sometimes usual to lower the sur- face of the block, before the engraving is executed, in such parts as should appear light and delicate ; they thus receive a mere touch of the paper in the press, the darker parts receiv- ing the whole pressure and coming out with double brilliancy. When careful printing is bestowed on cuts, it is sometimes usual to insure this good effect, by laying thin pieces of card or paper upon the tympan, of the shape needed to secure pressure on dark parts only. Wood engraving, as a most useful adjunct to the author, must always command a cer- tain amount of patronage. In works like the present, the author is greatly aided by a diagram, which can more clearly explain his meaning than a page of letter-press ; and it can be set up and printed with the type, a mode which no other style of art can rival in simplicity and cheapness. The taste for elaborately- executed wood engravings may again decrease, as we find it did for nearly two centuries ; but it was never a lost art, and never will be, owing to the practical advantages we speak of, unless it be superseded by some simpler mode of doing the same thing hitherto undiscovered. The number of persons who practise wood engraving in London alone, at present is more than 200, and when we con- sider the quantity done in the great cities of the continent, and the large amount of book illustration in constant demand, the creative power of one single genius — Thomas Bewick — shines forth in greater vigor than ever. — F. W. F. ENVELOPES. The manufacture of envelopes has so largely increased, that the old method of folding them by means of a '•'‘bone folding-stick^^' although a good workman could thus produce 3,000 a day, was not capable of meeting the demand ; hence the atten- tion of several was turned to the construction of machines for folding them. Amongst the most successful are the following ; — Envelope folding. — In the envelope-folding machine of Messrs. De la Kue & Co., each piece of paper, previously cut by a fly press into the proper form for making an envelope, (and having the emblematical stamp or wafer upon it,) is laid by the attendant on a square or rectangular metal frame or box, formed with a short projecting piece at each corner, to serve as guides to the paper, and furnished with a movable bottom, which rests on helical springs. A presser at the end of a curved compound arm (which moves in a vertical plane) then descends, and presses the paper down into the box, the bottom thereof yielding to the pressure ; and thereby the four ends or flaps of the piece of paper are caused to fly up ; the presser may be said to consist of a rectangular metal frame, the ends of which are at- tached to the outer part of the curved arm, and the sides thereof to the inner portion of the arm ; so that the ends and sides of the presser can move independently of each other. The ends of the presser then rise, leaving the two sides of it still holding down the paper ; two little lappet pieces next fold over the two side flaps of the envelope ; and immediately a horizontal arm advances, carrying a V-shaped piece charged with adhesive matter or cement, (from a saturated endless band,) and applies the same to the two flaps. A third lappet presses down the third flap of the envelope upon the two cemented flaps, and thereby causes it to adhere thereto ; and then a pressing-piece, of the same size as the finished en- velope, folds over the last flap and presses the whole flat. The final operation is to remove the envelope, and this is effected by a pair of metal fingers, with india-rubber ends, which descend upon the envelope, and, moving sideways, draw the envelope off the bottom of the box (the pressing piece having moved away and the bottom of the box risen to the level of the platform of the machine) on to a slowly-moving endless band, which gradually carries / i P ETHER. 519 the finished enTelopes away. A fresh piece of paper is laid upon the box or frame, and the above opf rations are repeated. This machine makes at the rate of 2,700 envelopes per hour. ^ ^ Another machine for the same object, was invented by Mr. A. Remond, of Birming- ham, and is that employed by Messrs. Dickinson & Co. The distinguishing feature of this arrangement is the employment of atmospheric pressure to feed in the paper which is to form the envelope, and to deflect the flaps of the envelope into inclined positions, to facili- tate the action of a plunger, which descends to complete the folding. The pieces of paper, cut to the proper form, are laid on a platform, which is furnished with a pin at each corner, to enter the notches in the pieces of paper, and retain them in their proper position, and such platform is caused alternately to rise and bring the upper piece of paper in contact with the instrument that feeds the folding part of the machine, and then to descend until a fresh piece is to be removed. The feeding instrument consists of a horizontal hollow arm, with two holes in the under side, and having a reciprocating movement. When it moves over the upper piece of paper on the platform, a partial vacuum is produced within it, by a suitabJle exhausting apparatus, and the paper is thereby caused to adhere to it at the holes in it^ under surface by the pressure of the atmosphere. The instrument carries the paper overja rectangular recess or box; and then, the vacuum within it being destroyed, it de- posit the paper between four pins, fixed at the angles of the box, and returns for another piec4 of paper. As the paper lies on the top of the box, the flap which will be undermost in the finished envelope, is pressed by a small bar or presser on to the upper edge of two angumr feeders, communicating with a reservoir of cement or adhesive matter, and thereby beconp.es coated with cement ; and at the same time, the outermost or seal flap may be stamped with any required device, by dies, on the other side of the machine. A rectangu- lar frdme or plunger now descends and carries the paper down into the box ; the plunger rises, leaving the flaps of the envelope upright ; streams of air, issuing from a slot in each side of the box, then cause the flaps to incline inwards : and the folding is completed by the plunger again descending ; the interior and under surface of such plunger being formed with projecting parts, suitable for causing the several flaps to fold in proper superposition. The bottom of the box (which is hinged) opens, and discharges the envelope down a shoot on to a table beloAV ; the feeding instrument then brings forward another piece of paper ; and a repetition of the above movements takes place. EREMACAUSIS, — dom combustion. This term has been applied to that constant com- bination of oxygen Avith carbon and hydrogen, to form carbonic acid and water, which is unceasingly going on in nature, as in the decay of timber, or the “heating” of hay or grain put together in a moist state. Perfect dryness, and a temperature below freezing, stops this eremacausis, or slow combustion. ETHER, C^H^O. Syn. Sulphuric ether., Oxide of ethyle., Ethylic or Vinic ether., &c. &c. By this term is known the very volatile fluid produced by the action on alcohol of substances having a powerful affinity for water. Preparation on small scale. — A capacious retort with a moderate-sized tubulature is connected with an efficient condensing arrangement. Through the tubulature passes a tube connected with a vessel full of spirit, sp. gr. 0’83. The tube must have a stopcock to reg- ulate the flow. A mixture being made of five parts of alcohol of the density given above, and nine parts of oil of vitriol, it is to be introduced into the retort, and a lamp flame is to be so adjusted as to keep the whole gently boiling. As soon as the ether begins to come over, the stopcock connected with the spirit reservoir is to be turned sufficiently to keep the fluid in the retort at its original level. Preparation on large scale. — The apparatus is to be arranged on the same principle, but, for fear of fracture, may be constructed of cast iron, lined with sheet lead in the part containing the mixture. The chief disadvantage of this arrangement is its opacity, whereby it becomes impossible to see the contents of the retort, and therefore not so easy to keep the liquid at its original level. In this case the quantity distilling over must be noted, and the flow of spirit into the retort regulated accordingly. The most convenient mode of pro- ceeding is to have a large stone bottle with a tubulature at the side near the bottom (like a water-filter) to hold the spirit. A tube passes from the bottle to the retort. It has at the end, near the retort or still, a bend downwards leading into the tubulature. If a glass still be used it must for safety be placed in a sand bath. The distillate obtained, either on the large or small scale, is never pure ether, but contains sulphurous and acetic acids, besides water and alcohol. To remove these, the distillate is introduced, along with a little cream of lime, into a large separating globe, such as that mentioned under Bromine. The whole is to be well agitated, and the lime solution then run off by means of the stopcock. The purified ether still contains alcohol and Avater, to remove which it should be rectified in a water bath. The fluid will then constitute the ether of commerce. If the second distilla- tion be pushed too far the ether will, if evaporated on the hand, leave an unpleasant after smell, characteristic of impure ether. If wished exceedingly pure, it must be shaken up in EXOSMOSE AND ENDOSMOSE. 520 the separating globe, with pure water. This will dissolve the alcohol and It'jave the ether, contaminated only by a little water, which may be removed by digestion with (ljuicklime and redistillation at a very low temperature on a hot water bath. Pure ether is a colorless mobile liquid, sp. gr. O.Vl. It boils at 95° F. The density of its vapor is 2.56 (calculated). Gay Lussac found it 2.586. , The word ether, like that of alcohol, aldehyde, &c., is now used as a generixo term to express a body derived from an alcohol by the elimination of water. Many chemi.^ts write the formula C^H^O, and call it oxide of ethyle in the same manner as they regard al cohol as the hydrated oxide of the same radical. But there is no just reason for departing from the law we have laid down with reference to the formulae of organic compounds. (See Chem- ical Formula.) We shall therefore write ether This view has many advan- tages. We regard, with Gerhardt and Williamson, ether and alcohol as derived frrtm the type water. Alcohol is two atoms of water in which one equivalent of hydrogen is rejilaced by ethyle ; ether is two atoms of water in which both atoms of hydrogen are replaced by that radical. But there is a large class of compound ethers procurable by a variety of processes. These ethers were long regarded as salts in which oxide of ethyle acted the part of a base. Thus, when butyrate of soda was distilled with alcohol and sulphuric acid, the resulting product was regarded as butyrate of oxide of eth'J^le. The compound ethers are regarded as two atoms of water in which one equivalent of hydrogen is replaced by the radical of an alcohol, and the other by the radical of an acid. In addition to those there are others more closely resembling the simple ethers. They are founded also on the water type,* both atoms of hydrogen being replaced by alcohol radicals, but by different individ- uals. They are called mixed ethers. The following formulae show the chemical constitu- tion of all these varieties placed for comparison in Juxtaposition with their type : — I O'* CMP 0 ^ CMP 0 ^ Water, (2 eqs.) Common ether. Methylo-ethylic ether. Butyric ether. In the above formulae the first represents the type water. The second common ether, the two equivalents of ethyle replacing the two of hydrogen. In the third we have a mixed ether, one of the equivalents of hydrogen being replaced by ethyle and the other by methyle. The fourth illustration is that of a compound ether : one of the hydrogens is there replaced by ethyle, and the other by the oxidized radical of butyric acid. Ether is largely used in medicine and chemistry. In small doses it acts as a powerful stimulant. Inhaled in quantity it is an anaesthetic. It is a most invaluable solvent in organic chemistry for resinous, fatty, and numerous other bodies. — C. G. W. EXOSMOSE and ENDOSMOSE. As some manufacturing processes involve the phe- nomena expressed by these twm words, it appears necessary briefly to explain them. When two liquids are separated by a porous sheet of animal membrane, unglazed earth- enware, porous stone, or clay, these liquids gradually diffuse themselves ; and supposing salt and water to be on one side of the division, and w^ater only on the other, the saline solution passes in one direction, while the water, though wdth less intensity, passes in another. Instead of the two words introduced by Dutrochet, Professor Graham proposes the use of the single term Osmose (from &- grape 1 equivalent of 1 sugar 180 water - - 9 I 4 eq. carbon 24 ■ 8 “ carbon 4S- 8 “ oxygen 64 ^ 4 “ oxygen 32 12 “ hydrog. 12. 4 eq. carbonic acid - eq. alcohol 83 92 180 ISO 180 180 These facts will sufficiently prove that vinous or alcoholic fermentation is but a metamor- phosis of sugar into alcohol and carbonic acid. Such are the generally received views. We find, however, some other views promul- gated which it is important to notice. Liebig calls putrefactive fermentation., — every process of decomposition which, caused by external influences in any part of an organic compound, proceeds through the entire mass without the further cooperation of the original cause. Fermentation., according to Liebig’s definition, is the decomposition exhibited in the presence of putrefying substances or ferments, by compounds nitrogenous or non-nitrogenous, which alone are not capable of putrefaction. He distinguishes, in both putrefaction and fermentation, processes in which the oxygen of the atmosphere continually cooperates, from such as are accomplished with- out further access of atmospheric air. Liebig opposes the view which considers putrefaction and fermentation as the result of vital processes, the development of vegetable formations or of microscopic animals. He !, ‘ ^ 524 FERMENTATION. adduces that no trace of vegetal formations are perceptible in milk whuph is left for some time in vessels carefully tied over with blotting paper, not even aft^r fermenta- • tion has regularly set in, a large quantity of lactic acid having been formed. \ He further remarks of fermentative processes, that alcoholic fermentation having been oibserved too exclusively, the phenomena have been generalized, while the explanation of this process ought to be derived rather from the study of fermentative phenomena of a more general character. ^ Blondeau propounds the view that every kind of fermentation is caused by the develop- ment of fungi. Blondeau states that alcoholic fermentation is due to a fungus w hich he designates Torvula cerevisice ; whilst another, Penicillium glaucum^ gives rise to lactic fer- mentation. The latter fermentation follows the former in a mixture of 30 grm. of sugar, 10 grm. of yeast, and 200 c. c. of water, which has undergone alcoholic fermentation at a temperature of about 20°, being terminated in about two days. Beer yeast, when left in contact with water in a dark and moist place, contains, according to Blondeau, germs both of Torvula cerevisue^ and of Penicillium glaucum ; the former can be separated by a filter, and will induce alcoholic fermentations in sugar water, whilst the latter are extremely minute, and pass through the filter ; the filtrate, mixed with sugar water, gives rise to lactic fermentation. Acetic fermentation is due to the development of Torvula aceti ; sugar is converted into acetic acid, without evolution of gas, if 500 grm. dissolved in a litre of water, be mixed with 200 grm. of casein, and confined in contact for a month at a temperature of about 20°. The conversion of nitrogenous substances into fat, (for instance, of casein, in the manufacture of Roquefort ' cheese ; of fibrin under similar circumstances,) which Blondeau designated by the term fatty fermentation, {fermentation adipeuse^) is caused by Penicillium glaucum or Torvula viridis ; and the former fungus is stated to act like- wise in butyric and in urea fermentation, (conversion of the urea into a carbonate of ammonia.) Opposed to this view Schubert has published an investigation upon yeast. In order to prove that the action of yeast is due merely to its porosity, he founds his investigation upon some experiments of Brendecke, (particularly in reference to the statement that fermenta- tion taking place in a solution of sugar in contact with porous bodies is due to an impurity of sugar;) according to which various porous bodies, such as charcoal, paper, flowers of sulphur, &c., to which some bitartrate of ammonia is added, are capable of inducing fer- mentation in a solution of raw sugar. His observations are also based upon some experi- ments of his own, which seem to indicate that porous bodies, even without the addition of a salt, are capable of exciting fermentation in a solution of (pure ?) cane sugar. Whatever may be the means whereby alcoholic fermentation is induced, he states it to be indispensa- ble that the body in question should be exposed for some time to the influence of air, and that oxygen and carbonic acid are absorbed by the ferment. Both oxygen and carbonic acid, being electro-negative substances, stand in opposition to the electro-positive alcohol, and therefore predispose its formation, but only when they are highly condensed by the powerful surface attraction of the yeast, or of any porous body. The electrical tension, he states, may be increased by many salts, provided that the latter do not at the same time chemically affect either the sugar or the ferment. C. Schmidt has communicated the results of his experiments to the Annale Chem. Pharm. After stating numerous experiments, he continues: “Nor are fungi the primum movens of saccharic fermentation ; the clear filtrate obtained by throwing almonds crushed in water upon a moist filter, soon induces fermentation in a solution of urea and of grape sugar ; in the latter case, no trace of ferment cells can be discovered under the microscope, not even after fermentation is fully developed. If the solution, still containing sugar, is allowed to stand eight days or a fortnight after fermentation has ceased, an exuberant development of cellular aggregations is observed, but no putrefaction ensues ; the fungi, well washed and introduced into a fresh solution of grape sugar, continue to grow luxuriantly, inducing, however, if at all, but very weak fermentation, which rapidly ceases ; hence the growth of fungi during fermentative processes is but a secondary phenomenon. The in- crease of the residuary ferment, which occurs after yeast has been in contact with sugar, arises from a development of ferment cellulose, which probably takes place at the expense of the sugar. If muscle, gelatine, yeast, &c., in a very advanced state of putrid decompo- sition, be introduced into a solution of 1 sugar in 4 water, all phenomena of putrefaction dis- appear ; after a few hours active fermentation sets in, ferment cells being formed, and the liquid contains alcohol, but no mannite. The inactivity of crushed yeast is due, not to the destruction of the fungi, but to the chemical changes which are induced in yeast during the considerable time necessary for complete comminution. The crushed cells, introduced into sugar water, give rise to the production of lactic acid, without evolution of gas.” Schmidt is of opinion that fermentation is a process analogous to the formation of ether. He believes that one of the constituents of yeast, together with the elements of grape sugar, gives rise to the formation of one or several compounds, which are decomposed in statu nascenti^ (like sulpho-vinic acid,) splitting into alcohol and carbonic acid. • FERMENTATION. 525 We believe'' that the preceding paragraphs fairly represent the views which have been promulgated upon the phenomena of change, which are in many respects analogous to those of combustion and of vitality, presented in the fermentative processes. Much has been done, but there are still some points which demand the careful attention of the chemist. In a practical point of view, the question which arises from the alteration in the specific gravity of the fluid by fermentation is a very important one, a knowledge of the original gravity of beer being required to fix the drawback allowed upon beer when exported, according to the terms of 10 Viet. c. 5. By this act a drawback is granted of 5s. per barrel of thirty-six gallons, upon beer exported, of which “the worts used before fermentation were not of less specific gravity than 1-054, and not greater specific gravity than T081,” and a drawback of 7s. 6c?. per barrel upon beer of which “the worts used before fermenta- tion were not of less specific gravity than T081.” The brewer observes the original gravity of his Aborts by means of some form of the hydrometer, and preserves a record of his obser- vation.' The revenue officer has only the beer, from which he has to infer the original gravity] From the great uncertainty which appeared to attend this question. Professors Grahand, Hofmann, and Redwood were employed by the Board of Inland Revenue to dis- cover now the original gravity of the beer might be ascertained most accurately from the prope«ies of the beer itself. When worts are fermented, the sugar passes into alcohol, and tl ey lose in density, and assume as beer a different specific gravity. The gravity of the wort is called the original gravity — that of the beer, beer gravity. The report of Graham, Hofmann, and Redwood, upon “ original gravities,” may be supposed to be in the hands of every brewer ; but as some of the points examined materially explain many ^f the phenomena of vinous fermentation, we have transferred a few paragraphs to our pages : — “ As the alcohol of the beer is derived from the decomposition of saccharine matter only, and represents approximately double its weight of starch sugar, a speculative original gravity might be obtained by simply increasing the extract gravity of the beer by that of the quantity of starch sugar known to be decomposed in the fermentation. The inquiry would then reduce itself to the best means of ascertaining the two experimental data, namely, the extract gravity and the proportion of alcohol in the beer, particularly of the latter. It would be required to decide whether the alcohol should be determined from the gravity of the spirits distilled from the beer ; by the increased gravity of the beer when its alcohol is evaporated off ; by the boiling point of the beer, Avhich is lower the larger the proportion of alcohol present ; or by the refracting power of the beer upon light — various methods recommended for the valuation of the spirits in tieer. “ Original gravities so deduced, however, are found to be useless, being in error and always under the truth, to an extent which has not hitherto been at all accounted for. The theory of brewing, upon a close examination of the process, proves to be less simple than is implied in the preceding assumption ; and other changes appear to occur in worts, simul- taneously with the formation of alcohol, which would require to be allowed for before original gravities could be rightly estimated. It was found necessary to study the gravity in solution of each by itself, of the principal chemical substances which are found in fer- mented liquids. These individual gravities defined the possible range of variation in original gravity, and they brought out clearly for the first time the nature of the agencies which chiefly affect the result. “ The use of cane sugar is now permitted in breweries, and the solution of sugar may be studied first as the wort of simplest composition. The tables of the specific gravity of sugar solutions, constructed by Mr. Bate, have been verified, and are considei-ed entirely trustworthy. The numbers* in the first and third columns of Table I., which follows, aT-e, however, from new observations. It is to be remarked that these numbers have all refer- ence to weights, and not to measures. A solution of cane sugar, Avhich contains 25 grains of sugar in 1000 grains of the fluid, has a specific gravity of lOlO’l, referred to the gravity of pure water taken as 1000 ; a solution of 50 grains of cane sugar in 1000 grains of the fluid, a specific gravity of 1020-2, and so on. The proportion of carbon contained in the sugar is expressed in the second column ; the numbers being obtained from the calculation that 171 parts by weight of cane sugar (C^^H“0“) consist of 72 parts of carbon, 11 parts of hydrogen, and 88 parts of oxygen; or of 72 parts of carbon combined with 99 parts of the elements of water. It is useful to keep thus in view the proportion of carbon in sugar solutions, as that element is not involved in several of the changes which precede or accompany the principal change which sugar undergoes during fermentation, and which changes only affect the proportion of the oxygen and hydrogen, or elements of water, combined with the carbon. The proportion of oxygen and hydrogen in the altered sugar increases or diminishes during the changes referred to ; but the carbon remains constant, and affords, therefore, a fixed term in the comparison of different solutions. ^ ■■ V r 526 FERMENTATION. “ Table I . — Specific gravity of solutions of Cane Sugar in watler. Cane Sugar, in 1000 parts by weight. Carbon in 1000 parts by weight. Specific Gravity. 25 10*53 1010*1 50 21*05 1020*2' 75 31*58 1030*2 100 42*10 1040*6 125 52*63 1051 150 63*16 1061*8 175 73*68 1072*9 200 84*21 1083*8 '• 225 94*73 1095*2 250 105*26 1106*7 “ When yeast is added to the solution of cane sugar in water, or to any other saccharine solution, and fermentation commenced, the specific gravity is observed to fall, owing* to the escape of carbonic acid gas, and the formation of alcohol, which is specifically lighte r than water; IVI grains of sugar, together with 9 grains of water, being converted into 92 grains of alcohol and 88 grains of carbonic acid, + HO = 2C^H®0^ + 4CO^) But if the process of fermentation be closely watched, the fall of gravity in cane sugar veill be found to be preceded by a decided increase of gravity. Solutions were observed to rise from 1055 to 1058, or 3 degrees of gravity, within an hour after the addition of the yeast, the last being in the usual proportion for fermentation. When the yeast was mixed in minute quantity only, such as 7s oo of the weight of the sugar, the gravity of the sugar solu- tion rose gradually in four days from 1055 to 105'7'91, or also nearly 3 degrees; with no appearance, at the same time, of fermentation or of any other change in the solution. This remarkable increase of density is owing to an alteration which takes place in the constitu- tion of the cane sugar, which combines with the elements of water and becomes starch sugar, a change which had been already proved by H. Bose and by Dubrunfaut, to precede the vinous fermentation of cane sugar. The same conversion of cane sugar into starch sugar, with increase of specific gravity, may be shown by means of acids as well as of yeast. A solution of 1000 parts of cane sugar in water, having the specific gravity 1054‘64, became with 1 part of crystallized oxalic acid added to it 1054*'7 ; and being afterwards heated for twenty-three hours to a temperature not exceeding 128° Fahr., it was found (when cooled) to have attained a gravity of 105'7'63 — an increase again of nearly 3° of gravity.” The difference between the gravities of solutions of cane sugar and starch sugar are of great practical value, but these must be studied in the original ; the result, however, being “ that the original gravity of a fermented liquid or beer must be different, according as it was derived from a wort of cane sugar or of starch sugar.” The gravity of malt wort was determined to be intermediate between that of pure cane sugar and starch sugar, and solutions containing an equal quantity of carbon exhibited the following gravities : — Cane sugar - 10'72’9. Pale malt - 10'74'2. Starch sugar - 1076'0. Two other substances were found to influence the original gravity of the wort : dextrin, or the gum of starch, and caramel. Tables are given of the specific gravities of these, from which the following results have been deduced : — Starch sugar, . . . . 1076 Dextrin, . - - - - 1066*9 Caramel, . - - - - 1062*3 Caramel is stated to interfere more than dextrin in giving lightness or apparent attenua- tion to fermented worts, without a corresponding pi*oduction of alcohol. “ Another constituent of malt wort, which should not be omitted, is the soluble azotized or albuminous principle derived from the grain. The nitrogen was determined in a strong wort of pale malt with hops, of the specific gravity 1088, and containing about 21 percent, of solid matter. It amounted to 0*217 per cent, of the wort, and may be considered as re- presenting 3*43 per cent, of albumen. In the same wort, after being fully fermented, the nitrogen was found to amount to 0*134 per cent., equivalent to 2*11 per cent, of albumen. The loss observed of nitrogen and albumen may be considered as principally due to the pro- duction and growth of yeast, which is an insoluble matter, at the cost of the soluble albu- minous matter. Solutions of egg-albumen in water, containing 3*43 and 2*11 per cent, respectively of that substance, were found to have the specific gravities of 1004*2 and FERMENTATION. I 527 1003*1. Hence a loss of density has occurred during fermentation of 1*1 degree on a wort of 10^8 original gravity, which can be referred to a change in the proportion of albuminous matter. It w ill be observed that the possible influence of this substance and of the greater or less production of yeast during fermentation, upon the gravity of beer, are restricted within narrow limits.” The reporters proceed : — “ The process required for the determination of the original gravity of beer, must be easy of execution, and occupy little time. It is not proposed, in the examination of a sam- ple, to separate by chemical analysis the several constituents which have been enumerated. In fact, we are practically limited to two experimental observations on the beer, in addition to the determination of its specific gravity. “ One of these is the observation of the amount of solid or extractive matter still remaining after fermentation, which is always more considerable in beer than in the com- pletely fermented wash of spirits. A known measure of the beer might be evapoiated to dryness, and the solid residue weighed, but this would be a troublesome operation, and could not indeed be executed with great accuracy. The same object may be attained with even a more serviceable expression for the result, by measuring exactly a certain quantity of the Veer, such as four fluid ounces, and boiling it down to somewhat less than half its bulk in Ian open vessel, such as a glass flask, so as to drive off the whole alcohol. The liquid when cool is made up to four fluid ounces, or the original measure of the beer, and the specjific gravity of this liquid is observed. It has already been referred to as to the ex- tract gravity of the beer, and represents a portion of the original gravity. Of a beer of which me history was known, the original gravity of the malt wort was 1121, or 121° ; the specifiq gravity of the beer itself before evaporation, 1043 : and the extract gravity of the beer 10'66*7, or 56*7'’. “ The second observation which can be made with sufficient facility upon the beer, is the determination of the quantity of alcohol contained in it. This information may be obtained most directly by submitting a known measure of the beer to distillation, continuing the ebullition till all the alcohol is brought over, and taking care to condense the latter without loss. It is found in practice that four ounce measures of the beer form a convenient quan- tity for the purpose. This quantity is accurately measured in a small glass flask, holding 1,750 grains of water when tilled up to a mark in the neck. The mouth of the small retort containing the beer is adapted to one end of a glass tube condenser, the other end being bent and drawn out for the purpose of delivering the condensed liquid into the small flask previously used for measuring the beer. The spirituous distillate should then be made up with pure water to the original bulk of the beer, and the specific gravity of the last liquid be observed by the weighing-bottle, or by a delicate hydrometer, at the temperature of 60° Fahr. The lower the gravity the larger will be the proportion of alcohol, the exact amount of which may be learned by reference to the proper tables of the gravity of spirits. The spirit gravity of the beer already referred to proved to be 985*25 ; or it was 14*05® of gravity less than 1000, or water. The ‘ spirit indication’ of the beer was therefore 14*05° ; and the extract gravity of the same beer, 66*7°. “ The spirit indication and extract gravity of any beer being given, do we possess data sufficient to enable us to determine with certainty the original gravity ? It has already been made evident that these data do not supply all the factors necessary for reaching the required number by calculation. “ The formation of the extractive matter, which chiefly disturbs the original gravity, increases with the progress of the fermentation ; that is, with the proportion of alcohol in the fermenting liquor. But we cannot predicate from theory any relation which the forma- tion of one of these substances should bear to the formation of the other, and are unable, therefore, to say beforehand that because so mueh sugar has been converted into alcohol in the fermentation, therefore so much sugar has also been converted into the extractive sub- stance. That a uniform, or nearly uniform, relation, however, is preserved in the formation of the spirits and extractive substanee in beer-brewing, appears to be established by the observations which follow. Such an uniformity in the results of the vinous fermentation is an essential condition for the success of any method whatever of determining original grav- ities, at least within the range of circumstances which affect beer-brewing. Otherwise two fermented liquids of this class, which agree in giving both the same spirit indication and the same extractive gravity, may have had different original gravities, and the solution of our problem beeomes impossible.” The following table, one of several of equal value, gives the results of a particular fer- mentation of cane sugar. “ Fifteen and a half pounds of refined sugar were dissolved in 10 gallons of water, making 10| gallons of solution, of which the specific gravity was 1055*3 at 60° ; and after adding three fluid pounds of fresh porter yeast, the specific gravity was 1055*95. The original gravity may be taken as 1055*3 ''55*3°.) FERMENTATION. 528 ■V- -V— \ i “Table II. — Fermentation of Sugar Wort of original gravity 1^55 '3. I. Number of Observation. II. Period of Fermentation. III. Degrees of Spirit Indication. IV. Degrees of Extract Gravity. r DegreCis of Extract GraV/ity loet. 1 Days. 0 Hours. 0 0 65*30 0*. 2 0 6 1*59 52*12 3*18 3 0 12 2*57 47*82 7*48 4 0 19 8-60 43*62 11*6.8 6 0 23 4*33 40*13 16-17 6 1 5 6*31 35-50 19-80 7 1 12 6-26 31*39 23*91 8 1 19 7-12 27-63 27-67 9 2 11 8-59 20-26 35-04 10 3 11 9*87 13*40 41-90 11 5 12 10-97 7-60 47-70 12 6 12 11-27 4-15 61-15 “ Columns iii. and v. respectively exhibit the spirit which has been produced, and the solid matter which has disappeared ; the first in the form of the gravity of the spirit, ex- pressed by the number of degrees it is lighter than water, or under 1,000, and the second by the fall in gravity of the solution of the solid matter remaining below the original grav- ity 1055-3. This last value will be spoken of as ‘ degrees of gravity lost’ ; it is always ob- tained by subtracting the extract gravity (column iv.) from the known original gravity. To discover whether the progress of fermentation has the regularity ascribed to it, it was necessary to observe whether the same relation always holds between the columns of ‘ de- grees of spirit indication ’ and ‘ degrees of gravity lost.’ It was useful, with this view, to find what degrees lost corresponded to whole numbers of degrees of spirit indication. This can be done safely from the preceding table, by interpolation, where the numbers observed follow each other so closely. The corresponding degrees of spirit indication and of gravity lost, as they appear in this experiment upon the fermentation of sugar, are as fol- lows: — “Table III. — Fermentation of Sugar Wort of original gravity 1055*3. Degrees of Spirit Indication. Degrees of Extract Gravity lost. Degrees of Spirit Indication. Degrees of Extract Gravity lost. 1 1-71 7 27-01 2 4-74 8 31-87 3 9-26 9 37-12 4 13-48 10 42-55 6 18-30 11 47*88 6 22-54 “ In two other fermentations of cane sugar, the degrees of gravity lost, found to corre- spond to the degrees of spirit indication, never differed from the numbers of the preceding experiment, or from one another, more than 0-9° of gravity lost. This is a sufficiently close approximation. “ It is seen from table lY., which is of much importance, that for 5° of spirit indication, the corresponding degrees of gravity lost are 18-3°. For 5 -9° of spirit indication, the cor- responding degrees of gravity lost are 22*2°. “ This table is capable of a valuable application, for the sake of which it was constructed. By means of it, the unknown original gravity of a fermented liquid or beer from cane sugar may be discovered, provided the spirit indication and extract gravity of the beer are ob- served. Opposite to the spirit indication of the beer in the table, we find the corresponding degrees of gravity lost, which last, added to the extract gravity of the beer, gives its origi- nal gravity. “ Suppose the sugar beer exhibited an extract gravity of '7‘9°, (1007-9,) and spirit in- dication of 11°. The latter marks, according to the table, 47-7° of gravity lost, which added to the observed extract gravity, 7-9°, gives 65-6° of original gravity for the beer, (1055-6.)” Similar tables are constructed for starch sugar, and for various worts with and without hops. / "A FERMENTATION. 529 “ Table IV. — Starch-Sugar. Degrees of Spirit Indication^ with corresponding degrees of gravity lost. Besides the degrees of gravity lost corresponding to whole degrees of spirit indication, the degrees -gravity lost corresponding to tenths of a degree of spirit indication are added from calculation. Degrees of Spirit Indication. •0 •1 •2 •3 •4 •5 •6 •7 •8 •9 0 •2 •3 •5 •7 •9 1-0 1-2 1-4 1*6 1 1-9 2-1 2-4 2-7 3-0 3*3 3-6 3-9 4-2 4-6 l{ 5-0 6-4 6'8 6-2 6-6 7-0 7-5 8-0 8-5 9-0 9-5 9*9 10-3 10-7 11-2 11*6 12-0 12-4 12-8 13-3 4 1 13-8 14-2 14-6 15-0 15-5 15-9 16-3 16-7 17'2 17-7 6 ; 18-3 18*7 19-1 19-5 19-9 20*3 20-8 21-2 21-7 22-2 6 22-7 23-1 23-5 23-9 24*4 24*7 25-2 25*6 26-1 26-6 7 { 27-1 27-6 28-1 28-6 29-1 29-6 30-0 30-5 31-0 31-5 8 1 32-0 32-5 33-0 33*5 34-0 34*5 35-0 35-5 36*0 36-6 9 1 37-2 37 '7 38-2 38-7 39-2 39-7 40-3 40-8 41-3 41*8 10 ( 42-4 47-7 42*9 43-4 44-0 44-5 45-0 45-6 46-1 46-6 47-2 After jexplaining many points connected with the problem, as it presented itself under varied conditions as it respected the original worts, the Report proceeds : — “ The object is still to obtain the spirit indication of the beer. The specific gravity of the beer is first observed by means of the hydrometer or weighing-bottle. The extract gravity of the beer is next observed as in the former method ; but the beer for this pur- pose may be boiled in an open glass flask till the spirits are gone, as the new process does not require the spirits to be collected. The spiritless liquid remaining is then made up to the original volume of the beer as before. By losing its spirits, the beer of course always increases in gravity, and the more so the richer in alcohol the beer has been. The difference between the two gravities is the new spirit indication, and is obtained by subtracting the beer gravity from the extract gravity, which last is always the higher dumber. “ The data in a particular beer were as follows : — Extract gravity, 1044‘'7 Beer gravity, 1035‘1 , Spirit indication, 9.6° “Now the same beer gave by distillation, or the former method, a spirit indication of 9‘9°. The new spirit indication by evaporation is, therefore, less by 0’3° than the old in- dication by distillation. The means were obtained of comparing the two indications given by the same fermented wort or beer in several hundred cases, by adopting the practice of boiling the beer in a retort, instead of an open flask or basin, and collecting the alcohol at the same time. The evaporation uniformly indicated a quantity of spirits in the beer nearly the same as was obtained by distillation, but always sensibly less, as in the preceding in- stance. These experiments being made upon fermented liquids of known original gravity, the relation could always be observed between the new spirit indication and the degrees of specific gravity lost by the beer. Tables of the degrees of spirit indication, with their cor- responding degrees of gravity lost, were thus constructed, exactly in the same manner as the tables which precede ; and these new tables may be applied in the same way to ascertain the original gravity of any specimen of beer. Having found the degrees of spirit indication of the beer by evaporation, the corresponding degrees of gravity lost are taken from the table, and adding these degrees to the extract gravity of the beer, also observed, the origi- nal gravity is found. Thus the spirit indication (by the evaporation method) of the beer lately referred to, was 9 ’6°, which mark 43° of gravity lost in the new tables. Adding these to 1044'V, the extract gravity of the same beer, 108'7*'7 is obtained as the original gravity of the beer.” The results of the extensive series of experiments made, were, that the problem could be solved in the two extreme conditions in which they have only to deal with the pure sugars entirely converted into alcohol. “ The real difficulty is with the intermediate condition, which is also the most frequent one, where the solid matter of the beer is partly starch sugar and partly extractive ; for no accurate chemical means are known of separating these substances, and so determining the quantity of each in the mixture. VoL. III.— 34 V ■ . ^ ^ \ 630 FERMENTATION". " “ But a remedy presented itself. The fermentation of the beer was completed by the addition of yeast, and the constituents of the beer were thus reduced to alcobol and extrac- tive only, from which the original gravity, as is seen, can be calculated. “For this purpose a small but known measure of the beer, such as four fluid ounces, ‘was carefully deprived of spirits by distillation, in a glass retort. To the fluid, when cooled, a charge of fresh yeast, amounting to 150 grains, was added, and the mixture kept at 80° for a period of sixteen hours. Care was taken to connect the retort, from the com- mencement, with a tube condenser, so that the alcoholic vapor which exhaled from the wash during fermentation should not be lost. When the fermentation had entir^ely ceased, heat was applied to the retort to distil off the alcohol, which was collected in a